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GEOSPATIAL ANALYSIS OF FLUORIDE CONTAMINATION IN GROUND WATER OF

TAMNAR AREA, RAIGARH DISTRICT, CHHATTISGARH STATE

M.K. Beg January, 2009

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GEOSPATIAL ANALYSIS OF FLUORIDE CONTAMINATION IN GROUND WATER OF TAMNAR AREA, RAIGARH DISTRICT, CHHATTISGARH STATE

by

M.K. Beg

Thesis submitted to the International Institute for Geo-information Science and Earth Observation in partial fulfilment of the requirements for the degree of Master of Science in Geo-information Science and Earth Observation, Specialisation: (Geo-hazards) Thesis Assessment Board Thesis Supervisors Examiner 1 : Dr. Cees van Westen, ITC (Chairman) Dr.E.J.M.Carranza, ITC Examiner 2 : Dr. G. J. Chakrapani, IIT, Roorkie (External) Drs.J.B.de Smeth, ITC Member : Prof. R.C.Lakhera, IIRS S.K.Shrivastav, IIRS Member : S.K.Shrivastav, IIRS

INTERNATIONAL INSTITUTE FOR GEO-INFORMATION SCIENCE AND EARTH OBSERVATION

ENSCHEDE, THE NETHERLANDS &

INDIAN INSTITUTE OF REMOTE SENSING, NATIONAL REMOTE SENSING CENTRE, DEPARTMENT OF SPACE, DEHRADUN, INDIA

Disclaimer This document describes work undertaken as part of a programme of study at the International Institute for Geo-information Science and Earth Observation. All views and opinions expressed therein remain the sole responsibility of the author, and do not necessarily represent those of the institute.

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Abstract The occurrence of dental/skeletal fluorosis among the population in the study area provided the motivation to investigate occurrence of fluoride in groundwater. The main objective of the present study is to gain insight into spatio-temporal variation of F- contents in groundwater and its relationship with fluorosis prevalence in the study area to answer the following two research questions – (1) What are the controls on spatial distribution of F- concentrations in groundwater (i.e. relation of F- concentration in groundwater vis-à-vis other hydrochemical parameters, lithology and electrical resistivity of subsurface, and plausible source(s) and geochemical processes leading to increase in F- concentration)?; and (2) Is there a temporal variation in F- concentration in groundwater in the area? Prior to this study, no systematic and scientific investigation has been conducted on F- contamination in groundwater in the area. For hydrochemical analysis, groundwater samples were collected from hand-pumps during three periods, pre-monsoon (N=83), mid-monsoon (N=20) and post-monsoon (N=81). The temperature, pH, electrical conductivity and depth to water level were measured in the field. The hydrochemical data, obtained through chemical analysis, have been subsequently analysed and interpreted using univariate and multivariate methods. X-ray diffraction (XRD) and petrographic analysis of rock samples collected from the high F- zone have been carried out for identification of minerals constituting the host rock. Geographic Information System (GIS) has been used for spatial analysis of geological and hydrochemical data. The F- concentration in groundwater varies from 0.09 to 8.8 mg/l in pre-monsoon and 0.0 to 7.1 mg/l in post-monsoon. The spatial distribution of F- concentration in the pre-monsoon and post-monsoon periods shows that about 60% of the total samples in the northern, southern and western parts of the study area have F- concentration below the minimum required level (0.6 mg/l); 15% samples in the eastern part of the area have F- concentration above the maximum permissible limit (>1.2 mg/l); and the remaining 25% samples in the eastern and central parts of the area have F- concentration within the optimum range (0.6–1.2 mg/l). Of the 39 villages where hydrochemical analysis has been carried out, five villages namely Muragaon, Pata, Kunjhemura, Saraitola and Dholnara are found to have F- concentrations higher than the maximum permissible limit, which match with the fluorosis prevalence in the area. The overall distribution of F- concentration in the study area during the three periods indicates slight dilution effect owing to fresh recharge on account of rainfall; however, in and around the high F- zone the effect of rainfall recharge is found to be negligible. With regard to the number of locations where elevated concentrations of F- in groundwater are recorded, it is found that at twelve locations F- values are consistently above the acceptable limit of 1.2 mg/l, whereas at one location F- concentration is high only during post-monsoon period. The number of affected villages, however, remains the same. Based on the geospatial analysis of the various geological and hydrochemical datasets, it has been observed that – (1) high F- concentration in ground water mainly occurs in Barakar Formation having a litho-assemblage of feldspathic sandstone/shale/coal; few places in Barren Measures Formation, adjacent to the contact between the Barakar and Barren Measures Formations in the groundwater

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movement direction, also have high F- content; (2) the groundwater with high F- concentration is associated with Na-Ca-HCO3, Na-Ca-Mg-HCO3 and Na-Mg-Ca-HCO3 types of water; (3) the ratio of Na+ and Ca2+ increases with the increase in F- content; (4) F- has significant positive correlation with Na+ and SiO2, and significant negative correlation with Ca2+, Mg2+, HCO3

-, alkalinity and total hardness (TH); additionally, F- also has poor but positive correlation with Li+, and negative but poor correlation with EC/TDS, K+, Cl- and NO3; and (5) high F- concentration in ground water is generally found in deeper (>110 m) wells. The positive correlation of F- with Na+ and SiO2 indicates the source of F- in groundwater to be from weathering of silicate minerals. Further, the groundwater types and increase in Na+:Ca2+ values with the increase in F- concentration indicate dissolution of feldspars which can be attributed to the association of high F- zone with feldspathic sandstones. Since the increase in Na+ concentration increases the solubility of F- bearing minerals, the geochemical processes leading to increase in Na+ and decrease in Ca2+ concentrations play an important role in F- enrichment in ground water. The presence of Li+ in the high F- zone suggests that micas, forming an important constituent of Barakar sandstones (as observed in the outcrops, XRD analysis and thin sections) and which contain fluorine at the OH- sites, may act as an important source of F- in groundwater on dissolution. Cation exchange (Na+ for Ca2+) accompanied with anion exchange (OH- for F-) may also be the important processes by which micas and clay minerals (containing fluorine at the OH- sites) may contribute to F- enrichment in groundwater. The clay layers intercalated with sandstones in the Barakar Formation are likely to play an important role in the context of anion exchange as the wells are not completely cased and there is an interaction of groundwater with them. The absence of PO4

3- in groundwater, in all the three periods, rules out the contribution from phosphate minerals (such as apatite and flour-apatite) and anthropogenic activities; high F- concentration in groundwater found in deeper wells also does not support the contamination from anthropogenic activities. Further, the negative correlation between F- and Ca2+ does not support the dissolution of fluorite which is considered to be an important source for releasing fluorine to groundwater. The lower values of the storativity and transmissivity and deeper wells are other important factors leading to increase in F- concentration in groundwater because of increase in temperature and residence time of groundwater. The spatio-temporal distribution maps of F- concentration in groundwater have been integrated in GIS to prepare the ‘health-risk map’ and to estimate the population at risk. The ‘health-risk map’ indicates that a large population in the area is at potential risk in addition to the already affected people. This will be useful for health officials to take up mitigation measures in the area so as to prevent the diseases caused due to either elevated or low F- concentration in groundwater.

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Acknowledgements I deeply give thanks to Dr. V.K.Dadhwal, Dean, IIRS, Dr.V.Hariprasad, In charge, Water Resource Division and programme coordinator, IIRS, Prof. R.C.Lakhera, Head, Geosciences Division, Dr. Cess van Westen (ITC), Dr. Michiel Damen, Course Coordinator, ITC-IIRS, Mr.I.C.Das (IIRS), Dr.Abbas Farshad and Dr. Druva (ITC) for their invaluable guidance, advice and support during my studies and research project at IIRS and ITC. Many thank to Dr. E.J.M. (John) Carranza, Drs. J.B. de Smeth my supervisor at ITC, who helped to sharpen my research question and explained how to do the interpretation of geochemical data and classify the maps using box and whisker plot. I am grateful to Mr. S.K.Srivastav, my IIRS, supervisor who always had the time to look in to my problem, whenever I was stuck at some stage during this research period. I am indebted to Dr.P.K.Bhat Director General, Chhattisgarh Council of Science and Technology, Raipur, Chhattisgarh, for forwarding my application and sponsoring me to attend this joint ITC-IIRS Geohazards M.Sc. Programme. I am thankful to Mr.Hingorani, Superintending Engineer, Public Health Engineering Department who took personal interest in Fluoride problem of Tamnar area of Raigarh, District and helped me to provide all support from office of the Executive Engineer, Raigarh Division. I must thanks to Mr.R.K.Tandan, Junior Engineer, Public Health Engineering Department, Tamnar for taking interest in Fluoride in groundwater, who personally accompanied me all the time during my pre-monsoon, mid-monsoon and post-monsoon, field campaign. I would like to give thanks to Dr.K.S.Patel, School of Studies in Chemistry, Pt. Ravishankar Shukla, University, Raipur for providing me all support for chemical analysis. Special thanks to Dhananjay Sahu, ph.D. Student of pt. Ravishankar Shukla University, Raipur for helping me in analytical analysis of pre-monsoon water samples at University lab. Dr.P.K.Mukherjee, Geologist, Wadia Institute of Himalayan Geology (WIHG), who explained the X-ray diffractometry and semi-quantitative analysis in X’Pert PRO high score plus software. Mr.J.R.Verma, Hydrogeologist, Central Groundwater Board, Raipur made available the published report and litholog of bore wells for making fence diagram of the study area. Mr. Prashant Kawishwar, Resource Scientist and Ex student of M.Sc.Geoinformatics, ITC-IIRS M.Sc. programme, 2006, from Chhattisgarh Council of Science and Technology, Raipur, who helped me during the research project. I would also like to thanks to my batch mates at IIRS for the time that we spent together and shared the knowledge, joy and hard time at IIRS and ITC. Mr. Mahendra Singh, Student at IIRS, helped in the analysis of post-monsoon water samples in the ion chromatography lab. This work would not have been complete without support from my wife Firoze, my daughter Sheenam and son Rahil who were always with me by living alone and I would like to convey my gratitude to them for being very cooperative and understanding during this time.

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Table of contents 1. Introduction ...................................................................................................................................... 1

1.1. Background to the research ..................................................................................................... 1 1.1.1. Effects of F- on human health ............................................................................................. 1

1.2. Research problem definition ................................................................................................... 3 1.3. Research objectives ................................................................................................................. 5 1.4. Research questions .................................................................................................................. 5 1.5. Thesis outline .......................................................................................................................... 6

2. Literature review .............................................................................................................................. 7 2.1. Groundwater geochemistry ..................................................................................................... 7 2.2. Environmental occurrence and geochemistry of fluorine ....................................................... 8

2.2.1. Factors of F- enrichment in groundwater ............................................................................ 9 2.3. Groundwater contamination by F- in India ........................................................................... 10

3. Description of the study area .......................................................................................................... 12 3.1. Location and extent ............................................................................................................... 12 3.2. Geomorphology .................................................................................................................... 13 3.3. Drainage ................................................................................................................................ 15 3.4. Hydrometeorology ................................................................................................................ 15 3.5. Geology ................................................................................................................................. 17

3.5.1. Lithostratigraphy .............................................................................................................. 17 Barakar Formation .......................................................................................................................... 17 Barren Measures Formation ........................................................................................................... 19 Raniganj Formation ........................................................................................................................ 19 Kamthi Formation .......................................................................................................................... 19 3.5.2. Structure ........................................................................................................................... 19 3.5.3. Subsurface geology .......................................................................................................... 20

3.6. Hydrogeology ....................................................................................................................... 21 3.6.1. Groundwater level ............................................................................................................ 22

4. Materials and methods .................................................................................................................... 25 4.1. Pre-field collection of data .................................................................................................... 25 4.2. Field data collection ............................................................................................................. 26

4.2.1. First phase: Pre-monsoon ................................................................................................. 26 4.2.2. Second phase: Mid- monsoon ........................................................................................... 27 4.2.3. Third phase: Post-monsoon .............................................................................................. 27

4.3. Field methods ........................................................................................................................ 28 4.3.1. Water sampling ................................................................................................................. 28 4.3.2. Resistivity survey method ................................................................................................ 29

4.4. Laboratory methods .............................................................................................................. 31 4.4.1. Chemical analysis ............................................................................................................. 31 4.4.2. XRD and Petrographic Analysis of Rock samples ........................................................... 34

4.5. Analysis of Geochemical Data .............................................................................................. 34 4.5.1. Univariate and multivariate methods of analyses of geochemical data ............................ 34 4.5.2. Spatial distribution of groundwater constituents .............................................................. 36

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5. Results and discussion .................................................................................................................... 39 5.1. Pre-monsoon groundwater geochemistry .............................................................................. 39

5.1.1. Groundwater quality ......................................................................................................... 39 5.1.2. Groundwater types ............................................................................................................ 41 5.1.3. Fluoride content vis-à-vis groundwater types .................................................................. 43 F-5.1.4. Correlation of F- with other geochemical parameters ....................................................... 45 5.1.5. Spatial distribution of geochemical parameters ................................................................ 48

5.2. Mid-monsoon groundwater geochemistry ............................................................................ 53 5.2.1. Groundwater quality ......................................................................................................... 53 5.2.2. Groundwater types ............................................................................................................ 54 5.2.3. Fluoride content vis-à-vis groundwater types .................................................................. 55 5.2.4. Correlation of F- with other geochemical parameters ....................................................... 56

5.3. Post-monsoon groundwater geochemistry ............................................................................ 58 5.3.1. Groundwater quality ......................................................................................................... 58 5.3.2. Groundwater types ............................................................................................................ 60 5.3.3. Fluoride content vis-à-vis groundwater types .................................................................. 60 5.3.4. Correlation of F- with other geochemical parameters ....................................................... 62 5.3.5. Spatial distribution of geochemical parameters ................................................................ 65 5.3.6. Comparison of pre- and post-monsoon data ..................................................................... 70

5.4. Spatio-temporal distribution of fluoride in groundwater and fluorosis prevalence .............. 71 5.4.1. Spatio-temporal distribution ............................................................................................. 71 5.4.2. Relation of F- with well depth .......................................................................................... 72

5.5. Resistivity measurements vis-a-vis Fluoride enrichments in groundwater ........................... 73 5.5.1. Mineralogical analysis ...................................................................................................... 75 5.5.2. Source and geochemical processes for fluoride enrichment in groundwater ................... 77

5.6. Fluorosis prevalence and health- risk.................................................................................... 79 5.7. Distribution of fluoride in groundwater vis-à-vis geology ................................................... 82

6. Conclusions .................................................................................................................................... 86 6.1. Research and questions ......................................................................................................... 86

What are the controls on the spatial distribution of fluoride contents in groundwater? ................. 86 6.1.1. Is the distribution of fluoride associated with the distribution of other geochemical parameters? ..................................................................................................................................... 86 6.1.2. What is the plausible source(s) of fluoride in groundwater in the area? .......................... 87 6.1.3. What relationship exists between litho-geochemical data and groundwater geochemical data? …………………………………………………………………………………………..87 6.1.4. What relation exists between sub-surface resistivity data and groundwater geochemical data? …………………………………………………………………………………………..87 6.1.5. Is there a temporal (pre-mid and post-monsoon) variation in F- con-centration of groundwater in the area? ................................................................................................................ 88

6.2. Recommendations ................................................................................................................. 88 6.2.1. Improvement of health status............................................................................................ 88 6.2.2. Management plan for treatment of high F- groundwater .................................................. 88 6.2.3. Combined resistivity and IP sounding .............................................................................. 88 6.2.4. Research and development ............................................................................................... 88

References .............................................................................................................................................. 89

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Annexure: Annexure 1: Bore hole litholog, station Samaruma (743761E, 2444295N) ...................................... 93 Annexure 2 : Bore hole litholog, station Gare (756822E, 2450398N) ............................................... 94 Annexure 3 : Bore hole litholog, station Kotrimar (747101E, 2460261N) ........................................ 95 Annexure 4 : Bore hole litholog, station Gharghoda (742421E, 2452699N) ..................................... 96 Annexure 5 : Bore hole litholog, station Deogarh (747041E,2449550N) .......................................... 97 Annexure 6 : Bore hole litholog, station Tamnar (751146E,2445472N) ........................................... 98 Annexure 7 : Resistivity measurement (VES1) at village Muragaon ................................................ 99 Annexure 8 : Resistivity measurement (VES2) at village Muragaon ................................................ 99 Annexure 9 : Resistivity measurement (VES3) at village Saraitola ................................................. 100 Annexure 10 : Resistivity measurement (VES4) at village Saraitola ............................................... 100 Annexure 11 : XRD analysis result of sample no 81 ....................................................................... 101 Annexure 12 : XRD analysis result of sample no 74 ....................................................................... 101 Annexure 13 : XRD analysis result of sample no 78 ....................................................................... 102 Annexure 14 : XRD analysis result of sample no 135 ..................................................................... 102 Annexure 15: Water level observation during pre- and post-monsoon periods .............................. 103 Annexure 16 : Physico-chemical properties of pre-monsoon groundwater samples ....................... 104 Annexure 17 : Physico-chemical properties of mid-monsoon groundwater samples ...................... 109 Annexure 18 : Physico-chemical properties of post-monsoon groundwater samples ...................... 110 Annexure 19 : Cation-anion balance for pre-, mid and post-monsoon water samples ..................... 115 Annexure 20 : Reference code and ICDD reference pattern matched with rock samples ................ 120 Annexure 21 : Diffractograph of sample No. 81 showing peaks and their counts .......................... 121 Annexure 22 : Diffractograph of sample No. 74 showing peaks and their counts .......................... 122 Annexure 23 : Diffractograph of sample No. 78 showing peaks and their counts ........................... 123 Annexure 24 : Diffractograph of sample No.135 showing peaks and their counts .......................... 124

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List of figures Figure 1.1 Dental fluorosis (left) and skeletal fluorosis (right) ................................................................ 2 Figure 1.2 Photograph showing irreversible dental and skeletal fluorosis in Tamnar area ...................... 5 Figure 3.1 Location map of study area ................................................................................................... 12 Figure 3.2 Satellite image (Aster) showing the study area ..................................................................... 13 Figure 3.3 Physiographic characteristics of study area: forest covered hills of northern highland (left) and gently sloping land (right) ............................................................................................................... 13 Figure 3.4 Geomorphological map prepared from visual interpretation of satellite imagery ................ 14 Figure 3.5 Drainage map of the study area. ........................................................................................... 15 Figure 3.6 Mean monthly variation in minimum and maximum temperature........................................ 16 Figure 3.7 Potential evapotranspiration .................................................................................................. 17 Figure 3.8 Geological map of the study area (Source: GSI). Lineaments are interpreted from satellite imagery. .................................................................................................................................................. 18 Figure 3.9 Sequential deposition in Barakar Formation near village Saraitola (left) and Sandstone exposed near village Muragaon with high mica content (right) ............................................................. 18 Figure 3.10 Sandstone of Raniganj Formation exposed near Parkipahri village ................................... 19 Figure 3.11 Cross section between Samaruma and Gare showing sub-surface geology ....................... 20 Figure 3.12 Fence diagram showing lithological units in the subsurface .............................................. 21 Figure 3.13 Depth to water level during pre-monsoon period ............................................................... 23 Figure 3.14 Depth to water level during post-monsoon period .............................................................. 23 Figure 3.15 Water level fluctuation map ................................................................................................ 24 Figure 3.16 Water table contour map ..................................................................................................... 24 Figure 4.1 Flow chart showing an overview of the methodology adopted in the present study ............ 25 Figure 4.2 Map showing locations of groundwater sampling during pre-monsoon period ................... 26 Figure 4.3 Map showing locations of groundwater sampling during mid-monsoon period .................. 27 Figure 4.4 Map showing locations of groundwater sampling during post-monsoon period .................. 28 Figure 4.5 Resistivity and resistance relation ......................................................................................... 29 Figure 4.6 Current and potential measurement system in resistivity survey .......................................... 29 Figure 4.7 Locations of resistivity survey .............................................................................................. 30 Figure 4.8 Histogram of cation anion balance (pre-monsoon) ............................................................... 32 Figure 4.9 Histogram of cation anion balance (mid-monsoon) .............................................................. 32 Figure 4.10 Histogram of cation balance (post-monsoon) ..................................................................... 33 Figure 4.11 Scatter plot of EC versus sum cations and sum anions (pre-monsoon) ............................ 33 Figure 4.12 Scatter plot of EC versus sum cations and sum anions ....................................................... 33 Figure 4.13 Graphical representation of water quality data using piper trillinear diagram (after Piper, 1944 cited by Deutch, 1997) .................................................................................................................. 35 Figure 4.14 Projected cation and anion concentration on piper diagram ............................................... 36 Figure 4.15 A Box plot representing characteristics of univariate data set (after Carranza, 2008) ........ 38 Figure 5.1 Piper diagram showing major ion chemistry of groundwater (pre-monsoon) ...................... 41 Figure 5.2 Piper diagram showing Ca (Mg) HCO3 type water (pre-monsoon) ..................................... 42 Figure 5.3 Piper diagram showing Ca (Mg) Cl type water (pre-monson) .............................................. 42 Figure 5.4 Piper diagrams showing water types with respect to F- content (pre-monsoon) ................... 43 Figure 5.5 Pie diagram showing relation between F- and major cations (a), and F- and major anions (b) (pre-monsoon) ........................................................................................................................................ 44

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Figure 5.6 Scatter plot of F- versus (a) Na+ (b) pH ................................................................................. 46 Figure 5.7 Scatter plot of F- versus SiO2 ................................................................................................ 46 Figure 5.8 Scatter plot of F- versus Ca2+ ................................................................................................ 47 Figure 5.9 Scatter plot of F- versus Mg2+ ............................................................................................... 47 Figure 5.10 Scatter plot of F- versus K+ ................................................................................................. 47 Figure 5.11 Scatter plot of F-versus TH ................................................................................................. 48 Figure 5.12 Scatter plot of F- versus (a) HCO3

- (b) alk .......................................................................... 48 Figure 5.13 Box plot and spatial distribution map of F- (pre-monsoon) ................................................ 49 Figure 5.14 Box plot and spatial distribution map of pH (pre-monsoon) .............................................. 49 Figure 5.15 Box plot and spatial distribution map of EC (pre-monsoon) .............................................. 50 Figure 5.16 Box plot and spatial distribution map of Na+ (pre-monsoon) ............................................. 50 Figure 5.17 Box plot and spatial distribution map of Ca2+ (pre-monsoon) ............................................ 51 Figure 5.18 Box plot and spatial distribution map of Mg2+ (pre-monsoon) ........................................... 51 Figure 5.19 Box plot and spatial distribution map of HCO3

- (pre-monsoon) ......................................... 52 Figure 5.20 box plot and spatial distribution map of SiO2 (pre-monsoon) ............................................ 52 Figure 5.21 Box plot and spatial distribution map of total hardness (TH) pre-monsoon ...................... 53 Figure 5.22 Piper diagram showing major ion composition of water samples (mid-monsoon) ............. 55 Figure 5.23 Piper diagram showing high F- water samples (mid-monsoon) .......................................... 55 Figure 5.24 Scatter plots F- versus (a) Na+, (b) Ca2+, (c) pH, (d) Mg2+, (e) TH, (f) Alkalinity (g) Li+ (h) K+ and (i) HCO3

- .............................................................................................................................. 58 Figure 5.25 Trillinear diagram showing major ion chemistry of post-monsoon water samples ............ 60 Figure 5.26 Piper diagram showing F- water types with respect to F- content (post-monsoon) ............. 61 Figure 5.27 Pie diagram showing relation between F- and major cation (A), and F- and major anion (B) (post-monsoon) ....................................................................................................................................... 62 Figure 5.28 Plots of F- versus Na+ (a) and F- versus Ca2+ (b) (post-monsoon) .................................... 63 Figure 5.29 Scatter plots of F- versus (c) HCO3

-, (d) Mg2+, (e) K+, (f) alkalinity (g) Li+ (h) TH and (i) pH ........................................................................................................................................................... 65 Figure 5.30 Box plot and spatial distribution map of F- (post-monsoon) ............................................. 66 Figure 5.31 Box plot and spatial distribution map of pH (post-monsoon) ............................................ 66 Figure 5.32 Box plot and spatial distribution map of EC (post-monsoon) ............................................ 67 Figure 5.33 Box plot and spatial distribution map of Na+ (post-monsoon) ........................................... 67 Figure 5.34 Box plot and spatial distribution map of Ca2+ (post-monsoon) .......................................... 68 Figure 5.35 Box plot and spatial distribution map of Mg2+ (post-monsoon) ......................................... 68 Figure 5.36 Box plot and spatial distribution map of HCO3

- (post-monsoon) ....................................... 69 Figure 5.37 Box plot and spatial distribution map of TH (post-monsoon) ............................................ 69 Figure 5.38 Spatial distribution map of Li+ (post-monsoon) ................................................................. 70 Figure 5.39 Spatial distribution of low, moderate and high F- categories during (a) pre-monsoon, and (b) post-monsoon periods ....................................................................................................................... 72 Figure 5.40 Scatter plot of fluoride versus well depth (a) pre- and (b) post-monsoon .......................... 73 Figure 5.41 Resistivity curve of vertical electrical sounding (VES1) at village Muragaon (XUTM 755034 YUTM 2452371) ....................................................................................................................... 74 Figure 5.42 Resistivity curve of vertical electrical sounding (VES2) at village Muragaon (XUTM 754425 YUTM 2452197) ....................................................................................................................... 74 Figure 5.43 Resistivity curve of vertical electrical sounding (VES3) at village Saraitola (XUTM 755556 YUTM 2451865) ....................................................................................................................... 74

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Figure 5.44 Resistivity curve of vertical electrical sounding (VES4) at village Saraitola (XUTM 755876 YUTM 2551722) ....................................................................................................................... 75 Figure 5.45 Quartz and feldspar under thin section (Courtesy: WIHG) ................................................ 76 Figure 5.46 Biotite under thin section (Xnicol, courtesy: WIHG) ........................................................ 76 Figure 5.47 Field photograph showing muscovite in Barakar sandstone ............................................... 79 Figure 5.48 Map showing prevalence of dental fluorosis ...................................................................... 80 Figure 5.49 Health-risk maps based on F- concentrations in groundwater during (a) pre-monsoon (b) post-monsoon ......................................................................................................................................... 81 Figure 5.50 Health risk map and population at risk based on F- concentration in groundwater ........... 81 Figure 5.51 Geological map (after GSI) and location of high F- wells .................................................. 83 Figure 5.52 Box and whisker plot showing concentration of F- with respect to lithostatigraphy during pre-monsoon (a) post-monsoon (b) ........................................................................................................ 83 Figure 5.53 Histogram showing fluoride distribution during (a) pre-monsoon (N= 83) and (b) post-monsoon (N=81) periods ........................................................................................................................ 84

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List of tables Table 1.1 Level of F- content in drinking water and corresponding effects on human health (Chaturvedi et al., 1990) ........................................................................................................................... 2 Table 1.2 Degree of dental fluorosis (after Dean, 1934) .......................................................................... 2 Table 1.3 Range of maximum allowable F- concentration (after USPHS, 1997) ..................................... 3 Table 2.1 Dissolved constituents in groundwater (after Davis and Dewiest, 1966) ............................... 7 Table 2.2 Range of F- concentration in groundwater of India and associated severity of fluorosis ....... 11 Table 3.1 Salient feature of Meteorological data for the year 2007 as recorded at Raigarh .................. 16 Table 3.2 Geological sequence of the area ............................................................................................. 17 Table 3.3 Transmissivity of Barakar formation ..................................................................................... 22 Table 4.1 Chemical analysis data at well no. 50 .................................................................................... 35 Table 5.1 Summarized hydro-geochemistry of pre-monsoon period ..................................................... 39 Table 5.2 Comparison of groundwater quality with Indian and WHO standards .................................. 40 Table 5.3 Classification of the groundwater samples on the basis of hardness ...................................... 41 Table 5.4 Correlation matrix of different parameters in groundwater (pre-monsoon) ........................... 45 Table 5.5 Summarized hydrogeochemistry of mid-monsoon period ..................................................... 53 Table 5.6 Classification of the water samples on the basis of hardness ................................................. 54 Table 5.7 Correlation matrix for different water quality parameters (mid-monsoon) ............................ 56 Table 5.8 Summarized hydrogeochemistry of post-monsoon period ..................................................... 59 Table 5.9 Classification of groundwater samples on the basis of hardness (post-monsoon) ................. 60 Table 5.10 Correlation matrix of different parameters in groundwater (post-monsoon) ....................... 63 Table 5.11 Comparison of pre and post monsoon parameters ............................................................... 70 Table 5.12 F- content in groundwater during pre-monsoon, mid-monsoon and post-monsoon periods 71 Table 5.13 Location of water samples contaminated by high F- and correlation with resistivity .......... 75 Table 5.14 Interpreted geo-electrical layer parameter ............................................................................ 75 Table 5.15 Mineral composition of Barakar sandstones by XRD analysis ............................................ 76 Table 5.16 Prevalence of dental fluorosis .............................................................................................. 79 Table 5.17 Affected villages and population at risk due to excess or deficient F- in groundwater ...... 82 Table 5.18 Statistical summery of F- concentration with respect to lithostatigraphy (pre-monsoon) .... 84 Table 5.19 Statistical summery of F- concentration with respect to lithostatigraphy (post-monsoon) .. 85


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1. Introduction

1.1. Background to the research The occurrence of fluoride (F-) in groundwater is mainly due to natural or geogenic contamination and the source of contamination is often unknown (Handa, 1975; Saxena and Ahmad, 2002). Geogenic contamination of groundwater depends mainly on the geological setting of an area. As rainwater infiltrates through the soil and reaches the water table, it can dissolve partly certain components of bedrock. The F- content of groundwater can thus originate from the dissolution of fluorine-bearing minerals in the bedrock. In other words, bedrock mineralogy is, in general, a primary factor for the variations in F- content of groundwater (Chae et al., 2007). F- contamination of groundwater is a function of many factors such as availability and solubility of fluorine-bearing minerals, temperature, pH, concentration of calcium and bicarbonate ions in water, etc. (Chandra et al., 1981; Largent, 1961). In contrast to anthropogenic contamination of surface water, geogenic contamination of groundwater is difficult to detect and is even more difficult to control. The presence of excessive concentrations of F- in groundwater may persist for years, decades or even centuries and can reach the food system (Todd, 1980). In recent years, there has been an increased interest in F- research because excess concentration of F- in groundwater causes adverse impact on human health. In order to mitigate excess F- in groundwater, it is essential to determine and monitor the causal factors of enrichment of F- concentration in groundwater in time and space (Ahmed et al., 2002).

1.1.1. Effects of F- on human health Groundwater is the main source of intake of F- even though food items like tea also contribute substantial amount of F- (Cao et al., 2000). The occurrence of F- in groundwater has drawn worldwide attention because it has considerable impact on human health. Fluoride in drinking water has both positive and negative effects on human health.

Small concentration of F- is essential for normal mineralization of bones and the formation of dental enamel (Bell and Ludwig, 1970; Fung et al., 1999; Shomar et al., 2004). However, excessive F- intake causes dental enamel to lose its lustre into either mild form of dental fluorosis, which is characterized by white, opaque areas on tooth surface, or into severe form of dental fluorosis, which is characterized by yellowish brown to black stains on the teeth (Choubasia and Sompura, 1996). Excessive F- intake may also result in slow, progressive crippling scourge known as skeletal fluorosis as shown in Figure 1.1.

As shown in Table 1.1, intake of F- concentrations above 1.0 mg/l may cause dental fluorosis and intake of F- concentrations above 3.0 mg/l may cause skeletal fluorosis (Handa, 1975; Ripa, 1993; USPHS, 1987; WHO, 1984). Normally, the degree of fluorosis depends on the amount of exposure up to the age of 8 to 10. Due to isomorphic substitution, F- mainly gets deposited in joints of the neck, knee, pelvis and shoulder and makes it difficult to move or walk. An advanced stage of osteoporosis in long bones and bony outgrowth may occur, vertebrae may fuse together and a victim may be crippled (Meenakshi and Maheshwari, 2006). These negative health effects of F- are permanent and irreversible (Rajgopal and Tobin, 1991).


2

Figure 1.1 Dental fluorosis (left) and skeletal fluorosis (right) Table 1.1 Level of F- content in drinking water and corresponding effects on human health (Chaturvedi et al., 1990)

F- concentratio

n (mg/l)

Corresponding effects on human health

≤1 safe limit 1-3 dental fluorosis 3-4 stiff and brittle bones/joints ≥4 deformities in knees; crippling fluorosis; bones finally paralysed resulting in inability to

walk or stand straight Dental fluorosis is the damage of tooth enamel, which is caused by the long time consumption of water with high F- content during the period of development of tooth. After tooth enamel is completely formed, dental fluorosis can not develop even if excessive fluoride is ingested (WHO, 1984). Hence, older children and adults are not at risk for dental fluorosis. Teeth impacted by fluorosis have visible discolouration from white spots to brown and black stains. Dental fluorosis has been classified in a number of ways. (Dean, 1934) suggested one of the most accepted classifications of dental fluorosis, wherein Dean’s index is used to measures the degree of mottled enamel (fluorosis) in teeth (Table1.2). According to the damage of tooth, dental fluorosis can be classified into very mild, mild, moderate and severe categories Table 1.2. Table 1.2 Degree of dental fluorosis (after Dean, 1934)

Dean’s index

Tooth damage

I Very mild fluorosis: Small opaque, paper white areas scattered irregularly over the tooth but not involving as much as 25% of the tooth surface

II Mild fluorosis: The white opaque areas in the enamel of the teeth are more extensive but do not involve as much as 50 % of the tooth

III Moderate fluorosis: All enamel surface of the teeth are affected and the surface subject to attrition shows wear; brown stain is frequently a distinguishing feature

IV Severe fluorosis: All enamel surfaces are affected and hyperplasia is so marked that the general form of the tooth may be affected. Brown stains are widespread and often present a corroded appearance.

(Choubasia, 1997) has examined the prevalence of dental fluorosis in 15 tribal villages of Rajasthan with F- concentrations varying from 0.3 mg/l to 10.8 mg/l. In tribal villages with mean F-


3

concentration of 0.4 mg/l in drinking water, dental fluorosis was observed among 26.6% of school children (<16 years) and 23.9% of adults. In tribal villages with mean F- concentration of 6 mg/l in drinking water, dental fluorosis was observed among 84.4% of school children (<16 years) and 96.9% of adults.

Endemic skeletal fluorosis was reported in India in the 1930s. It was first observed in bullocks used for ploughing in Andhra Pradesh, where farmers noticed the bullocks’ inability to walk, apparently due to painful and stiff joints. Several years later, the same disease was observed in humans (Short et al., 1937). (Choubasia, 1997) has examined the prevalence of skeletal fluorosis in the adults of Rajasthan. In areas with mean F- content of 1.4 mg/l in drinking water, about 4% of adults were reported to have been affected with skeletal fluorosis, while in areas with mean F- content of 6 mg/l in drinking water, about 63% of adults were reported to have been affected with skeletal fluorosis. The prevalence of skeletal fluorosis was found to be higher in males and increased with increasing F- levels and age. Skeletal fluorosis affects children as well as adults. It does not easily manifest until the disease attains an advanced stage. According to WHO, the permissible limit for F- in drinking water is 1.5 mg/l (WHO, 1984) whereas (USPHS, 1987) has set a range of allowable F- concentration in drinking water for regions depending on their climatic conditions because the amount of water consumed and consequently the amount of F- ingested is influenced primarily by air temperature (Table 1.3). Table 1.3 Range of maximum allowable F- concentration (after USPHS, 1997)

Annual average maximum daily air temperature (°C)

Recommended F- concentration (mg/l)

Maximum allowable F- concentration (mg/l)

Lower Optimum Upper ≤12 0. 9 1. 2 1. 7 2. 4

12.1-14.6 0. 9 1. 1 1. 5 2. 2 14.7-17.7 0. 8 1. 0 1. 3 2. 0 17.8-21.4 0. 7 0. 9 1. 2 1. 8 21.5-26.2 0. 7 0. 8 1. 0 1. 6

≥26.3 0. 6 0. 7 0. 8 1. 4 In view of the environmental and socio-economic conditions of the Indian subcontinent, the desirable limit of F- is set at 0.60 1.20 mg/l and the maximum permissible limit in absence of any other source is set at 1.5 mg/l for drinking water (ISI, 1983). A low content of fluoride (< 0.60 mg/l) causes dental carries and high content (> 1.20 mg/l) results in fluorosis prevalence. Hence, it is essential to have a safe limit of F- concentration between 0.60 and 1.20 mg/l in drinking water (Subba Rao and Devdas, 2003).

1.2. Research problem definition About 80% of the diseases in the world are due to poor quality of drinking water (WHO, 1984). Large groups of people in the following countries suffer from fluorosis due to intake of F- rich groundwater: Argentina, U.S.A., Morocco, Algeria, Libya, Egypt, Jordan, Turkey, Iran, Iraq, Kenya, Korea, Tanzania, South Africa, China, Australia, New Zealand, Japan, Thailand, Canada, Saudi Arabia, Iran, Sri Lanka, Syria and India (Apambire et al., 1997; Binbin et al., 2005; Dissanayake, 1991; Grimaldo, 1995; Mameri, 1998; Meenakshi and Maheshwari, 2006; Ramamohna et al., 1993; Shomar et al., 2004; Teotia et al., 1981; Zhang et al., 2003). Dental fluorosis has also been reported in Korea due to consumption of elevated fluoride concentrations in groundwater over a long period of time (Choi, 2004; Shin et al., 1998; Yi et al., 2001). India is among the 23 nations around the globe where health problems occur due to high F- concentrations in water. An estimated 62 million people including 6


4

million children suffer from fluorosis in India because of consuming water contaminated with F- (UNICEF, 1999). However, it is not easy to arrive at an accurate or reliable estimate of the number of people at risk. Scientific efforts to address the problem of F- in rural water supplies in India have been led by the Rajiv Gandhi National Drinking Water Mission with considerable support from external agencies, particularly UNICEF (UNICEF, 1999). As the assessment of groundwater quality has not been given due importance, water-borne diseases have become common (Subba Rao and Devdas, 2003) . This is because of difficulty of sampling groundwater from millions of hand pumps spread across India. Existing sampling has been selective and unstructured, taking some samples from villages in districts and from few water pumps in each village (UNICEF, 1999). Further, there are no comprehensive health surveys to assess the problem of dental and skeletal fluorosis. Nevertheless, in the most affected States of India, at least 50% of the districts have villages with groundwater supplies having high F- concentrations (UNICEF, 1999). In these States, it is estimated that 10-25% of the rural population is at risk (UNICEF, 1999). The presence of F- concentration in groundwater can not be predicted. The presence of high F- concentrations in groundwater is often recognised only when people exhibit symptoms of fluorosis. The first step towards developing measures to prevent and cure groundwater quality deterioration is to generate reliable, accurate information through water quality analysis, scientific study on F- distribution in groundwater and geochemical knowledge with spatial information on geology and climate to understand the source/cause, type and level of F- contamination. However, in India there are few observation stations that cover all the essential parameters for water quality assessment and hence the data obtained are not decisive on the water quality status. Secondly, water quality management involves expensive and sophisticated equipments that are difficult to operate and maintain and require substantial expertise in collecting, analyzing and managing data. The existing methodology for addressing the water quality problem is inadequate to identify the various sources of F- contamination. It is difficult to understand the issues related to epidemic diffusion simply by groundwater quality analysis as it lacks spatial information. Therefore, combination of both groundwater quality parameters and GIS methods is very useful to researchers to model the health related issues as GIS provides efficient capacity to visualize the spatial data. F- contamination in groundwater has recently (in 2004) been reported in Tamnar area of Raigarh district of Chhattisgarh State in central India by the State Public Health Engineering Department (PHED). Due to the predominantly large rural population, groundwater based systems are the only sources of drinking water supply in the area. Despite the high number of water use points (more than 1000 hand pumps) in the area, potable water supply is limited to only 40% (Personal oral communication with PHED). Due to high concentration of F- in groundwater, both dental and skeletal fluorosis is prevalent. Dental fluorosis, especially mottling and pitting of teeth has become a common feature among the children and adults in Muragaon, Saraitola and Pata villages because of the excessive intake of F- contaminated water. Few cases of dental and skeletal fluorosis in Tamnar area are shown in the Figure1.2. In the addition to already affected population, still a larger fraction of population is potentially at risk. In order to take any meaningful action towards elimination or minimization of the problem, it is essential to have a comprehensive study to ascertain the causative factor and to delineate areas and extent of F- contamination.


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Dental fluorosis Skeletal fluorosis

Skeletal fluorosis Skeletal fluorosisFigure 1.2 Photograph showing irreversible dental and skeletal fluorosis in Tamnar area

With this background the present study is taken up to gain insight into spatio-temporal distribution and factors that influence the levels of F- concentrations in the shallow and deep aquifers in the sedimentary terrain of the Tamnar area of Raigarh District, Chhattisgarh. Prior to this study, no scientific investigation has been conducted on F- contamination in groundwater in the State.

1.3. Research objectives

The main objective is to study the spatio-temporal variation of fluoride (F-) contents in groundwater and its relationship with fluorosis prevalence in Tamnar area. The sub-objectives are: 1) To understand the controls on the spatial distribution of F- and other ions in groundwater. 2) To determine if F- contents in groundwater vary with time. 3) To analyse the relationship between fluorosis prevalence and spatio-temporal distribution of F- in

groundwater.

1.4. Research questions

What are the controls on spatial distribution of F- contents in groundwater in the area? Is the distribution of F- associated with the distribution of other geochemical parameters? What is the plausible source(s) of fluoride contamination in groundwater in the area? What relationship exists between litho-geochemical data and groundwater geochemical

data? What relationship exists between subsurface resistivity data and groundwater geo-


6

chemical data? Is there a temporal (pre-, mid- and post-monsoon) variation in F- concentration in

groundwater in the area?

1.5. Thesis outline The thesis consists of six chapters, which are outlined as follows. Chapter 1: Background to the research, effects of F- on human health, research problem definition, research objectives, and research questions are included in this chapter. Chapter 2: Literature review on groundwater geochemistry, environmental occurrence and geochemistry of fluorine, factors of F- enrichment in groundwater, and status of F- contamination in groundwater in India, are included in this chapter. Chapter 3: Description of the study area – location and extent, drainage, geology, geomorphology, hydrometeorology, and hydrogeology – is given in this chapter. Chapter 4: Materials and methods – overview of methodology, pre-field data collection, field methods (groundwater sampling and resistivity survey), laboratory methods, and hydrochemical data analysis methods – are described in this chapter. Chapter 5: Results and discussion about pre-monsoon, mid-monsoon and post-monsoon hydrogeochemistry, groundwater quality of the area, water types and their relation with F-

concentration, correlation of F- with other hydrochemical parameters, spatio-temporal distribution of F- in groundwater vis-à-vis fluorosis prevalence and health-risk, geology vis-à-vis F- concentration, and plausible source(s) and geochemical processes leading to F- enrichment, are presented in this chapter. Chapter 6: Conclusions and recommendations.


7

2. Literature review

2.1. Groundwater geochemistry Water is a very universal solvent capable of dissolving most solid to some degree. Inorganic and organic solids, organic liquids and gases found in subsurface, dissolve in groundwater. The major factors controlling the geochemical evolution and quality of groundwater are chemical composition of rain water, soil types and mineralogy of rock formations. The geochemical reactions in the soil zone and in the underlying unsaturated and saturated zones, temperature, pressure, duration of contact of percolating water and surrounding media determine the chemical composition of groundwater. Thus, the composition of groundwater provides information about the environment through which water has circulated (Appelo and Postma, 1993). Of the many solutes found in groundwater, only a relatively few are present at concentrations greater than 1 mg/l under natural conditions. Inorganic constituents are classified as major ion constituents with concentration greater than 10 mg/l, minor constituents with concentration ranging from 0.01 mg/l to 10 mg/l, and trace elements with concentration less than 0.01 mg/l (Deutsch, 1997). The ions commonly available in water are positively (cations) and negatively (anions) charged. The major cations include sodium (Na+), potassium (K+), calcium (Ca2+), and magnesium (Mg2+), and major anion, chloride (Cl-), sulphate (SO4

2-), fluoride (F-), and nitrate (NO3-). Table 2.1 presents the

details of dissolved constituents in groundwater. Alkalinity is a measure of the total acid-neutralizing capacity of the water, while acidity is the base-neutralizing capacity of the water. Alkalinity is expressed in terms of bicarbonate (HCO3

- ) and carbonate (CO3-- ) and acidity of water generally

expressed as concentration of Hydrogen (H+ ) ion (Walton, 1970). According to Davis and Dewiest (1996 cited in Walton 1970), the following dissolved constituents are present in groundwater (Table 2.1). Table 2.1 Dissolved constituents in groundwater (after Davis and Dewiest, 1966)

Major constituents ( range of concentrations 1. to 1000 mg/l Sodium Bicarbonate Calcium Sulphate Magnesium Chloride Silica Secondary constituents ( range of concentration 10-2 to 10 mg/l ) Iron Carbonate Strontium Nitrate Potassium Fluoride Boron Minor constituents ( range of concentration 10-5 to 10-1 mg/l ) Antimony, Bromide, Aluminium, Arsenic, Phosphate, Iodide, Barium, Cadmium, Chromium, Cobalt, Copper, Zinc, Germanium, Lead, Lithium, Manganese, Molybdenum, Nickel, Rubidium, Selenium, Titanium, Uranium, Vanadium Trace constituents ( range of concentration < 0.001 mg/l) Beryllium, Bismuth, Cerium, Caesium, Gallium, Gold, Indium, Lanthanum, Niobium, Platinum, Radium, Ruthenium, Scandium, Silver, Thallium, Thorium, Tin, Tungsten, Ytterbium, Yttrium, Zirconium


8

2.2. Environmental occurrence and geochemistry of fluorine Fluorine is one of the most reactive of all the chemical elements. It is, therefore, not found as fluorine in the environment. Being the most electronegative of all the elements (Hem, 1989) it has a strong tendency to acquire a negative charge and form fluoride ion (F-) in solution. F- ions have the same charge and nearly the same radius as that of hydroxide ions and may replace each other in mineral structure. F- thus forms mineral complexes with number of cations and some common mineral species of low solubility contain F- (Hem, 1989). Its concentration in natural waters depends on such factors as temperature, pH, solubility of F- bearing minerals, anion exchange capacity of aquifer materials (OH- for F-), type of geological formation traversed by water and the amount of time that water remains in contact with the formation (Apambire et al., 1997). Minerals which have F- are fluorite, apatite, mica, amphiboles, clay and villauamite. Certain clay minerals (illite, chlorite, smectites) show good anion exchange media from which large amounts of F- concentration can be generated (Boyle, 1992; Boyle and Chagnon, 1995). The average F- concentration in the earth crust is estimated at 0.05-0.1% or 500-1000 mg/kg (Adriano, 1986). It is enriched during differentiation in the late stages of crystallization of magmas as well as in the residual solution and vapour. Consequently, it is concentrated in highly siliceous granitic and alkaline rocks and in hydrothermal mineral deposits (Hopkins, 1997). Soils dominated by clay minerals have high sorption capacity and frequently serve as natural geochemical barriers preventing pollutants from reaching groundwater (Subba Rao, 2003). F- are adsorbed on clay minerals, where ionic exchange takes place, i.e. F- ions partly replace OH- ions (Hitchon, 1995). More than 90 % of natural F- in soils is bound to clay particles. The role of micas and amphiboles in the occurrence and mobility of F- in soils is enhanced by their relative readiness to disintegrate in weathering process. F- in micas are likely to be released soon after the onset of weathering. According to (Korting, 1972) 80-90 % of fluorides are contained in muscovite, illite and related minerals of the mica group. In groundwater, fluorine occurs as fluoride ions (F-) which forms complexes with inorganic and organic compounds. F- is released into aqueous solution during weathering process of rocks, minerals and through anthropogenic pollution. Solubility of F- from F- bearing minerals is relatively low under normal conditions but slow process of dissolution enhances leaching and F- enrichment in groundwater (Hem, 1989). Part of F- may occur in groundwater as a result of fluorite (CaF2) dissolution. The solubility product of fluorite (Kfluor) can be determined according to the following dissolution formula (Helgeson, 1969): CaF2 ↔ Ca2+ + 2F- Kflour = [aCa

2+] * [aF- ] 2 = 10-9.07 at 25°C ------------------------------------------------------ -----------2.2-1

Where [aCa2+] and [aF

- ] are the activity of the concerned ions and K is the equilibrium constant.

(Handa, 1975) reported the Kflour value of 10-10.75. Due to relatively low solubility of F-, the occurrence of aqueous F- is predominantly controlled by the availability of free Ca2+ ions in water (Jacks et al., 2004).The dissolution constant of calcium carbonate (CaCO3) is much larger than the fluorite. CaCO3 (s) + H+ ↔ Ca2+ + HCO3

- Kcal = [aCa

2+]* [aHCO3- ] / [aH

- ] = 0.97 * 102 -------------------------------------------------- ------------2.2-2 Since the solubility product of fluorite is constant, the activity of F- is directly proportional to HCO3

- if pH is constant. While computing the thermodynamics equilibrium in the groundwater system in contact with both calcite and fluorite, a combined equation is derived (Handa, 1975). CaCO3 (s) + H+ + 2F- = CaF2 (s) + HCO3

-


9

Kcal-fluor = [aHCO3-]/ [aH

+]* [aF

-] 2 = 1.06 * 10-11 ----------------------------------------------- ------------2.2-3 From the equation (2.2-3) it can be concluded that the aqueous concentration are proportional to HCO3

- concentration and pH values. Consequently, high F- water is usually HCO3- dominated which

favours the dissolution of F- from soils and rocks. Therefore, water with high F- concentration can form in the areas where alkaline, i.e. carbonate-containing, waters are in contact with F- bearing rocks. F- concentrations are relatively independent of the other water soluble components but noteworthy correlation exists between F- and pH values. The F- solubility in soil is lowest in the pH range of 5.0-6.5 (Adriano, 1986). At higher pH value, ionic exchange occur between F- and OH- ions (illite, chlorite, micas and amphiboles) resulting in increase of F- concentration in groundwater. At pH < 6, both F- and Al3+ combine into water and formation of [ AlF]2+ and [AlF2]+ complexes mainly takes place in solution (Hem, 1989; Wenzel and Blum, 1992). (Hitchon, 1995) observed that the formation of [MgF]+ complexes on the account of F- ions intensifies while the saltiness of groundwater, Ca2+ and temperature increases.

Apart from natural sources, a considerable amount of F- may be contributed due to anthropogenic activities. Remarkable amounts of F- are transferred into agricultural soil by phosphate fertilizer. Phosphate may contain up to 4% of F- depending on its origin and contents of fluorapatite. The steel, aluminium, glass, brick and ceramic industries use F- in their production process that occur with the encounter of F- containing aerosols, dust, wastewater into the surrounding environment (Jacks et al., 2004).

2.2.1. Factors of F- enrichment in groundwater The concentration of F- in groundwater depends on the geological, chemical and physical characteristics of aquifers (e.g., porosity and acidity of soils and rocks, temperature, depth, etc.) (Abu Rukah and Alsokhny, 2004; Jacks et al., 2004). Rock chemistry, groundwater age, well depth, hydrologic condition, residence time and geologic structures are important factors of F- rich groundwater (Kim and Jeong, 2005). Other factors of F- enrichment in groundwater are high evapo-transpiration rate, extensive and long-term irrigation, and heavy use of fertilizers (Subba Rao and Devdas, 2003). In the Indian context, the occurrence of F- in groundwater is mainly due to geological factors (Saxena and Ahmed, 2001).The presence of high HCO3

-, Na+ and pH favour release of F- from aquifer matrix into groundwater (Guo et al., 2007). A variety of geochemical studies have been carried out on various aspects of F- in groundwater particularly on the relationship between F- concentration and water-rock interaction in aquifers in different geologic settings (Gaciri and Davies, 1993; Ghosh and Bandyopadhyay, 1980; Handa, 1975; Nordstrom and Jenne, 1977a; Saxena and Ahmed, 2001). Rock-water interaction allows F- rich minerals in bedrock to be decomposed resulting in enrichment of F- in groundwater (Bardsen et al., 1996; Wenzel and Blum, 1992). The concentration of F- in groundwater is frequently proportional to the degree of water-rock interaction because F- basically originates from bedrock (Banks et al., 1995; Carrillo-Rivera et al., 2002; Dowgiallo, 2000; Frengstad et al., 2001; Gizaw, 1996). The mineralogical/chemical composition of lithology is, therefore, considered an important factor for F- concentration in groundwater. Groundwater in aquifers of alkali granite and metamorphic rocks is generally enriched in F- (Banks et al., 1995; Dowgiallo, 2000). The common fluorine-bearing minerals in alkali granite and metamorphic rocks are apatite, selecite, topaz, fluorite, fluorapatite, cryolite, amphiboles and micas (Bardsen et al., 1996; Handa, 1975; Pickering, 1985; Ramamohna et al., 1993; Subba Rao and Devdas, 2003; Wenzel and Blum, 1992; Zhang et al., 2003). The mineral fluorite is considered to be the main


10

source of F- in groundwater particularly in granitic terrains (Deshmukh et al., 1995; Shah and Danishwar, 2003). However, its solubility in water is low and its dissolution rate is remarkably slow (Nordstrom and Jenne, 1977b). Some researchers suggest that high F- concentration in groundwater may be due to weathering of biotite (Chae et al., 2007; Li et al., 2003; Nordstrom and Jenne, 1977b). Sedimentary horizons also have apatite as an accessory mineral and fluorite also frequently occurs as cement in sandstone (Abu Rukah and Alsokhny, 2004). Dissolution of evaporative salts deposited in arid conditions can also be an important source of F-. (Handa, 1975) and (Chae et al., 2006a) reported positive correlation between F- and silica as well as between F- and sodium in groundwater, which indicate a silicate-mineral source of F-. Handa (1975) noted a general negative correlation between F- and calcium in Indian groundwater. High F- concentration may, therefore, be expected in groundwater in Ca-poor aquifers and in areas where F- rich minerals are common. Handa (1975) also reported F- enrichment in groundwater where cation exchange of Ca for Na takes place. Low calcium and high bicarbonate alkalinity favour high F-

concentration in groundwater (Bulusu and Pathak, 1980). Water with high F- concentration is generally soft with high pH and contains high silica concentration (Bulusu and Pathak, 1980). (Apambire et al., 1997) reported F- contamination qualitatively in the coarse grained hornblende granite and syenite of upper regions of Ghana. They suggested that the dissolution of fluorite and ion exchange with micaceous minerals and their clay alteration products as the cause of the F- enrichment in groundwater. Thus, the occurrence of F- in groundwater is due to solution precipitation, reactions, and adsorption-desorption processes. Groundwater in arid regions is prone to high F- concentrations because groundwater flow is usually slow, which favours water-rock reactions. The F- contents of groundwater may increase due to evaporation if water solutions remain in equilibrium with calcite and if alkalinity is greater than hardness. Dissolution of evaporative salts may be an important source/factor of F- enrichment in arid condition. Enrichment of F- in groundwater is less pronounced in humid tropics because high rainfall results in dilution of groundwater.

2.3. Groundwater contamination by F- in India The problem of high concentrations of F- in groundwater in India was first reported in the Nellore district in 1937 in Andhra Pradesh (Short et al., 1937). In 1987, it was estimated that about 25 million people suffer from fluorosis (FRRDF, 1999). In 1991, it was reported that drinking water in 13 of India’s 32 States and union territories contain naturally high concentrations of F- (Mangla, 1991). By 1999, the number of States in India with drinking water containing naturally high concentrations of F- has gone up to 17 (UNICEF, 1999). The most seriously affected areas are in the States of Andhra Pradesh, Punjab, Haryana, Rajasthan, Gujarat, Tamil Nadu, Kerala Madhya Pradesh Punjab, Bihar and Uttar Pradesh (Kumaran et al., 1971; Teotia, 1984). The highest F- concentration in groundwater reported to date in India is 48 mg/l in the Rewari District of Haryana State (UNICEF, 1999). At present, there are at least 17 states in India that are affected with elevated F- levels in drinking water (WHO, 2006). The affected areas have been progressively identified since the first report by (Short et al., 1937), with Assam being the most recently identified State with high F- levels in drinking water, which is associated with endemic fluorosis. Dental fluorosis is endemic in 14 States and in 150,000 villages in India (Pillai and Stanley, 2002). Only the states in the north-eastern corner of India are free from fluorosis (Chadha, 1999). It has been estimated that more than 66 million people in India consume drinking water containing elevated F- concentrations (Andezhath et al., 1999). The ranges and regional distribution of F- concentrations in groundwater in India and the associated


11

severity of most cases of fluorosis are given in Table 2.2. The study area is situated in Chhattisgarh State of central India. Table 2.2 Range of F- concentration in groundwater of India and associated severity of fluorosis (Agarwal et al., 1997)

Region/State Range of F- concentration (mg/l) Severity of fluorosis North-West India 0.4 – 19 Severe Central India 0.2 – 10 Moderate South India 0.2 – 20 Severe Deccan Province 0.4 – 8 Moderate


12

3. Description of the study area

3.1. Location and extent The study area is situated within the Raigrah district in the north-eastern part of the Chhattisgarh State (Figure 3.1) and lies between latitudes 22º 05' 00''N and 22º 15' 00''N and longitudes 83º 20' 00''E and 83º 30' 00''E. The Raigarh district is bounded by Surguja district in the north, by Jashpur district in the north-east, by Bilaspur and Mahasamund districts in the west, by Raipur district in the south and by Sundergarh, and Sambalpur districts of Orissa state in the east. The specific area investigated forms a part of Pahaj River watershed in Tamnar Block (Figure 3.2). Pahaj River is a tributary of Kelo River which in turn is a tributary of Mahanadi River. The areal extent of the study area is 243 sq.km. Raigarh railway station is the nearest railhead in the Howrah-Bombay main-line of the South Eastern railway and all the important places within the district are well connected by network of State highways and all weather roads.

Figure 3.1 Location map of study area


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Figure 3.2 Satellite image (Aster) showing the study area

3.2. Geomorphology Physiographically, the area can be divided into two units: (1) northern highland comprising of foot hills and hill ranges running in NW-SE direction and covered mostly by reserved forest (between 300 and 580 m above MSL) and (2) flat to gently sloping land of 260 to 300 m elevation above MSL in and around Tamnar and Gharghoda towns with occasional outcrops of low dipping sandstone of Lower Gondwana Group (Figure.3.3). The soil in the area attains a thickness of up to 10 m and contains varying proportion of clay, silt, sand and gravel.

Figure 3.3 Physiographic characteristics of study area: forest covered hills of northern highland (left) and gently sloping land (right)


14

As many as six geomorphic units have been identified in the study area based on the visual analysis of satellite imagery. The image elements, drainage characteristics, pedogenic and morphogenetic expression, authenticated by field checks have been used for identification and mapping of geomorphic units. The geomorphic units (Figure 3.4) have been classified on the basis of differential erosion of rock material, erosion process, weathered zone and relief of the area and the sequence of these units in increasing order of antiquity is given below: Flood plain: Formed due to deposition of sediment along river bank. Valley fill: Narrow, linear surface with thick overburden along drainage Deeply buried pediplain: Nearly flat, erosional surface with thick overburden (up to10 m) Moderately buried pediplain: Nearly flat, erosional surface with moderately thick overburden (5 to 10 m) Pediment: Gently sloping erosional surface with detritus of sandstone and very thin soil cover on the imagery. Structural hills: Formed due to differential erosion process showing trend lines

1 0 1 Kilometers

N

EW

S

Flood plainValley fillDeeply buried pediplain

PedimentStructural HillsWater body

Moderately buried pediplain

Figure 3.4 Geomorphological map prepared from visual interpretation of satellite imagery


15

3.3. Drainage The study area is drained by Pahaj River and its tributaries (Figure 3.5). Pahaj River is a fourth order of stream and flows from north to south. Pahaj River is an intermittent stream and its tributaries are of ephemeral in nature. The drainage pattern in the northern part of the area has complex arrangement with considerable variation that is controlled by topography, slope, rock type and structural deformations. In low relief areas, streams exhibit parallel appearance in upper reaches and join the main stream at more or less right angle. This suggests that the pattern is largely controlled by joints/lineaments/fractures. The eastern and central part of the area is characterised by sub-parallel to sub dendritic type of drainage pattern with low drainage density indicating low runoff and high infiltration while in the south western part, dendritic drainage pattern is developed on the sandstone and shale of Raniganj Formation having high drainage density and structurally controlled.

Figure 3.5 Drainage map of the study area.

3.4. Hydrometeorology The area experiences sub-tropical climate, characterised by extreme summer and moderate winter. The summer extends from March to May. April and May are the hottest months with frequent dust storm and hot waves during this period. The rainy season extends from June to September with well distributed rainfall through southwest monsoon. Monsoon generally commences in the second week of June and rainfall is highest in July and August. Winter season in the area is marked by dry and cold weather with intermittent showers during the months of December to February. The meteorological data from the observatory located at the district headquarters i.e. at Raigarh situated about 40 km from study area) were collected from Land Records Department and Water Resources Department. Meteorological data pertaining to temperature, rainfall, relative humidity, wind speed and evaporation for the year 2007 summarized in the Table 3.1.


16

Table 3.1 Salient feature of Meteorological data for the year 2007 as recorded at Raigarh Month

Mean monthly rainfall(mm)

Mean monthly temperature Max(ºc) Min(ºc)

Mean monthly relative humidity (%)

Mean monthly wind speed (km/hr)

Mean monthly evaporation

No. of rainy days

January 26.2 27.4 10.2 49.9 5.3 32 3 February 19.1 30.8 14.3 39.8 6.1 44 2 March 26.7 35.2 20.8 32.4 6.9 54 2 April 13.1 39.4 25.3 30.2 8.4 91 2 May 24.5 45.0 28.2 31.6 10.7 116 2 June 205.9 37.1 26.4 65.0 12.1 68 11 July 392 35.8 23.9 86.1 11.8 37 19 August 358.8 30.1 23.9 87.3 10.4 37 19 September 221.2 31.1 23.8 75.6 7.4 36 12 October 57.3 31.2 26.6 64.2 6.0 39 5 November 17.8 29.2 16.1 53.5 4.1 35 2 Dec. 3.4 27.1 13.1 52.3 4.4 30 3

Source: Land Records and water Resource Department, Chhattisgarh The area receives maximum rainfall during the south-west monsoon which starts in the middle of June and ceases by the end of September or beginning of October. About 87 % of the annual rainfall takes place between June and September. Only 9 % of the annual rainfall takes place during winter season from October to February and about 4% of the annual rainfall takes place during the summer season, i.e. between March and May. The mean monthly variation in minimum and maximum temperature in the area is shown in Figure 3.6. The minimum and maximum mean monthly temperature are about 10.2°C in the month of January and 45°C in the month of May respectively. The temperature in the area start rising after February and reaches maximum during the month of May. The daily mean maximum temperature during the month of May is around 45°C. On the arrival of monsoon at the end of June or middle of June, there is a dip in temperature and weather becomes pleasant. After withdrawal of monsoon at the end of September, there is a slight increase in the day temperature and then both day and night temperature starts falling as the winter approaches.

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Figure 3.6 Mean monthly variation in minimum and maximum temperature


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The trend of evaporation (Figure 3.7) is almost sympathetic with the variation of temperature as shown in Fig.3.6. Evaporation is maximum (116mm) during the month of May and minimum (30mm) during the month of December. The atmospheric humidity is low during summer months (March-May). The minimum humidity recorded is 31.6 % in the month of May which increases to > 80 % upon the arrival of south-west monsoon. The highest recorded mean monthly humidity (i.e.87.3%) is in the month of August.

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Figure 3.7 Potential evapotranspiration

3.5. Geology 3.5.1. Lithostratigraphy The area of study is occupied by the Gondwana Supergroup of rocks consisting of thick sequence of sandstone, shale, carbonaceous shale, clay and coal seams. The geological formations that crop out in the area, in chronological order are given in Table 3.2. The description of each Formation is given below (GSI, 2008) and the geological map is shown in the Figure 3.8. Table 3.2 Geological sequence of the area

Age Group Formation Lithology Recent to sub recent Alluvium Soil and alluvium Sand, clay, gravel laterite, Permian Triassic Lower Gondwana Kamthi Formation Sandstone and argillaceous beds Upper Permian Lower Gondwana Raniganj Formation Sandstone and carbonaceous shale Upper Permian Lower Gondwana Barren Measure

Formation Ferruginous sandstone and clay

Lower Permian Lower Gondwana Barakar Formation

Feldspathtic sandstone, shale and carbonaceous shale with coal seams

Source: (after GSI 2008)

Barakar Formation The rocks belonging to the Barakar Formation are exposed in the more or less flat areas around Gharghoda and Tamnar. Exposures of Barakar Formation are found around Konpara, Kathrapali, Muragaon and Saraitola villages. The rocks have gentle dip (2 to 5º) towards west and southwest and are represented by cyclic sequence of coarse to fine grained feldspathic sandstone, shale, carbonaceous shale, alternating sequences of shale and fine grained sandstone with coal horizons. Soil cover in the area poses problem in establishing the vertical organisation of the Barakar Formation. The only good exposures and sequential depositions are, however, found along the stream about two miles west of


18

Saritola village (Figure 3.9 left). High content of mica in Barakar sandstone near village Muragaon is also observed during the field work (Figure.3.9 right).

Figure 3.8 Geological map of the study area (Source: GSI). Lineaments are interpreted from satellite

imagery.

Figure 3.9 Sequential deposition in Barakar Formation near village Saraitola (left) and Sandstone

exposed near village Muragaon with high mica content (right)


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Barren Measures Formation The Barakar Formation is conformably overlain by 300-350 m thick sediments belonging to Barren Measures Formation. The general trend of the Formation is NW-SE with very low (2 -3°) dips towards southwest which become horizontal at places. The characteristic litho-assemblage of this formation are fine grained sandstone to sandy shale, grey shale and hard compact ferruginous sandstone. Fine grained sandstone displays sedimentary structures like ripple drift lamination, ferruginous colour banding and co-sets of cross laminations.

Raniganj Formation The Barren measures Formation is conformably overlain by Raniganj Formation whose main litho-units are fine to medium grained greyish white sandstone and carbonaceous shale with occasional ferruginous layer of sandstone (Figure 3.8). These litho-units are exposed along the foot hills of Silot reserve Forest near Dholnara and Bhalumura villages and also Parkipari village (Figure 3.10).

Figure 3.10 Sandstone of Raniganj Formation exposed near Parkipahri village

Kamthi Formation Towards the north-eastern corner of the area, in the vicinity of Silot Pahar (Hill) Raniganj Formation is overlain by coarse grained sandstone and argillaceous sediments. This Formation stands out as high ridges with elevation ranging between 340 and 580m. The sandstone of this formation is frequently iron stained and intersected by ferruginous bands. The sandstones are sometimes granular and pebbly. The granules and pebbles comprising predominantly of quartz, are mostly angular in shape within siliceous and ferruginous matrix.

3.5.2. Structure The rocks of the Gondwana Supergroup occurring in the area have been subjected to deformation and crustal movements during Palaeozoic times and so they show many structural evidences of folding and faulting. The structural hill in the area characterised by NW-SE trending upland (Silot Pahar) occur in the northern part. This upland descends radially in the northern and southern direction and distinctly characterised by arcuate drainage controlled by structural fabric/elements (C.G.W.B., 2006). Repetition of sandstone and argillaceous bed and sandstone and shale (younger formation) on northern and southern section clearly indicate folding. The general trend of the beds of the Barakar Formation, Barren Measure formation and Raniganj Formation is NW-SE with very low dip (2 -5°) due south to south-west. In the vicinity of Silot Pahar, both the Barakar and Barren Measures Formation are overlain by the Kamthi Formation. The area has undergone repeated structural deformation during Proterozoic time and has been subjected to the block faulting during Gondwana times. Three major


20

faults occurring in the area are marked on the map (Figure 3.8) as F-F. There are three major sets of lineaments, viz NW-SE, NNE-SSW to NE-SW and NNW-SSE to N-S

3.5.3. Subsurface geology The available data on bore wells and also the observations made in the field from the existing dug wells in the study area have been used to understand subsurface lithological details. A cross-section between samaruma and Gare (Figure 3.11) and a fence diagram using lithologs of bore wells at six locations (Annexure 1- 6 and Figure 3.12) are drawn. These diagrams are effective at demonstrating changes in lithology with depth and truncations of litho-units of geological Formations occurring in the area. The subsurface geology of the area reveals that south-western part of the area is underlain by younger Kamthi Formation which is composed of sandstone and argillaceous bed followed by thin bed of sandstone and carbonaceous shale of Raniganj Formation. The central part of the area is made up of ferruginous sandstone and clay of Barren Measures Formation and the north eastern part of the area is underlain by feldspathic sandstone, shale, and carbonaceous shale of the Barakar Formation.

Figure 3.11 Cross section between Samaruma and Gare showing sub-surface geology

(data sourceC.G.W.B.)


21

L E G E N D

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Figure 3.12 Fence diagram showing lithological units in the subsurface

3.6. Hydrogeology The hydrogeological formations on the basis of lithostatigraphy can be classified into five different layers. Layer 1- Recent or Quaternary formation comprising of sand, clay, laterite and gravel. Layer 2- Feldspathic sandstone and shale horizon, comprising of alternate bands of sandstone, shale and clay with coal seams (Barakar Formation) Layer 3- Ferruginous sandstone and clay, of Lower Permian age (Barren Measure Formation) Layer 4- Sandstone and carbonaceous shale of Lower Permian age (Raniganj Formation) Layer 5- Sandstone and argillaceous bed (Kamthi Formation) . The hydrogeological formations (layers 2-5) belong to the Gondwana Supergroup of rocks and possess both primary and secondary porosity, where primary porosity dominates secondary porosity. Weathering and fracturing impart secondary porosity to these rocks. The aquifer system consists of diverse assemblage of sandstone, shale clay and coal beds. Groundwater occurs in both phreatic and semi- confined to confined conditions. Shallow aquifers are phreatic to semi-confined whereas deeper aquifers are generally confined and often produce artesian conditions. The deeper confined artesian aquifer at Tamnar town (well no 31, latitude 22˚˚05'40'' N and longitude 83˚25’54’’E) has water temperature of 41.5˚C. The feldspathic sandstone of Barakar Formation favours productive aquifer


22

having granular zone down to the depth of 450 m with discharge ranges from 1 to 10 lps (litre per second) (C.G.W.B., 2006). The thick shale and clay bed of Barakar Formation act as confining layers. The upper part of the Gondwana aquifer system with thickness of 30 meter is extremely weathered and fractured with numerous cracks and joints. The aquifer performance test in Barakar Formation at two locations, Gare (latitude 22˚ 08' 00'' N and longitude 83˚ 29' 20'' E) and Kotrimar (22˚13'48'' N and 83˚23' 0'' E) has been conducted by CGWB. The Transmissivity and storage coefficient for Barakar Formation as estimated by CGWB is given in the Table 3.3. Table 3.3 Transmissivity of Barakar formation

Location

Formation Lithology Transmissivity (T) in m2 /day Storage co-efficient

Gare Barakar Feldspathic sandstone 54 1.72 *10-2

Kotrimar Barakar Feldspathic sandstone 143 9.95*10-2

Source: CGWB

3.6.1. Groundwater level One of the most common measurements in groundwater investigation is the determination of the depth to groundwater. Such data are needed to define depth to water level during pre-monsoon and post-monsoon periods, groundwater flow direction, changes in water level over time and effects of pumping. In the present study, groundwater levels have been undertaken during field campaigns in the pre-monsoon (early June’08) and post-monsoon (early November’08) periods. For obtaining water depth, a steel tape was lowered into the well and water level was recorded during pre- and post- monsoon periods. Observation wells were established in such a way that different physiographic and geologic variability is represented, and wells are more or less equally distributed. The depth to water in the area during pre-monsoon ranges from about 12 to more than 34 meters below ground level (m bgl) (Annexure, 15). Deeper water level (> 25 m) is mostly observed in the eastern part of the study area. The depth to water level map for pre-monsoon period is shown in the Figure 3.13.

The depth to water level during post-monsoon period in the area shows a wide range and varies from 5 to 30 m bgl (Annexure, 15). However, the general range of depth to water level in the area is between 10 and 15 m. Deeper depth to water level in the range of 15 to 20 m is encountered in north-eastern and western part of the area (Figure 3.14). The water level fluctuation between pre-monsoon and post-monsoon period is important as it reflects the effective groundwater recharge due to rainfall. The fluctuation in water level between pre-monsoon and post-monsoon periods has been determined by taking the difference between the observed depths to groundwater levels during the two periods (Annexure, 15). The water level fluctuation map is shown in the Figure 3.15. The increase in water level in general is between 5 and 10 m. The water level fluctuation gradually increases from west to east. In order to determine the direction of groundwater flow, water table elevation contour have been drawn using reduced water levels. The elevation of water table has been calculated from the spot height measured from the GPS. Water table contour map is shown in the Figure (3.16). Water table elevation varies from about 280 to 220 m amsl. The general direction of movement of groundwater is towards south i.e. same as the direction of the stream flow. Flow direction is marked on the map with black arrow


23

Figure 3.13 Depth to water level during pre-monsoon period

Figure 3.14 Depth to water level during post-monsoon period


24

Figure 3.15 Water level fluctuation map

Figure 3.16 Water table contour map


25

4. Materials and methods

As mentioned in Chapter 1, the main objective of the present study is spatio-temporal variation of F- contents in groundwater and its relationship with other geochemical parameters, geology and fluorosis prevalence. An overview of the methodology adopted for the study is given in the Figure 4.1. The detailed explanation for methods applied is enumerated in the rest of the chapter.

Problem identification

Literature review Pre-field data collectionSampling plan

Groundwater sampling (multi-season)In-situ water quality, water level & GPS measurements

Laboratory analysis

Water quality data

InterpretationInterpolation

Geospatial analysis of F-

Contamination & conclusions

Laboratory analysis Geological map

Groundwater level & well depths

Rock sampling Geophysical survey

XRD & Petrographic analysis

Figure 4.1 Flow chart showing an overview of the methodology adopted in the present study

4.1. Pre-field collection of data F- in groundwater is primarily a geogenic phenomenon; therefore, to study the relation between F- content and litho-structural parameters, geological map on 1:50,000 scale was collected from Geological Survey of India, Nagpur. For understanding the sub-surface geology, lithologs were collected from Central Ground Water Board, Raipur, and for establishing correlation between the well depth and F- concentration; data on depth of the sampling wells were collected from Public Health Engineering Department, Raigarh. Since enrichment of F- concentration is depend on temperature, rainfall and evapotranspiration, (Subba Rao, 2003), thus hydrometeorological data were collected from Land Record Department, Raigarh.


26

4.2. Field data collection To collect the required data, field work was planned and conducted in three phases; - Pre-monsoon, mid-monsoon and post-monsoon periods. The details during each phase are furnished below.

4.2.1. First phase: Pre-monsoon The first phase of field surveys for pre-monsoon sampling was carried out from 8th June to 20th June 2008 during which following task was accomplished:

• A total of 83 groundwater samples were collected from hand pumps (Figure 4.2) for chemical analysis. Locations of sampling points were fixed using Global Positioning system (GPS) in Universal Transverse Mercator (UTM) coordinates (WGS-84 datum)

• The pH and electrical conductivity of the groundwater samples were measured by using portable pH and electrical conductivity (EC) meters.

• The depth to water levels were measured at 24 locations, at remaining 59 locations, water level could not be measured due to problem in opening of hand pumps.

• Ground truthing for understanding the geological and geomorphological set-up and establishing correlation between satellite image signatures and geological/geomorphological units has been carried out.

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Figure 4.2 Map showing locations of groundwater sampling during pre-monsoon period


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4.2.2. Second phase: Mid- monsoon Second phase of field survey was carried out from 3rd September to 10th September 2008. Due to Heavy rains during this period, the approachability was difficult as unpaved roads were cut-off. During this phase, a total of 20 groundwater samples (Figure 4.3) from high F- zone as well as low F- concentration areas around it were collected from the corresponding locations of pre-monsoon sampling wells. The pH and EC of the water samples were also measured using portable pH and EC meters.

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Figure 4.3 Map showing locations of groundwater sampling during mid-monsoon period

4.2.3. Third phase: Post-monsoon Third and final field survey was carried out from 1st November to 7th November 2008. During this the following tasks were accomplished:

• A total of 81 groundwater samples were collected (Figure 4.3). Due to breakdown of hand pumps, it was not possible to collect samples from two locations (well number 8 and 51).

• The depths to water levels were measured at 24 places by lowering the steel tape into the bore wells.

• Resistivity surveys at high F- locations (four vertical electrical sounding (VES) in Muragaon and Saraitola villages) were conducted. Due to water in the paddy fields, it was not possible to take more number of soundings.


28

• The pH and EC of the water samples were measured using portable pH and electrical EC meters.

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Figure 4.4 Map showing locations of groundwater sampling during post-monsoon period

4.3. Field methods

4.3.1. Water sampling Groundwater sampling locations were established in such a way that different physiographic regions, geological formations are represented and wells are more or less uniformly distributed in the study area. For assessment of groundwater quality it was ensured that maximum villages of study area were covered for sampling, so as to arrive at meaningful and realistic analysis with reference to F-

contamination in groundwater. The sampling locations were fixed using a hand-held GPS. The samples were collected in polylab pre-cleaned bottles of one litre capacity from hand-pumps after pumping out the volume of water standing in casing. Two samples from each well were collected. Samples for cation analysis were acidified by adding few drops of ultra-pure nitric acid. Hydrogen ion concentration (pH), Temperature and electrical conductivity (EC) were determined on the site using portable pH meter (model-pH tester 30 Eutech) and EC meter (Corning, model 831).


29

4.3.2. Resistivity survey method Electrical resistivity technique makes use of the variation in electrical resistivity of the ground. The resistivity of material is defined as the resistance offered by a unit cube when a unit current passes normal to its surface and the potential obtained across its opposite faces is unity (Figure.4.5). The units are expressed in Ohm-m. The resistivity is computed, by passing electric current (in mille-amperes) into the ground through two current electrodes and measuring the potential drop (in mille volts) resulting from the resistance offered by the ground with the help of two other potential electrodes placed co-linearly and symmetrically about the centre of the electrode arrangement (Figure 4.6). Non- polarized electrodes are used for the potential measurement in order to eliminate the polarization potential. The apparent resistivity is given by equation 4.3-1:

Figure 4.5 Resistivity and resistance relation

IVa /ΚΔ=ρ ---------------------------------------------------------------------------------------------- 4.3-1

Where, K is a geometrical factor, Δ V is the potential in mille-volt and I is the current in mille ampere. The electrical resistivity method makes use of the differences in electrical characteristics of various rock formations occurring in the area at different depths. The electrical resistivity varies from formation to formation and depends on the degree of water saturation and its compactness.

Figure 4.6 Current and potential measurement system in resistivity survey


30

Schlumberger array, one of the most frequently used electrode arrangements in vertical electrical soundings (VES) has been used for resistivity survey in the present study. This array has four collinear point electrodes, placed along a straight line symmetrically over centre point ‘O’. Current is sent through the outer current electrodes A, B and the potential is measured across inner potential electrodes M and N. (Figure.4-6). The configuration factor for the schlumberger array is given in the equation 4.3-2.

( ) ( ) 2/2/

2/2/ 22

πMN

MNABK −= -----------------------------------------------------------------------------------4.3-2

The ratio between the developed potential and the current injected into the ground gives the resistance of the ground to a depth that depends on the electrode configuration and electrode spacing. The apparent resistivity of the ground, which is a function of electrode separation, has been computed by multiplying the ratio of the measured potential difference and amount of current injected into the ground with geometric factor of electrode configuration. Successive measurements were made over the same centre point with increasing separation between the electrodes in a pre-determined steps. A resistivity meter model SSR-MP-AT manufactured by Integrated Geo-instruments and services (P) limited, Hyderabad, India, has been used for resistivity sounding in the present study. Four Vertical Electrical Soundings by Schlumberger configuration were conducted on 3rd and 4th November 2008 in the Muragaon and Saritola villages where high F- concentration in groundwater was found. Two soundings were taken in Saritola village near well number 76 and 78 (Figure 4.7). As the paddy fields were filled with water and due to lack of space, resistivity survey at other site was not possible. The maximum current electrode spacing (AB) was taken as 200 m due to space constraints for spreading the wire.

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Figure 4.7 Locations of resistivity survey


31

As mentioned earlier, the resistance value measured by the instrument was multiplied with geometric factor (K) to get the apparent resistivity values for each electrode spacing (Annexure 7- 10). The field apparent resistivity data were plotted on log-log paper against the half current electrode separation (AB/2) to get the VES curves (Figure 4.8 to Figure 5.41-5.44).

The curve is drawn on double logarithmic sheet as this serves to make the size and shape of the curve independent of the units of measurements. The advantage of the logarithmic plot is that the curve matching process yields an immediate reading of the apparent resistivity and probable thickness of the subsurface layer (Orellana and Mooney, 1966). In the first instance, the quantitative interpretation of VES data has been made by conventional curve matching techniques using two and three layer master curves corresponding to the shape of the field curve. In this technique, the field sounding curve is compared with theoretical sounding curves computed for various layer parameters. When the field curve matches with particular theoretical curve, the layer parameters of the theoretical curve are taken as the solution for the field sounding data. The interpreted layer parameters obtained through conventional curve technique have been modelled with computer software for deriving proper hydro-geological inferences.

4.4. Laboratory methods

4.4.1. Chemical analysis Water samples from 83 bore wells (located in 39 villages) during the pre-monsoon, 81 samples during post monsoon and 20 samples during mid-monsoon were analysed for major ion chemistry employing the standard methods (APHA, 1992). As mentioned earlier, pH and EC were measured on the site itself during sampling, Total hardness (TH) was measured titrimetric method using standard (0.1M) ETDA solution (Ethylene diamine tetra acetic acid). Sodium (Na+) and Potassium (K+) were analysed by systronics flame photometer. Calcium (Ca2+) and Magnesium (Mg2+) ion concentrations were analysed by titrimetric analysis using standard ETDA. Carbonate (CO3

2-) and bicarbonate (HCO3-)

were estimated by titration with H2SO4. Sulphate (SO42-), Nitrate (NO3

-), Fluoride (F-) and Chloride (Cl-) were analysed, by Systronics spectrophotometer. Major cation and anions in the mid-monsoon and post-monsoon water samples were analysed by ion chromatograph (Metrohm, 861, Advanced Compact IC) barring the HCO3

- content which was determined titrimetrically. The quality of analytical data (concentration of cation and anion) is evaluated by computing the ionic balance. For statistical summaries of analytical data of water samples minimum, maximum, mean, median, standard deviation (SD) and median of absolute difference (MAD) were determined for all the data sets. MAD is estimated as median of absolute difference between individual data value and data median. The ionic balance of the solution is calculated by comparing the sum of the equivalents of the cations with the sum of the equivalents of the anions (Hounslow, 1995) using the following formula

( ) ( ) 100/ ∗+−= ∑∑∑ ∑ anioncationanioncationBalance ----------------------------- ------4.4-1

A positive number means that either there are excess cations or insufficient anions in the analysis, whereas a negative balance corresponds to excess anions or insufficient cations. For fresh water balance is assumed to be good if it is ± 10 % (Celesceri et al., 1998). For determination of possible errors and inconsistencies in data sets cation-anion balance methods was applied to pre-monsoon, mid-monsoon and post-monsoon water samples for further


32

analysis. The total numbers of wells with ion values were 83 in pre-monsoon, 20 in mid-monsoon and 81 in post-monsoon. The histogram of ion balance for pre-monsoon (Figure 4.8) show 81 samples are within the acceptable limit of ± 10% (Celesceri et al., 1998) while 2 samples have more than the acceptable limit because of insufficient cations. The ionic balance of mid-monsoon is shown in the (Figure 4.9). Histogram of mid-monsoon water samples shows that data are lacking in cations. In the post-monsoon, 78 samples have been found within the acceptable limit of ± 10% while remaining 3 samples have more than acceptable limit (Figure 4.10). The Cation anion balance of pre-monsoon, mid-monsoon and post-monsoon water samples are given in (Annexure, 19)

20.0

10.0

0.0

10.0

20.0

30.0

40.0

1 5 9 13 17 21 25 29 33 37 41 45 49 53 57 61 65 69 73 77 81

No of samples

Sum

of i

on b

alan

ce (m

eq/l)

Figure 4.8 Histogram of cation anion balance (pre-monsoon)

-12.0

-10.0

-8.0

-6.0

-4.0

-2.0

0.0

2.0

4.0

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

No of samples

Sum

of i

on b

alan

ce(m

eq/l)

Figure 4.9 Histogram of cation anion balance (mid-monsoon)


33

-40.0-35.0-30.0-25.0-20.0-15.0-10.0-5.00.05.0

10.015.0

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58 61 64 67 70 73 76 79

No. of samples

Sum

of i

on b

alan

ce (m

eq/l)

Figure 4.10 Histogram of cation balance (post-monsoon)

Ion balance was also compared by generating the scatter plot between EC and sum cation and sum anion of pre- and post-monsoon water samples. Scatter plot of pre-monsoon water samples shows that sum of cations and sum of anions are equally balanced and linearly placed (Figure 4.11). Scatter plot of EC versus sum cations and sum anions of post-monsoon water samples showing linear relation but many samples are deviating (Figure 4.12).

Figure 4.11 Scatter plot of EC versus sum cations and sum anions (pre-monsoon)

Figure 4.12 Scatter plot of EC versus sum cations and sum anions


34

4.4.2. XRD and Petrographic Analysis of Rock samples X-ray diffraction (XRD) is an analytical method for characterizing the crystallographic structure of a mineral. Any crystalline substance when present in pure state, always produces its distinct diffraction pattern. This concept is the basis for the diffraction method of all analysis done by using X-ray diffraction. Four rock samples from the F- contaminated zone were collected from the field for XRD analysis. These samples were powdered to the 0.02-0.003 mm particle size and placed into the sample holder for obtaining smooth and flat surface and then inserted in the XRD machine for recording the diffractograph of individual samples. The diffractograph shows the peak positions and intensity of mineral structure. For identification of peaks semi-quantitative analysis was done by X’Pert PRO high score plus software using RIR (reference intensity ratio method). All the peaks were identified and matched with the ICDD (International council for diffraction data base) reference pattern. The diffractograph of analysed rock samples are shown in the Annexure (Figure 20 to 24). The analysis was done by the Wadia Institute of Himalayan Geology (WIHG), Dehradun.

4.5. Analysis of Geochemical Data

4.5.1. Univariate and multivariate methods of analyses of geochemical data Basic statistics on mean, median and mode give an idea of the centre of distribution; whereas, variance and standard deviation are generally used to describe the variability within the data. Most of the statistical analyses are based on the assumption that data follow a normal (symmetric) distribution. Geochemical data usually exhibit asymmetric distribution. Certain transformations are applied so that data follow a more or less symmetric distribution, therefore, certain transformation are applied so that data follows a more or less symmetric distribution. Groundwater quality data have major cation and anion which represent the quality of groundwater. Results of chemical quality of groundwater may be difficult to interpret, particularly when more than a few analyses are involved. To overcome this, graphic representations are useful for display purpose, for comparing analysis and for emphasizing similarities and differences (Todd, 1980). Graph can also aid in detecting the mixing of water of different compositions and in identifying chemical process occurring as groundwater moves (Todd, 1980). Water quality data may be interpreted on the basis of both individual analysis and set of analysis from one sampling location or different sampling locations in an area. One of the most useful graphs for representing and comparing water quality analysis is the trillinear diagram by Piper shown in (Figure 4.13). In the Piper plot, major ions are plotted as cation and anion percentage of milli-equivalents in two base triangles. The total cations in meq/l , and the total anions in meq/l, are set equal to 100 %.The data point in the two triangle are then projected onto the central diamond shaped grid parallel to the upper edges of the central area. The projection indicates certain useful properties such as similarities and differences among groundwater samples. Those with similar quality will tend to plot together as groups and simple, mixture of two water sources can also be identified (Todd, 1980).


35

Figure 4.13 Graphical representation of water quality data using piper trillinear diagram (after Piper,

1944 cited by Deutch, 1997) The data of well No.50 (Table 4.1) is plotted on Piper diagram (Figure 4.14) as an example. Piper diagram indicates Ca-HC03 type of water. Table 4.1 Chemical analysis data at well no. 50 Ions Concentration mg/l Concentration meq/l % meq/l Calcium (Ca) 19.8 0.98 60 Magnesium (Mg) 4.82 0.39 22 Sodium(Na) potassium (K) 9.41 0.24 18 Bicarbonate (HCO3 ) 77.1 1.26 85

Sulphate (SO4 ) 10.96 0.22 10 Chloride (Cl) 5.47 0.15 5


36

Figure 4.14 Projected cation and anion concentration on piper diagram

4.5.2. Spatial distribution of groundwater constituents For estimation of groundwater quality of unsampled locations, spatial interpolation is required with a satisfying level of accuracy. Interpolation is based on the principle of spatial auto-correlation or spatial interdependence, which measure the degree of relationship between near and distance points. Spatial auto-correlation determines if values are interrelated. There are many spatial interpolation algorithms for spatial data sets. (Shepard, 1968), discussed in detail inverse distance weighting, (Deutsch and Journel, 1998) kriging and (Goodman and O'Rourke, 1997), discussed in detail about splines. There are two categories of interpolation techniques, deterministic and geostatistical. Deterministic interpolation technique creates surfaces based on the measured points or mathematical formulas. Methods such as inverse distance weighting (IDW) are based on the extent of the similarity of the cells while geostatistics interpolation such as kriging are based on statistics and are used for more advance prediction surface modeling that also include some measure of the accuracy of the prediction. Kriging is similar to IDW in the sense that it uses a weighting mechanism that assigns more influence to the nearer data points to interpolate values at unknown locations. However, instead of using inverse distance weighting approach kriging uses variograms. As a measure of spatial variability, a variogram replaces the Euclidean distance by a structural distance that is specific to the attribute and the field under study (Deutsch and Journel, 1998). For special correlation, a perfect semivariogram is required for which parameters can be determined. The geochemical data in the study area are non-stationary because many of the closely located points have values drastically different from each other. Because of this reason, IDW method has been used for interpretation of data points instead of kriging in order to generate maps of continuous maps of geochemical parameters. IDW interpolation determines cell values using a linearly-weighted combination of a set of sample points. The weight is a function of inverse distance. The farther an input point is from the output cell location, the less importance it has in the calculation of the output value. Because the IDW is a weighted distance average, the average cannot be greater than the highest or less than the lowest input. Therefore, it cannot create ridges or valleys if these extremes have not already been sampled.


37

Also, because of the averaging, the output surface will not pass through the sample points. The best results from IDW are obtained when sampling is well distributed to represent the local variation that needs to be simulated. In IDW, the measured values (known values) closer to prediction location will have more influence on the predicted value (unknown value) than those farther away. More specifically, IDW assumes that each measured point has a local influence that diminishes with increase in distance. Thus, points in the near neighborhood are given high weights, whereas points at a far distance are given small weights (Lixin Li, 2004). The general formula of IDW interpolation is the following (Johnston and Lucas, 2001):

ii

N

iwyxw λ∑

=

=1

),( ------------------------------------------------------------------------------4.5-1

∑=

⎟⎠⎞

⎜⎝⎛

⎟⎟⎠

⎞⎜⎜⎝

⎛

=N

k

p

p

ii

dk

d

1

1

1

λ------------------------------------------------------------------------------------ 4.5-2

where w(x,y) is the predicted value at location (x,y), N is the number of nearest known points surrounding ( x,y), λi are the weights assigned to each known point value wi at location (xi,yi), di are the Euclidean distances between each (xi,yi) and (x,y), and p is the exponent, which influences the weighting of wi on w. in the present study, p value of 2 and search radius of 5000 m have been used for interpolation. For depicting the spatial distribution of geochemical parameters into different classes, Box plot have been used to fix the limits of the lasses. Classification based on the box plot has strong ability to display the spatial distribution of uni-element data without assumption of normal distribution model or prior information about the factors that influence the geochemical data (Carranza, 2008). Box plot provide the important characteristics of geochemical data such as central tendency, spread, skew ness and outliers. Box plot classes obtained from the interpolation of geochemical data can be represented with different colours. “The colours used to represent classes of geochemical data sets as obtained through Box plot serve to objectivity portray in a map the structure and spatial distribution of that data set with balanced visual impression” (Carranza, 2008). A typical box plot representing characteristics of univariate data set is shown in the Figure 4.15. Median divides the data values (minimum to maximum) in to two parts. The lower hinge (LH) value and upper hinge (UH) value are determined from minimum to the median and maximum to the median, respectively. The lower hinge, median and upper hinge, thus divides the data set into four equal parts which is known as quartiles. Values from the minimum to the lower hinge are called the 1st

quartile (Q1), while values from the lower hinge to the median are called the 2nd quartile (Q2), values from the median to upper hinge is called 3rd quartile (Q3) and the values from the upper hinge to the maximum are called 4th quartile (Q4). A box is then generated between the lower and upper hinges. The absolute difference between lower and upper hinges are called the inner quartile range (IQR) or hinge width.(Carranza, 2008).


38

The most extreme value in the data set is considered as outlier. Box plot represents two quartile (50%) of data sets and in a data set at the maximum 25% can be outliers but these outlier values does not affect the median and hinge value. Thus, box plot is robust against the outliers in univariate data set.

Figure 4.15 A Box plot representing characteristics of univariate data set (after Carranza, 2008) Spatial distribution maps of geochemical parameters such as pH, EC, Na+, Ca2+, Mg2+,K+, HCO3

-, F-, and Cl- were generated with the classes obtained as per box plots. For this, the geochemical data were first transformed to natural log using excel software and then box plot of each variable was generated. Then, the following classes were obtained from the box plots:

• Minimum value to Lower whisker (LW) • Lower whisker (LW) to Lower hinge ( LH) • Lower hinge (LH) to Upper hinge (UH) • Upper hinge (UH) to Upper whisker ( UW) • Upper whisker (UW) to Maximum value

Values of box plot were then converted into real values which were used for classifying the interpolated maps of different geochemical parameters.


39

5. Results and discussion

5.1. Pre-monsoon groundwater geochemistry

5.1.1. Groundwater quality The summarized hydrochemistry of groundwater during pre-monsoon period is presented in Table 5.1. The details of individual samples are given in (Annexure, 16). Table 5.1 Summarized hydro-geochemistry of pre-monsoon period Parameter Minimum Maximum Mean Median SD MAD pH 5.36 7.85 7.02 7.02 0.48 0.3 EC 78.2 2760 334 380 332.7 89.0 TDS 51 1380 214 239 168.7 67.0 TH 34.7 841 164.9 143.5 113.3 49.5 ALK 19.4 380.2 155.2 150 71.3 45.1 Ca2+ 9.9 130.7 32.3 25.7 20.6 9.9 Mg2+ 2.4 125.2 20.2 16.8 15.9 5.4 Na+ 0.6 62.7 18.2 16.8 12.9 8.4 K+ 3.0 80.5 21.3 17.3 15.7 10.1 SiO2 10.0 150 58.7 60 31.5 30.0 HCO3

- 24.4 483.6 188 186 87.7 52.3 CO3

-- ND ND - - - - Cl- ND 335.8 23.9 11.9 45.8 7.1 NO3

- 0.0 106.3 4.15 0.52 14.0 0.3 SO4

2- 1.5 31.8 10.5 9.56 5.7 2.2 PO43- ND ND - - - - F- 0.09 8.88 1.02 0.65 1.59 0.25

SD: Standard deviation, MAD= Median of absolute difference; ND= Not detectable The groundwater quality of the Tamnar area is evaluated by comparing the range of values of different geochemical parameters with drinking water standards both Indian (ISI, 1983) and (WHO, 1984) (Table 5.2). Physico-chemical properties of analysed water samples show considerable variation in the water quality with respect to their chemical composition. The logarithm of the reciprocal of the hydrogen ion concentration (pH) in the pre monsoon water samples varies from 5.36 (Baihamura) to 7.85 (Devgarh) with mean value of 7.02. All the samples, except that from Baihamura village are within the recommended limits (7.0-8.5) for human consumption. The electrical conductivity (EC) values are found to be within the range of 78.2 μS/cm to 2760 μS/cm with mean value of 334 μ/cm; higher EC is found in artesian well located in Tamnar town. The concentrations of total dissolved solids (TDS) ranges from 51.0 mg/l (Kurwahi) to 1380 mg/l (Basanpali) with mean value of 214. The total hardness (TH) ranges from 34.7 mg/l to 841 mg/l in the water samples. According to (Durfor and Becker, 1964) classification of water types based on total hardness, 51 samples of the total 83 samples are under ‘hard’ and very hard categories (Table 5.3). Calcium (Ca2+) ion concentrations in pre-monsoon period show wide variation from a minimum of 9.9 mg/l to as high as 130.7 mg/l. One


40

sample from Tamnar town exceed the maximum permissible limit, however, all the samples are within the maximum permissible limit according to Indian Standard. Table 5.2 Comparison of groundwater quality with Indian and WHO standards

Parameter Minimum Maximum Indian Standard (ISI, 1983) WHO (1984) Highest

desirable limit Maximum

permissible limit pH 5.36 7.85 7.0-8.5 6.5-9.2 6.5-8.5 EC 78.2 2760 500 2000 -- TDS 51 1380 500 1500 500 TH 34.7 841 300 600 500 Ca2+ 9.9 130.7 75 200 75 Mg2+ 2.4 125.2 30 100 150 Na+ 0.6 62.7 -- -- 200 K+ 3.0 80.5 -- -- -- HCO3

- 24.4 483.6 -- -- -- CO3

-- ND ND -- -- -- Cl- ND 335.8 200 1000 500 NO3

- 0.0 106.3 45 No relaxation 45

SO42 1.5 31.8 150 400 400

PO43- ND ND - - - F- 0.09 8.88 0.6-1.2 1.2 1.5

*All the values except pH and EC, are in mg/l, ND= Not detectable The magnesium (Mg2+) concentration varies from 2.4 mg/l to 125.2 mg/l. All the samples, except that from Tamnar town are within the maximum permissible limit. Sodium (Na+) recorded values varying from 0.6 mg/l to 62.7 mg/l which are within the permissible limits. The potassium (K+) varies from 3.0 mg/l to 80.5 mg/l. The chloride (Cl-) concentration ranges from 0 mg/l to 335 mg/l, while Sulphate (SO4

2-) ranges from 1.5 to 31.8 mg/l, both Cl- and SO42- are within the recommended limits. The

Nitrate (NO3-) content ranges from negligible amount to about 106.3 mg/l; only one sample at Amaght

village exceed the recommended limit of 45 mg/l. No carbonate (CO32-) in the groundwater is observed

during chemical analysis while bicarbonate (HCO3-) varies from 24.4 mg/l to 483.6 mg/l. Fluoride (F-)

concentration varies from 0.09 mg/l (Kachkoba) to 8.8 mg/l (Muragaon); 12 samples of the 83 samples analysed exceed the acceptable limit of 1.2 mg/l as per the Indian standard, whereas 9 samples exceed the acceptable limit of 1.5 mg/l as recommended by WHO. F- affected groundwater is found to occur in the eastern part of the study area in five villages, namely Muragaon, Pata, Kunjhemura (Bandhapali), Saraitola and Dholnara.


41

Table 5.3 Classification of the groundwater samples on the basis of hardness (Pre-monsoon period)

Type of water Hardness (mg/l) No. of samples in Tamnar area

Soft 0- 60 3 Moderately hard 61-120 29 Hard 121-180 26 Very hard > 180 25

First two columns are after Durfor and Becker (1964)

5.1.2. Groundwater types The ionic concentration of major cations and anions found in groundwater of the study area are plotted in Piper’s trillinear diagram (Figure 5.1). Among the total 83 samples of pre-monsoon, cations are clustered within the area of 25-70% Ca, 25-60% Mg and 5-50% Na+K, while anions fall within the area of 20-99% HCO3, 0-80% Cl and 0-20% SO4.

Figure 5.1 Piper diagram showing major ion chemistry of groundwater (pre-monsoon) The analysis of piper diagram suggests that the following general water types exist in the study area:

• Ca(Mg) HCO3 type of water • Ca( Mg)Cl type of water • Mixed group ( no dominant type of water)

The majority of groundwater samples belong to the calcium/magnesium-bicarbonate type. Weathering of Ca-Mg bearing minerals are responsible for the dominance of Ca-Mg in groundwater of the study area. Total 39 water samples belong to this group with bicarbonate ranging from 80-100% and calcium/magnesium contents ranging from 40-60% (Figure 5.2). The F- concentration in this type of water ranges from 0.11 to 1.11 mg/l with average and median values of 0.59 mg/l and 0.54 mg/l respectively.


42

Figure 5.2 Piper diagram showing Ca (Mg) HCO3 type water (pre-monsoon)

Water samples at three places (number 8, 28 and 32) in the study area represent Ca (Mg) Cl water type (Figure 5.3). The F- concentration in this water type ranges from 0.12 to 0.39 mg/l.

Figure 5.3 Piper diagram showing Ca (Mg) Cl type water (pre-monson)

Apart from the above two major water types a variety of mixed group is found as given below:

• Mg-Ca-Na-HCO3-Cl • Ca-Mg-Na-HCO3- • Na-Ca-Mg-HCO3 • Na-Mg-Ca-HCO3 • Na-Mg-Ca-K-HCO3 • Na-Ca-HCO3


43

• Ca-Mg-K-HCO3-Cl • Mg-K-Ca-Na-HCO3 • K-Mg-Na-HCO3

The F- concentration in these water type ranges from 0.09 to 8.88 mg/l with average and median values of 1.68 mg/l and 0.81 mg/l, respectively.

5.1.3. Fluoride content vis-à-vis groundwater types According to (Apambire et al., 1997) groundwater with high F- concentration is generally of HCO3-Na type, particularly with poor Ca2+. Several authors have shown that in water with high F-

concentration, the amount of F- is proportional to the HCO3- concentration and pH (Handa, 1975;

Saxena and Ahmed, 2001). In order to understand the relation between F- concentration and groundwater type, three sets of Piper diagram have been plotted by dividing the water samples into three classes – (1) F- < 0.6 mg/l (2) F- ranging between 0.6-1.2 mg/l, and (3) F- > 1.2 mg/l according to Indian drinking water standard ( Figure 5.4). It is observed in the present study that the elevated F- concentration (i.e.> 1.2 mg/l) is associated with mixed water group where Na+ concentration is relatively higher than other cations. Such mixed group of water types are Na-Mg-Ca-HCO3, Na-Ca-Mg-HCO3, Na-Mg-Ca-K-HCO3, Na-Ca-HCO3 and Mg-Ca-Na-HCO3-Cl.

F- < 0.6 mg/l 0.6 < F- < 1.2 mg/l

F > 1.2 mg/l

Figure 5.4 Piper diagrams showing water types with respect to F- content (pre-monsoon)


44

The above mentioned observation suggest that an increase in Na+ concentration in groundwater is associated with increase in F- concentration, is also depicted in pie diagram (Figure 5.5 a). It is clear from this diagram that the ratio between Na+ and Ca2+ (i.e. Na: Ca) increases from 0.31 to 1.37 as the F- content in groundwater increases From < 0.6 mg/l to > 1.2 mg/l. No such relationship is, however, found between HCO3

- and F- (Figure 5.5 b) as reported by earlier researcher. According to Apambire et al. (1997), anion exchange (OH+ for F-) is the dominant process in the sedimentary basin which leads to base exchange (Na+ for Ca2+ and Mg2+) resulting in an increase in Na+ content. Further, the fact that high concentration of Na+ increases the solubility of F- bearing minerals (Apambire et al., 1997; Guo et al., 2007) explains the enrichment in F- concentration with increase in Na+ content in groundwater of the study area.

F- < 0.6 mg/l F 0.6-1.2 mg/l F > 1.2 mg/l

Na:Ca 0.31 Na:Ca 0.59 Na:Ca 1.37

(a)

(b)

Figure 5.5 Pie diagram showing relation between F- and major cations (a), and F- and major anions (b) (pre-monsoon)


45

5.1.4. Correlation of F- with other geochemical parameters To examine the relationships of F- with other geochemical parameters, correlation matrix and scatter plots have been generated for derived parameters of pre-monsoon groundwater samples. The correlation matrix (Table 5.4) exhibits excellent positive correlation among Electrical conductivity (EC) TDS, TH, Ca2+, Mg2+, and Cl-. This is due to the fact that conductivity depends on total dissolved solids and main constituents of TDS in water are Ca2+, Mg2+ and Cl-. Total hardness is positively and significantly correlated with Ca2+, Mg2+ and Cl-. Also, high correlation is found among Ca2+, Mg2+, HCO3

- and Cl- indicating that these soluble salts are predominant in groundwater of the study area. F- has poor but significant positive correlation with Na+ and SiO2; on the other hand, still poor but significant negative correlation is found with Ca2+ and Mg2+. This is an accordance with observation made earlier (previous section) that as F- concentration increases, Na+ concentration, increases and Ca2+ and Mg2+ concentration decreases.

Table 5.4 Correlation matrix of different parameters in groundwater (pre-monsoon)

1.28** 1.31** .99** 1.37** .95** .94** 1.44** .89** .89** .95** 1.31** .96** .94** .97** .87** 1.33** .43** .47** .38** .39** .36** 1.10 .34** .38** .22* .19* .24* .16 1.67** .46** .50** .58** .62** .55** .56** .13 1.10 .92** .90** .84** .80** .82** .36** .34** .17 1-.54** .02 .06 -.04 -.08 -.06 .01 .26** -.29** .13 1-.03 -.15 -.11 -.16 -.16 -.13 .12 -.18 -.03 -.20* .00 1-.09 -.22* -.23* -.30** -.37** -.24* .20* -.14 -.18* -.20* -.18 .19* 1.03 -.11 -.10 -.22* -.22* -.20* .31** -.17 -.10 -.12 -.11 .12 .36** 1

pHECTDSTHCaMgNaKHCO3ClNO3SO4SiO2F

pH EC TDS TH Ca Mg Na K HCO3 Cl NO3 SO4 SiO2 F

Correlation is significant at the 0.01 level .**.

Correlation is significant at the 0.05 level*.

The scatter plots between F- and other ionic constituents (Na+, pH, SiO2 Ca2+, Mg2+, K+, TH, HCO3

-, and alkalinity) have been drawn and are shown in Figure 5.6 to 5.12. Moderate to strong positive correlation of F- with Na+ and SiO2 is observed when F- concentration is greater than 1 mg/l (Figure 5.6 a and 5.7) suggesting that there may be a contribution of F- to groundwater from the decomposition of silicates. At elevated level F- is positively correlated with pH (Figure 5.6 b). F- is negatively correlated with Ca2+ and Mg2+; however, the correlation is not strong (Figure 5.8 and 5.9). High F- and low Ca2+ and Mg2+ may be due to precipitation of CaCO3 (Fung et al., 1999).The association of F- enrichment groundwater with low Ca2+ and Mg2+ has been reported by (Miana and Gaciri, 1984). The negative relation of F- with total hardness (TH), through correlation is not strong (Figure 5.11) may also be because of precipitation of Ca2+ and Mg2+ (Miana and Gaciri, 1984). No conclusive relation is found between F- and K+ (Figure 5.10). F- shows negative but poor relation with HCO3

- and alkalinity (Figure 5.12 a, 5.12 b) as also observed negative correlation with HCO3

- by earlier researcher with deeper aquifer (Tiwari et al., 2008).


46

Figure 5.6 Scatter plot of F- versus (a) Na+ (b) pH

Figure 5.7 Scatter plot of F- versus SiO2


47

Figure 5.8 Scatter plot of F- versus Ca2+

Figure 5.9 Scatter plot of F- versus Mg2+ Figure 5.10 Scatter plot of F- versus K+


48

Figure 5.11 Scatter plot of F-versus TH

Figure 5.12 Scatter plot of F- versus (a) HCO3- (b) alk

5.1.5. Spatial distribution of geochemical parameters The spatial distribution of F- and some important geochemical parameters (pH, EC, Na+, Ca2+, Mg2+, HCO3

-, SiO2 and total hardness) are presented in Figure 5.13 to Figure 5.21. IDW method has been used for interpolation of point data and box plots have been used for dividing the concentrations in five classes as discussed in Chapter 4. An interesting feature is observed in the spatial distribution maps are that there is a distinct NW-SE running linear trend in the southern part of the area. This linear trend coincides with a lineament observed in the satellite image with an alignment of a stream (Digi Nala) along it. This lineament most probably follows the anticlinal axis as younger geological formations are encountered towards north and south of it. It is envisaged that high weathering along this lineament might have resulted in increased dissolution of minerals in groundwater. The spatial distribution of F- (Figure 5.13) indicates that high level of F- in groundwater primarily occur in the


49

eastern part of the area. The southern part of the area has low level of F- in groundwater, while in the remaining area F- concentration is more or less within the optimum range. The analysis of spatial distribution maps of various geochemical parameters indicate that the high F-

zone is associated with slightly acidic to slightly alkaline water as indicated by pH distribution; low to moderate EC; high concentration of SiO2 and; relatively low values of total hardness (TH). The spatial distribution of K+ shows (not shown) high variability in K+ concentration in the high F- zone. These observation matches with earlier observation made through correlation matrix and scatter plots.

Figure 5.13 Box plot and spatial distribution map of F- (pre-monsoon)

Figure 5.14 Box plot and spatial distribution map of pH (pre-monsoon)


50

Figure 5.15 Box plot and spatial distribution map of EC (pre-monsoon)

Figure 5.16 Box plot and spatial distribution map of Na+ (pre-monsoon)


51

Figure 5.17 Box plot and spatial distribution map of Ca2+ (pre-monsoon)

Figure 5.18 Box plot and spatial distribution map of Mg2+ (pre-monsoon)


52

Figure 5.19 Box plot and spatial distribution map of HCO3

- (pre-monsoon)

Figure 5.20 box plot and spatial distribution map of SiO2 (pre-monsoon)


53

Figure 5.21 Box plot and spatial distribution map of total hardness (TH) pre-monsoon

5.2. Mid-monsoon groundwater geochemistry 5.2.1. Groundwater quality Groundwater quality of monsoon samples (20 representative wells) corresponding to pre-monsoon observation wells is evaluated so as to know the possible variation in groundwater during pre-and monsoon periods in the study area. The summarized hydrochemistry of groundwater during monsoon period is presented in Table 5.5. The details of individual samples are given in (Annexure 17). Table 5.5 Summarized hydrogeochemistry of mid-monsoon period

Parameter Minimum Maximum Mean Median SD MAD pH 6.22 7.64 6.99 6.98 .31 4.7 EC 166 710 387 376 137.9 76.5 TDS 99 391 221 205.5 81.0 45.5 TH 75 245 131.4 110 54.0 35 ALK 62.5 326.2 153.4 147.5 63.6 42.2 Ca2+ 12.3 40.9 22.25 17.0 9.15 4.7 Mg2+ 4.47 22.6 10.6 8.65 5.43 2.9 Na+ 2.72 50.4 21.6 20.4 10.9 8.2 K+ 2.77 91.7 15.6 10.2 19.4 4.9 HCO3

- 76.3 397.8 187.2 180 77.6 51.4 CO3

-- ND ND - - - - Cl- 4.33 56.7 17.0 13.9 12.5 12.7 N03

- 0.05 .34 .20 0.17 .095 0.07 SO42- 0.8 40.7 8.0 1.97 12.8 1.56 PO43- ND - - - - - F- 0.29 7.15 2.57 1.49 2.25 1.13 Li+ 0.0 0.07 0.02 0.03 0.02 0.02

SD: Standard deviation, MAD= Median of absolute difference


54

The pH value varies from 6.22 to 7.64 in the area with mean value of 6.99. All the water samples are within the permissible pH range of 6.5 to 8.5 for drinking water. The electrical conductivity (EC) values are between 166 to 710 μS/cm indicating potable nature of the groundwater. The concentrations of total dissolved solids ranges from 99 to 391 with mean value of 221.The total hardness (TH) denotes the concentration of calcium and magnesium and are important criteria for determining the usability of water for domestic supplies ranges from 75 to 245 mg/l with mean value of 131.4 mg/l. According to Durfor and Becker (1964) classification of total hardness, at five locations, groundwater is under very hard category (Table 5.6). Calcium and magnesium are within the permissible limit, ranges from 12.3 to 40.9 mg/l and 4.47 to 22.6 respectively. The concentration of sodium and potassium, in groundwater are found to be within permissible limits. Alkalinity varies from 62.5 to 326.2 mg/l while bicarbonate ranges from 76.3 to 397.8 mg/l. The WHO acceptable limit for alkalinity in drinking water is 200 mg/l. At one location the total alkalinity was higher than the acceptable limit. The Cl- and NO3

- concentration ranges from 4.33 to 56.7 mg/l and 0.05 to 0.34 mg/l respectively. The F- concentration in groundwater varies from 0.29 to 7.15 mg/l with median value of 1.49

mg/l is found occur in the eastern part of the area, as observed in pre-monsoon samples. Table 5.6 Classification of the water samples on the basis of hardness

No Type of water Hardness (mg/l) No of samples ( (20)

1 Soft 0- 60 1 2 Moderately hard 61-120 9 3 Hard 121-180 5 4 Very hard > 180 5

5.2.2. Groundwater types Groundwater samples of mid-monsoon period have been analysed through Piper plot (Figure 5.22). The plot suggests that among the cation species, Ca2+ and Na+ dominate in the aquifers which tend to shift towards Na+. On the other hand, bicarbonate is the major anion showing dominance over the others anions. In mid-monsoon groundwater samples following two types of water have been identified. 1- Ca-Mg-HCO3/Mg-Ca-HCO3 2- Mixed group of water. Majority of groundwater samples belong to the mixture of Ca2+, Mg2+ and Na+ ions. In mixed group of water following hydro-chemical types is found with their increasing ionic percentage.

• Ca-Na-Mg-HCO3 • Ca-Mg-Na-HCO3 • Na-Ca-Mg-HCO3 • Na-Ca-HCO3


55

Figure 5.22 Piper diagram showing major ion composition of water samples (mid-monsoon)

5.2.3. Fluoride content vis-à-vis groundwater types High F- values of mid-monsoon are associated with Na-Ca-Mg-HCO3 and Na-Ca-HCO3 water group, where favourable hydro-chemical conditions for dissolved F- in groundwater exist. As the hydro-chemical types of water change to Ca-Na-Mg-HC03 or Ca-Mg-Na-HCO3 water type, the concentration of F- falls and further reduced when water dominated by Mg-Ca-HCO3 or Ca-Mg-HCO3 (Figure 5.23).

Figure 5.23 Piper diagram showing high F- water samples (mid-monsoon)


56

5.2.4. Correlation of F- with other geochemical parameters For establishing the relationship of F- with other geochemical parameters correlation matrix (Table 5.7) and scatter plots have been drawn. Correlation coefficient of F- is significant and positive between F- and Na+. The statistical analysis of correlation matrix showed that EC has positive and significant correlation with TDS, TH, Ca2+ Mg2+, K+, HCO3

- and ALK. The total hardness is positively and significantly correlated with Ca2+, Mg2+, HCO3

- and ALK. A positive correlation is found between pH, and F- which shows the alkaline nature of water that probably promotes the dissolution of F- and hence the cause of the concentration of F- in groundwater. F- is negatively correlated with bicarbonate and negative correlation is generally reported in deeper condition of groundwater (Tiwari et al., 2008). F- shows negative but not significant correlation with Ca2+ and Mg2+ and TH. The scatter plots between F- and other geochemical parameters (Na+, Ca2+, pH, Mg2+, total hardness, alkalinity, lithium, K+ and HCO3

-) are shown in Figure 5.24. F- is positively and significantly related with Na+, and negatively related with Ca2+ concentration (Figure 5.24 a and 5.24 b). F- has positive relation with pH (Figure 5.24 c). According to Chae et al (2007) hydrogeochemical process that increases the F- concentration is closely related to a process that increase Na+ concentration and sink for Ca2+. This is in accordance with the observation made in pre-monsoon groundwater samples. F- is also negatively correlated with Mg2+ (Figure 5.24 d ). High F- low Ca2+ and Mg2+ in mid-monsoon water samples may be due precipitation of calcium carbonate, as observed with pre-monsoon water samples. The negative relation of F- with total hardness (Figure 5.24 e) is because of its precipitation as carbonates (Gaciri and Davies, 1993). F- show negative relation with alkalinity (Figure 5.24 f). At elevated level, F- shows poor but positive relation with lithium (Figure 5.24 g). However, few samples are also associated with low F-. Positive relation with lithium indicates the source of F- to be the weathering of micas (Apambire et al., 1997). No conclusive relation is found between F- and K+ (Figure 5.24 h). As observed in pre-monsoon water samples F- is negatively correlated with HCO3

-

(Figure 5.24 i).

Table 5.7 Correlation matrix for different water quality parameters (mid-monsoon)

1.64 1.70 .98** 1.23 .86* .77 1.16 .78 .68 .98** 1.19 .77 .65 .96** .94** 1.89* .29 .37 -.15 -.23 -.11 1.54 .80 .88* .53 .42 .31 .23 1.60 .97** .91* .91* .85* .88* .28 .63 1

-.45 -.47 -.40 -.30 -.20 -.46 -.46 -.16 -.52 1.03 -.04 .10 -.19 -.19 -.45 -.04 .44 -.22 .76 1

-.77 -.34 -.44 .16 .31 .17 -.89* -.47 -.23 .51 -.08 1.46 -.26 -.18 -.62 -.69 -.51 .82* -.20 -.27 -.26 -.05 -.75 1.60 .97** .91* .91* .85* .88* .27 .63 1.00** -.52 -.22 -.23 -.27 1.01 .17 .25 .10 -.01 .00 .09 .36 .09 .26 .52 -.27 .16 .09 1

pHECTDSTHCaMgNaKHCO3( /l)NO3ClSO4FALKLi

pH EC TDS TH Ca Mg Na K HCO3 NO3 Cl SO4 F ALK Li


Correlation is significant at the 0.01 level**.


57

0.0 10.0 20.0 30.0 40.0 50.0 60.0Na ( mg/l)

0.0

2.0

4.0

6.0

8.0F

(m

g/l)

(a)

10.0 20.0 30.0 40.0Ca (mg/l)

0.0

2.0

4.0

6.0

8.0

F (m

g/l)

(b)

6.50 7.00 7.50pH

0.0

2.0

4.0

6.0

8.0

F (m

g/l)

(c)

5.0 10.0 15.0 20.0 25.0Mg (mg/l)

0.0

2.0

4.0

6.0

8.0

F (m

g/l)

(d)

50.0 100.0 150.0 200.0 250.0TH

0.0

2.0

4.0

6.0

8.0

F (m

g/l)

(e)

50.0 100.0150.0200.0250.0 300.0350.0ALK (mg/l)

0.0

2.0

4.0

6.0

8.0

F (m

g/l)

(f)


58

0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07Li (mg/l)

0.0

2.0

4.0

6.0

8.0F

(mg/

l)(g)

Figure 5.24 Scatter plots F- versus (a) Na+, (b) Ca2+, (c) pH, (d) Mg2+, (e) TH, (f) Alkalinity (g) Li+ (h) K+

and (i) HCO3-

5.3. Post-monsoon groundwater geochemistry

5.3.1. Groundwater quality Summarized hydro-geochemistry of post-monsoon groundwater samples are presented in the Table 5.8. The details of individual samples are given in (Annexure 18).The variation in the different geochemical parameters is evaluated by comparing the range of values of post-monsoon and pre-monsoon periods. In the post-monsoon pH value vary from 6.91 to 8.96 with mean value of 8.08 while in the pre-monsoon samples 5.36 to 7.84 with mean value of 7.02 indicating increase in pH and hence its moderate alkaline nature. The electrical conductivity values are found to be within the range of 95 to 1268μS/cm in the post-monsoon period, and in the range of 78.2- 2760μS/cm in the pre-monsoon period. The total dissolved solids (TDS) ranges from 47 to 634 mg/l with mean value of 227 mg/l in the post-monsoon samples and 39 to 1380 with mean value of 214 mg/l in the pre-monsoon samples.


59

The groundwater with total hardness (TH) values of less than 75 mg/l is considered as soft. The hardness of groundwater from pre-monsoon (34mg/l to 841mg/l) to post-monsoon (44.6 to 401 mg/l) is decreasing. Groundwater is mostly ‘hard’ and ‘very hard’ in both the periods. Classification of water samples on the basis of hardness is given in the Table5.9.

Calcium concentration in groundwater samples in the post-monsoon period is 4.79 to 62.6 mg/l while 9.9 to 130.7 mg/l in the pre-monsoon periods.Mg2+ contents range from 1.97 to 42.2 mg/l and 2.41 to 125.2 mg/l in post and pre-monsoon respectively. Sodium concentration is varies from 0.98 to 84.6 mg/l and 0.6 to 62.7 mg/l in post- and pre-monsoon seasons respectively. These major ions concentration in groundwater are decreasing from pre- to post monsoon periods. The potassium contents ranges from 1.05 to 44.9 mg/l and 3 to 80.5 mg/l in post- and pre- monsoon seasons respectively. Bicarbonate ion is varies from 30.3 to 519.4 mg/l and 24.4 to 483.6 mg/l in post and pre-monsoon periods respectively. Carbonate ions observed in post-monsoon water samples. The concentration of carbonate ions ranges from 0 to 29.2 mg/l. Chloride concentrations ranges from 0.98 to 90.4 mg/ and 0 to 335.8 mg/l in the groundwater samples of post- and pre-monsoon periods respectively. Nitrates concentration ranges from 0 to 36.4 mg/ and 0 to 106.3 mg/l in post- and pre-monsoon periods respectively. No phosphate in the groundwater is observed during chemical analysis while sulphate varies from 0 to 215 mg/l in the post-monsoon periods and 1.5 to 31.8 mg/l in the pre-monsoon periods. The concentration of F- is varies from 0 to 7.12 mg/l and 0.09 to 8.88 mg/l in post- and pre-monsoon periods respectively. During the chemical analysis Li+ ions were observed in the post-monsoon water samples and the concentration varies from 0.0 to 0.08 mg/l. Table 5.8 Summarized hydrogeochemistry of post-monsoon period

Parameter Minimum Maximum Mean Median SD MAD pH 6.91 8.96 8.09 8.18 .49 0.38 EC 95.0 1268 453.3 400 226.1 112 TDS 47.0 634 227 207 113 56 TH 44.6 401 163 146 81.0 51.9 ALK 14.9 425.7 167.7 153.5 82.5 49.5 Ca2+ 4.79 62.6 26.2 22.3 13.9 9.85 Mg2+ 1.97 42.2 13.1 11.0 8.29 3.88 Na+ 0.98 84.6 16.4 13.9 13.5 7.17 K+ 1.05 44.9 14.9 11.7 10.6 7.49 HCO3

- 30.3 519.4 198.3 182.3 93.9 58.5 CO3

- 0.0 29.2 2.36 0.0 5.77 - Cl- 0.98 90.4 15.4 10.9 16.9 5.8 N03

- 0.0 36.4 2.2 0.48 5.42 0.43 SO42- 0.0 215 6.7 2.9 23.89 2.57 PO43- ND - - - - - F- 0.0 7.12 1.02 0.5 1.51 0.17 Li+ 0.0 0.08 0.009 0.0 0.02 0.0

SD: Standard deviation, MAD= Median of absolute difference ND= not detected


60

Table 5.9 Classification of groundwater samples on the basis of hardness (post-monsoon) No Type of water Hardness (mg/l) No of

samples (81) 1 Soft 0- 60 3 2 Moderately hard 61-120 26 3 Hard 121-180 23 4 Very hard > 180 29

5.3.2. Groundwater types The ionic concentrations of major cations and anions found in post-monsoon groundwater are plotted in Piper’s trillinear diagram (Figure 5.25). Using the trillinear plots 81 post-monsoon water samples have been analysed and classified. The groundwater samples of post-monsoon period showing 25-70 Ca, 20-50 Mg, 5-60% Na+K, and on other hand bicarbonate is the major anions dominate over others ions with 60-100%, HCO3, 0-80% Cl and 0-70% SO4. The analysis of Piper diagram indicates that the following three groundwater types exist in the study area.

• Ca-Mg-HCO3 • Ca-Mg-Cl • Ca-Mg-SO4 • No dominant type (mixture of these three group)

Figure 5.25 Trillinear diagram showing major ion chemistry of post-monsoon water samples

5.3.3. Fluoride content vis-à-vis groundwater types In order to compare the F- content and groundwater types in post-monsoon water samples, three sets of piper diagram have been plotted by dividing the water samples into 3 classes as shown in Figure 5.26. The classification of F- content in groundwater proposed by (ISI, 1983) is used to compare the F- in different water group. The F- content in each type of water is varying. The lowest F- content (F- 0.6<


61

F- < 1.2mg/l) occur in Ca-Mg-HCO3, Ca-Mg-HCO3-Cl and Ca-Mg-SO4 type of water. The high F-

concentration is associated with mixed group of water which are as follows (Figure 5.26): • Na-Ca-HCO3, Na-Mg-Ca-HCO3, • Na-Ca-Mg-HCO3 • Mg-Ca-Na-HCO3 type of water

F- < 0.6 mg/l F- 0.6 < F- < 1.2 mg/l

F-> 1.2 mg/l

Figure 5.26 Piper diagram showing F- water types with respect to F- content (post-monsoon) As observed earlier, high F- concentration in post-monsoon groundwater is associated with increase in Na+ concentration is also illustrated in pie diagram (Figure 5.27). It is observed that at F- (< 0.6 mg/l), Na+ concentration is high while Ca2+ concentration is low and as the F- increases (> 1.2 mg/l) Na+ is also increases and Ca2+ is reduces. It is clear from the (Figure 5.27 A) that ratio between Na+ and Ca2+ (Na: Ca) increases from 0.45 to 1.14 as the F- concentration in groundwater increases from < 0.6 mg/l to > 1.2 mg/l. However, no such relation is found between bicarbonate and F- (Figure 5.27 B) as reported by earlier researcher.


62

Na:Ca 0.45 Na:Ca 0.61 Na:Ca 1.14

(A)

(B)

Figure 5.27 Pie diagram showing relation between F- and major cation (A), and F- and major anion (B) (post-monsoon)

5.3.4. Correlation of F- with other geochemical parameters In order to examine the relationships of F- with other geochemical parameters correlation matrix and scatter plots have been generated for derived parameters of post-monsoon groundwater samples. Correlation matrix of groundwater samples of post-monsoon shows excellent positive relation between EC, TH, ALK, Ca2+, Mg2+, Na+, Cl- and HCO3

-. Total hardness (TH) is significantly correlated with ALK, Ca2+, Mg2+; HCO3

-. F- is not significantly correlated with any studied parameters. (Table5.10). F- has poor but positive correlation with Na+; on the other hand, negative correlation is found with Ca2+, Mg2+, K+, HCO3

-, and total hardness. This observation are in accordance with the observation made earlier with pre-monsoon water samples. Scatter plots between F- and other geochemical parameters ( Na+, Ca2+, HCO3

-, Mg2+, K+, alkalinity, lithium, TH and pH, ) are shown in Figure 5.28 and 5.29. F- is positively correlated with Na+ (Figure 5.28 a) but negatively correlated with all the parameters mentioned above. As observed in pre-and mid-monsoon water samples, F- is negatively correlated with Ca2+, HCO3

- and Mg2+ (Figure 5.28 b, c and 5.29 d). The association of high F- groundwater with low concentration of Ca2+ has been reported


63

by (Chae et al., 2007; Guo et al., 2007). The negative correlation with HCO3- is reported by (Tiwari et

al., 2008). F- Shows negative correlation with K+ and alkalinity (Figure 5.30 e and 5.30 f). Poor positive correlation is found between F- and Li+ (Figure 5.30 g). F- is negatively correlated with TH (Figure 5.30 h) and no conclusive relation is found between F- and pH (Figure 5.30 i).

Table 5.10 Correlation matrix of different parameters in groundwater (post-monsoon)

1.25* 1.24* 1.00** 1.31** .92** .92** 1.36** .82** .82** .88** 1.21* .85** .85** .89** .76** 1.10 .73** .73** .52** .42** .57** 1.18 .22* .21* .08 .06 .04 .04 1.38** .81** .81** .82** .77** .86** .60** .09 1.03 .18 .18 .07 .14 .06 .22* .11 .01 1.07 .69** .69** .51** .50** .44** .66** .29** .35** .27** 1

-.04 .20* .20* .25* .33** .11 -.01 .06 -.10 .03 .06 1-.22* -.22* -.22* -.30** -.33** -.24* .21* -.18* -.22* -.04 -.10 -.05 1-.24* .08 .08 .05 -.07 .14 .12 .12 .08 -.10 -.10 -.02 .14 1.41** .80** .80** .82** .75** .85** .58** .12 .98** -.03 .32** -.09 -.25* .11 1

pHECTDSTHCaMgNaKHCO3( /l)NO3ClSO4FLiALK

pH EC TDS TH Ca Mg Na K HCO3 NO3 Cl SO4 F Li ALK


Correlation is significant at the 0.01 level**.

0.0 20.0 40.0 60.0 80.0 100.0Na (mg/l)

0.0

2.0

4.0

6.0

8.0

F (m

g/l)

(a)

0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0Ca (mg/l)

0.0

2.0

4.0

6.0

8.0

F (m

g/l)

(b)

Figure 5.28 Plots of F- versus Na+ (a) and F- versus Ca2+ (b) (post-monsoon)


64

0.0 100.0200.0 300.0400.0 500.0600.0HCO3 (mg/l)

0.0

2.0

4.0

6.0

8.0F

(mg/

l)(c)

0.0 10.0 20.0 30.0 40.0 50.0Mg (mg/l)

0.0

2.0

4.0

6.0

8.0

F (m

g/l)

(d)

0.0 10.0 20.0 30.0 40.0 50.0K (mg/l)

0.0

2.0

4.0

6.0

8.0

F (m

g/l)

(e)

0.0 100.0 200.0 300.0 400.0 500.0ALK

0.0

2.0

4.0

6.0

8.0

F (m

g/l)

(f)

0.00 0.02 0.04 0.06 0.08 0.10Li (mg/l)

0.0

2.0

4.0

6.0

8.0

F (m

g/l)

(g)


65

Figure 5.29 Scatter plots of F- versus (c) HCO3

-, (d) Mg2+, (e) K+, (f) alkalinity (g) Li+ (h) TH and (i) pH

5.3.5. Spatial distribution of geochemical parameters The spatial distribution of F- and other geochemical parameters (pH, EC, Na+, Ca2+, Mg2+, HCO3

-, total hardness and Li+) of post-monsoon period are presented in Figure 5.30 to Figure 5.38. For obtaining the spatial distribution of above mentioned geochemical parameters IDW (Inverse distance weighting) method has been used to interpolate the point data. For classification of spatial distribution, box plot classes have been used. As observed in spatial distribution maps of pre-monsoon, the similar trend of ion concentration along NW-SE in the southern part of the study area is also observed, in the spatial distribution maps post-monsoon period. The spatial distribution map of F- (Figure 5.31) shows that in the post monsoon period high F- in groundwater is mainly occur in eastern part of the study area while in the remaining area, concentration of F- is within the permissible limit. The analysis of spatial distribution maps of above mentioned geochemical parameters suggest that high F- is associated with alkaline pH, moderate EC, moderate to high Na+, low Ca2+, low Mg2+, moderate to low HCO3

- and low concentration of total hardness. As observed earlier, F- has poor positive relation with li+ and in spatial distribution map Li+ is present in high F- zone while in the remaining area it is absent as it is not detected during chemical analysis (Figure5.38). These observations are matches with the observation made through the correlation matrix and analysis of scatter plots of various geochemical parameters.


66

Figure 5.30 Box plot and spatial distribution map of F- (post-monsoon)

Figure 5.31 Box plot and spatial distribution map of pH (post-monsoon)


67

Figure 5.32 Box plot and spatial distribution map of EC (post-monsoon)

Figure 5.33 Box plot and spatial distribution map of Na+ (post-monsoon)


68

Figure 5.34 Box plot and spatial distribution map of Ca2+ (post-monsoon)

Figure 5.35 Box plot and spatial distribution map of Mg2+ (post-monsoon)


69

Figure 5.36 Box plot and spatial distribution map of HCO3

- (post-monsoon)

Figure 5.37 Box plot and spatial distribution map of TH (post-monsoon)


70

Figure 5.38 Spatial distribution map of Li+ (post-monsoon)

5.3.6. Comparison of pre- and post-monsoon data Groundwater samples of pre- and post-monsoon (N=81) are compared for mean and median value. It is observed that pH, EC, TH, HCO3

- and alkalinity increases from pre-monsoon to post- monsoon

period while the concentration of major cations Ca2+, Mg2+, Na+ and K+ and major anions Cl-, NO3-

and SO42- decreasing from pre- to post monsoon periods. Mean value of F- remains the same while

median value varies from 0.83 to 0.5 mg/l during pre- and post-monsoon periods respectively. The comparison of pre-and post-monsoon parameters are presented in the Table 5.11.

Table 5.11 Comparison of pre and post monsoon parameters Parameter N=81

Mean pre

Mean post Median pre Median post

pH 7.02 8.09 7.02 8.18 EC 433 453.3 352 400 TDS 262 227 225 207 TH 162.8 163 111.3 146 Ca2+ 31.3 26.2 21.7 22.3 Mg2+ 19.8 13.1 13.2 11.0 Na+ 17.6 16.4 21.7 13.9 K+ 21.1 14.9 17.3 11.7 HCO3- 190.4 198.3 179.7 182.3 Cl- 21.4 15.4 11.6 10.9 N03

- 4.2 2.2 0.49 0.48 SO42- 10.5 6.7 10.3 2.9 F- 1.1 1.02 0.83 0.5 ALK 155.4 167.7 125.6 153.5


71

5.4. Spatio-temporal distribution of fluoride in groundwater and fluorosis prevalence

5.4.1. Spatio-temporal distribution In order to study the spatio-temporal variation of F- content in groundwater and its relationship with fluorosis prevalence in the study area, pre-monsoon, mid-monsoon (representative samples) and post-monsoon samples have been compared (Table 5.12). The concentration of F- in groundwater in pre-monsoon period (N = 83) varies from 0.09 to 8.88 mg/l and in post-monsoon period (N = 81) from 0.0 to 7.12 mg/l with mean value 1.02 for both the periods. The median value of F- concentration in pre-monsoon period (= 0.65 mg/l) is slightly higher than that in post-monsoon period (= 0.50 mg/l). Selective sampling (N= 20) in and around high fluoride zone carried out during mid-monsoon period indicates that the concentration of F- varies from minimum 0.29 to maximum 7.15 mg/l with mean and median values of about 2.4 and 1.5 mg/l, respectively. For spatio-temporal variation of F- content in groundwater corresponding wells (N= 20) of pre-monsoon, mid-monsoon and post-monsoon have been compared (Table 5.12). It is observed from Table 5.12 that though the upper level of the F-

concentration range is higher in pre-monsoon period as compared to that in mid-monsoon and post-monsoon periods, but the median values are about the same in all the three periods in and around the high F- zone. Thus, the overall distribution of F- concentration in the study area indicates slight dilution effect owing to fresh recharge on account of rainfall; however, in and around the high F- zone there is negligible effect of rainfall recharge. With regard to the number of places where high F- concentration is found, it is found that at twelve locations F- values are consistently above the acceptable limit of 1.2 mg/l, whereas at one location (village, Pata), F- concentration is high only during post-monsoon period. The number of affected villages, however, remains the same. Table 5.12 F- content in groundwater during pre-monsoon, mid-monsoon and post-monsoon periods

Sampling time Samples Minimum Maximum Mean Median Std. deviation

Pre-monsoon N=83 0.09 8.88 1.02 0.65 1.59

post-monsoon N=81 0.0 7.12 1.02 0.5 1.51

Pre-monsoon N=20 0.41 8.88 2.74 1.49 2.65

Mid-monsoon N=20 0.29 7.15 2.37 1.46 2.25

Post-monsoon N=20 0.14 7.12 2.72 1.5 2.33

On the basis of concentration of F- prescribed for drinking water (ISI, 1983), the area could be classified into three categories (Subba Rao and Devdas, 2003):

• Low fluoride with < 0.60 mg/l • Moderate fluoride with 0.60 – 1.20 mg/l • High fluoride with > 1.20 mg/l

The spatial distribution of F- concentration in the pre-monsoon and post-monsoon period shows that about 60% of the total samples in western part of the study area fall within the low F- category, 25 % samples in the eastern part of the area under moderate F- category, and remaining 15% in the eastern part of the study area are under high F- category. As mentioned earlier, of the 39 villages, five villages namely Muragaon, Pata, Kunjhemura, Saritola, and Dholnara are found to have F- concentrations higher than the permissible limits. The spatial distribution of low, moderate and high F- categories in the pre- and post-monsoon periods is shown in Figure 5.39. It is observed from figure 5.39 that the F- affected areas are approximately the same during pre- and post-monsoon periods.


72

(a) (b) Figure 5.39 Spatial distribution of low, moderate and high F- categories during (a) pre-monsoon, and (b)

post-monsoon periods

5.4.2. Relation of F- with well depth High F- concentration can be increased by those groundwater that have long residence time in the host rock (Saxena and Ahmed, 2001). On other hand shallow groundwater usually has low concentration of F- as it represents recently infiltrated rainwater. Deeper (older) groundwater with long residence time most likely may contain high concentration of F-. Analytical results show that most of the wells with high concentration of F- are in the depth range of 110 to 150 m. The scatter plot between F- and depth of well pre- and post-monsoon (Figure 5.40 a, b) shows positive correlation between F- concentration and well depth. The correlation is stronger when F- concentration is more than 1 mg/l and well depth is more than 100 m. This is probably caused by increase in temperature and residence time with increasing depth, which enhances the dissolution of F- bearing minerals present in rock formation (Nordstrom et al., 1989; Saxena and Ahmad, 2002). Another reason for increase in residence time could be low hydraulic conductivity of the formation. The Barakar Formation which mainly contains the F- affected groundwater is exposed at two places in the area – one in the northern part which is characterized by low fluoride zone and the other in the eastern part characterized by high fluoride zone. The transmissivity (hydraulic conductivity) of the Barakar formation occurring in the eastern part is lower than that occurring in the northern part (Table 3.3) Moreover, clay beds present between sandstones at various depths also reduce the hydraulic conductivity (Subba Rao, 2003). Because of low hydraulic conductivity, water can remain in the aquifer zone for longer time which might have produced enhanced active dissolution of F- bearing minerals and thus high concentration of F- with increasing depth. The low F- values are detected in shallow wells where groundwater is replenished fast by infiltrating rainwater. In the study area, high F- groundwater is mostly found where water level is deep in pre- and post-monsoon periods (Figure 3.13, 3.14), fluctuation is high (Figure 3.15) and high F- wells are located between recharge and discharge areas (Figure 3.16).


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Figure 5.40 Scatter plot of fluoride versus well depth (a) pre- and (b) post-monsoon

5.5. Resistivity measurements vis-a-vis Fluoride enrichments in groundwater

In the first instance, the quantitative interpretation of VES data, acquired at four locations in the F-

enriched zone (Table 5.13) has been made by conventional curve matching techniques using two and three layer master curves. The interpreted layer parameters obtained through conventional curve technique have been modelled with computer software (Schlum) for refining inferences. The VES curves obtained form the four locations (Figure 4.7) are of HA (VES-1, 2, 3 p1>p2<p3<p4) (Figure 5.41, 5.42 and 5.43) and KH (VES-4 p1<p2>p3<p4) (Figure 5.44) types which indicated the presence of a sequence of 4 to 5 geo-electrical layers within a depth range of 40 to 60 m bgl in the area. The interpreted layer parameters (Table 5.14) indicate that the true resistivity values of geo-electrical layers range between 32.7 and 765 ohm-m. The occurrence of ‘high’ and ‘low’ resistivity layers in the study area indicates the interlay ring sandstone and clay. The thickness of top soil cover varies between 0.80 and 1.2 m. Most of the investigated area is occupied by Barakar sandstone; resistivity of Barakar formation is similar in nature i.e. HA type (VES1.VES2, VES3) may be grouped into following categories.

1- Resistivity 104.3- 183.5 ohm-m corresponding to highly weathered portion of sandstone including overburden.

2- Resistivity 32.7- 438.5 ohm-m representing fractured/ jointed clay followed by sandstone 3- Resistivity between 121.5 to 765 ohm-m corresponding to cay and hard sandstone

The result of sounding VES4 shows four layers of resistivity 112.3 correspond to overburden/ weathered sandstone, 345 ohm-m to compact sandstone, resistivity of 166.4 corresponds to shale/clay and 245.7 ohm-m represents to sandstone. At all the four locations, neither low order of resistivity nor good contrast in resistivity values have been found as reported by Das et al.(2007). Therefore, based on limited sounding data, it is concluded that strong correlation between occurrence of high F- in groundwater and sub-surface resistivity does not exist in the area. Das et al. (2007) have shown that F-


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zones are associated with combined presence of low resistivity as well as low induced polarization (IP) values. Therefore, IP and deeper resistivity sounding may be conducted in future to find the relation between geophysical signature and F- enrichment in groundwater, if any.

Figure 5.41 Resistivity curve of vertical electrical sounding (VES1) at village Muragaon (XUTM 755034

YUTM 2452371)

Figure 5.42 Resistivity curve of vertical electrical sounding (VES2) at village Muragaon (XUTM 754425

YUTM 2452197)

Figure 5.43 Resistivity curve of vertical electrical sounding (VES3) at village Saraitola (XUTM 755556

YUTM 2451865)


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Figure 5.44 Resistivity curve of vertical electrical sounding (VES4) at village Saraitola (XUTM 755876

YUTM 2551722)

Table 5.13 Location of water samples contaminated by high F- and correlation with resistivity SL No

Location Sounding point

F- concentration (mg/l)

Formation

1 Muragaon (81 VES1 8.8 Barakar (Feldspathic sandstone and clay) 2 Muragaon (73) VES2 6.03

3 Saraitola (76) VES3 6.23 4 Saraitola ( 78) VES4 6.34

Table 5.14 Interpreted geo-electrical layer parameter

Sounding points

Layers resistivity (ohm-m) Layers Thickness (m) ρ 1 ρ 2 ρ3 ρ4 ρ5 h1 h 2 h 3 h4 Th

VES1 104.3 46.8 97.5 132.6 234 0.8 4.4 41.8 12.3 59.3

VES2 112.5 32.7 82.6 121.5 188 0.9 3.3 42.3 9.6 56.1

VES3 183.5 102.4 438.5 765 - 1.2 3.1 37.3 - 41.6

VES4 112.3 342.5 166.4 245.7 - 0.8 11.4 28.6 - 40.6

5.5.1. Mineralogical analysis It became necessary to carry out the mineralogical analysis of the Barakar sandstones occurring in the eastern part of the study area where groundwater contains high level of F-. For this purpose, XRD (X-ray diffractometry) and petrographic analysis (through optical microscopy) of the sandstones of Barakar Formation, collected from four locations of high F- concentration, have been carried out (courtesy Wadia Institute of Himalayan Geology, Dehradun). Of the four rock samples analysed, three samples are surface samples and one sample is subsurface sample (from 135 m below the ground surface, collected while drilling of new well). XRD analysis of rock samples revealed that quartz, feldspar and micas make-up the major mineralogy of the sandstones with quartz outscoring other minerals (Table 5.15). These minerals were also identified through petrographic analysis done by preparing thin section of the rock samples. Photomicrographs of minerals identified are shown in Figure 5.45 and 5.46. Apart from quartz and feldspar, substantial amount of white mica, biotite and clay minerals are found in all the four samples. In view of the limitation of XRD technique where the phases <1% in abundance are not effectively detected, no exclusive F- bearing accessory or minor


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mineral, such as fluorite, fluor-apatite, topaz, cryolite etc. was found except for the micas and clay minerals. Hydrated minerals like micas or clay minerals can contain high F- content as replacement for OH- ion (Jacks et al., 2004). In absence of any other clue, it is assumed that one of or several of the phyllosilicates (micas/clay minerals) may be the main source for the high F- ion in deep groundwater in the eastern sector. The identified minerals and diffractogram of the analysed four samples were matched with ICDD data base and results are presented in the (Annexure 11 to 14 and 20 to 24; courtesy Wadia Institute of Himalayan Geology). Table 5.15 Mineral composition of Barakar sandstones by XRD analysis

Sample No/village Lithology Quartz (%)

Feldspar (%)

Micas+clay (%)

Kaolinite (%)

74 (village Muragaon) Sandstone 61 29 10 - 135 (village Saraitola ) Sandstone 39 35 18 8 78 (Village Saraitola) Sandstone 82 9 9 - 81 (Village Muaragaon) Sandstone 43 40 17 -

Figure 5.45 Quartz and feldspar under thin section (Courtesy: WIHG)

(WIHG = Wadia Institute of Himalayan Geology)

Figure 5.46 Biotite under thin section (Xnicol, courtesy: WIHG)

(WIHG = Wadia Institute of Himalayan Geology)

Plagioclase feldspar

Quartz

Biotite


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5.5.2. Source and geochemical processes for fluoride enrichment in groundwater Fluoride in ground water is primarily derived from decomposition, dissociation and dissolution of F-

bearing minerals, and occasionally from anthropogenic activities such as use of phosphatic fertilizers which have F- as an impurity (Saxena and Ahmed, 2002). Ascertaining the source of F- in groundwater is essential for taking up mitigation measures. The results obtained from the geochemical analysis of groundwater in the area as discussed in the previous sections are used to put constrain on the source and geochemical processes leading to elevated concentrations of F- in groundwater. Some of the significant observations and inferences are:

• F- contamination in groundwater exists mainly in the Barakar Formation comprising of feldspathic sandstone, shale and coal sequence; few samples in Barren Measures Formation, adjacent to the contact between the Barakar and Barren Measures Formations in the direction of groundwater movement, also have high F- content.

• The F- rich groundwater in the study area is associated with Na-Ca-HCO3, Na-Ca-Mg-HCO3

and Na-Mg-Ca-HCO3 types of water; the ratio of Na+ and Ca2+ (i.e. Na+:Ca2+) increases with the increase in F- content.

• F- has significant positive correlation with Na+ and SiO2, and significant negative correlation

with Ca2+, Mg2+, HCO3-, alkalinity and total hardness (TH). Additionally, F- has poor but

positive correlation with Li+, and negative but poor correlation with EC/TDS, K+, Cl- and NO3-

• The presence of PO4

3- is not detected in either of the pre-, mid- and post-monsoon groundwater samples.

• The wells yielding F- rich groundwater are generally deeper (>110 m).

The positive correlation of F- with Na+ and SiO2 indicates the source of F- in groundwater to be from weathering of silicate minerals (Kortinig, 1992; Chae et al., 2006a; Chae et al., 2007). Several researchers (Chae et al., 2007; Guo et al., 2007; Handa, 1975) have shown that F- is generally positively correlated with Na+ and negatively correlated with Ca2+ which is the case in the present study as well. Thus, the hydrochemical process that promote F- enrichment in groundwater is related to the processes that increase Na+ concentration and decrease Ca2+ concentration (Chae et al., 2007). The increase in Na+ and decrease in Ca2+ concentrations may be because of cation/base exchange (Na+ for Ca2+) (Handa, 1975; Miana and Gaciri, 1984; Subba Rao, 2003). Calcite may be precipitated by increasing the pH and CO3

2- activity (Chae et al., 2007). However, in the study area it is observed that F- contaminated zone is mainly associated with relatively low pH and low HCO3

- concentration (except during post-monsoon period), thereby indicating that calcite precipitation may not be the important process. Chae et al. (2006a) indicated that Ca2+ ion can exchange with Na+ ion which originates from albite hydrolysis. The water types associated with F- enriched zone with relatively higher concentration of Na+ as compared to Ca2+ and Mg2+ concentrations also reflect a predominance of feldspar dissolution (Apambire et al., 1997). The fact that F- enriched zone is mainly associated with feldspathic sandstones of Barakar Formation as also confirmed by XRD and petrographic analyses, dissolution of feldspars and cation exchange are most likely to be the dominant geochemical processes leading to increase in Na+ and decrease in Ca2+ concentrations. The association of relatively


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soft groundwater with F- enriched zone and negative relation between F- and total hardness may, therefore, be because of cation exchange and/or calcite precipitation. Since the increase in Na+ concentration increases the solubility of F- bearing minerals (Guo et al., 2007), the process leading to increase in its concentration plays an important role in F- enrichment in ground water. Many researchers have shown that F- is positively correlated with HCO3

- (Guo et al., 2007). Tiwari et al. (2008) found that for deeper aquifers the correlation between F- and HCO3

- is negative which they attributed to low partial pressure of CO2

-- in deeper zones. The negative correlation between F- and HCO3

- found in the present study may also be attributed to the same reason as F- enrichment is mainly associated with deeper wells. The negative correlation found between F- and K+ may be due to resistance in weathering of K+ and its fixation in micas and clay minerals (Subba Rao, 2003). Fluoride in groundwater may result from dissolution of many F- rich minerals, such as fluorite, apatite, fluorapatite, topaz, amphiboles, cryolite, villiamite, micas and clay minerals. Many researchers have argued that micas and clay minerals often form the dominant source for F- enrichment in ground water as other minerals occur as accessory minerals in rocks (Apambire et al., 1997; Chae et al., 2007; Subba Rao and Devdas, 2003). Micas and clay minerals which constitute the major minerals in rocks contain fluorine at the OH- sites (Chae et al, 2007). Fluorine present in these minerals can contribute considerable amount of fluoride in groundwater on weathering and dissolution, especially at low pH values which is presently the case (Apambire et al., 1997). Concentrations of fluoride in clastic sediments are usually tied up in micas and resistant minerals such as topaz and apatite (Apambire et al., 1997). The field photograph (Figure 5.47), XRD and petrographic studies in the study area show that the feldspathic sandstones of Barakar Formation contain good fraction of micas and clay minerals. The analysis of mid-monsoon and post-monsoon groundwater samples has indicated the presence of Li+ in the F- enrichment zone. This association of F- and Li+ may indicate the source of F- to be weathering of micas (Apambire et al., 1997). Anion exchange (OH- for F-), a dominant process in the sedimentary terrain (Boyle, 1992; Boyle and Chagnon, 1995; Guo et al., 2007) in the micas and clay minerals may also be contributing for increasing the F- concentration in groundwater. The clay layers intercalated with sandstones in the Barakar Formation are likely to play an important role in the context of anion exchange as the wells are not completely cased and there is an interaction of groundwater with them. The absence of PO4

3- in groundwater samples in all the three seasons rules out the contribution from phosphate minerals, such as apatite and fluorapatite, and also from anthropogenic activities. The negative correlation between F- and Ca2+ also does not favour the dissolution of fluorite (Apambire et al., 1997; Subba Rao, 2003) which is considered to be an important source for releasing fluorine to groundwater. The observation that F- contaminated groundwater is mainly associated with deeper wells and that the transmissivity of the Barakar Formation is relatively lower, temperature and residence time are other important factors leading to increased dissolution of F- bearing minerals (Nordstrom et al., 1989; Saxena and Ahmad, 2002). The proposed model, highlighting the source of F- in groundwater and the probable geochemical processes, provides the most plausible explanation for elevated concentrations of F- in the groundwater in the eastern sector of the study area with the available data.


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Figure 5.47 Field photograph showing muscovite in Barakar sandstone

5.6. Fluorosis prevalence and health- risk Fluoride in groundwater has beneficial as well as harmful effect on human health. Low concentration of F- in groundwater causes dental caries, while high concentrations cause dental and skeletal fluorosis. As mentioned earlier, spatial distribution of F- concentrations in groundwater during the pre-, mid- and post-monsoon periods suggests that elevated concentrations of F- are restricted to eastern part of the study area. Local enquiries made during ground campaigns revealed that there are incidences of dental and skeletal fluorosis in five villages, namely Muragaon, Pata, Kunjhemura, Saraitola and Dholnara. These villages fall within the high zone (Figure 5.49) mapped through systematic groundwater sampling and hydrochemical analysis. The spatial distribution maps showing F- concentration in groundwater (Figure 5.49), however, indicate a still larger area prone to fluorosis.

The prevalence of dental fluorosis and skeletal fluorosis in these villages has been measured on the basis of number of affected people divided by the total population. The prevalence of dental fluorosis in the study area is given in Table 5.16 and is also depicted in Figure 5.48. Dental fluorosis is mainly found to occur among children of 10-15 years age group. Skeletal fluorosis is reported only in Muragaon village where only 8 people are found to be affected; prevalence of skeletal fluorosis here is 1.24 %. The prevalence of dental fluorosis is highest (6.03%) in Saraitola and lowest (1.26%) in Dholnara with F- concentration varying from 0.41 mg/l to 8.88 in pre-monsoon and 0.14 to 7.12 mg/l in post-monsoon periods. Table 5.16 Prevalence of dental fluorosis

Villages No. of people affected by dental fluorosis

Population Prevalence rate %

Pata 17 352 4.82 Kunjhemura 07 287 2.43 Saraitola 19 315 6.03 Muragaon 29 642 4.64 Dholnara 2 147 1.26

Population source: Land Record, Dept. of Chhattisgarh, No of affected people source: local enquiry by the author since there is no official record


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Figure 5.48 Map showing prevalence of dental fluorosis

Considering the level of F- content in drinking water and corresponding effects of human health (Chaturvedi et al., 1990; refer to Table 1.1) and the Indian standards (ISI, 1983; BIS, 1991), ‘health-risk maps’ based on F- levels in groundwater’s of the study area for the pre- and post-monsoon periods has been prepared (Figure 5.49). The maximum permissible limit for F- in groundwater is taken as 1.0 as incidences of dental fluorosis have been reported in some Indian communities beyond this level (Apambire et al., 1997). Areas with F- content <0.6 mg/l are prone to ‘dental caries and poor bone development’; those with ranging between 0.6 and 1.0 mg/l are classified under ‘safe’ category; those with F- concentration ranging between 1.0 and 3.0 mg/l are prone to ‘dental fluorosis’ and; those with F- concentrations > 3.0 mg/l are prone to ‘dental as well as skeletal fluorosis’

The perusal of health-risk maps for the pre- and post-monsoon periods (Figure 5.49) indicate that the health-risk varies in space and time. For example, a safe area in the pre-monsoon period becomes prone to dental caries. In order to take care of such a temporal variability, the health-risk maps of pre- and post-monsoon periods have been crossed in the GIS domain, and the resultant map has been reclassified into the four health-risk categories in such a way that if an unsafe zone is encountered in either of the two periods, it is mapped as unsafe zone and its effect on human health is assigned (Figure 5.49). While preparing this map, the interpolation errors in health risk map of post-monsoon periods have been avoided. Further, population data is superimposed over this health-risk


81

map to estimate the population at risk due to excess or deficient F- concentration in groundwater (Figure 5.50 and Table 5.17). It is clear that in addition to the affected population, a large fraction of the population in the area is potentially at risk. Therefore, the health-risk map prepared in this study provides the baseline information to the health officials for taking mitigation measures.

Figure 5.49 Health-risk maps based on F- concentrations in groundwater during (a) pre-monsoon (b)

post-monsoon

Figure 5.50 Health risk map and population at risk based on F- concentration in groundwater


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Table 5.17 Affected villages and population at risk due to excess or deficient F- in groundwater Health-risk category No of villages prone

to health risk Population at risk*

Area prone to dental caries and poor bone development

32 20306

Area prone to dental fluorosis 8 2632 Area prone to dental and skeletal fluorosis

12 4228

*Census2001

5.7. Distribution of fluoride in groundwater vis-à-vis geology In order to examine the relationship between F- levels in groundwater and geology, wells having high F- (> 1.2 mg/l) were plotted on geological map (Figure.5.51). It is observed that of the 13 wells which have F- content > 1.2 mg/l, 8 wells are located in Barakar Formation and 5 wells are located in Barren Measure Formation just near the contact with Barakar Formation. The statistical summery of the F-

concentration in groundwater with respect to lithostatigraphy in pre- and post-monsoon periods is given in the Table 5.18 and Table 5.19, respectively, and the distribution is also depicted in the form of box and whisker plots (Figure 5.52). The highest concentration of F- in groundwater occurs in the feldspathic sandstone of Barakar Formation, both in pre- as well as in post-monsoon periods. The average F- concentration is highest (2.45 mg/l) in feldspathic sandstone of Barakar Formation, followed by 0.63 mg/l in Barren Measure Formation, 0.55 mg/l in Kamthi Formation, and 0.39 mg/l in Raniganj Formation during the pre-monsoon period. The same trend is observed in post-monsoon period also. Even the median value of the F- concentration in groundwater is found to be highest in Barakar Formation; median value is important for comparison since the data are asymmetrical. Thus, it is clear that lithological, mineralogical composition of the formations have influence on F- concentration in groundwater of the area. Since high F- wells are occurring in Barren Measure Formation are located very close to the contact with Barakar Formation in the direction of groundwater movement and that most of the wells having high F- content are located in Barakar Formation, it is quite likely that feldspathic sandstone of Barakar Formation may be contributing F- to groundwater.


83

#Y#Y

#Y#Y #Y#Y#Y#Y#Y

#Y

FaultsLineament

#Y High fluoride0 1 2

km

N

EW

S

#Y#Y

#Y

1234

F

F

F

F

F

F

F

F

F

F

F

F

( >1.2 mg/l)

Figure 5.51 Geological map (after GSI) and location of high F- wells

1- Kamthi Formation (sandstone and argillaceous bed), 2- Raniganj Formation (sandstone and shale), 3- Barren Measure Formation (Ferruginous sandstone and clay) 4- Barakar Formation (Feldspathic sandstone and clay)

Figure 5.52 Box and whisker plot showing concentration of F- with respect to lithostatigraphy during pre-

monsoon (a) post-monsoon (b)


84

1= Sandstone and argillaceous bed (Kamthi formation), 2= Sandstone and shale (Raniganj formation), 3= Ferruginous sandstone and clay (Barren Measure Formation), 4= Feldspathic sandstone and clay (Barakar formation).

Figure 5.53 Histogram showing fluoride distribution during (a) pre-monsoon (N= 83) and (b) post-monsoon (N=81) periods

The average concentration of F- in pre- and post-monsoon is 1.09 mg/l and 1.02 mg/l but the median value in pre-and post-monsoon is 0.65 mg/l and 0.5 mg/l respectively, because distribution is skewed. Histogram of F- distribution in pre-and post-monsoon groundwater samples are presented in Figure 5.53. Table 5.18 Statistical summery of F- concentration with respect to lithostatigraphy (pre-monsoon)

Rock types Samples (N=83)

Minimum

Maximum Mean Median SD MAD

Sst. and argillaceous bed (Kamthi Fm.)

2 0.41 0.69 0.55 0.55 0.19 0.37

Sst. and shale (Raniganj Fm)

8 0.12 0.70 0.39 0.41 0.21 0.16

Ferruginous shale/clay (Barren Measure Fm)

51 0.09 2.40 0.63 0.58 0.39 0.19

Fedspathic sst. and clay (Barakar Fm)

22 0.39 8.88 2.45 0.94 2.63 0.42

SD=Standard deviation, MAD= Median of absolute difference, Sst = sandstone, Fm= Formation


85

Table 5.19 Statistical summery of F- concentration with respect to lithostatigraphy (post-monsoon) Rock types Samples

(N=81) Minimum Maximu

m Mean Median SD MAD

Sst. and argillaceous bed (Kamthi Fm.)

1 0.45 0.45 0.45 0.45 - -

Sst.and shale (Raniganj Fm)

8 0.04 0.53 0.34 0.41 0.177 0.04

Ferruginous shale/clay (Barren Measure Fm)

50 0.0 2.65 0.57 0.49 0.465 0.14

Fedspathic sst. and clay (Barakar Fm)

22 0.19 7.12 2.13 0.77 2.31 0.32

SD=Standard deviation, MAD= Median of absolute difference, Sst = sandstone, Fm= Formation


86

6. Conclusions

The conclusions drawn from geospatial analysis of hydrochemical and geological datasets with reference to occurrence of F- in groundwater in a sedimentary aquifer system of Gondwana Supergroup of rocks in Central India are highlighted in this chapter by answering the proposed research questions. The recommendations for further research are also given.

6.1. Research and questions

What are the controls on the spatial distribution of fluoride contents in groundwater?

6.1.1. Is the distribution of fluoride associated with the distribution of other geochemical parameters?

The groundwater samples collected from hand-pumps during three periods, pre-monsoon (N=83) mid-monsoon (N=20) and post-monsoon (N=81), have been analysed for different hydrochemical parameters such as pH, EC, TDS, alkalinity, total hardness, Na+, K+, Ca2+, Mg2+, Li+, HCO3

-, CO32-, F-,

Cl-, NO3-, SO4

2- and SiO2. Of the 39 villages where hydrochemical analysis has been carried out, five villages namely Muragaon, Pata, Kunjhemura, Saraitola, and Dholnara, occurring in the eastern part of the study area are found to have F- concentrations in groundwater higher than the permissible limit.The highest desirable limit (HDL) of F- concentration is 0.60 mg/l and the maximum permissible limit (MPL) is 1.20 mg/l is prescribed for drinking water (Subba Rao and Devdas, 2003).

The analysis of the correlation matrix of hydrochemical parameters, scatter plots between F- and other hydrochemical parameters, Piper’s diagrams, pie charts, and spatial distribution maps of different hydrochemical parameters, revealed that F- has significant positive correlation with Na+ and SiO2, and significant negative correlation with Ca2+, Mg2+, HCO3

-, alkalinity and total hardness (TH). Additionally, F- has poor but positive correlation with Li+, and negative but poor correlation with EC/TDS, K+, Cl- and NO3

-. The increase in Na+ concentration increases the solubility of F- bearing minerals; therefore, high Na+ and low Ca2+ concentrations favour presence of high concentration of F- in groundwater (Chae et al., 2007; Guo et al., 2007; Handa, 1975). The positive correlation between F- and Na+ and negative correlation between F- and Ca2+ found in the present study also support this view. The association of high F- zone with feldspathic sandstones and negative correlation between F- and TH indicate that dissolution of feldspars, cation/base exchange (Na+ for Ca2+) are most likely to be the hydrogeochemical processes operating in the area leading to increase in Na+ and decrease in Ca2+ concentrations with increase in F- concentration in groundwater.

Generally, high HCO3- concentration (or alkalinity) favours the occurrence of high F-

concentration in groundwater (Saxena and Ahmed, 2002; Meenakshi and Maheshwari, 2006; Subba Rao and Devadas, 2003; Guo et al., 2007). In the present study, negative correlation has been found between F- and HCO3

-. Such a negative relation was also found by Tiwari et al. (2008) in deeper aquifers of basaltic terrain which they attributed to low partial pressure of CO2 in deeper zones. The same reason may also be attributed to the negative correlation between F- and HCO3

- found in the present study as the high F- zone is mainly associated with deeper wells.


87

6.1.2. What is the plausible source(s) of fluoride in groundwater in the area?

The groundwater types (Na-Ca-HCO3, Na-Ca-Mg-HCO3 and Na-Mg-Ca-HCO3) in the high F- zone and positive correlation of F- with Na+ and SiO2 indicates the source of F- in groundwater to be from weathering of silicate minerals. Further, the groundwater types and increase in Na+:Ca2+ values with increase in F- concentration indicate dissolution of feldspars which can be attributed to the association of high F- zone with feldspathic sandstones. The presence of Li+ in the high F- zone suggests that micas, forming an important constituent of Barakar sandstones (as observed in the outcrops, XRD analysis and thin sections) and which contain fluorine at the OH- sites, may act as an important source of F- in groundwater on dissolution. Cation exchange (Na+ for Ca2+) accompanied with anion exchange (OH- for F-) may also be the important processes by which micas and clay minerals (containing fluorine at the OH- sites) may contribute in increasing the F- concentration in groundwater. The clay layers intercalated with sandstones in the Barakar Formation are likely to play an important role in the context of anion exchange as the wells are not completely cased and there is an interaction of groundwater with them. The absence of PO4

3- in groundwater samples in all the three periods rules out the contribution from phosphate minerals, such as apatite and fluor-apatite, and also from anthropogenic activities. The association of high F- zone with deeper wells also does not support the contribution from anthropogenic activities. Further, the negative correlation between F- and Ca2+ also does not favour the dissolution of fluorite which is considered to be an important source for releasing fluorine to groundwater. The lower values of the storativity and transmissivity and deeper wells are other important factors leading to increase in F- concentration in groundwater because of increase in temperature and residence time of groundwater.

6.1.3. What relationship exists between litho-geochemical data and groundwater geochemical data?

High F- concentration in groundwater is found to occur mainly in the Barakar Formation comprising of feldspathic sandstone, shale and coal sequence; few places in Barren Measures Formation, adjacent to the contact between the Barakar and Barren Measures Formations in the direction of groundwater movement, also have high F- content. Mineralogical studies of rock samples by X-ray diffractometry (XRD) and optical microscopy as well as observations of outcrops reveal that quartz, feldspar and mica make-up the major mineralogy of the rock samples with quartz outscoring other minerals. As explained above, the groundwater types in the high F- zone, significant positive correlation of F- with Na+ and SiO2, and presence of Li+ in groundwater in the high F- zone, indicate that strong relation between litho-geochemical and groundwater geochemical data.

6.1.4. What relation exists between sub-surface resistivity data and groundwater geochemical data?

The resistivity/conductivity contrast plays a major role in identification of contaminated groundwater zones. The interpretation of VES data at four locations in the high F- zone does not indicate either low order of resistivity or good contrast in resistivity values. Therefore, “Due to limited subsurface resistivity data, a conclusion about its correlation with F- concentrations in groundwater cannot be made”.


88

6.1.5. Is there a temporal (pre-mid and post-monsoon) variation in F- concentration of groundwater in the area?

The overall distribution of F- concentration in the study area during the three periods indicates slight dilution effect owing to fresh recharge on account of rainfall; however, in and around the high F- zone the effect of rainfall recharge is found to be negligible.

6.2. Recommendations

6.2.1. Improvement of health status

The ‘health-risk map’ prepared in this study should be used by the health officials to take up mitigation measures in the area. Awareness and education mechanism is necessary among the rural masses about the adverse impact of high F- concentration in drinking water to human health

6.2.2. Management plan for treatment of high F- groundwater

• Because F- is negatively related with Ca2+, a proper management plan for treatment of high F- groundwater may be developed by maintaining high concentration as recommended by Chae et al. (2007

• A proper management plan needs to be developed for developing deeper aquifers as occurrence of fluoriferous groundwater is mainly found to be associated with deeper wells.

6.2.3. Combined resistivity and IP sounding

• Combined resistivity and induced polarisation (IP) surveys may be carried out to correlate the geophysical signatures of high F- zones in groundwater.

6.2.4. Research and development

• To check fluorosis incidences in the adjacent district in relation to the Barakar Formation • Chemical analysis of non-weathered mica minerals from the Barakar Formation for

fluorine outside the high fluorine areas. • Variation between all the deep and shallow wells of high fluorine zone existing in the

area


89

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93

Annexure 1: Bore hole litholog, station Samaruma (743761E, 2444295N)

Lithological description Depth range in m Thickness Formation: Kamthi ; Total depth : 201.5 m From To Sandstone: Light brown colour sandy soil, medium grained with clay.

0.00 3.00 3.00

Sandstone: Coarse to medium grained, light brown colour quartz and feldspar grains weathered cementing material.

3.00 13.10 10.10

Sandstone: Medium grained sub rounded quartz and feldspar grains, light brown colour.

13.10 22.10 9.00

Sandstone and Clay: Medium grained quartz sand grains and clay, quartz gains light brown colour.

22.10 25.10 3.00

Sandstone: Medium grained light brown colour grains with arenaceous cementing material.

25.10 37.15 12.05

Sandstone: Coarse to medium grained, light brown colour quartz and feldspar grains.

37.15 58.0 20.85

Sandstone ,Shale and Coal seams: Alternate layers of Sandstone shale and Coal seam-Sandstone- Coarse to medium grained, light brown colour quartz and feldspar, ferruginous cementing material, Shale- grey in colours ,bedded hard and compact and Coal- pitch black ,soft with interaction of shale

58.0 97.0 39.0

Sandstone & shale: fine grained, grey colour quartz and feldspar grains with grey compact and hard shale.

97.0 105.0 8.0

Shale: Grey colour, compact. 105.0 113.0 8.0 Sandstone ,Shale and Coal seams: Alternate layers of Sandstone shale and Coal seam-Sandstone- Coarse to medium grained, light brown colour quartz and feldspar, ferruginous cementing material, Shale- grey in colours ,bedded hard and compact and Coal- pitch black ,soft with interaction of shale

113.0 166.00 53.0

Shale: Grey colour compact hard. 166.00 170.26 4.26 Sandstone: Medium to fine grained, grey colour sub angular to sub rounded quartz grains.

170.26 193.59 23.33

Sandstone: Coarse grained, grey colour sub angular quartz grains. 193.59 200.59 7.00

Shale: Grey shale converted into sticky and stopped the drilling beyond this depth.

200.59 201.50 0.91


94

Annexure 2 : Bore hole litholog, station Gare (756822E, 2450398N)

Lithological description Depth range in m Thickness Formation: Barakar; Total depth: 345 m From To Top soil: Light brown colour sandy soil, fine to medium grained. 0.00 3.4 3.4 Sandstone: Coarse to medium grained, light brown colour quartz and feldspar, ferruginous cementing material.

3.4 6.4 3.0

Coal- pitch black ,soft with interaction of shale 6.4 16.04 9.64 Sandstone: Coarse grained sub rounded quartz and feldspar grains, light brown colour.

16.04 19.04 3.0

Shale- grey in colours ,bedded hard and compact 19.04 69.49 50.45 Sandstone: Medium grained quartz sand, quartz gains light brown colour.

69.49 84.29 14.8

Shale- grey in colours ,bedded, compact 84.29 111.65 27.36 Sandstone: Very fine grained light brown colour grains with calcareous cementing material.

111.65 114.58 2.93

Coal-pitch black ,soft with interaction of shale 114.58 117.58 3.0 Shale and coal- grey in colours ,bedded 117.58 138.30 20.72 Sandstone: Coarse to medium grained, light brown colour quartz and feldspar grains.

138.3 150.15 11.85

Shale- grey in colours ,bedded hard and compact 150.15 170.95 20.8 Sandstone: Fine grained light brown colour quartz feldspar grains. 170.95 176.9 5.95 Sandstone: Coarse grained, grey colour quartz 176.9 183.0 6.1 Clay-Greyish, plastic and sticky 183 186 3.0 Sandstone: Coarse grained grey colour sub rounded quartz grains with ferruginous cementing materials.

186.0 204.0 18.0

Clay-Greyish, plastic and sticky 204.0 221.4 17.4 Sandstone: Medium to fine grained, grey colour sub angular to sub rounded quartz grains.

221.4 227.4 6.0

Clay-Greyish, plastic and sticky 227.4 236.3 8.9 Sandstone: Coarse grained, grey colour sub angular quartz grains with ferruginous cementing materials.

236.3 242.25 5.95

Clay-Greyish, plastic and sticky 242.25 251.1 8.85 Sandstone: Coarse grained, grey colour sub angular quartz grains with ferruginous cementing materials.

251.1 274.8 23.7

Clay-Greyish, plastic and sticky 274.8 286.7 11.9 Sandstone: Coarse grained, grey colour sub angular quartz grains. 286.7 304.45 17.35 Clay-Greyish, plastic and sticky 304.45 307.45 3.0 Sandstone: Coarse grained, grey colour sub angular quartz grains. 307.45 322.3 14.85 Clay-Greyish, plastic and sticky 322.3 332.3 10.0 Sandstone Coarse grained, grey, sub angular quartz. 332.3 345.00 8.9


95

Annexure 3 : Bore hole litholog, station Kotrimar (747101E, 2460261N)

Lithological description Depth range in m Thickness Formation: Barakar; Total depth: 300m From To Top soil: Light brown colour sandy soil, fine to medium grained with clay materials.

0.00 3.0 3.0

Sandstone: Coarse to medium grained, light brown colour quartz and feldspar grains ferruginous cementing material.

3.0 21.4 18.4

Sandstone :medium grained sub rounded quartz and feldspar grains, light brown colour with thin layers of coal

21.4 36.35 14.95

Shale- grey in colours ,bedded 36.35 57.82 21.47 Sandstone: Medium to coarse grained quartz sand, quartz gains light brown colour with greyish shale.

57.82 81.63 23.81

Shale- grey in colours ,bedded with thin layers of coal seams 81.63 93.5 11.87 Sandstone: Very fine grained light brown colour grains with calcareous cementing material.

93.5 102.45 8.95

Shale- grey in colours, bedded with alternate layers of coal seams and fine grained sandstone.

102.45 120.46 18.01

Sandstone: Coarse to medium grained, light brown colour quartz and feldspar grains with thin layers of coal seams.

120.46 135.42 14.96

Shale- grey in colours, bedded, hard and compact. 135.42 140.0 4.5 Sandstone: Coarse grained, light brown colures quartz and feldspar grains.

140.0 150.23 10.23

Clay-Greyish, plastic and sticky 150.23 156.33 6.10 Shale- grey in colours ,bedded ,hard and compact 156.33 167.18 10.85 Clay-Greyish, plastic and sticky 167.18 182.09 14.91 Sandstone: Medium to fine grained, grey colures sub angular to sub rounded quartz grains.

182.09 188.03 5.97

Clay-Greyish, plastic and sticky 188.03 208.9 20.87 Shale- grey in colours ,bedded ,hard and compact 208.9 217.86 8.96 Sandstone: Fine grained, grey colour sub angular quartz grains. 217.86 229.79 11.93 Shale- grey in colours ,bedded ,hard and compact 229.79 256.5 26.61 Sandstone: Fine grained, grey colures sub angular quartz grains. 256.5 262.45 5.95 Shale- grey in colours ,bedded ,hard and compact with Greyish, plastic and sticky clay

262.45 286.25 23.8

Sandstone: Coarse grained, grey colures sub angular quartz grains with thin layer of shale.

286.25 300.0 13.75


96

Annexure 4 : Bore hole litholog, station Gharghoda (742421E, 2452699N)

Lithological description Depth range in m Thickness Formation: Barren Measure; Total depth: 300.46m From To Top soil: Light brown colures sandy soil, fine to medium grained with clay materials.

0.00 10.2 10.2

Sandstone: Coarse to medium grained, light brown colour quartz and feldspar grains ferruginous cementing material.

10.2 16.46 6.26

Coal and Shale- pitch black ,soft with interaction of shale 16.46 101.7 85.24 Shale and Clay: Clay-Greyish, plastic and sticky, with bedded ,black shale

101.7 132.91 31.21

Carbonaceous Shale- Black in colours ,bedded 132.91 138.74 5.83 Shale- grey in colours ,bedded 138.74 141.74 3.0 Clay and Coal- pitch black ,soft with interaction of Coal 141.74 159.17 17.74 Clay-Greyish, plastic and sticky 159.17 165.31 5.85 Sandstone: Very fine grained light brown colour grains with argillaceous cementing material.

136.31 182.89 17.13

Shale - grey in colours ,bedded and hard 182.89 203.91 21.02 Sandstone: Coarse to medium grained, light brown colour quartz and feldspar grains.

203.91 219.27 12.36

Clay-Greyish, plastic and sticky 219.27 225.49 6.76 Sandstone: Fine grained light brown colure quartz feldspar grains. 225.49 265.77 40.28 Clay-Greyish, plastic and sticky 265.77 283.94 18.17 Sandstone: Coarse grained grey colour sub rounded quartz grains with argillaceous materials.

283.84 300.46 16.52

SOURCE: CGWB


97

Annexure 5 : Bore hole litholog, station Deogarh (747041E,2449550N)

Lithological description Depth range in m Thickness Formation: Barren Measure; Total depth : 204m From To Top soil: Light brown colour sandy soil, fine to medium grained with clay materials.

0.00 3.0 3.0

Sandstone and Shale: Alternate layers of Sandstone and shale-Sandstone- Coarse to medium grained, light brown colour quartz and feldspar, ferruginous cementing material, Shale- grey in colour ,bedded hard and compact

3.00 44.0 41.0

Sandstone ,Shale and Coal seams: Alternate layers of Sandstone shale and Coal seam-Sandstone- Coarse to medium grained, light brown colour quartz and feldspar, ferruginous cementing material, Shale- grey in colour ,bedded hard and compact and Coal- pitch black ,soft with interaction of shale

41.0 74.0 33.0

Sandstone :Coarse grained sub rounded quartz and feldspar grains, light brown colour

74.0 86.0 12.0

Shale- grey in colour ,bedded hard and compact 86.0 94.0 8.0 Sandstone ,Shale and Coal seams: Alternate layers of Sandstone shale and Coal seam-Sandstone- Coarse to medium grained, light brown colour quartz and feldspar, ferruginous cementing material, Shale- grey in colour ,bedded hard and compact and Coal- pitch black ,soft with interaction of shale

94.0 132.0 38.0

Sandstone :Coarse grained sub rounded quartz and feldspar grains, light brown colure

132.0 147.0 15.0

Shale- grey in colour ,bedded hard and compact 147.0 154.0 7.0 Clay-Greyish, plastic and sticky 154.0 168.0 14.0 Shale- grey in colour ,bedded hard and compact 168.0 174.0 6.0 Clay-Greyish, plastic and sticky 174.0 188.0 14.0 Shale- grey in colour ,bedded hard and compact 188.0 198.0 10.0 Clay-Greyish, plastic and sticky 198.0 204.0 6.0 SOURCE: CGWB


98

Annexure 6 : Bore hole litholog, station Tamnar (751146E,2445472N)

Lithological description Depth range in m Thickness Formation : Barren Measure; Total depth: 190 m From To Top soil : Light brown colour sandy soil, fine to medium grained. 0.00 3.4 3.4 Sandstone and Shale: Alternate layers of Sandstone and shale-Sandstone- Coarse to medium grained, light brown colour quartz and feldspar, ferruginous cementing material, Shale- grey in colour ,bedded hard and compact

3.0 26.0 23.0

Sandstone ,Shale and Coal seams: Alternate layers of Sandstone shale and Coal seam-Sandstone- Coarse to medium grained, light brown colour quartz and feldspar, ferruginous cementing material, Shale- grey in colour ,bedded hard and compact and Coal- pitch black ,soft with interaction of shale

26.0 85.0 59.0

Sandstone: Coarse to medium grained, light brown colure quartz and feldspar, ferruginous cementing material.

85.0 100.0 15.0

Shale- grey in colours ,bedded, compact 100.0 120.0 20.0 Sandstone ,Shale and Coal seams: Alternate layers of Sandstone shale and Coal seam-Sandstone- Coarse to medium grained, light brown colour quartz and feldspar, ferruginous cementing material, Shale- grey in colour ,bedded hard and compact and Coal- pitch black ,soft with interaction of shale

120.0 150.0 30.0

Sandstone :Coarse grained sub rounded quartz and feldspar grains, light brown colour

150.0 175 25.0

Clay-Greyish, plastic and sticky 175.0 190.0 15.0 SOURCE: CGWB


99

Annexure 7 : Resistivity measurement (VES1) at village Muragaon

AB/2 (m)

MN/2(m) G Factor(K) Resistance (ohm) Apparent resistivity(ohnm)

1.0 0.5 2.355 36.96 87.04 2.0 0.5 11.775 5.53 65.11 3.0 0.5 27.475 2.14 58.79 5.0 1.0 37.68 1.75 65.94 7.0 1.0 75.36 0.77 58.02 10 1.0 155.43 0.45 69.94 20 1.0 626.43 0.13 81.43 20 2.0 310.66 0.25 77.71 30 2.0 703.36 0.184 129.41 40 2.0 1252.86 0.115 144.07 50 2.0 1959.36 0.07 137.15 60 2.0 2822.86 0.052 146.78 60 5.0 1122.85 0.131 147.05 80 5.0 2001.75 0.0821 164.34 90 5.0 2535.55 0.07 177.48 100 5.0 3132.15 0.058 181.66 150 5.0 7057.15 0.026 183.48 200 5.0 12552.15 0.0181 227.19

Annexure 8 : Resistivity measurement (VES2) at village Muragaon

AB/2 (m)

MN/2(m) G Factor(K) Resistance (ohm) Apparent resistivity(ohm)

1.0 0.5 2.355 40.37 95.07 2.0 0.5 11.775 3.6 42.39 3.0 0.5 27.475 1.38 37.91 5.0 0.5 77.715 0.547 42.51 10 0.5 313.215 0.178 55.75 10 1.0 155.43 0.334 55.91 20 1.0 626.43 0.112 70.16 30 1.0 1411.43 0.612 86.00 40 1.0 2510.43 0.039 97.90 50 1.0 3923.43 0.027 105.93 50 5.0 777.15 0.147 114.24 60 5.0 1122.55 0.109 122.35 80 5.0 2001.75 0.065 130.11 100 5.0 3132.15 0.045 140.99 100 10 1554.3 0.092 143.92 120 10 2245.1 0.067 150.42 150 10 3516.8 0.048 168.80 200 10 6264.3 0.027 169.13


100

Annexure 9 : Resistivity measurement (VES3) at village Saraitola

AB/2 (m)

MN/2(m) G Factor(K) Resistance (ohm) Apparent resistivity (ohm)

1.5 0.5 6.2866 23.68 148.710 2.0 0.5 11.775 12.4 146.01 2.5 0.5 18.84 6.31 118.88 3.0 0.5 27.475 4.21 115.66 4.0 0.5 49.455 2.59 128.08 5.0 0.5 77.715 1.76 136.77 6.0 0.5 112.255 1.25 140.31 8.0 0.5 200.175 0.805 161.14 10 0.5 313.215 0.599 187.61 10 2.0 75.36 2.31 174.08 15 2.0 173.485 1.45 251.55 20 2.0 310.86 1.144 355.62 25 2.0 487.485 0.963 469.44 25 5.0 188.4 1.7 320.28 30 5.0 274.75 1.41 387.39 40 5.0 494.55 0.961 475.26 50 5.0 777.15 0.633 491.93 60 5.0 1122.55 0.473 530.96 80 5.0 2001.75 0.338 676.59 100 5.0 3132.15 0.23 720.39 150 5.0 7057.15 0.195 1376.14

Annexure 10 : Resistivity measurement (VES4) at village Saraitola

AB/2 (m) MN/2(m) G Factor-K Resistance (ohm) Apparent Reistivity(ohm)

1.0 0.5 2.355 71.6 168.61 2.0 0.5 11.775 23.58 277.65 3.0 0.5 27.475 10.63 292.05 5.0 0.5 77.715 3.90 303.08 10 0.5 313.215 1.15 360.19 10 2.0 75.36 5.58 420.50 20 2.0 310.86 0.941 292.51 30 2.0 703.36 0.292 205.38 40 2.0 1252.86 0.143 179.15 50 10 376.80 0.528 198.95 80 10 989.10 0.266 263.10 100 10 1554.30 0.168 261.12


101

Annexure 11 : XRD analysis result of sample no 81

Reference code: 01-075-0948 Mineral name: Muscovite 2M1 No. h k l d [A] 2Theta[deg] I [%]

1 0 0 2 9.97387 8.859 9.9

2 0 0 4 4.98694 17.771 6.9

3 1 1 0 4.47639 19.818 5.8

4 0 2 1 4.39897 20.170 2.2

5 1 1 1 4.29213 20.678 100.0

6 -1 1 2 4.21712 21.049 2.3

7 0 2 2 4.10940 21.608 1.0

8 1 1 2 3.96262 22.418 0.3

9 -1 1 3 3.86531 22.990 27.0

(Courtesy WIHG = Wadia Institute of Himalayan Geology, Dehradun)


Reference code: 01-078-2315 Mineral name: Quartz No. h k l d [A] 2Theta[deg] I [%]

1 1 0 0 4.25425 20.864 20.8

2 0 1 1 3.34268 26.646 100.0

3 1 1 0 2.45620 36.554 6.8

4 1 0 2 2.28080 39.478 6.5

5 1 1 1 2.23605 40.302 3.2

6 2 0 0 2.12713 42.462 4.9

7 2 0 1 1.97930 45.807 2.8

8 1 1 2 1.81747 50.153 11.0

(Courtesy WIHG = Wadia Institute of Himalayan Geology, Dehradun)


102


Reference code: 01-071-1540 Mineral name: Orthoclase No. h k l d [A] 2Theta[deg] I [%]

1 1 1 0 6.61492 13.374 5.6

2 0 2 0 6.48150 13.651 9.3

3 -1 1 1 5.86716 15.088 9.8

4 0 2 1 4.58123 19.360 2.1

5 -2 0 1 4.21977 21.036 62.1

6 1 1 1 3.94230 22.535 19.2

7 2 0 0 3.84588 23.108 6.5

8 1 3 0 3.76725 23.597 73.3

(Courtesy WIHG = Wadia Institute of Himalayan Geology, Dehradun


Reference code: 01-079-1570 Mineral name: Kaolinite 1A No. h k l d [A] 2Theta[deg] I [%]

1 0 0 1 7.15389 12.363 100.0

2 0 2 0 4.47038 19.845 16.3

3 -1 1 0 4.36120 20.347 49.5

4 -1 -1 1 4.18091 21.234 47.1

5 -1 1 1 4.12893 21.504 23.3

6 0 -2 1 3.84300 23.126 32.4

7 0 2 1 3.74118 23.764 15.0

8 0 0 2 3.57694 24.872 51.8

(Courtesy WIHG = Wadia Institute of Himalayan Geology, Dehradun


103

S.N.

Village location

XUTM YUTM RL of ground (m amsl)

Depth to water level (m bgl)

RL of water table (m amsl)

Water level fluctuation(m)

Pre-monsoon Post-monsoon

Pre-monsoon

Post-monsoon

1 Raikera 751393 2460026 315 23.08 20.08 291.92 294.92 3.00 2 Kathrapalli 745879 2462155 310 12.31 10.13 297.69 299.87 2.18 3 Kognar 744217 2457462 290 18.46 15.64 271.54 274.36 2.82 4 Chorbhanta 744704 2455168 275 33.85 29.80 241.15 245.20 4.05 5 Gharghoda 742421 2452698 286 21.85 19.58 264.15 268.42 4.27 6 Bhendra 741649 2451805 265 20.62 16.26 244.38 248.74 4.36 7 Amlidih 740622 2446741 298 17.54 13.45 280.46 284.55 4.09 8 Auraimura 745441 2457252 290 20.00 20.00 270 279.70 9.70 9 Parkipahri 743637 2443601 305 17.85 10.85 287.15 294.15 7.00 10 Amaghat 748656 2444030 250 23.08 5.45 226.92 244.55 17.63 11 Basanpalli 750272 2445851 245 34.77 25.75 210.23 219.25 9.02 12 Jerekela 748774 2447968 250 24.62 12.24 225.38 237.76 12.38 13 Devgarh 747055 2449577 245 24.31 11.5 220.69 233.50 12.81 14 Patrapali 746999 2451603 250 23.38 12.12 226.82 237.88 11.26 15 Kolam 750749 2452959 286 29.54 23.63 256.46 262.37 5.91 16 Chitwahi 751189 2453018 290 35.08 25.45 254.92 264.55 9.63 17 Rodopali 752295 2453097 300 32.62 24.24 267.38 275.76 8.38 18 Dholnara 753710 2453981 305 34.15 26.66 270.85 278.34 7.49 19 Kunjhemura 756047 2448579 265 26.15 10.60 238.85 254.40 15.55 20 Pata 754143 2450112 285 31.69 16.66 253.31 268.34 15.03 21 Dolesara 751394 2452196 283 20.62 9.09 262.38 273.91 11.53 22 Muragaon 754425 2452196 276 27.38 15.75 248.62 260.25 11.63 23 Saraitola 755552 2451860 274 23.69 20.30 250.31 253.70 3.39 24 Kurwahi 757065 2453328 278 23.08 10.03 254.92 267.97 13.05

RL= Reduced level, m amsl= meter above mean sea level, m bgl = meter below ground lev Annexure 15: Water level observation during pre- and post-monsoon periods


104

Annexure 16 : Physico-chemical properties of pre-monsoon groundwater samples

Well XUTM YUTM pH EC TDS TH ALK Ca2+ Mg2+ Na+ K+ NO3

- HCO3- Cl- SO4

2- SiO2 F-

1 751393 2460026 7.53 646 355 292 284.34 73.26 26.49 20.48 3.81 0.697 347.7 17.41 5.72 40.0 0.65 2 747101 2460262 7.01 379 205 128 150.04 23.76 16.80 12.05 26.69 0.573 183 10.22 10.78 30.0 0.43 3 745870 2462155 6.70 156 102 79 79.0 13.86 10.84 3.61 5.51 0.415 97.6 - 6.67 40.0 0.42 4 744217 2457462 7.16 416 274 227 214.3 45.54 27.69 13.61 8.51 0.860 267.4 0.22 20.65 50.0 0.55 5 744704 2455168 7.46 488 322 212 227.7 41.58 26.49 26.51 18.22 0.471 277 7.63 21.31 25.0 0.70 6 739453 2450918 5.67 152 102.3 54 24.0 11.88 6.02 4.82 9.74 29.41 30.5 15.48 16.76 40.0 0.09 7 744502 2451541 7.59 515 339 232 219 53.66 24.08 22.89 31.78 0.577 268.4 51.90 11.32 40.0 0.30 8 742421 2452698 7.44 1268 696 475 184 112.8 46.96 57.83 18.64 2.47 225.7 225.1 8.31 20.0 0.16 9 741649 2451805 7.61 459 275 202 169.7 45.54 21.67 14.45 19.07 3.312 207.4 27.66 20.24 40.0 0.35 10 742133 2450783 7.02 307 168 257 129.3 28.76 18.16 10.84 6.36 8.32 158.6 10.58 4.21 50.0 0.47 11 742137 2447890 6.32 104 80 49 50.6 11.88 4.82 1.20 6.78 0.495 61 2.34 11.70 40.0 0.18 12 740622 2446741 6.55 347 229 143 150 25.74 14.26 24.10 12.29 00 183 5.18 11.76 60.0 0.64 13 742273 2447105 6.55 231 152 94 100.07 19.80 10.84 16.87 5.51 1.43 122 2.19 16.31 20.0 0.46 14 745441 2457252 7.03 230 151 118 109.9 25.74 13.24 1.20 4.24 0.556 134 0 17.86 40.0 1.11 15 745549 2456881 6.93 360 237 193 174 37.62 24.06 1.20 5.51 0 213 0 9.21 60.0 1.06 16 745489 2456419 6.06 475 313 178 89.58 39.60 11.26 15.66 13.98 41.87 109 52.92 9.85 40.0 0.92

*All the values are in mg/L, except pH and EC PO43- and CO3-- Not detected

cont……


105

Well XUTM YUTM pH EC TDS TH ALK Ca2+ Mg2+ Na+ K+ NO3- HCO3

- Cl- SO42- SiO2 F-

17 747032 2455086 7.10 314 207 128 144.3 21.78 18.06 16.87 14.41 0.407 176 5.25 10.47 20.0 1.03 18 747061 2454785 7.29 461 304 178 205.1 37.62 20.47 16.87 37.29 2.67 250 18.25 9.04 20.0 1.03 19 748276 2452787 6.74 634 418 168 184.6 37.62 18.06 30.12 77.12 22.73 225 48.98 11.70 40.0 0.40 20 748509 2452546 7.19 439 289 168 180.3 35.64 19.26 16.87 35.59 0.076 221 15.69 8.21 40.0 0.67 21 748563 2452301 7.27 640 352 277 250.2 53.46 34.26 27.71 24.58 0.501 305 37.15 2.69 20.0 0.69 22 743637 2443610 6.66 248 163 113 125 21.78 14.45 4.82 7.63 0.98 152 0.29 7.75 40.0 0.41 23 743761 2444279 7.15 287 189 143 139.9 23.76 20.47 7.23 9.74 0.205 170 4.89 9.56 60.0 0.44 24 745474 2443572 6.57 173 114 69 70.5 13.86 8.43 8.43 2.97 0.093 85 8.83 8.54 60.0 0.37 25 745835 2443725 6.29 133 73 59 55.05 9.90 4.43 2.41 3.81 1.271 67 4.83 6.32 20.0 0.29 26 747151 2446752 6.99 1002 602 430 380.6 71.26 61.40 42.65 25.85 7.15 483 69.9 9.09 40.0 0.11 27 747208 2446522 6.35 497 328 148 80.05 23.76 12.67 15.66 53.89 51.26 97 48.25 9.99 60.0 0.20 28 748656 2444030 5.36 505 333 123 19.68 17.82 19.26 21.69 47.88 106.29 24 62.26 9.96 20.0 0.12 29 748648 2443759 6.52 343 195 148 104.9 33.66 15.65 6.02 3.39 16.965 129 10.56 7.89 20.0 0.75 30 751147 2445468 7.56 469 309 193 175 45.54 19.26 12.05 28.39 1.23 213 30.44 7.65 40.0 0.76 31 750905 2445307 6.96 307 202 74.25 94.0 9.90 12.04 14.06 40.25 0.889 115 14.96 21.60 20.0 0.24 32 750272 2445851 6.99 2760 1380 841 124.6 130.68 125.22 18.79 53.39 0.522 152 335.77 6.76 40.0 0.36 33 748774 2447968 7.60 1146 573 391 284 67.32 54.18 10.12 22.88 0.286 347 84.24 5.76 40.0 0.15

*All the values are in mg/L, except pH and EC

cont…….


106

Well XUTM YUTM pH EC TDS TH ALK Ca2+ Mg2+ Na+ K+ NO3

- HCO3- Cl- SO4

2- SiO2 F- 34 748485 2448255 7.74 448 294 202 195.1 43.56 22.88 8.43 29.66 0 237 21.68 13.34 20.0 0.39 35 747055 2449577 7.80 430 253 193 185.1 45.54 19.26 6.02 26.27 0.22 225 12.77 4.34 20.0 0.58 36 746707 2449761 7.85 444 293 188 195.1 47.52 16.86 8.43 27.54 0.415 237 14.45 10.77 20.0 0.51 37 743196 2449821 7.45 1032 516 396 350.2 65.34 56.59 52.65 20.76 2.46 427 92.26 3.98 40.0 0.20 38 743311 2449485 7.74 676 371 242 225.5 51.48 27.69 30.13 28.39 0.201 274 57.01 2.41 20.0 0.17 39 746999 2451603 7.74 485 243 207 219.8 43.56 24.08 10.84 28.88 0.117 268 14.89 7.76 10.0 0.39 40 748248 2451352 7.55 464 306 178 200.1 43.56 16.86 9.64 32.20 0.024 244 10.66 5.35 20.0 0.54 41 750749 2452959 7.07 404 266 128 165.0 27.72 14.45 19.28 38.14 1.23 201 17.37 9.23 30.0 1.17 42 750815 2452867 7.25 573 316 247 265.1 47.52 31.30 20.48 12.71 0.432 323 5.04 11.17 20.0 0.92 43 751189 2453018 6.90 574 376 262 234.5 47.52 34.92 9.64 8.90 0.520 288 1.68 2.43 20.0 0.90 44 751366 2453100 7.19 426 281 153 185.3 29.70 19.26 14.46 37.29 0.577 225 17.30 6.52 15.0 0.64 45 752008 2454157 6.90 240 133 99 109.9 19.80 10.84 6.02 7.20 0.149 134 1.31 10.41 20.0 0.39 46 751812 2454133 6.77 442 243 178 185.3 35.64 21.67 20.48 27.54 0.250 225 19.42 1.53 80.0 0.73 47 752295 2453097 7.84 332 219 118 159.9 19.80 16.86 20.48 15.68 0.417 195 8.25 11.23 80.0 0.77 48 752286 2453109 6.57 296 162 108 109.9 21.78 13.24 12.05 11.44 0.124 134 2.26 23.87 10.0 0.52 49 753710 2453981 6.10 176.5 96 74 71.56 17.12 7.22 3.61 7.20 1.107 87 0.95 7.91 100 0.73 50 753698 2454100 6.55 157.2 102 69 54.95 19.80 4.82 6.02 3.29 0.193 77 5.47 10.96 100 0.48

*All the values are in mg/L, except pH and EC cont……..


107


- Cl- SO42- SiO2 F-

51 754110 2453999 6.38 248 136 103 97.95 23.76 10.84 6.02 9.32 0.315 119 4.96 10.93 80.0 0.67 52 754119 2453931 7.53 380 209 123 113.1 29.70 12.04 12.05 36.02 0.237 138 26.93 8.79 60.0 0.41 53 754063 2453743 6.35 191.9 126 89 80.37 17.82 10.84 2.41 80.51 0.475 97 3.87 8.82 80.0 0.81 54 756047 2448579 6.96 306 201 84 114.8 11.80 13.24 16.88 39.83 0.342 140 15.40 3.23 100 0.67 55 754610 2449070 6.84 295 194 74 121.2 11.88 10.84 18.07 33.47 0.370 148 10.22 11.98 80.0 0.69 56 754466 2449286 7.12 377 248 133 150.0 23.76 18.06 9.64 36.86 0.225 183 16.64 10.59 80.0 0.85 57 754491 2449370 6.92 268 176 79 104.9 13.86 10.84 13.35 29.24 6.683 128 10.07 9.24 80.0 0.97 58 754676 2449731 7.53 461 253 168.3 194.3 31.68 21.67 24.10 27.12 0.394 237 18.54 7.89 100 0.85 59 755883 2448452 6.85 311 202 74.25 109.9 11.88 11.43 15.66 39.83 0.615 134 15.04 5.67 80.0 0.46 60 754143 2450112 7.32 464 306 153.45 189.4 29.70 19.26 27.71 32.20 0.475 231 24.38 10.54 70.0 1.23 61 753982 2450056 7.30 348 229 113.85 144.3 21,78 14.45 21.69 26.69 0.294 176 11.7 2.31 90.0 1.35 62 754016 2450270 7.34 534 352 178.2 244.4 33.66 22.88 36.14 27.54 1.16 298 14.23 8.56 80.0 1.57 63 753808 2450253 7.50 395 260 108.9 164.8 21.78 13.24 26.51 33.05 1.12 201 12.85 12.23 90.0 2.40 64 752782 2450360 7.56 788 433 257.4 236.2 49.50 32.51 53.01 30.93 1.656 288 69.08 3.73 100 0.90 65 752759 2450845 7.16 558 306 193.05 195.1 39.60 22.88 25.30 31.78 0.243 237 34.01 4.80 80.0 0.67 66 752628 2450858 7.42 620 409 227.5 316.7 41.58 30.10 62.65 17.37 0.367 386 7.96 31.80 100 0.57

*All the values are in mg/L, except pH and EC cont…….


108


- Cl- SO42- SiO2 F-

67 751394 2450912 7.02 209 137 103.95 95.14 15.84 15.65 2.41 7.63 2.56 115.9 0 13.59 90.0 0.49 68 751125 2450759 7.41 351 231 158.4 178.1 25.74 21.67 19.28 9.32 1.74 217.3 0 14.52 90.0 0.81 69 750160 2451156 7.55 557 360 242.5 250.1 45.54 31.30 25.30 17.37 0.671 305 10.07 21.92 70.0 0.58 70 750097 2451223 6.96 336 221 148.5 155.0 29.54 18.06 13.25 11.02 0.374 189.1 2.34 17.18 80.0 0.42 71 754425 2452196 7.06 186 122 74.25 90.22 21.78 4.82 11.28 3.39 1.29 109.8 0 7.65 150 0.52 72 754435 2452151 6.88 363 239 143.55 144.7 25.74 19.26 25.30 12.71 0.403 186.5 14.47 20.85 100 1.86 73 754496 2452300 6.80 325 214 89.1 160.0 15.84 12.04 32.53 10.17 0.154 196 8.10 13.21 100 6.03 74 754595 2451608 6.97 399 258 168.3 163.6 31.68 20.47 16.87 16.95 0.503 201.3 11.31 16.35 100 0.71 75 754532 2451507 6.92 441 241 168.3 175.5 33.66 20.47 19.28 19.49 0.593 213.5 18.76 7.36 90.0 0.71 76 755552 2451860 6.94 337 188 84.15 100.0 17.82 9.63 28.92 6.78 0.571 121 11.97 22.76 100 6.23 77 755789 2451755 7.16 319 210 69.3 104.9 13.86 8.43 30.12 10.17 2.89 125 4.82 18.07 100 6.08 78 755875 2451724 6.81 396 217 99 178.1 17.82 13.34 31.32 15.25 0.275 217 15.11 8.41 90.0 6.34 79 755785 2451559 6.87 320 208 84.15 111.6 17.82 9.63 25.30 7.63 0.713 136 10.11 11.39 90.0 5.00 80 755846 2451457 6.95 354 233 118.8 95.14 19.80 13.24 19.28 15.68 1.45 119 24.67 11.38 80.0 2.06 81 755011 2452307 7.27 394 260 103.95 114.1 23.76 10.84 39.76 15.25 2.41 139 18.72 7.32 80.0 8.88 82 756700 2453619 6.30 78.2 51 34.65 19.42 9.90 2.41 0.60 5.08 0.363 24.4 10.32 3.31 80.0 0.39 83 757066 2453328 6.75 206 135 99 90.05 19.80 12.04 2.41 5.93 0.677 109.8 0.95 10.06 60.0 0.54



109

Annexure 17 : Physico-chemical properties of mid-monsoon groundwater samples

Well pH EC TDS TH AK Ca2+ Mg2+ Na+ K+ NO3- HCO3

- Cl- SO42- F- Li+

47 6.99 489 245 175 235 30.10 18.83 15.64 10.08 0.05 286.7 5.02 3.35 0.73 0.036 50 6.22 221 111 75 65 15.78 4.84 5.50 2.77 0.27 79.3 14.51 5.43 0.28 0.000 52 6.83 818 408 185 155 33.99 15.00 11.10 91.70 189.1 56.72 37.71 0.35 0.000 60 7.26 508 254 145 220 25.13 11.73 24.43 24.60 268.4 24.04 0.56 1.46 0.056 61 6.98 344 172 105 135 17.00 8.01 14.53 17.87 164.7 11.70 7.98 1.24 0.033 62 7.18 691 345 240 275 35.27 19.96 34.38 19.30 335.5 14.86 31.39 1.42 0.055 63 7.36 467 234 135 190 21.55 9.76 21.07 27.83 0.16 231.8 17.62 0.58 2.21 0.051 64 7.21 640 320 185 220 32.14 14.72 28.55 24.75 268.4 44.12 10.05 1.53 0.048 66 7.32 782 391 245 340 40.96 22.63 50.41 11.73 414.8 13.31 40.73 0.49 0.037 70 6.99 436 218 165 185 31.49 13.22 13.72 8.22 225.7 8.44 10.48 0.35 0.000 71 6.81 198 99 85 95 16.34 4.46 2.71 3.09 115.9 4.32 0.55 0.52 0.000 72 7.37 422 210 110 170 17.19 9.29 31.31 10.41 207.4 17.21 2.19 4.50 0.000 73 7.64 348 174 75 140 14.53 6.14 30.95 7.21 0.14 170.8 12.13 0.81 6.38 0.000 74 7.05 472 236 165 195 29.82 14.73 15.65 13.60 0.26 237.9 16.70 4.11 0.66 0.000 76 6.69 282 141 75 105 12.33 5.68 19.91 4.44 0.17 128.1 12.37 1.73 5.55 0.055 77 6.92 334 167 80 130 12.41 5.81 28.76 6.58 158.6 11.95 0.24 7.15 0.067 78 6.90 390 195 95 145 16.17 7.82 27.25 11.02 176.9 17.43 0.07 4.95 0.050 79 6.78 322 161 85 125 16.38 6.88 20.96 5.56 152.5 13.03 0.86 4.75 0.000 80 6.74 292 146 185 110 14.04 6.14 18.47 7.43 134.2 18.14 0.62 3.06 0.054 81 6.75 261 131 55 95 12.30 6.05 16.50 4.96 0.34 115.9 6.34 1.65 3.80 0.056



110

Annexure 18 : Physico-chemical properties of post-monsoon groundwater samples


- CO3- Cl- SO4

2- F- Li+

1 751393 2460026 8.18 541 271 252.5 247.5 56.23 11.04 15.05 2.14 0.31 302 ND 12.06 1.81 0.38 ND 2 747101 2460262 7.91 396 198 143.6 153.5 20.76 9.29 8.85 22.93 0.71 187.3 ND 5.71 0.41 0.38 ND 3 745870 2462155 8.36 167 84 73.2 79.2 10.66 7.56 3.12 3.33 0.35 90.6 ND 1.3 1.54 0.41 ND 4 744217 2457462 8.19 486 243 247.5 237.6 43.25 17.29 7.49 5.11 0.48 289.9 ND 1.18 1.13 0.56 ND 5 744704 2455168 8.57 537 268 193.1 247.5 35.12 14.27 24.00 13.38 3.36 289.9 4.87 6.84 9.13 0.53 ND 6 739453 2450918 8.28 938 469 371.3 247.5 53.35 31.90 27.44 14.06 0.58 302 ND 68.85 0.0 0.23 ND 7 744502 2451541 8.56 795 398 292.1 252.5 39.82 17.45 27.23 21.36 0.0 308.1 ND 41.12 2.98 0.28 ND 8 742421 2452698 - - - - - - - - - - - - - - -9 741649 2451805 8.67 525 263 190.6 173.3 39.56 14.52 14.10 10.90 4.31 211.4 ND 30.76 7.18 0.23 ND 10 742133 2450783 8.79 331 165 156.5 120.7 21.11 13.28 8.92 4.43 17.13 147 ND 9.31 2.33 0.46 ND 11 742137 2447890 7.45 170 85 84.2 47.54 7.29 3.82 2.15 3.47 0.27 57.7 ND 2.59 0.12 0.43 ND 12 740622 2446741 7.57 97 49 143.6 148.5 19.19 10.17 20.00 8.26 0.0 181.2 ND 4.76 6.25 0.39 ND 13 742273 2447105 8.2 328 164 104 123.8 21.69 4.07 20.18 2.07 2.86 151 ND 8.97 1.65 0.50 ND 14 745441 2457252 8.41 443 222 118.8 116.3 22.83 9.45 0.98 2.89 0.07 141.3 ND 0.98 3.43 0.65 ND 15 745549 2456881 8.38 281 140 141.1 123.8 25.95 9.87 1.78 2.81 0.0 151 ND 2.24 0.33 0.82 ND 16 745489 2456419 6.93 553 277 183.2 187.67 34.62 14.76 13.59 8.11 21.74 229.6 ND 11.65 5.16 0.28 ND

*All the values are in mg/L, except pH and EC, PO43- Not detected cont………


111

Well XUT

M YUTM pH EC TDS TH ALK Ca2+ Mg2+ Na+ K+ NO3

- HCO3- CO3

- Cl- SO42- F- Li+

17 747032 2455086 7.72 355 178 138.6 149.15 18.38 11.01 13.95 8.47 1.14 182.3 ND 5.07 2.53 0.42 ND 18 747061 2454785 8.88 578 289 212.9 237.45 36.74 16.76 25.32 14.75 5.82 289.9 7.3 16.94 1.93 0.51 ND 19 748276 2452787 8.52 511 256 153.5 212.9 30.05 10.79 16.74 36.69 2.49 259.7 ND 16.90 0.57 0.59 ND 20 748509 2452546 8.31 486 243 181.2 198.18 29.64 6.29 12.82 28.92 0.60 241.7 ND 7.46 0.13 0.68 ND 21 748563 2452301 8.96 497 249 173.3 208 32.00 11.33 13.87 24.75 0.0 235.6 7.3 11.2 0.0 0.11 ND 22 743637 2443610 7.98 327 164 143.6 138.6 20.00 8.25 4.69 4.42 0.37 169.1 ND 1.44 5.21 0.45 ND 23 743761 2444279 8.13 275 138 108.9 99 17.95 13.88 6.11 4.21 0.74 120.8 ND 5.0 2.48 0.44 ND 24 745474 2443572 8.47 186 93 79.2 79.2 10.96 2.04 3.01 1.05 0.28 96.6 ND 7.72 0.72 0.37 ND 25 745835 2443725 7.3 146 73 59.4 49.5 4.79 3.44 2.65 1.98 0.31 60.4 ND 5.63 0.62 0.26 ND 26 747151 2446752 8.25 1041 521 376.2 371.3 58.92 34.85 49.34 15.78 1.56 453 ND 65.06 7.65 0.11 ND 27 747208 2446522 7.51 264 132 79.2 39.6 6.98 4.78 4.44 23.69 0.1 48.3 ND 12.76 12.55 0.10 ND 28 748656 2444030 7.37 612 306 143.6 24.8 11.74 5.97 17.57 37.80 0.0 30.3 ND 66.78 4.31 0.04 ND 29 748648 2443759 7.5 314 157 138.6 113.9 28.48 8.04 5.09 2.30 7.05 139 ND 9.8 5.83 0.39 ND 30 751147 2445468 7.89 326 163 69.3 180.66 34.06 13.07 5.11 18.98 0.04 220.9 ND 17.42 2.63 0.53 ND 31 750905 2445307 8.23 484 242 188.1 193.1 14.87 7.33 9.42 31.87 0.07 177.5 2.4 4.06 2.32 0.19 ND 32 750272 2445851 8.26 466 233 193 198 33.12 12.54 12.67 19.13 0.97 241.6 ND 10.9 0.11 0.54 ND 33 748774 2447968 8.16 1268 634 326.7 297 59.09 28.41 84.65 9.41 16.2 362.3 ND 90.43 8.34 0.0 ND



112

Well XUT


- HCO3- CO3

- Cl- SO42- F- Li+

34 748485 2448255 8.74 483 242 207.9 203 36.25 14.21 6.54 21.73 0.15 241.6 2.4 12.8 1.34 0.41 ND 35 747055 2449577 8.56 471 235 188.1 203 36.86 14.50 3.91 19.69 0.59 247.6 ND 12.64 0.03 0.49 ND 36 746707 2449761 8.34 569 285 217.8 227.7 45.17 17.26 8.60 20.04 0.31 277.8 ND 25.77 3.70 0.43 ND 37 743196 2449821 8.13 1010 505 366.3 425.7 52.69 42.22 43.77 8.58 0.7 519.4 ND 37.81 2.91 0.16 ND 38 743311 2449485 8.37 827 414 262.4 252.5 46.62 22.71 38.84 20.06 0.94 302 2.4 64.47 6.07 0.06 ND 39 746999 2451603 8.94 508 254 212.9 230.7 39.39 15.23 9.70 21.82 0.06 365.7 4.9 12.14 0.23 0.41 ND 40 748248 2451352 8.54 498 249 207.9 227.8 21.43 17.73 8.46 28.93 0.05 259.7 7.3 5.76 0.01 0.49 ND 41 750749 2452959 8.63 251 126 133.7 138.7 20.99 9.39 14.49 27.89 0.46 163.1 2.4 18.04 0.14 1.03 ND 42 750815 2452867 8.71 611 306 262.4 282.2 39.66 23.33 19.97 7.60 1.50 296 19.5 9.60 12.05 0.96 ND 43 751189 2453018 7.86 560 280 232.7 292.1 35.40 21.38 9.10 15.00 0.64 286 24.3 7.52 9.24 0.77 ND 44 751366 2453100 8.21 500 250 185.6 222.9 27.49 14.92 12.24 23.57 0.25 199.3 29.2 17.26 3.64 0.58 ND 45 752008 2454157 8.45 277 138 118.8 143.6 18.77 9.01 8.80 8.54 2.40 175.2 ND 4.89 0.23 0.49 ND 46 751812 2454133 7.96 518 259 173.3 203 29.53 15.45 15.59 18.96 0.55 223.4 9.7 18.4 3.45 0.72 ND 47 752295 2453097 7.71 720 360 306.9 302 45.08 35.39 15.63 9.93 0.60 308 24.3 4.56 7.68 0.59 0.03 48 752286 2453109 7.42 309 155 121.3 138.6 14. 86 9.12 17.51 7.89 0.06 169.1 ND 5.57 3.94 0.51 ND 49 753710 2453981 6.91 248 124 94.1 86.08 14.48 5.84 4.69 8.37 0.59 105.3 ND 4.1 1.94 0.67 0.07 50 753698 2454100 7.43 167 84 59.4 69.3 17.01 3.30 6.78 2.70 1.31 84.5 ND 5.10 8.79 0.14 ND



113


- CO3- Cl- SO4

2- F- Li+

51 754110 2453999 - - - - - - - - - - - - - - - 52 754119 2453931 7.8 740 370 316.8 59.4 62.68 17.67 7.44 19.39 1.42 72.5 ND 20.32 215 0.85 ND 53 754063 2453743 7.91 214 107 89.1 118.8 16.30 5.71 3.15 35.21 0.12 144.9 ND 7.23 4.02 1.08 0.07 54 756047 2448579 7.68 341 171 74.3 122.1 9.88 8.96 11.81 31.74 0.0 149.1 ND 1.46 7.97 0.36 ND 55 754610 2449070 7.96 330 165 96.5 128.3 10.50 8.73 13.76 28.34 0.0 157.3 ND 12.12 7.98 0.41 ND 56 754466 2449286 7.9 413 207 153.5 164.6 18.87 12.98 8.10 30.34 0.04 201.8 ND 17.19 0.01 0.54 0.04 57 754491 2449370 8.36 391 196 118.8 155.2 14.40 8.53 18.48 27.52 5.73 189.3 11.9 6.61 0.07 0.94 ND 58 754676 2449731 8.14 452 226 163.4 183.2 24.58 12.98 22.86 16.63 0.65 223.4 ND 16.12 0.09 1.02 ND 59 755883 2448452 7.7 347 173 94.1 123.8 22.33 12.48 11.08 38.26 0.0 151 ND 15.95 5.79 0.42 0.03 60 754143 2450112 8.18 512 256 146 128.7 22.85 11.75 24.56 24.52 0.0 157 ND 21.62 0.82 1.62 0.04 61 753982 2450056 8.73 268 134 89.1 143.6 12.32 8.45 20.21 20.31 0.48 175.2 ND 6.93 6.02 1.44 ND 62 754016 2450270 7.47 1083 542 401 331.7 34.95 41.57 42.16 14.48 2.76 404.7 ND 11.99 4.12 1.53 0.08 63 753808 2450253 8.02 468 234 121.3 188.1 20.83 10.80 24.24 26.12 0.33 229.5 ND 10.05 6.35 2.65 0.06 64 752782 2450360 8.33 697 349 193.1 187.1 31.98 16.62 33.07 24.87 0.47 226.1 11.9 29.22 10.51 1.48 0.04 65 752759 2450845 7.74 378 189 113.9 178.2 17.85 19.70 24.33 16.98 7.57 217.4 ND 12.79 6.79 0.34 ND 66 752628 2450858 8.72 802 401 247.5 361.4 40.23 23.79 53.19 11.26 0.37 404.6 17.8 12.16 30.3 0.49 ND

*All the values are in mg/L, except pH and EC cont………


114

Well XUT


- HCO3- CO3

- Cl- SO42- F- Li+

67 751394 2450912 8.06 341 171 163.4 153 22.59 15.27 3.47 6.54 3.89 187.3 ND 1.56 2.90 0.52 0.07 68 751125 2450759 8.2 400 200 148.5 194 21.39 18.13 15.74 6.13 0.27 237.8 ND 1.50 7.16 0.89 ND 69 750160 2451156 8.57 578 289 222.8 262 43.37 22.28 17.58 10.53 0.18 283.9 17.8 10.98 14.6 0.54 ND 70 750097 2451223 8.92 393 197 148.5 153. 27.03 12.66 12.52 7.43 0.22 175.2 5.9 5.62 8.65 0.40 ND 71 754425 2452196 8.33 184 92 104 69.3 15.49 4.63 2.53 3.10 0.37 84.6 ND 3.59 1.17 0.44 ND 72 754435 2452151 8.7 311 156 138.6 108 11.96 8.79 20.75 5.60 1.46 132.9 ND 10.84 5.03 3.93 ND 73 754496 2452300 8.2 362 181 94.1 123 12.48 5.99 33.26 7.06 0.49 151 ND 11.83 0.74 7.12 ND 74 754595 2451608 8.36 442 221 173.3 178 27.83 13.65 14.16 11.70 0.57 217.4 ND 15.14 4.52 0.68 0.03 75 754532 2451507 8.74 643 322 163.4 113 34.12 9.75 19.42 44.92 36.4 139 ND 41.19 16.09 0.19 ND 76 755552 2451860 7.77 297 149 89.1 94.1 11.29 5.75 22.33 4.59 1.18 114.8 ND 9.43 2.48 6.43 ND 77 755789 2451755 7.68 353 176 91.6 128 14.51 7.44 26.66 7.89 1.15 157 ND 8.60 0.26 5.76 ND 78 755875 2451724 7.27 187 93 64.35 66.5 11.71 7.43 2.12 14.11 11.53 81.2 ND 32.11 0.85 5.44 ND 79 755785 2451559 7.4 313 157 74.3 111 13.78 6.22 23.36 6.80 0.24 139 ND 13.72 0.79 5.28 ND 80 755846 2451457 7.36 314 157 84.2 99 14.33 6.66 18.66 8.32 0.15 120.8 ND 19.92 1.94 3.04 0.03 81 755011 2452307 7.31 291 146 86.6 101 11.0 6.24 21.58 5.19 1.42 123.8 ND 7.46 0.68 5.15 0.06 82 756700 2453619 7.55 95 47 44.6 24.8 6.11 1.97 1.68 3.89 0.0 30.3 ND 3.05 7.38 0.45 ND 83 757066 2453328 7.34 227 114 94.1 96.5 18.71 6.78 3.39 4.85 0.0 117.7 ND 6.35 0.72 0.57 ND



115

Annexure 19 : Cation-anion balance for pre-, mid and post-monsoon water samples

Well Pre-monsoon(meq/l) Mid-monsoon(meq/l) Post-monsoon(meq/l) Sum cation Sum anion Balance Sum cation Sum anion Balance Sum cation Sum anion Balance

1 6.82 6.34 3.65 4.42 5.37 -9.63 2 3.78 3.54 3.22 2.77 3.28 -8.40 3 1.88 1.77 3.13 1.37 1.59 -7.13 4 5.36 4.86 4.90 4.04 4.86 -9.27 5 5.87 5.25 5.61 4.31 5.32 -10.46 6 1.55 1.76 -6.58 6.84 6.92 -0.58 7 6.46 6.12 2.65 5.15 6.30 -9.98 8 12.49 10.27 9.75 - - - 9 5.17 4.67 5.07 4.06 4.57 -5.86

10 3.56 3.14 6.25 2.65 3.03 -6.69 11 1.22 1.33 -4.40 0.87 1.05 -9.65 12 3.82 3.42 5.47 2.88 3.26 -6.34 13 2.75 2.45 5.89 2.34 2.84 -9.66 14 2.53 2.64 -2.02 2.03 2.45 -9.37 15 4.05 3.75 3.89 2.26 2.59 -6.97 16 3.94 4.21 -3.27 3.74 4.56 -9.92

cont……


116


17 3.68 3.32 5.09 2.65 3.23 -9.98 18 5.25 4.90 3.45 4.69 5.53 -8.20 19 6.65 5.71 7.56 4.04 4.83 -8.89 20 5.01 4.28 7.81 3.54 4.23 -8.90 21 7.38 6.15 9.08 3.77 4.31 -6.69 22 2.68 2.71 -0.48 1.99 2.95 -19.34 23 3.43 3.16 4.16 2.41 2.22 4.20 24 1.83 1.85 -0.53 0.87 1.84 -35.75 25 1.39 1.40 -0.47 0.69 1.18 -26.51 26 11.12 10.19 4.41 8.36 9.47 -6.24 27 4.29 4.01 3.40 1.54 1.42 4.04 28 4.64 4.08 6.39 2.81 2.47 6.36 29 3.32 2.89 6.84 2.36 2.82 -8.79 30 5.11 4.58 5.48 3.48 4.21 -9.41 31 3.14 2.80 5.81 2.57 3.13 -9.80 32 19.01 12.14 -22.05 3.73 4.33 -7.46

cont……


117


33 8.84 8.21 3.73 9.21 8.92 1.57 34 5.18 4.81 3.73 3.82 4.43 -7.36 35 4.79 4.18 6.77 3.71 4.46 -9.26 36 4.83 4.56 2.82 4.56 5.40 -8.39 37 10.74 9.73 4.91 8.23 9.69 -8.15 38 6.88 6.17 5.48 6.40 6.97 -4.25 39 5.36 5.00 3.48 4.19 5.08 -9.60 40 4.80 4.47 3.57 3.64 4.42 -9.68 41 4.39 4.05 3.97 3.16 3.29 -2.03 42 6.16 5.73 3.65 4.96 5.79 -7.72 43 5.89 4.89 9.34 4.56 5.35 -8.00 44 4.65 4.37 3.15 3.73 4.36 -7.73 45 2.33 2.48 -3.13 2.28 2.75 -9.38 46 5.16 4.32 8.82 3.92 4.48 -6.60 47 3.67 3.71 -0.62 4.00 4.34 -4.15 6.10 5.80 2.48 48 2.99 2.79 3.52 2.46 2.88 -8.03

cont…….


118


49 1.82 1.68 4.26 1.62 1.94 -8.89 50 1.73 1.67 1.72 1.50 1.80 -9.12 1.48 1.74 -8.03 51 2.58 2.37 4.17 - - - 52 3.92 3.23 9.58 5.76 5.52 2.28 5.40 6.31 -7.78 53 3.95 1.94 34.01 2.32 2.73 -8.05 54 3.44 2.84 9.45 2.55 3.10 -9.77 55 3.13 3.01 1.89 2.57 3.11 -9.65 56 4.03 3.74 3.81 3.14 3.83 -9.94 57 2.91 2.73 3.09 2.93 3.57 -9.89 58 5.11 4.64 4.81 3.71 4.19 -6.04 59 3.23 2.77 7.74 3.60 3.07 7.90 60 5.10 4.78 3.21 3.91 4.73 -9.51 3.80 3.30 7.14 61 3.90 3.34 7.79 2.60 3.01 -7.30 2.71 3.23 -8.70 62 5.84 5.58 2.27 5.39 6.10 -6.16 7.37 7.20 1.15 63 4.17 4.96 -8.57 3.51 4.11 -7.91 3.65 4.33 -8.54 64 8.24 6.83 9.40 4.69 5.72 -9.89 5.04 5.05 -0.08 65 5.77 5.00 7.19 4.00 4.21 -2.54 cont……….


119

Well No Pre-monsoon Mid-monsoon Post-monsoon Sum cation Sum anion Balance Sum cation Sum anion Balance Sum cation Sum anion Balance

66 7.72 7.25 3.15 6.40 7.79 -9.80 6.57 7.95 -9.55 67 2.38 2.25 2.78 2.70 3.28 -9.63 68 4.14 3.93 2.60 3.40 4.15 -9.96 69 6.39 5.78 5.03 5.03 5.61 -5.45 70 3.82 3.55 3.63 3.47 3.78 -4.38 3.13 3.34 -3.37 71 1.99 2.01 -0.34 1.38 1.52 -4.89 1.34 1.55 -7.02 72 4.29 4.01 3.42 3.25 3.96 -9.85 2.37 2.83 -8.85 73 3.46 4.04 -7.73 2.76 3.36 -9.72 2.74 3.21 -7.89 74 4.43 4.00 5.08 3.73 4.30 -7.06 3.43 4.14 -9.42 75 4.70 4.23 5.29 4.50 4.37 1.42 76 3.11 3.13 -0.30 2.15 2.62 -9.92 2.13 2.56 -9.30 77 2.96 2.93 0.45 2.52 3.04 -9.42 2.70 3.15 -7.74 78 3.73 4.50 -9.30 2.92 3.57 -9.99 2.78 2.73 0.97 79 2.98 3.03 -0.88 2.44 2.96 -9.72 2.39 2.92 -10.00 80 3.32 3.08 3.67 2.20 2.69 -10.04 2.29 2.75 -9.20 81 4.20 3.47 9.46 1.96 2.33 -8.63 2.14 2.55 -8.88 82 0.85 0.79 3.79 0.64 0.76 -8.60 83 2.24 2.08 3.71 1.76 2.15 -9.96


120

Annexure 20 : Reference code and ICDD reference pattern matched with rock samples

ICDD = International council for diffraction data base (Courtesy: Wadia Institute of Himalayan Geology (WIHG), Dehradun)


121

Position [°2Theta]

10 20 30 40 50 600

5000

10000

81

Annexure 21 : Diffractograph of sample No. 81 showing peaks and their counts

(Courtesy: WIHG, Dehradun)


122

Position [°2Theta]

10 20 30 40 50 60

Counts

0

5000

10000

15000 74




123

Position [°2Theta]

10 20 30 40 50 60

Counts

0

10000

20000

78




124

Position [°2Theta]

10 20 30 40 50 60

Counts

0

5000

10000

15000 135

Annexure 24 : Diffractograph of sample No.135 showing peaks and their counts


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