phytoremediation potential of paragrass— an in situ approach for...

International Journal of Phytoremediation, 14:796–805, 2012Copyright C© Taylor & Francis Group, LLCISSN: 1522-6514 print / 1549-7879 onlineDOI: 10.1080/15226514.2011.619595

PHYTOREMEDIATION POTENTIAL OF PARAGRASS—AN IN SITU APPROACH FOR CHROMIUMCONTAMINATED SOIL

Monalisa Mohanty and Hemanta Kumar PatraLaboratory of Environmental Physiology, Post Graduate Department of Botany,Utkal University, Bhubaneswar, Orissa, India

The present in situ phytoextraction approach uses paragrass (Brachiaria mutica (Forssk)Stapf) as a hyper accumulator for attenuation of chromium level in soil and mine wastewater at South Kaliapani chromite mine area of Orissa. The bioconcentration factor (BCF)for Cr was maximum (0.334) in 100 days grown paragrass weeds. Transportation index (Ti)i.e. 6.16 and total accumulation rate (TAR) i.e. 8.2 mg kg−1day−1 was maximum in 125 daysold paragrass grown in Cr contaminated experimental cultivated plots. Cr bioaccumulationin roots was nearly 1000 times more than shoots. Paragrass showed luxuriant growth withmassive fibrous roots when grown over Cr contaminated soils (11,170 mg/ kg dry soil). Crbioaccumulation varies significantly with plant age, biomass and level of Cr contaminationin irrigated mine waste water and soil. Paragrass could be used as hyperaccumulators as itshowed rapid massive growth with a high tolerance to Cr.

KEY WORDS: chromium, paragrass, bioconcentration factor

INTRODUCTION

Heavy amounts of toxic contaminants are released to the environment by increasingindustrial and urban activities which cause severe pollution problems. Among the toxicelements, hexavalent chromium (Cr+6) is one of the major contaminants found in industrialand mine waste effluents. Cr+6 has been found as a major contaminant in the mine wastewater at South Kaliapani chromite mine area of Orissa (Mohanty et al. 2005b; Mohantyand Patra 2011). The state of Orissa accounts for 98% of total chromite reserves of thecountry (India) and South Kaliapani chromite mine area of Orissa contributes about 97%of the total chromite reserve of the state (IBM 2004). Extensive opencast mining activitiesin the area has raised the concern regarding the possible accumulation of elevated levelsof Cr and toxic hexavalent chromium (Cr+6) in plants (Mohanty et al. 2005b; Mohantyet al. 2009; Mohanty et al. 2011). Similar types of studies have been reported by others(Zayed and Terry 2003; Mohanty and Patra 2011).

Contamination of soil and water in chromite mining areas is a widespread and seriousproblem. Chromium toxicity results in inhibition of plant growth and metabolism, whichincludes stunted growth, chlorosis, reduced crop yield, delayed germination, senescence,

Address correspondence to Monalisa Mohanty, Laboratory of Environmental Physiology, Post Graduate De-partment of Botany, Utkal University, Bhubaneswar-751004, Orissa, India. E-mail: [email protected]

796

CR PHYTOEXTRACTION BY PARAGRASS—AN IN SITU PHYTOREMEDIATION APPROACH 797

premature leaf fall, biochemical lesions, loss of enzyme activities and reduced biosyn-thesis (Panda and Patra 1997; Zayed et al. 1998; Zayed and Terry 2003; Mohanty et al.2005a; Mohanty et al. 2009; Mohanty and Patra 2011). Phytoremediation is an emergingcost-effective, environment-friendly technology that employs the use of higher plants forcleaning up the contaminated environment.

The objectives of this study were to assess the extent of chromium contaminationin mine waste water and soil. The study also deals with the attenuation of toxic levels ofCr from contaminated soil and water at South Kaliapani Chromite mine area of Orissausing novel techniques of phytoremediation. The present in situ phytoremediation pro-gramme employs phytoextraction and rhizofiltration mechanisms for reducing the total soilCr content and attenuating the toxicity load of Cr+6 from irrigated mine waste water usingparagrass (Brachiaria mutica (Forssk) Stapf) as a green tool for phytoremediation. Phytoac-cumulation ability of paragrass was interpreted from their Bio Concentration Factor (BCF),Transportation index (Ti) and Total Accumulation Rate (TAR) values for Chromium. Thestudy depicts the severity of chromium pollution in the chromite mining environment andits accumulation in plants through a designed in situ phytoremediation programme.

MATERIALS AND METHODS

Study Site

South Kaliapani chromite mine area (latitudes 20◦ 53′ and 21◦ 05′ and longitudes85◦ 40′ and 85◦ 53′) of Sukinda valley of Orissa, (India), was selected as the study site.The experimental land of 2,000 sq ft. was selected for cultivation of paragrass near themining site of Orissa Mining Corporation (OMC). The plot design was made showing thepassage of irrigated untreated mine waste water through four successive experimentallydesigned plots (each of size: 20′ × 25′) of paragrass. Experimental plots were prepared ina completely randomized design.

Plant Material

Paragrass (Brachiaria mutica (Forssk.) Stapf) plants were used as green tools of phy-toremediation. Four weeks-old paragrass saplings were transported from Fodder ResearchInstitute, Cuttack, Orissa to South Kaliapani Area. The grass slips were transplanted in theexperimentally designed plots.

Cultivation and Fertilizer Treatment

Rooted paragrass slips in a bunch of two were transplanted in experimental plots with1′ spacing. Chemical fertilizers like N (234 kg ha−1), P2O5 (51 kg ha−1) and K2O (81 kgha−1) were applied in the plots of paragrass after transplantation. The commercial fertilizersused in the field are urea, gromer and Di-Ammonium Phosphate (DAP). Before fertilizertreatment, the experimental field soil (sandy loam) was amended with green manure at therate of 12.5 tonnes per hectare. Cr+6 contaminated mine waste water was passed througheach experimental plot in a zigzag pathway with a coverage of an area of 500 sq. ft passageroute to 2000 sq. ft. (for 4 consecutive plots). The water flow (rate of water flow: 950 ml/min) to different successive experimental paragrass plots was continuous.

798 M. MOHANTY AND H. KUMAR PATRA

Sampling and Analysis

Soil, water, and plant samples were collected from the experimental plots by randomsampling method for analysis. The soils were sampled and processed for analysis as de-scribed by Mohanty et al. (2011). The soil samples were air-dried for 5 days and crushedto fine powders of desired soil size (<2 mm) (Ghosh et al. 1983). Analysis of physico-chemical parameters like pH, Electrical Conductivity (E.C.), Total Dissolved Solids (TDS),PO−3

4 -P, NO−3 -N, Cr, Ca, Mg, and total Cr contents were conducted for the sieved soils.

Soil samples were collected at the harvesting stage (125 Days after transplantation) foranalysis of total Cr and other chemical properties (Bonet et al. 1991).

Irrigated mine waste water was sampled and analyzed for physico-chemical parame-ters before and after its passage through different experimental cultivated plots of paragrassduring different period of plant growth, i.e., on 75 and 100 Days after transplantation(DAT). The Cr+6 contaminated mine waste water was irrigated in the successively arrangedexperimental cultivated plots and were analyzed for pH, E.C., PO−3

4 - P, NO−3 -N, Ca, Mg,

and Na contents (HACH 1992; APHA 1995). Irrigated mine waste water was analysed forits Cr+6 content using HACH- DR -890 colorimeter (APHA 1995) on 75 and 100 days aftertransplantation of paragrass plants. The analyses were performed for irrigated mine wastewater collected at different passage distances i.e., 500, 1000, 1500, and 2000 sq. ft. andalso on 75 and 100 DAT of the paragrass plants.

Paragrass plants from different experimental plots were sampled on 75, 100 and125 days after transplantation and analyzed for total Cr content in root, stem and leaves(Bonet et al. 1991). Shoot and root parts were separated from the plant samples harvestedfrom different experimental plots. The plants were oven-dried at 70◦C for 72 h, powderedand digested using a solution of HNO3:HClO4 (10:1 v/v) for Cr analysis in an InductivelyCoupled Plasma Atomic Emission Spectrometer (ICPES). Before analysis of total Crcontent, the roots were rinsed with 0.01N HCl followed by washing with distilled water forremoving mixed Fe and Cr hydrous oxides which precipitated on the root surfaces.

BCF (Bio Concentration Factor), Total Accumulation Rate (TAR) and Transportationindex (Ti) values for Cr in the plant mass was calculated as per following method (Zurayket al. 2002; Ghosh and Singh 2005b).

BCF = Cr concentration in plant tissue (mg/kg)

Initial concentration of chromium in the external nutrient solution (mg/kg)

TAR = (Shoot concentration × Shoot biomass + Root concentration × Root biomass)

[(Shoot biomass + Root biomass) × days of growth]

N.B.: TAR (mg/kg/day), Biomass (gm dry wt.) and Concentration (mg/kg dry matter)

Ti = Cr concentration of leaves (mg/kg)

Cr content of root (mg/kg)× 100

Statistical Analysis and Presentation of Data

Sampling of soil, water and plants were conducted in triplicates. Data are presentedin the figures and tables as AM ± SEM of three replicates. Analysis of Variance (ANOVA)


was performed to calculate the F-values at P ≤ 0.05 and the statistical difference in the datawas interpreted.

RESULTS AND DISCUSSION

Physico Chemical Analysis and Total Chromium Level in Soil

Soils of experimental plots were slightly alkaline and contained very low concentra-tions of N, P, and K. (Table 1). The pH value of soil was ideal for crop production as shownfrom the comparative soil quality study. After ploughing and compost amendment the pHvalue of soil was noted as 6.7 which was optimum for most of the crops (HACH 1992). Thechange in pH from 7.2 to 6.7 may be attributed to the addition of compost and enhancedmicrobial activity. A significant increase in E.C., NO3-N, and Organic Carbon content ofsoil was noted after ploughing and green manure amendment. The NO3-N content of exper-imental plots were less under high soil Cr content which may be due to negative correlationof N-Mineralization with contamination level (Bath 1989). High values of chromium werenoted for soil samples (11170 mg of Cr kg−1 dry soil), which exceeds the recommendedguideline (Natural soil: 30–300 mg kg−1 as described by Katz and Salem 1994; Mohantyet al. 2005b). Total Cr (11,170 mg kg−1 dry soil) content of soils in experimental plotswas very high in comparison to the normal soil (Zayed and Terry 2003, Mohanty and Patra2011). The soil of experimental plots can be categorized as serpentine one as it has therange of Cr concentration from 634–125, 000 mg kg−1 (Adriano 1986). It was observed thatafter 125 days of paragrass growth, total chromium content of the soil (on dry weight basis)falls from 11,170 mg kg−1 to a minimum of 5,150 mg kg−1 and maximum of 8,030 mgkg−1. The soil chromium content was within the range from 3,100 to 9, 400 mg kg−1 drysoil (after 75 days of plant growth) and 5, 350 to 8,200 mg kg−1 dry soil (after 100 daysof plant growth). The reduced Cr content of soils may be attributed to the enhanced abilityand rate of accumulation of Cr in response to the increasing biomass content with the ageof the plant growth.

Physico-Chemical Parameters and Cr+6 Content of Irrigated Mine

Waste Water

Irrigated mine waste water showed a value of 0.65 mg l−1and 0.74 mg l−1 for Cr+6

and total Cr respectively. This value was higher than the permissible limit as recorded for

Table 1 Physico-chemical parameters of the experimental field soil before and after ploughing and compostamendment

Physico-chemical properties Before ploughing After ploughing

PH 7.2 6.7E.C. (mS/cm) 0.05 0.08W.H.C (%) 36.32 49.89PO−3

4 -P (kg/ha) 24.25 24.49NO−

3 -N (kg/ha) 20.75 28.21Organic C (mg/kg) 31.5 59Exchangeable K (kg/ha) 194 194Total Cr (mg/kg dry soil) — 11170Total Fe (mg/kg dry soil) — 223415


Table 2 Physico-chemical properties of Cr+6 contaminated mine waste water irrigated in experimental plots ofparagrass

E.C. TDS PO−34 P NO−

3 -N Ca & Mg Na Cr+6 Total CrpH (mS) (mS cm−1) (mg l−1) (mg l−1) (mg l−1) (mg l−1) (meq l−1) (mg l−1) (mg l−1)

8.4 0.5 0.125 0.81 0.37 2.96 2.2 7.78 0.645 0.74

fresh water life: 0.001 mg l−1; irrigation water: 0.008 mg l−1 and drinking water: 0.01mg l−1 (Zayed and Terry 2003). Although the flow rate of water to cultivated plots ofparagrass was slow and continuous, a significant reduction in Cr+6 level in irrigated minewaste water was noted which may be due to its positive correlation with the biomass ofthe plants. Phosphorus (0.37 mg l−1) and NO3-N level (2.96 mg l−1) were much less ascompared to normal irrigation water. Irrigated mine waste water showed a high alkalinepH value (8.4) (Table 2). The Cr+6 in the irrigated waste water was 0.65 mg l−1 whichcrosses the toxic limit i.e., > 0.008 mg l−1 (Mohanty et al. 2011). The level of Cr+6 inirrigated mine waste water reflects the value of available chromium in growing plant parts(Table 3). Very less amount of Ca- Mg (2.2 mg l−1) was noted in mine waste water whereasNa content (7.78 mg l−1) was relatively high. Cr+6 levels in the samples of irrigated minewater from different experimental plots were found to decrease with increasing passagearea of flowing mine waste water (Figure 1) through successive plots. Percent reductionin Cr+6 level in irrigated mine waste water was calculated (Figure 1). After 100 days of

Figure 1 Reduction percent of hexavalent Cr content from irrigated mine waste water after passage throughcultivated plots of paragrass on 75 DAT and 100 DAT.

Tabl

e3

Tota

lCr

cont

ento

fpl

ants

ampl

esco

llect

edfr

omdi

ffer

ente

xper

imen

talp

lots

ofpa

ragr

ass

duri

ng75

,100

,125

DA

T(v

alue

sar

eA

M±

SEM

)

Tota

lCr

cont

ent(

mg/

kgdr

ym

ass)

Roo

ts∗

Day

sA

fter

Stem

s(o

rSh

oots

inW

H)∗

Lea

ves∗

Day

sA

fter

Tra

nspl

anta

tion

(DA

T)

Day

sA

fter

Tra

nspl

anta

tion

(DA

T)

Tra

nspl

anta

tion

(DA

T)

Plan

tsam

ple

Plot

No.

7510

012

575

100

125

7510

012

5

PG+F

115

66±

13.1

3528

±14

.721

10±

15.9

10±

0.87

28.5

±2.

48.

5±

1.4

42±

0.96

130

±11

.413

8±

11.4

411

09±

15.7

2687

±16

.515

57.5

±12

.623

±0.

8520

±1.

112

±1.

877

±1.

210

6.5

±9.

511

6.5±

9.5

Abb

revi

atio

ns:P

G+F

:Par

agra

ssw

ithfe

rtili

zer

trea

tmen

t.N

B:I

nitia

ltot

alC

rco

nten

t(m

g/kg

dry

mas

s)in

root

and

shoo

tof

para

gras

sis

48an

d6.

5re

spec

tivel

y.A

M±

SEM

:ari

thm

etic

mea

n±

stan

dard

erro

rof

mea

n;∗

Cr

bioa

ccum

ulat

ion

inro

ots

was

sign

ifica

ntly

high

(atP

≤0.

05)

than

stem

san

dle

aves

Two

fact

orA

NO

VA

with

outr

eplic

atio

n:∗ F

valu

esfo

rto

talC

rco

nten

tin

diff

eren

tpla

ntpa

rts

ofpa

ragr

ass

show

edsi

gnifi

cant

diff

eren

ceat

P≤

0.05

and

P≤

0.01

,df=

5;bu

tthe

reis

nosi

gnifi

cant

diff

eren

cein

Cr

bioa

ccum

ulat

ion

obse

rved

with

diff

eren

tage

ofpl

ants

.

801


transplantation, the percentage reduction of Cr+6 level in irrigated mine water runningthrough successive paragrass plots (passage distance of 2000 sq ft.) was 19–33%. Thepercent reduction of Cr+6 was less for the plants grown for 75 days which may be attributedto low biomass content as compared to 100 days grown plants. It was also observed that theplot wise sequential reduction of Cr+6 level of irrigated mine waste water was also significant(Figure 1).

Chromium Phytoaccumulation in Paragrass

Total chromium (Cr) content of different plant parts showed a high degree of variation(Table 3). A significantly high Cr accumulation was noted in roots (at P ≤ 0.05 and 0.01)followed by stems and leaves on all age group (75, 100, and 125) of plants. Maximumaccumulation of total Cr was observed in roots of paragrass on 100 DAT in comparison to75 and 125 days after transplantation. Aerial parts of the paragrass showed 10 to 100 foldless Cr as compared to roots. Similar type of results were also reported earlier by severalworkers (Pulford and Watson 2003; Zayed and Terry 2003; Ghosh and Singh 2005a; Donget al. 2007; Erenoglu et al. 2007; Zhang et al. 2007; Mohanty et al. 2011). High bioavail-ability of metals in roots and low translocation to shoots is the most common resistance trait(Dickinson and Lepp 1997; Zayed and Terry 2003) for metal tolerance as found in paragrassin the present study. Chromium concentration in plants growing in “normal” soil is usuallyless than 1 mg kg−1, rarely exceed 5 mg kg−1 and is typically in the order of 0.02–0.2 mgCr kg−1 dry weight (DW) (Zayed and Terry 2003). The high Cr accumulation in root cellswas supported by Shanker et al. (2004) who suggested immobilization of chromium fromthe vacuoles.

Cr phytoaccumulation expressed in terms of bio-concentration factor (BCF) valuesincreased with increasing external Cr levels in soil as well as the age of plants. BCF valuefor Cr in paragrass was maximum (0.334) on 100DAT. Maximum Cr bioaccumulation (interms of BCF) was observed in 100 days grown paragrass plants (0.334) in comparison to75 Days (0.145) and 125 (0.201) days grown plants. BCF values significantly vary with ageof plants as shown by their F-Values at P ≤ 0.05. Ti values in paragrass indicated that rootto shoot translocation of Cr was very high after 100 days of growth period which indicatedtheir ability to translocate Cr from the root to the shoot, or to compartmentalize it, in orderto continue absorption of Cr from the substrate. Better translocation is advantageous tophytoextraction; as it can reduce Cr concentration and thus reduce toxicity potential tothe root (Mohanty et al. 2009). Translocation to the shoot is one of the mechanisms ofresistance to high Cr concentration (Ghosh and Singh 2005b). After 125 days of growth,paragrass showed a general trend of increase in Ti with increased chromium concentration.Bio-concentration factor (BCF) for Cr increased with increase in time, this indicated thatCr was accumulated up to maturity (Table 4). The amount of chromium decreased withincrease in time which depicts that the accumulation of chromium was non-linear andshowed a negative correlation. In both the test plants BCF values for roots were generallymaximum than leaves and stems during 125 days of growth.

The recovery of Cr can be interpreted from the values of total accumulation rate(TAR), which was 8.29 mg Cr per kg dry biomass day−1 in paragrass (Table 4).

The results suggest that the paragrass can be considered as a hyper-accumulatorwhich may be used as a tool of rhizofiltration and phytoextraction to combat the problemof in situ Cr contamination. The study provides the idea of biomass-based phytoextraction

Tabl

e4

Bio

-Con

cent

ratio

nFa

ctor

(BC

F),T

rans

port

atio

nin

dex

(Ti)

and

Tota

lAcc

umul

atio

nR

ate

(TA

R)

ofpa

ragr

ass

from

diff

eren

texp

erim

enta

lplo

ts

Ti

Bio

Con

cent

ratio

nFa

ctor

ofTo

talP

lant

∗

Exp

erim

enta

lplo

tsPl

ant

75D

AT

100

DA

T12

5D

AT

75D

AT

100

DA

T12

5D

AT

TAR

(mg

kg−1

Day

−1)

1PG

+F2.

684.

856.

160.

145

0.33

40.

201

8.23

4PG

+F6.

941.

956.

840.

108

0.24

70.

150

8.29

Two

fact

orA

NO

VA

with

outr

eplic

atio

n:∗ F

valu

esfo

rpa

ragr

ass

Plot

s(b

etw

een

diff

eren

tage

s)=

42.6

0at

P≤

0.05

,df=

5;th

ere

issi

gnifi

cant

diff

eren

cein

BC

Fva

lues

.∗ F

valu

esfo

rpa

ragr

ass

Plot

s(b

etw

een

diff

eren

tplo

tsi.e

.1an

d4)

=15

.34

atP

≤0.

05,d

f=

5;th

edi

ffer

ence

inB

CF

valu

esis

nots

igni

fican

t.

803


using high biomass producing paragrass species growing luxuriantly under field conditionwith high root accumulation capacity.

The results of field experiments conducted at experimentally designed cultivated plotsof paragrass indicate that Cr uptake and bioaccumulation differ significantly with plant ages.The test plants could be used as hyperaccumulators for reduction of Cr from contaminatedsoil and mine waste water due to high bioconcentration of Cr in plant tissues. Moreover thedrought tolerant paragrass species can withstand short term flooding and water logging andis highly tolerant to saline or sodic soil conditions. So it is an excellent phytoremediation toolfor reclamation of contaminated soil. The Cr accumulation in paragrass can be verified fromthe BCF, TAR and Ti values. The extensive and massive fibrous root systems of paragrassare the helpful means for filtering out the pollutants through rhizofiltration mechanism atthe mining sites. There is a great phytoremediation ability of paragrass (Brachiaria mutica(Forssk.) Stapf) which can be used in the remediation of Cr contaminated mine waste waterand soil as evident from the present filed experiment at South Kaliapani Chromite minearea. Paragrass showing high biomass had a strong tolerance to Cr which can be used as atool of phytostabilisation for reclamation of heavy metal contaminated mining sites. Thestudy also give a suggestive measure for the farmers growing fodder crops irrigated withcontaminated water at the Cr polluted sites.

ACKNOWLEDGMENT

The authors are grateful to Indian Bureau of Mines, Government of India for financialsupport in the form of a research Project.

ABBREVIATIONS

PG+F: Paragrass with fertilizer treatment.DAT: Days after transplantation.

REFERENCES

Adriano DC. 1986. Trace Elements in the Environment. New York:Springer-Verlag. p. 105–123.American Public Health Association (APHA). 1995. Standard methods for the examination of water

and wastewater. 19th ed. Washington (DC): APHA.Bath E. 1989. Effecs and heavy metals in soil on microbial processes and populations (A. review).

Water Air Soil Poll. 47:335–379.Bonet A, Poschenrieder CH, Barcelo J. 1991. Chromium–III iron interaction in Fe deficient and Fe

sufficient bean plants. I. Growth and nutrient content. J. Pl. Nutr. 14(4):403–414.Dickinson NM, Lepp NW. 1997. Metals and trees: impacts, responses to exposure and exploitation

of resistance traits. In: Prost R, editor. Contaminated soils. The 3rd International Conferenceon the Biogeochemistry of Trace Elements. Paris: INRA. p. 247–254.

Dong J, Wu F, Huang R, Zang G. 2007. A Chromium tolerant plant growing in Cr-contaminatedland. Int. J. Phytoremediat. 9:167–179.

Erenoglu BE, Patra HK, Khodr H, Romheld V, Wir’en NV. 2007. Uptake and apoplasmic retentionof EDTA and phytosiderophore-chelated chromium (III) in maize. J. Plant. Nutr. Soil. Sci.170(6):788–795.

Ghosh AB. Bajaj JC, Hasan R, Singh D. 1983. Collection and preparation of soil samples for analysis.In: Soil and water testing method-A laboratory manual. Division of soil science and agriculturalchemistry. Indian Agricultural Research Institute. New Delhi, India: Yugantar Press.


Ghosh M, Singh SP. 2005a. A review on phytoremediation of heavy metals and utilization of itsby-products. Appl. Ecol. Environ. Res. 3(1):1–18.

Ghosh M, Singh SP. 2005b. Comparative uptake and phytoextraction study of Soil induced chromiumby accumulator and high Biomass weed species. Appl. Ecol. Environ. Res. 3(2):67–79.

HACH. 1992. Soil and Irrigation water manual, SIW kit. 24960-88. Loveland (CO): Hach Company.p. 1–72.

IBM (Indian Bureau of Mines). 2004. Annual Report of IBM. Nagpur, India: Govt. of India.Katz SA, Salem H. 1994. The Biological and Environmental Chemistry of Chromium. New York:

VCH Publishers, Inc.Mohanty M, Jena AK, Patra HK. 2005a. Effect of chelated chromium compounds on chlorophyll

content and activities of catalase and peroxidase in wheat seedlings. Ind. J. Agr. Biochem.8(1):25–29.

Mohanty M, Patra HK. 2011. Attenuation of Chromium Toxicity by Bioremediation Technology.Rev. Environ. Contam. Toxicol. 210:1–34.

Mohanty M, Pattnaik MM, Mishra AK, Patra HK. 2005b. Assessment of soil and water quality ofchromite mine area of South Kaliapani, (Sukinda, Orissa). Bull. Environ. Sc. 23(2):109–113.

Mohanty M, Pattanaik MM, Misra AK, Patra HK. 2009. Chromium detoxification from mine wastewater by rice – A case study at South Kaliapani chromite mine area, Sukinda, Orissa. e-Planet.7(1):26–31.

Mohanty M, Pattnaik MM, Mishra AK, Patra HK. 2011. Chromium bioaccumulation in rice grown incontaminated soil and irrigated mine waste water - A case study at South Kaliapani chromitemine area, Orissa, India. Int. J. Phytoremediat. 13:397–409.

Panda SK, Patra HK. 1997. Physiology of chromium toxicity in plants - A review. Pl. Physiol.Biochem. 24(1):10–17.

Pulford ID, Watson C. 2003. Phytoremediation of heavy metal contaminated land by trees-A review.Environ. Int. 29:529–540.

Shanker AK, Djanaguiraman M, Sudhagar R, Chandrashekar CN, Pathmanabhan G. 2004. Differentialantioxidative response of ascorbate glutathione pathway enzymes and metabolites to chromiumspeciation stress in green gram (Vigna radiata (L.) R. Wilczek) roots. Pl. Sci. 166:1035–1043.

Zayed A, Lytle CM, Qian JH, Terry N. 1998. Chromium accumulation, translocation and chemicalspeciation in vegetable crops. Planta. 206:293–299.

Zayed AM, Terry N. 2003. Chromium in the Environment: factor affecting biological remediation.Plant Soil. 249:139–156.

Zhang XH, Liu J, Huang HT, Chen J, Zhu YN, Wang DQ. 2007. Chromium accumulation by thehyperaccumulator plant Leersia hexandra Swartz. Chemosphere. 67:1138–1143.

Zurayk R, Sukkariyah B, Baalbaki R, Ghanem DA. 2002. Ni phytoaccumulation in Mentha aquaticaL. and Mentha sylvestris L. Water Air Soil Poll. 139:355–364.

Copyright of International Journal of Phytoremediation is the property of Taylor & Francis Ltd and its content

may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express

written permission. However, users may print, download, or email articles for individual use.

phytoremediation potential of paragrass— an in situ approach for...

Documents