a study on the impact of pollution in bellandur lake due to urbanization

1

A STUDY ON THE IMPACT OF

POLLUTION IN BELLANDUR

LAKE DUE TO URBANIZATION

Done by-AMARTYA SHANKAR JHA

2

INDEX

1. Research and planning 1

2. Hypothesis 9

3. Methodology 10

4. Data collection and presentation 11

5. Observation 15

6. Socio-Economic survey 24

7. Conclusion 25

8. Evaluation 29

3

RESEARCH AND PLANNING

LAKES

Lakes are a dynamic inland aquatic ecosystem that support and maintain a parity in

the food web of organisms of that area. They are surrounded by land on all sides

and have no direct access to the sea. Lakes are mainly fed and drained by rivers

and streams.

CLASSIFICATION OF LAKES:

The first level of classification of lakes is based on origin. However, in the context

of lake use and assessments such a classification is of little value. Lakes can be

classified into two other systems, which provide basis for assessment strategies and

interpretations. These are the physical or thermal lake classification and the

classification by trophic levels.

Physical/thermal lake types

This is defined by the uptake of heat from the solar radiation by lake waters,

and the cooling by the convection loss of heat, resulting in major physical or

structural changes in the water column.

Figure 1: Typical temperature profile from a stratified lake in the temperate zone, showing

the division of the water into three layers of different density

4

Trophic status

The ability of a lake to support plant and animal life defines its level of

productivity or trophic state. The process of eutrophication underlying this

scheme is one of the most significant processes affecting lake management.

Figure 2:

Classifying lakes

according to the

degree of

eutrophication.

5

Lake Pollution:

Pollution is the introduction of contaminants into the natural environment that

causes adverse change. India is associated to having major problems with water

pollution, predominantly due to untreated sewage, high levels of biological oxygen

demand. Majority of lakes are eutrophic due to extensive urbanization.

Eutrophication is the excessive richness of nutrients in a water body, due to

runoff from the land, which causes dense growth of algae, leading to algal blooms.

An abundance of algae provides excessive decaying material, and hence a greater

reduction in oxygen as the material decomposes. With lack of sunlight and oxygen

the entire food web collapses.

ECOLOGICAL ROLE OF LAKE:

ROLE OF A LAKE

Regulating the flow of the river Storage of water during dry seasons

Maintaining the ecosystem Generation of Hydro-electric power

Biodiversity conservation areas Buffer for shore lines against erosion

Domestic use Fishing Water source

Tourist and recreational locations Natural balance preserving reservoirs

6

Lakes in Bangalore

Bangalore was once called “The city of a 1000 lakes”. The cities tanks were its

lifeline- they irrigated fields supplied fresh drinking water, recharged ground water

and supported teeming wildlife. As the city exploded with growth, we lost our

lakes to unplanned urbanization, encroachment, numerous high rises, sewage

dumping and even a malaria eradication program. In 1960 Bangalore had 282

lakes. Today, barely 34 remain.

Figure 1 shows the map of Lakes in Bangalore.

7

Bellandur Lake

Balladur Lake lies to the southeast of the city of Bangalore and is the largest lake

in the city. The lake is a receptor from three chains of lakes upstream, and has a

catchment area of about 148 square kilometers. Water from Bellandur flows to

Varthur Lake, ultimately joining the Pennar River.

Bellandur Lake is also the most polluted lake in Bangalore. Most of Bangalore

treated and untreated sewage is let into this lake, thus immensely polluting the

lake, and thus destroying its ecosystem.

Urbanization of the lake region has also played a major role in the degradation of

the lake and the depletion of the flora and fauna. The conversion of watershed area

of the lake to residential and commercial layouts has altered the hydrological

regime while enhancing the silt movement – lowering water yield in the catchment,

affecting the groundwater recharge. There has been a drastic increase in pollutants

and the waste dumped into the lake. The untreated sewage dumped into lake

hampers the ecological balance of the system. This has led to an enrichment of

nutrients, and has resulted in the eutrophication of the lake.

Figure 2 shows the map of Bellandur Lake.

8

FLORA AND FAUNA

Bellandur Lake once had diverse species of flora and fauna. At present, the number

of species has reduced drastically and is almost negligible.

Plate 1: Species that no longer inhabit the Bellandur lake area.

9

Hypothesis

“To investigate the impacts of urbanization on Bellandur Lake, where the problem

of lake management is becoming a serious issue and to understand the present

scenario and shortcomings.”

OBJECTIVES

To analyze the ecological peril posed on the water body.

To investigate the gravity of the situation of the degradation of the lake.

To provide sustainable solutions that will replenish the overall quality of the

lake and also resurrect the lake’s ecosystem.

Figure 3: Bellandur Lake at present.

Figure 4: Bellandur Lake in the past.

10

METHODOLOGY

The investigative study includes an extensive research through the survey of the

lake area, determination of water quality by water quality analysis and socio-

economic surveys.

1. Survey of the lake:

The lake was observed and surveyed. The points of water inflow and outflow were

examined. And the water samples were collected from three different areas of the

lake. Safety measures were followed while collecting the samples.

2. Water Quality Analysis:

Water samples were collected from three different sites of the lake. The following

parameters were taken in for the study for determining the water quality:

Turbidity

Conductance

pH

BOD (Biochemical Oxygen Demand)

COD (Chemical Oxygen Demand)

Coliform bacteria

DO (Dissolved Oxygen)

Measuring Water Quality Index

3. Secondary sources of data:

Journals, magazines and websites were used for reference to supplement my

research.

11

Data collection and presentation

Site A: Bellandur area

It is surrounded by small scale industries and shops. These industries have a direct

exposure to the lake. This part of the lake emits a pungent smell that can be

detected throughout the region. The lake has vast amount of foam floating on it.

Plate 2: Bellandur area

12

Site B: Yemalur Area

Apartment complexes and residential areas surround this part of the lake. This

region appears less turbid than the Bellandur area, but still looks polluted.

Plate 3: Yemalur Area

13

Site C: Kempapura area

This region is completely surrounded by agricultural belt. This part of the lake is

covered with water hyacinth showing intense eutrophication.

Plate 4: Kempapura area

14

Collection of samples

To determine the overall water quality, water samples were collected from 10-

40cm below the water surface in the morning. Samples were collected in 1liter

plastic containers and taken to the lab within 2 hours of collection for chemical

analysis.

Water quality analysis

Onsite analysis includes temperature and transparency of the water samples. Lab

analysis included parameters like pH, DO, BOD, COD, electrical conductivity,

turbidity and coliform testing. Water analysis followed standard procedures using

water quality testing kits.

Procedure

(1.) Temperature: With the help of a digital thermometer, temperature was

recorded for 3 sites.

(2.) pH: The degree of acidity or alkalinity can be determined by the pH value of

the water source. A digital pH meter was used to test the samples.

(3.) Dissolved oxygen: Low DO values represent severe pollution, healthy lake

with high DO values supports a wide range of aquatic life. DO was tested by

titration method.

(4.) BOD: It is a measure of the quantity of oxygen used by the microorganisms in

the aerobic oxidation of organic matter. BOD was tested by incubation method.

(5.) COD: It is a measure of oxygen consumed during the oxidation of organic

matter by a strong oxidizing agent.

(6.) Turbidity: It is the amount of particulate matter suspended in water. Turbidity

was measured using a turbidometer.

(7.) Coliform bacteria test: Coliform bacteria are found in the feces of humans

and other warm blooded animals. It spreads water borne diseases.

The samples were given for testing to Aquadiagnostics Water Research and

Technology Centre Ltd.

15

Observations

Results for the analysis at the 3 sites are presented in table 1 along with the

standard value for unpolluted water.

Table 1

Parameters Results Standard Value

SITE A

(Bellandur

area)

SITE B

(Yemalur

area)

SITE C

(Kempapura

area)

Temperature ºC 27.0 27.0 27.0 -

Electrical conductivity

ms/Cm

0.815 0.817 0.801 300

pH value 7.02 7.0 7.03 6.5-8.5

Turbidity NTU 9.20 2.90 114.0 5

BOD mg/L 24.0 48.0 24.0 2.0

COD mg/L 80.0 120.0 1000.0 20.0

Dissolved oxygen mg/L 5.60 5.0 4.60 6

Total Phosphate mg/L

mg/L

1.03 1.13 0.97 0.005-0.020

Nitrate mg/L 06.60 06.60 14.14 45

Total dissolved solids

mg/L

531.0 486.0 473.0 500

Total coliforms

MNP/100ml

1600 1600 1600 Absent

Fecal Coliform

MNP/100ml

240 170 900 Absent

16

WATER QUALITY INDEX (WQI)

In an attempt to devise a system to compare lakes in various parts of the country,

the National Sanitation Foundation (NSF) created and designed a standard index

called the Water Quality Index (WQI). The overall results of nine separate tests are

used to determine whether a particular stretch of the water body is healthy.

The WQI consists of nine tests:

Dissolved Oxygen

Fecal Coliform

pH

BOD (Biochemical Oxygen Demand)

Temperature

Total Phosphate

Nitrates

Turbidity

Total Solids

After completing the nine tests, the results are recorded and transferred to a

weighting curve chart where a numerical value is obtained. For each test, the

numerical value or Q-value is multiplied by a “weighting factor”. The resulting

values are then added to arrive at an overall water quality index.

Water Quality Factors and Weights

Factor Weight

Dissolved Oxygen 0.17

Fecal coliform 0.16

pH 0.11

Biochemical oxygen demand 0.11

Temperature change 0.10

Total phosphate 0.10

Nitrates 0.10

Turbidity 0.08

Total solids 0.07

17

Table 2.1: Bellandur

Parameters Raw data Q value Weighting

factor

Total

pH 7.02 88 0.11 9.68

DO 5.60 5 0.17 0.85

BOD 24.0 8 0.11 0.88

Fecal

coliform

240 36 0.16 5.76

Total

phosphates

1.03 39 0.10 3.9

Nitrates 06.60 59 0.10 5.9

Turbidity 09.20 78 0.08 6.24

Total solids 531.0 20 0.07 1.4

Based on 8 factors the WQI is 38

Water Quality Index Legend

Range Quality

90-100 Excellent

70-90 Good

50-70 Medium

25-50 Bad

0-25 Very bad

The WQI of Bellandur area suggests that the quality of water is bad.

18

Table 2.2: Yemalur


factor

Total

pH 7.0 88 0.17 14.96

DO 5.0 5 0.11 0.55

BOD 48.0 5 0.16 0.8

Fecal

coliform

170 39 0.10 3.9

Total

phosphates

1.13 37 0.10 3.7

Nitrates 06.60 59 0.08 4.72

Turbidity 2.9 90 0.07 6.3

Total solids 486.0 34 0.11 3.74

Based on 8 factors entered, the WQI is 41


Range Quality

90-100 Excellent

70-90 Good

50-70 Medium

25-50 Bad

0-25 Very bad

The WQI of Yemalur area suggests that the quality of water is bad.

19

Table 2.3: Kempapura


factor

Total

pH 7.03 89 0.17 15.13

DO 4.60 4 0.11 4.4

BOD 24.0 8 0.16 1.28

Fecal

coliform

900 23 0.10 2.3

Total

phosphates

0.97 41 0.10 4.1

Nitrates 14.14 44 0.08 3.52

Turbidity 114 5 0.07 0.35

Total solids 473.0 36 0.11 3.96

Based on 8 factors, the WQI is 29


Range Quality

90-100 Excellent

70-90 Good

50-70 Medium

25-50 Bad

0-25 Very bad

The WQI of Kempapura area suggests that the quality of water is bad.

20

Weighted Curve Charts

In order to indicate the water quality of the three sites, weighted curve charts were

drawn and the coordinates of where the three sites lie on the curve charts are

mentioned next to these graphs.

Weighted curve chart for fecal coliform:

Coordinates of the three sites on the graph:

Bellandur (240, 36)

Yemalur (170, 39)

Kempapura (900, 23)

Weighted curve chart for BOD:


Bellandur (24, 8)

Yemalur (48, 5)

Kempapura (24, 8)

21

Weighted curve chart for Total solids:


Bellandur (531, 20)

Yemalur (486, 34)

Kempapura (473, 36)

Weighted curve chart for DO:


Bellandur (5.60, 5)

Yemalur (5, 5)

Kempapura (4.60, 4)

22

Weighted curve chart for pH:


Bellandur (7.02, 88)

Yemalur (7.0, 88)

Kempapura (7.03, 89)

Weighted curve chart for turbidity:



Yemalur (2.9, 90)

Kempapura (114, 5)

23

Weighted curve chart for nitrates:

Coordinates for the three sites on the graph:

Bellandur(06.60,59)

Yemalur(06.60,59)

Kempapura (14.14,44)

Weighted curve chart for total phosphates:

Coordinates for the three sites on the

graph:


Yemalur (1.13, 37)

Kempapura (0.97, 41)

24

SOCIO-ECONOMIC SURVEY

A socio-economic survey was conducted to collect relevant data for planning and

formulating data. I understood the impact of lake pollution on the people residing

in Bellandur lake and also learnt about the transition of the lake from clean to a

contaminated one. Following is a summary of my interaction with the residents.

Residents were highly concerned about the severe water contamination. The lake

had been used for swimming, fishing, drinking purposes in the yester years. People

barely come out of their houses due to the stench and foam emitting from the lake.

Ground water has become contaminated, people are forced to buy water cans,

bore wells are drilled to depths of 1,200ft and beyond. Over the past seven years,

agricultural production had declined, 90% of farm land were sold to companies.

Doctors complain that they receive about 50 patients with complaints of wheezing,

respiratory illness, malaria, dengue and skin related problems every day.

Bellandur Lake, once was a biological hotspot is now a burden to the people living

in the vicinity.

25

CONCLUSION

Based on the water analysis and WQI of the three sites, the following conclusion

can be drawn.

The PH of the water samples were 7.02, 7.0 and 7.03 for sites A, B and C

respectively. Hence the water samples were found to be slightly alkaline.

Turbidity of an area determines the presence of toxic contaminants of the lake and

thus increases the chance of water borne diseases. Site one (9.2) and site three

(114) had a very highly turbid value.

DO is required for the survival of aquatic life. All the three sites had an extremely

low DO value. Low DO values create an anoxic condition that can be detrimental

to living organisms.

High BOD and COD values indicate the influx of sewage into the lake. It signifies

the decomposition of organic matter and is the main factor leading to low DO levels.

Aquatic plants consume much of the oxygen during nighttime respiration. High

BOD values denote that the samples comprises largely of degradable organic matter

and less amount of inorganic constituents that cannot be oxidized by bacteria.

Fecal coliform bacteria are positive for all three sites. This increases the risk of

hepatitis, dysentery, skin diseases etc.

Levels of nitrates are less than the standard values attributing to the process of

ammonification- conversion of organic nitrogen to ammonium during the

decomposition of organic matter. Due to low oxygen concentration, nitrate is

converted to nitrite and this process is responsible for the lower nitrates

concentration in the water. During periods of high plant growth, the levels of nitrates

may be significantly reduced.

The WQI for the three sites indicates that the lake is totally deteriorated, highly

eutrophic with foams emitting from the lake due to presence of chemicals.

26

Problems Faced by Bellandur

lake

Garbage dumped in the

lakeEutrophication

Salinization

Acidification

Saprobization

Urbanization

Nobody is held accountable

for the pollution of

the lake

No initiative has been

taken to clean up the lake so

far

Large scaale encroachment

of the land adjoining the water body

Fire due to methane emission

Frothing of the lake

Problems faced by Bellandur Lake

27

Impact on the environment:

Micro-climatic changes.

Reduction in flora and fauna diversity.

Ground water contamination.

Loss of fresh water.

Impact on the people

Serious health concerns including cancer

Unhealthy living environment

Scarcity of water

In recent years, population pressures and anthropogenic activities had led to the

expansion of unplanned infrastructure. Lakes are either drained or converted in to

solid waste dumping sites. The 1000 year old Bellandur lake is losing its charm

due to sustained inflow of industrial effluents, untreated sewage, dumping of

building debris and solid waste. Heavy metals are causing severe groundwater

pollution in the neighbouring areas of the lake, high nitrate levels could take health

concerns.

Serious restoration efforts has to be taken up by the citizens of Bangalore and the

government of Karnataka.

28

Lake Restoration

Fencing the lake

boundaries to prevent trespassing

Desiltation of the lake

Educating the public and

Encouraging ecotourism

activities as a part of school

curriculum

reduction of non-point

source, waste minimization

Setting up of more sewage

treatment plants &

increasing their capacity

Organising rallies and

fundraisers for the restoration

of the lake

Imposing fines on those who contribute to

the degradation of the lake

Recommendations for lake restoration

29

EVALUATION

Through my study, I have understood the fragility of fresh water ecosystems and

the responsibility mankind should adopt to conserve water bodies. I was made

aware of the adversity faced by the residents of Bellandur. I am satisfied with my

work, as I have explored the major aspects of the impact caused by urbanization on

the lake body. The time provided for doing this coursework was sufficient and this

was helpful as the Bellandur lake pollution was an ongoing problem during the

time I was working on this study. Bellandur lake has been one of the most

prominent lakes in Karnataka and is worsening at a rapid rate. BWSSB Chairman

T M Vijay Bhaskar said that it will take at least five years to get rid of the toxic

foam that has been emanating from the Bellandur Lake in the City.

Restoration of the lake would require adequate funds, dedication and constant

support.

a study on the impact of pollution in bellandur lake due to urbanization

Environment