Andreas Hellohf

Uppsats för avläggande av naturvetenskaplig kandidatexamen iMiljövetenskap

15 hpInstitutionen för växt- och miljövetenskaper

Göteborgs universitet

Juni 2011

The Bhopal Heritage – Soil analysis at

UCIL factory site from a chemical hazard

perspective

1

Summary

Bhopal is most known as the city where the worst chemical accident ever took place. The

UCIL factory site where the accident occurred is today a decaying monument and a place

associated with death and devastation. With the ambition to create something positive out of a

tragedy, the project Bhopal 2011 was set up. This is an interdisciplinary project, which aims

to transform the factory area into an industrial heritage. A place where history can be told,

questions asked and victims can be remembered. In order to implement the project, it’s

necessary that soil and water are analyzed to determine what types of contaminants that are

left and that could pose a threat to humans and the environment. One problem has been that

the studies undertaken have been questioned from an interest perspective. The aim of this

study was to examine the similarities and differences in the reports that have been published

by Greenpeace, the Centre for Science and Environment (CSE) and National Environmental

Engineering Research Institute (NEERI). The results show that there are some major

differences in the reports and that there is a need for additional sampling in the area to

determine which pollutants that can be detected, where they are and in what quantities they

can be found.

Sammanfattning

Bhopal är mest känt som staden där tidernas värsta kemikalieolycka inträffade. UCIL:s

fabriksområde, där olyckan inträffade, är idag ett sönderfallande monument och en plats

förknippat med död och förödelse. Med ambitionen att skapa någonting positivt ur någonting

tragiskt så inleddes projektet Bhopal 2011. Detta är ett tvärvetenskapligt projekt, med målet

att förvandla området till en industriell kulturminnesarvsplats. En plats där historien kan

berättas, frågor ställas och offren bli ihågkomna. För att kunna genomföra projektet så krävs

det att mark och vatten undersöks för att fastslå vilka typer av föroreningar som finns kvar

och som kan utgöra ett hot mot människor och miljö. Ett problem har varit att utförda

undersökningar har ifrågasatts utifrån ett intresseperspektiv. Denna rapport syftade till att

undersöka vilka likheter och skillnader som fanns i de rapporter som tidigare har publicerats

av Greenpeace, Centre for Science and Environment (CSE) och National Environmental

Engineering Research Institute (NEERI). Resultaten visar att det finns en del stora skillnader i

rapporterna, och att det finns ett behov av ytterligare provtagning inom området för att

fastställa vilka föroreningar som finns, var de finns och i hur stora mängder.

2

Table of Contents

Summary................................................................................................................................1

Sammanfattning .....................................................................................................................1

1. Introduction.....................................................................................................................3

1.1 The accident............................................................................................................3

1.2 The product and the production...............................................................................3

1.3 An industrial heritage..............................................................................................4

1.4 Pollution .................................................................................................................4

1.5 Possible pollutants ..................................................................................................5

1.6 Aim of the study .....................................................................................................5

2. Methods ..........................................................................................................................5

2.1 Literature review.....................................................................................................5

2.2 Visit at the UCIL site in 2011..................................................................................6

2.3 Soil toxicity bioassay ..............................................................................................6

3. Results ............................................................................................................................7

3.1 Metals .....................................................................................................................7

3.2 Pollutants in samples...............................................................................................9

3.3 Mobility of water fleas (Daphnia magna) ..............................................................12

3.4 Pollutant at site D..................................................................................................13

3.5 Sample value min/max ..........................................................................................13

4.1 Variance in values.................................................................................................14

4.2 Sampling methods.................................................................................................14

4.3 Site risk assessment...............................................................................................14

5. Conclusions...................................................................................................................15

6. Acknowledgement.........................................................................................................16

7. References.....................................................................................................................16

8. Annex 1.........................................................................................................................17

3

1. Introduction

The Bhopal factory was built in 1969 by Union Carbide India Limited (UCIL) and taken into

operation in 1977 to produce Carbaryl, a pesticide more known as Sevin. Methylisocyanate

(MIC) is used as one of the raw materials in the production of Sevin and it was the leakage of

MIC during the night of 3rd December 1984 that led to the catastrophe (Indian Institute of

Chemical Technology, 2010). The factory has been closed ever since the accident occurred,

and today there are no traces of MIC or other substances remaining from the accident in the

surrounding area. Contamination of soil and groundwater may still occur though, from non

regulated waste dumping within and around the premises and from the disintegrating factory

(NEERI, 2010). The project Bhopal 2011 aim is to turn the factory site into an industrial

heritage, to honour the victims as well as trying to create something positive out of a tragedy

(Joshi, 2011).

1.1 The accident

The accident that took place on the night of December 2-3rd 1984 in Bhopal, India was the

largest chemical industrial accident ever (Eckerman, 2006). The direct cause of the accident

was a large amount of water that leaked into a MIC storage tank, T-610, containing 42 tons of

methyl isocyanate. The water caused an exothermic reaction and a temperature increase to

over 200 °C. The high temperature in the tank raised the pressure and led to the release of

MIC gas through a valve, into the atmosphere (Indian Institute of Chemical Technology,

2010). According to Union Carbide Corporations (UCC) own report all major safety systems,

that could have prevented the accident or mitigated the effects, were either shut off or

dysfunctional (Jayaprakash, N.D, 2010). The time spent on educating and training new

recruits was significantly shortened from the first day till the day of the accident. When

initiating the production of Sevin, a chemical or mechanical engineer required a 6 months

training period to be an operator at the plant. At the time of the accident, two weeks training

was enough to take independent charge of an operator’s position. On the night of the accident,

no trained engineer was at the site (Eckerman, 2005).

Over half a million people were exposed to the gases after the disaster and approximately

8.000 persons died within the first weeks and 100.000 received permanent injury (Eckerman,

2006). The acute effects on health after the accident were difficulty to breathe and blindness,

which later was resolved in most cases. Within the 5 first days 2000 people died, main death

cause was damage to respiratory system. The long term effects were an increased rate of

miscarriage and early infant death, visual acuity and damaged respiratory capacity (OEHHA,

2001).

1.2 The product and the production

The pesticide factory in Bhopal opened in 1969 to produce carbamate pesticides. Sevin, the

third most used insecticide in USA was discovered by Union Carbide in 1958. In 1977 a

4

facility was set up in Bhopal to produce Sevin and the highly reactive intermediate MIC was

imported from the USA. In 1980 the Bhopal plant started producing MIC at site (Eckerman,

2005). Carbaryl can be produced in different ways. UCIL used MIC to treat 1-naphtol to form

carbaryl, the alternative method also includes 1-naphtol, but it’s first converted to

chloroformate and is then treated with methylamine to form carbaryl. The later process

excludes the formation of MIC and even if not free from toxic substances, it involves lower

risk (Wikipedia, 2011). This process was used by UCIL between 1958 and 1973 but was

changed to the first one for economical reasons (Eckerman, 2005). Union Carbide also

produced Temik (trade name for aldicarb) and Sevidol, a mixture of carbaryl and gamma-

hexachlorocyclohexan (γ-HCH) (CSE, 2009).

1.3 An industrial heritage

The project Bhopal 2011 is an initiative taken by School of Planning – New Delhi, Modern

Asia Architecture Network and The International Committee for the Conservation of

Industrial Heritage. The industrial heritage aim to turn the factory site into a cultural heritage

to revitalize the precinct and community around the factory, as well as turn it into a place to

honour the victims and where history can be told and questions regarding sustainability can be

asked. A ten days workshop with fifty students from different disciplines and countries was

launched in 2011. Recognizing the challenge in turning a place of tragedy into a place of

remembrance, five different themes was explored from a design, urban regeneration and

heritage management perspective. The five groups of ten were led by two masters with

expertise in respective theme. The themes were:

1. Authenticity of Heritage and Interpretation

2. Public Art as Commemoration

3. Space as a Container for Memory

4. Public Participation and the Rehabilitation Process

5. Heritage Sites as Urban Resource

A three day symposium was launched 1st of February 2011 to discuss the Bhopal Gas Tragedy

from different perspective and to evaluate the results and thoughts reached during the

workshop (Joshi, 2011).

1.4 Pollution

Since the accident occurred, no remedial action has been taken and the status of the soil and

groundwater is still disputed. According to NEERI, there is no contamination of the

groundwater exceeding drinking water standards (NEERI, 2010). Groundwater samples taken

by CSE and GP contain high levels of chlorinated compounds, above Bureau of Indian

Standards (BIS). The UCIL factory is the only source of chlorinated benzene compounds and

pesticides in the vicinity. Chemicals detected by CSE in groundwater samples matches the

ones found at the factory site (CSE, 2009).

5

1.5 Possible pollutants

Substances of interest that has been found at and around the factory site are heavy metals (Cd,

Cr, Hg, Pb), organochlorines, carbaryl and aldicarb (Greenpeace, 1999).

1.6 Aim of the study

An industrial heritage at UCIL factory site, Bhopal India, would involve public access to the

former industrial site. This study was made to examine if the soil at the site still contain any

substances that could be a threat to the environment by comparing different reports made by

different organizations.

2. Methods

2.1 Literature review

Reports by Greenpeace (GP), Centre for Science and Environment (CSE) and National

Environmental Engineering Research Institute (NEERI) were used to assess the

contamination at the UCIL factory site (Fig. 1).

A: Pilot plant

B: Sevidol plant

C: Sevin plant

D: Dumpsite

E: Former Solar Evaporation Pond

6

Figure 1 Sampling sites at UCIL factory site

2.1.1 Site descriptions

Site A – The pilot plant. Near the Temik plant where aldicarb was produced

Site B – Sevidol plant.

Site C – Sevin plant.

Site D – Dumpsite. An area used as dumpsite before the construction of the SEP (Greenpeace,

1999)

Site E – Former Solar Evaporation Pond. A constructed waste disposal site (CSE, 2009)

2.2 Visit at the UCIL site in 2011

The UCIL site was visited in February 2011 during the Workshop by Maria Greger,

Stockholm University, and surface (0-5 cm) soil samples were taken at the sites shown in

Fig. 2.

Fig. 2. Sampling sites used in 2011 to take superficial soil samples to Sweden for Daphnia bioassays

and chemical analysis.

2.3 Soil toxicity bioassay

Samples from UCIL factory site taken in 2011 were tested for toxicity to Daphnia magna

according to ISO (1989). Each sample was prepared by muddling it into a homogeneous site

distribution sample. Then 5.0 g of each sample and 20 ml deionized water was put into a 50

ml plastic test tube. The test tube was centrifuged for 30 minutes. 15 ml of each supernatant

was pipetted out of the test tube and poured into the Petri dish and 10 water fleas, about 48

hours old, were added into each dish. Immobilization was recorded after 24 and 48 hours. A

reference toxicant test with potassium dichromate was made simultaneously with

concentrations of 4, 2, 1, 0.5, 0.25, 0 mg/l (ISO, 1989).

7

3. Results

The results are presented first for the analyzed metals (3.1), with estimation of risks (3.1.1)

and comments on specific metals. Then pollutants (pesticides) are presented in the same way

(3.2) and finally the results of the soil bioassays are presented (3.3).

3.1 Metals

Concentrations of metals are shown in Table 1

GREENPEAC

E1 NEERI2 CSE3

Sample4 Sample4 Sample4

Result

Are

a

Met

al

1 2 1 2 3 4 5 6 1 2 3 Mean

Pb N/A 3.18 4.30 111.8 39.8

Cd N/A 0.58 0.54 N/D 0.37

Cr N/A 2.22 1.98 297.7 101 A

Hg N/A N/D N/D 74.14 24.71

Pb 19.4 4.29 2.37 N/D 6.52

Cd N/D 0.41 0.18 N/D 0.15

Cr 85.7 2.32 1.65 108.4 49,5 B

Hg 2.6 1.29 1.29 N/D 1,30

Pb 174.6 6.64 5.92 84.05 67.8

Cd N/D 1.32 0.74 N/D 0.52

Cr 480.7 1.83 1.48 192.1 169 C

Hg 128000 N/D N/D 8188 34047

Pb 11.0 15.7 3.18 2.16 3.08 2.62 1.22 1.46 46.39 17.13 4.85 9.89

Cd N/D N/D 0.65 0.58 0.76 0.82 1.34 1.62 N/D N/D N/D 0.52

Cr 73.0 52.9 1.10 2.10 2.06 2.31 2.18 2.04 70.84 74.05 18.18 27.3 D

Hg 0.8 8.1 0.14 N/D 0.63 N/D N/D N/D N/D N/D N/D 0.88

Pb 17.0 4.6 3.53 1.59 22.34 9.81

Cd N/D N/D 1.40 1.14 N/D 0.51

Cr 73.0 35.5 5.21 2.09 1065 236 E

Hg 1.1 0.4 0.30 N/D 18.00 3.96

Mean Value

Min Max Total

Pb 6.52 67.8 26.8

Cd 0.15 0.52 0.41

Cr 27.3 236 116.6

AB

CD

E

Hg 0.88 34047 6815

Table 1 Measured concentrations of metals at UCIL factory site. All values in ppm.

1 GREENPEACE, 1999 2 NEERI, 2010 3 CSE, 2009 4 Annex 1

8

3.1.1 Estimation of metal risk

� less than criteria: low risk

� 1-10 times the criteria: moderate risk

� 10-100 times the criteria: high risk

� >100 times the criteria: extremely high risk5

Mean Value Soil Criteria

Guidelines (SCG)7

Estimated Risk Value Metal

Min Max Total BGC

6

Min8 Max

9 Mean Min Max Mean

Pb 6.52 67.8 26.8 10-30 70 260 165 0.025 0.97 0.16

Cd 0.15 0.52 0.41 0.01-2.0 1.4 22 11.7 0.0068 0.37 0.035

Cr 27.3 236 116.6 1-100 64 87 75.5 0.31 3.69 1.54

Hg 0.88 34047 6815 0.02-0.625 6.6 24 15.3 0.036 5159 445

Min/

Max

Max/

Min

Mean/

Mean

Table 2. Measured concentrations of metals in soil at UCIL and soil quality criteria used to estimate

numerical risks as the ratio between measured concentrations and criteria concentrations. All values

in ppm. BGC=Background Concentration.

All metals are considered to have low risk at minimum level. At maximum and mean level

chromium is considered to have moderate risk and mercury to have extremely high risk.

3.1.2 Mercury

Mercury has been detected at all test sites with a total mean value of 6815 ppm. The three

reports differ widely in value within area C, The Sevin tank. Greenpeace detected 128000

ppm at the site while NEERI report states that levels are below detection limit. CSE report

high levels as well, 8188 ppm. Mean risk value is 445 which is considered as extremely high

risk. Mercury was used as a sealant in the Sevin plant (CSE, 2009)

Methylmercury is the most toxic form and affects the neurological system. Children are more

sensitive to exposure than adults. Fetuses in the womb exposed by the mothers’ uptake of

methylmercury may affect the development of cognitive thinking, memory, language and

visual spatial skills. Other observed effects are lack of coordination, impairment of speech,

hearing and walking (EPA, 2010).

5 Ford (2004) 6 Alloway (1990)

7 Canadian Council of Ministers of the Environment, (2007) 8 Agricultural land use 9 Commercial land use

9

3.1.3 Chromium

Levels above the mean SCG value have been detected at three out of five sites. The risk is

estimated at a maximum of 3.69 which is considered as moderate risk. Chromium was used as

a coolant in the cooling plant (CSE, 2009)

Even though chromium is naturally occurring in the Earth’s crust; high concentrations can be

harmful to human health and the environment, depending on which valence state it occurs in.

Trivalent chromium (III) is an essential ingredient in a balanced diet and its deficiency is

detrimental to the metabolism in humans and other mammals (EPA, 1998). Hexavalent

chromium (VI) is toxic and high concentrations can cause cancer, breathing problems and

damage to male reproductive system (ATSDR, 2008).

3.1.4 Cadmium

No site mean value exceeds the Soil Criteria Guideline (SCG) value.

3.1.5 Lead

No site mean value exceeds the Soil Criteria Guideline (SCG) value.

3.2 Pollutants in samples

The chemical pollutants measured at the UCIL site are shown in Table 3.

10

NEERI CSE

Sample10 Sample11

Are

a

Compound

1 2 3 4 5 6 1 2 3 Min Max Mean

Carbaryl 24.3 14.2 N/D N/D 24.3 12.8

Aldicarb N/D 923 N/D N/D 923 307

1,3 DCB 29.22

1,4 DCB 83.12

1,2 DCB

N/D 0.000

20.75

N/D 83.12 26.6

TCB N/A N/A 4.94 4.94 4.94 4.94

HCB N/A N/A 1.70 1.70 1.70 1.70

A

γ HCH N/D 16.54 264.2 16.54 264.2 93.58

Carbaryl 1.3 N/D 7.47 N/D 7.47 2.92

Aldicarb N/D N/D 190.7 N/D 190.7 63.6

1,3 DCB 489.8

1,4 DCB 541.7

1,2 DCB

N/D 0.000

1017

N/D 541.7 409.7

TCB N/A N/A 507.1 507.1 507.1 507.1

HCB N/A N/A 1.12 1.12 1.12 1.12

B

γ HCH 5.52 0.568 2782 0.568 2782 929

Carbaryl N/D 0.126 N/D N/D 0.126 0.042

Aldicarb N/D N/D N/D N/D N/D N/D

1,3 DCB 8.01

1,4 DCB 7.90

1,2 DCB

N/D 0.000

11.02

N/D 8.01 5.39

TCB N/A N/A 23.72 23.72 23.72 23.72

HCB N/A N/A 12.37 12.37 12.37 12.37

C

γ HCH N/D 0.08 198.0 N/D 198 66.0

Carbaryl 0.273 1.577 N/D N/D N/D 2.728 N/D N/D N/D N/D 2.728 0.51

Aldicarb N/D N/D N/D N/D N/D N/D 116.5 N/D 56.17 N/D 116.5 19.19

1,3 DCB 113.4 1.78 112.3

1,4 DCB 63.69 0.57 108.7

1,2 DCB

0.165 0.000 N/D N/D 0.10

8 N/D

20.92 N/D 16.5

N/D 113.4 29.2

TCB N/A N/A N/A N/A N/A N/A 6.47 N/D 104.7 N/D 104.7 37.1

HCB N/A N/A N/A N/A N/A N/A 50.57 4.56 5.16 4.56 50.57 20.1

D

γ HCH 1.83 2.48 2.06 3.41 N/D N/D 555.9 45.23 702.3 N/D 555.9 145.9

Carbaryl 6.888 N/D N/D N/D 6.888 2.296

Aldicarb 8.158 N/D N/D N/D 8.158 2.72

1,3 DCB 0.49

1,4 DCB 0.62

1,2 DCB

N/D N/D

0.14

N/D 0.62 0.25

TCB N/A N/A 0.09 0.09 0.09 0.09

HCB N/A N/A 1.34 1.34 1.34 1.34

E

γ HCH N/D N/D N/D N/D N/D N/D

Mean

Min Max Total

Carbaryl 0.042 12.8 3.71

Aldicarb N/D 307 78.5

DCB 0.25 409.7 94.2

TCB 0.09 507.1 114

HCB 1.12 20.1 7.32

AB

CD

E

γ HCH N/D 929 247

10 Annex 1

Table 2 Measured concentrations of pollutants at

UCIL factory site. All values in ppm.

11

3.2.1 Estimation of pollutant risk

� less than criteria: low risk

� 1-10 times the criteria: moderate risk

� 10-100 times the criteria: high risk

� >100 times the criteria: extremely high risk11

Mean Value Soil Criteria Guidelines

(SCG)12

Estimated Risk Value

Metal

Min Max Total Min13 Max14 Mean Min Max Mean

Carbaryl 0.042 12.8 3.71 N/A N/A N/A N/A N/A N/A

Aldicarb N/D 307 78.5 N/A N/A N/A N/A N/A N/A

1,3 DCB

1,4 DCB

1,2 DCB

0.25 409.7 94.2 0.1 10 5.05 .025 4097 18.7

TCB 0.09 507.1 114.6 0.05 10 5.03 0.009 10142 22.78

HCB 1.12 20.1 7.32 0.05 10 5.03 0.112 402 1.46

γ HCH N/D 929 246.9 0.01 N/A 0.01 0 92900 24690

Min/

Max

Max/

Min

Mean/

Mean

Table 4. Measured concentrations of metals in soil at UCIL and soil quality criteria used to estimate

numerical risks as the ratio between measured concentrations and criteria concentrations. All values

in ppm.

All values at minimum level are considered low risk. All maximum and mean risk values

indicate that there is a moderate to extremely high risk.

3.2.2 Carbaryl

There are no SCG specifically for Carbaryl in soil. Chronic exposure to high levels of

carbaryl can lead to cholinesterase inhibition. The symptoms are headache, memory loss,

muscle weakness etc (CSE, 2009).

3.2.3 Aldicarb

There are no SCG specifically for Aldicarb in soil. Aldicarb is one of the most acutely toxic

pesticides registered on the U.S. market. Symptoms of poisoning are nausea, dizziness,

salivation, vomiting, difficulty breathing and leads to death if level of exposure is high

enough. The oral OD50 is between 0.3 and 0.9 milligram/kilo bodyweight (Cox, 1992).

11 Ford (2004) 12 Canadian Council of Ministers of the Environment, (2007) 13 Agricultural land use 14 Commercial land use

12

3.2.4 Chlorinated benzenes

Levels of dichlorobenzene above the mean SCG value have been detected at three out of five

sites. The mean risk value is 18.7 and indicates high risk. Trichlorobenzene above the mean

SCG value have been detected at three out of five sites. Symptoms after chronically exposure

are nervous system effects such as headache, numbness, dizziness, cyanosis, hyperesthesia,

and muscle spasms (OEHHA, 2000).

3.2.5 Hexachlorobenzene (HCB)

Levels above the mean SCG value have been detected at two out of five sites. The mean risk

value is 1.46 and indicates moderate risk, but the max value is 402 and an extremely high risk.

HCB is included in the “dirty dozen”, a group of persistent organic pollutants. Chronically

exposure to HCB can lead to porphyria cutanea tarda, a condition which involves

photosensitivity, muscle pain, depression, insomnia etc (UNEP, 2001). HCB is found as an

impurity in HCH. HCH was used at UCIL factory to extract γ-HCH from, for use in the

production of Sevidol. The remaining isomers were dumped. HCB also occurred as a

byproduct in chemical processes at UCIL (CSE, 2009).

3.2.6 Lindane, γ-Hexachlorocyclohexan (HCH)

Levels above the mean SCG value has been detected at all sites within the UCIL premises, but

not at the SEP area, E. Within the UCIL premises the min value is 66.00 and an extremely

high risk. Lindane is the pollutant that exceeds the extremely high risk value most times.

12/21 samples are over extremely high risk level (1 ppm). Symptoms of acute exposure to

lindane are vomiting, nausea and convulsions. Chronic exposure has been associated with

effects on liver and nervous, cardiovascular and immune systems (EPA, 2000).

3.3 Mobility of water fleas (Daphnia magna)

Table 5. Immobility (%) of Daphnia in bioassays with soil leachates

made with samples taken in 2011 (se Fig. 2).

Two samples, 3 and 5, showed toxicity. Sample 5 correspond to site D Table 1. Sample 3 does

not correspond to any of the sites.

13

3.4 Pollutant at site D

� Lindane have been detected in 7/9 samples at a mean concentration of 145.9 ppm

which gives a 14590 risk value and is to be considered as extremely high risk.

� Dichlorobenzene have been detected in 6/9 samples and at a mean concentration of

26.2 ppm which gives a 5.2 risk value and is to be considered as moderate risk

� Trichlorobenzene have been detected in 2/3 samples at a mean concentration of 29.2

ppm which gives a 5.8 risk value and is to be considered as moderate risk

� Hexachlorobenzene have been detected in 3/3 samples at a mean concentration of 20.1

ppm which gives a 4.0 risk value and is to be considered as moderate risk

� Carbaryl have been detected in 3/9 samples

� Aldicarb have been detected in 2/9 samples

� Every single metal sample value leads to low risk

Lindane, a neurotoxin, is found at high levels at the site where the sample is taken and might

be the toxin that caused the immobilization of Daphnia magna in the soil bioassay.

3.5 Sample value min/max

The table shows the minimum and maximum value for each report and each substance.

NEERI Greenpeace CSE

Min Max Diff Min Max Diff Min Max Diff

Pb 1.59 6.64 5.05 11.0 174.6 163.6 N/D 111.8 111.8

Cd 0.18 1.62 1.44 N/D N/D - N/D N/D -

Cr 1.10 5.21 4.11 73.0 480.7 407.7 18.18 1065 1047

Hg N/D 1.29 1.29 0.8 128000 127999 N/D 8188 8188

Carbaryl N/D 24.3 24.3 N/A N/A - N/D 7.47 7.47

Aldicarb N/D 923 923 N/A N/A - N/D 190.7 190.7 1,3 DCB

1,4 DCB

1,2 DCB

N/D 0.165 0.165 N/A N/A - N/D 541 541

TCB N/A N/A - N/A N/A - N/D 507.1 507.1

HCB N/A N/A - N/A N/A - 1.12 50.57 49.45

γ HCH N/D 16.54 16.54 N/A N/A - 45.23 2782 2737

Table 6. Minimum, maximum and difference (max-min) value for each report. All values in

ppm.

NEERIs values have little variance between maximum and minimum compared to

Greenpeace and CSE, except for aldicarb.

14

4. Discussion

The variance in values is discussed (4.1), the sampling methods (4.2), the different sampling

sites are analyzed (4.3).

4.1 Variance in values

There are some notable differences in the reports.

Soil samples collected by NEERI have a lower overall value than samples collected by

Greenpeace and CSE. Soil samples taken by NEERI for metal analysis vary from N/D to 6.64

ppm. Soil samples taken by Greenpeace for metal analysis vary from N/D to 128000 ppm.

Soil samples taken by CSE for metal analysis vary from N/D to 8188 ppm.

NEERI has no value in Table 1 that leads to more than low risk and no value in any sample

that is over the upper limit for background concentration. Neither Greenpeace nor CSE

detects cadmium in a single sample, while NEERI finds it in every sample. Carbaryl is

detected by NEERI at all sites but only at one site by CSE. CSE mean value for lindane at site

A-D is 758 ppm and NEERIs is 2.71.

4.2 Sampling methods

Greenpeace has taken six samples within the premises CSE seven samples and NEERI twenty

seven samples times two, surface and subsurface. All samples were collected from a known or

suspected hot spot. Only one sample was collected from each site by CSE and Greenpeace.

Greenpeace used 0.5 gram soil per sample. Using more than 0.5 gram soil would give a more

accurate result.

Question marks will remain whether finding pollutants or avoiding finding them is the desired

outcome. Using a grid system along with samples from hot spots would minimize the chance

of missing any unknown dumping site and more important; it would give a truer overall soil

status. Taking multiple samples from the same spot and mixing them together would give a

truer picture of the soil status.

4.3 Site risk assessment

What substances are detected at each site and where it could origin from are discussed below.

4.3.1 Site A - The Temik formulation plant

The highest single and mean value of aldicarb was found here; 923/307 ppm. The highest

single and mean value of carbaryl was found here 24.3/12.8 ppm. The Temik plant was where

aldicarb was being manufactured, which could explain the high levels.

4.3.2 Site B - The Sevidol formulation plant

The highest single and mean value of lindane was found here; 2782/929 ppm. Lindane was

used as an ingredient when manufacturing Sevidol. The highest single and mean value of

trichlorobenzene was found here; 507/507 ppm. The highest single and mean value of

15

dichlorobenzene was found here; 541/409 ppm. Chlorinated benzene compounds could be

degradation residues from HCB or lindane or isomers left over after extracting lindane (γ-

HCH).

4.3.3 Site C - The Sevin plant

Mercury was used as a sealant in the Sevin plant and the highest single and mean value of

mercury was found here; 128000/34047 ppm. High levels of chromium were found here,

which came from the cooling plant.

4.3.4 Site D - The Dumpsite

High levels of lindane were found by CSE, but low levels were found by NEERI. Low levels

of heavy metals were found. The highest single and mean value of HCB was found here;

50.57/20.1 ppm. HCB was a byproduct in chemical processes and most likely dumped at the

site.

4.3.5 Site E – Former solar evaporation pond

The highest single and mean value of chromium was found here 1065/235 ppm. Discharge of

cooling water from the UCIL cooling plant could be the reason.

5. Conclusions

� Values differ widely in samples taken within the same area by different organizations.

� Metal values varies very little (min-max) in samples taken by NEERI, but differs a lot

in samples taken by GP and CSE.

� All samples were collected from known or suspected hot spots.

� Cadmium and lead are to be considered low risk based on the mean value. Cadmium

was not detected by GP and CSE.

� Chromium and hexachlorobenzene (HCB) are to be considered as moderate risks

based upon total mean values.

� Dichlorobenzene and trichlorobenzene are to be considered as high risk based upon

total mean values.

� Mercury and lindane are to be considered extremely high risk based upon total mean

values. Lindane is considered as extremely high risk at all sites within the premises.

� Sample nr 3 in the Daphnia magna immobilization test had the highest rate of

immobilization. Neither GP nor CSE has taken samples from that area.

� Sample nr 5 in the Daphnia magna immobilization test, from area “D” in fig 1,

showed toxicity. Corresponding samples in the reports had measured concentrations

with low to moderate risk levels except for lindane that was considered to have

extremely high risk, which suggest causality (lindane toxicity) at area D.

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6. Acknowledgement

Thanks to Göran Dave, Maria Greger and Bosse Lagerqvist for support, advice and guidance.

7. References

Alloway, B.J. (1990) Heavy metals in soil, Springer

ATSDR, (2008), Chromium, http://www.atsdr.cdc.gov/tfacts7.pdf

Canadian Council of Ministers of the Environment, (2007), Canadian Soil Quality Guidelines

for the Protection of Environmental and Human Health,

http://www.ccme.ca/assets/pdf/rev_soil_summary_tbl_7.0_e.pdf

CSE (Centre for Science and Environment), (2009) Contamination of soil and water inside

and outside the Union Carbide India Limited, Bhopal

Cox, C. (1992) Aldicarb, Journal of pesticide reform, 1992, Volume 12, nr. 2, page 35.

Eckerman, I. (2005) The Bhopal Saga, Universities Press

Eckerman, I. (2006) Asian Pacific Newsletter, The Bhopal disaster 1984, Volume 13, nr 2,

page 24

EPA, (1998) Toxicological review of trivalent chromium, CAS No. 16065-83-1

EPA, (2000), Lindane (Gamma-Hexachlorocyclohexane),

http://www.epa.gov/ttnatw01/hlthef/lindane.html

EPA, (2010), Mercury, Health Effects http://www.epa.gov/mercury/effects.htm#meth

Ford, K. (2004), Risk Management criteria for metals at BLM mining sites, Bureau of Land

Management National Science and Technology Center Denver, CO

Greenpeace, (1999-10) The Bhopal Legacy,

https://webdrive.service.emory.edu/users/vdhara/www.BhopalPublications/Environmental%2

0Health/Greenpeace%20Bhopal%20Report.pdf

Indian Institute of Chemical Technology, Council of scientific & industrial research (2010-

02) Detoxification, decommissioning and dismantling of Union Carbide Plant

ISO, (1989), “ISO 6341”

Jayaprakash, N.D. (2010-09-07) The Crime of Union Carbide,

http://www.counterpunch.org/jayaprakash09072010.html

Joshi, M. (2011) http://www.bhopal2011.in, (2011-04-03)

NEERI (National Environmental Engineering Research Institute), (2010-06) Assessment and

Remediation of Hazardous Waste Contaminated Areas in and around M/s Union Carbide

India Ltd., Bhopal

OEHHA, (2000), Chronic toxicity summary; chlorobenzene

http://oehha.ca.gov/air/chronic_rels/pdf/108907.pdf

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OEHHA, (2001) Chronic toxicity summary; methyl isocyanate,

http://oehha.ca.gov/air/chronic_rels/pdf/methyliso.pdf

UNEP, (2001) Hexachlorobenzen, http://www.chem.unep.ch/gpa_trial/16hexac.htm

Wikipedia, (2011) The Bhopal disaster, http://en.wikipedia.org/wiki/Bhopal_disaster

8. Annex 1

Sample references

Greenpeace NEERI CSE

B1=IT9013 A1=S-08 A1=S6

C1=IT9012 A2=S-08 B1=S5

D1=IT9014 B1=S-07 C1=S7

D2=IT9015 B2=S-07 D1=S2

E1=IT9017 D1=S-15 D2=S3

E2=IT9042 D2=S-15 D3=S4

D3=S-16 E1=S8

D4=S-16

D5=S-17

D6=S-17

E1=DS-01

E2=DS-01

1=Surface

2=Subsurface