The Bhopal Heritage – Soil analysis at
UCIL factory site from a chemical hazard
perspective
Andreas Hellohf
Uppsats för avläggande av naturvetenskaplig kandidatexamen i
Miljövetenskap
15 hp
Institutionen för växt- och miljövetenskaper
Göteborgs universitet
Juni 2011
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.
1
Table of Contents
Summary................................................................................................................................1
Sammanfattning .....................................................................................................................1
1.
2.
3.
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
Methods ..........................................................................................................................5
2.1
Literature review.....................................................................................................5
2.2
Visit at the UCIL site in 2011..................................................................................6
2.3
Soil toxicity bioassay ..............................................................................................6
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
2
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
3
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 gammahexachlorocyclohexan (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).
4
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
5
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).
6
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).
Metals
3.1
A
B
C
D
ABCDE
E
Metal
Area
Concentrations of metals are shown in Table 1
Pb
Cd
Cr
Hg
Pb
Cd
Cr
Hg
Pb
Cd
Cr
Hg
Pb
Cd
Cr
Hg
Pb
Cd
Cr
Hg
Pb
Cd
Cr
Hg
GREENPEAC
E1
Sample4
1
2
N/A
N/A
N/A
N/A
19.4
N/D
85.7
2.6
174.6
N/D
480.7
11.0
N/D
73.0
0.8
17.0
N/D
15.7
N/D
52.9
8.1
4.6
N/D
1
3.18
0.58
2.22
N/D
4.29
0.41
2.32
1.29
6.64
1.32
1.83
N/D
3.18
0.65
1.10
0.14
3.53
1.40
73.0
1.1
35.5
0.4
5.21
0.30
128000
Min
6.52
0.15
27.3
0.88
Mean Value
Max
67.8
0.52
236
34047
2
4.30
0.54
1.98
N/D
2.37
0.18
1.65
1.29
5.92
0.74
1.48
N/D
2.16
0.58
2.10
N/D
1.59
1.14
2.09
N/D
NEERI2
CSE3
Sample4
3
4
Sample4
2
3.08
0.76
2.06
0.63
5
2.62
0.82
2.31
N/D
1.22
1.34
2.18
N/D
6
1.46
1.62
2.04
N/D
1
111.8
N/D
297.7
74.14
N/D
N/D
108.4
N/D
84.05
N/D
192.1
8188
46.39
N/D
70.84
N/D
22.34
N/D
34047
17.13
N/D
74.05
N/D
Table 1 Measured concentrations of metals at UCIL factory site. All values in ppm.
GREENPEACE, 1999
NEERI, 2010
3
CSE, 2009
4
Annex 1
7
Mean
39.8
0.37
101
24.71
67.8
0.52
169
Total
26.8
0.41
116.6
6815
2
3
6.52
0.15
49,5
1,30
1065
18.00
1
Result
4.85
N/D
18.18
N/D
9.89
0.52
27.3
0.88
9.81
0.51
236
3.96
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
Metal
Pb
Cd
Cr
Hg
Soil Criteria
Guidelines (SCG)7
Mean Value
BGC
Min
Max
Total
6.52
0.15
27.3
0.88
67.8
0.52
236
34047
26.8
0.41
116.6
6815
6
10-30
0.01-2.0
1-100
0.02-0.625
Estimated Risk Value
Min8
Max9
Mean
Min
Max
Mean
70
1.4
64
6.6
260
22
87
24
165
11.7
75.5
15.3
0.025
0.0068
0.31
0.036
Min/
Max
0.97
0.37
3.69
5159
Max/
Min
0.16
0.035
1.54
445
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)
Alloway (1990)
7
Canadian Council of Ministers of the Environment, (2007)
8
Agricultural land use
9
Commercial land use
6
8
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.
9
1
24.3
N/D
2
14.2
923
1,3 DCB
1,4 DCB
1,2 DCB
N/D
0.000
TCB
N/A
HCB
γ HCH
N/A
N/D
Carbaryl
1.3
Aldicarb
1,3 DCB
N/D
1,4 DCB
N/D
Area
Carbaryl
Aldicarb
A
B
C
3
CSE
Sample11
4
5
6
ABCDE
10
2
3
Min
N/D
N/D
Max
24.3
923
Mean
12.8
307
29.22
N/D
83.12
26.6
N/A
83.12
20.75
4.94
4.94
4.94
4.94
N/A
16.54
1.70
264.2
1.70
16.54
1.70
264.2
1.70
93.58
N/D
7.47
N/D
7.47
2.92
N/D
190.7
489.8
N/D
190.7
63.6
0.000
541.7
N/D
541.7
409.7
N/A
N/A
1017
507.1
507.1
507.1
507.1
HCB
N/A
N/A
1.12
1.12
1.12
1.12
γ HCH
Carbaryl
5.52
N/D
0.568
0.126
2782
N/D
0.568
N/D
2782
0.126
929
0.042
Aldicarb
N/D
N/D
N/D
N/D
N/D
N/D
0.000
8.01
7.90
N/D
8.01
5.39
23.72
12.37
23.72
12.37
23.72
12.37
N/D
198
66.0
N/D
N/D
2.728
116.5
0.51
19.19
113.4
29.2
1,3 DCB
1,4 DCB
N/D
11.02
1,2 DCB
N/A
N/A
N/A
N/A
23.72
12.37
γ HCH
N/D
0.08
Carbaryl
Aldicarb
0.273
N/D
1.577
N/D
N/D
N/D
N/D
N/D
N/D
N/D
2.728
N/D
198.0
1,3 DCB
1,4 DCB
1,2 DCB
0.165
0.000
N/D
N/D
0.10
8
N/D
N/D
116.5
N/D
N/D
N/D
56.17
113.4
1.78
112.3
0.57
N/D
N/D
108.7
16.5
104.7
N/D
N/D
104.7
37.1
4.56
45.23
5.16
702.3
4.56
N/D
50.57
555.9
20.1
145.9
N/D
N/D
6.888
8.158
2.296
2.72
TCB
N/A
N/A
N/A
N/A
N/A
N/A
63.69
20.92
6.47
HCB
γ HCH
N/A
1.83
N/A
2.48
N/A
2.06
N/A
3.41
N/A
N/D
N/A
N/D
50.57
555.9
Carbaryl
Aldicarb
6.888
8.158
N/D
N/D
1,4 DCB
1,2 DCB
N/D
N/D
0.62
0.14
N/D
0.62
0.25
TCB
N/A
N/A
0.09
0.09
0.09
0.09
HCB
γ HCH
N/A
N/D
N/A
N/D
1.34
N/D
1.34
N/D
1.34
N/D
1.34
N/D
Min
Mean
Max
Total
Carbaryl
Aldicarb
0.042
N/D
12.8
307
3.71
78.5
DCB
0.25
409.7
TCB
HCB
0.09
1.12
507.1
20.1
94.2
114
7.32
γ HCH
N/D
929
247
N/D
N/D
0.49
1,3 DCB
E
1
N/D
N/D
1,2 DCB
TCB
TCB
HCB
D
NEERI
Sample10
Compound
Table 2 Measured concentrations of pollutants at
UCIL factory site. All values in ppm.
Annex 1
10
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
Soil Criteria Guidelines
(SCG)12
Mean Value
Metal
Estimated Risk Value
Min
Max
Total
Min13
Max14
Mean
Min
Max
Mean
Carbaryl
0.042
12.8
3.71
Aldicarb
N/D
307
78.5
N/A
N/A
N/A
N/A
N/A
N/A
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
0.05
0.05
0.01
10
10
N/A
5.03
5.03
0.01
0.009
0.112
0
Min/
Max
10142
402
92900
Max/
Min
22.78
1.46
24690
Mean/
Mean
TCB
0.09
507.1
114.6
HCB
1.12
20.1
7.32
γ HCH
N/D
929
246.9
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)
Canadian Council of Ministers of the Environment, (2007)
13
Agricultural land use
14
Commercial land use
12
11
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.
12
Pollutant at site D
3.4
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.
Sample value min/max
3.5
The table shows the minimum and maximum value for each report and each substance.
Greenpeace
NEERI
Pb
Cd
Cr
Hg
Carbaryl
Aldicarb
1,3 DCB
1,4 DCB
1,2 DCB
TCB
HCB
γ HCH
CSE
Min
Max
Diff
Min
Max
Diff
Min
Max
Diff
1.59
0.18
1.10
N/D
N/D
N/D
6.64
1.62
5.21
1.29
24.3
923
5.05
1.44
4.11
1.29
24.3
923
11.0
N/D
73.0
0.8
N/A
N/A
174.6
N/D
480.7
128000
N/A
N/A
163.6
407.7
127999
-
N/D
N/D
18.18
N/D
N/D
N/D
111.8
N/D
1065
8188
7.47
190.7
111.8
1047
8188
7.47
190.7
N/D
0.165 0.165
N/A
N/A
-
N/D
541
541
N/A
N/A
N/D
N/A
N/A
16.54 16.54
N/A
N/A
N/A
N/A
N/A
N/A
-
N/D
1.12
45.23
507.1
50.57
2782
507.1
49.45
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.
13
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
14
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 (γHCH).
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.
15
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 (201002) 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
16
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
17