Lingering health impacts decades after the Bhopal disaster

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several decades on, the Bhopal disaster has been all but forgotten by most of the world. This assignment was completed for a Public health topic on environmental health

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Lingering health impacts decades after the Bhopal disaster

  1. 1. 1. ScenarioBhopal is a industrial city of approximately 1.6 million people situated in central Indian in thestate of Madhya Pradesh (Figure 1). Residents in the city and nearby tend to be of low socio-economic status. Two large man-made lakes are situated in Bhopal, collectively known as theBhoi Wetland. Their combined catchment is approximately 370km2, and the upper lake(which has the largest catchment) feeds into the Kolans River.1Figure 1: Location of Madhya Pradesh2 Figure 2: residential settlements next to UCIL factory3The city is situated on the sandstone Malwa Plateau4 which contains an aquifer that providesdrinking, cleaning and agricultural water for surrounding lands. Surrounding lands are hilly.Madhya Pradesh is renowned for its forests – about one third of the state is forested, althoughdeforestation is progressing rapidly.5 Bhopal hinterlands are largely used for agriculture.In 1969, US owned Union Carbide (now owned by Dow Chemicals) established a factory onthe north west edge of the city, on the banks of the larger upper lake. ‘Squatter settlements’ ofworkers in very substandard housing grew around the plant6 (Figure 2), housing up to 10,000people within 1km radius of the factory.7 Union Carbide chose the site because of itseffective railway system and cheap local labour. The factory was licensed to producephosgene, mono-methyl amine, methyl isocyanate, and carbaryl.8Early in the morning of 3 December 1984 water entered storage tank 610 of the Bhopal unionCarbide Factory, producing 40 empirical tons of methyl isocyanate (MIC) gas, causing the1 www.answers.com/tpic/bhopal?method=5 Accessed 4 February 20062 ibid3 Agarwal R. Nair A. Wankhade K. Surviving Bhopal 2002: Toxic present – toxic future. A report onthe human and environmental chemical contamination around the Bhopal disaster site. Srishti. Factfinding Mission on Bhopal. www.bhopal.net/oldsite/documentlibrary/survivingbhopal2002.docaccessed 7 February 20064 www.worldrom.com/pages/cg_bhopal/fastfacts/bhopal_fastfacts.phtml Accessed 4 February 20065 “Madhya Pradesh” encyclopedia Britannica Online. www.britannica.com/eb/article?tocId=46063accessed 4 February 20066 Weir D. The Bhopal Syndrome: Pesticides, environment and health. Sierra Club Books, SanFrancisco. 1987. P367 Muller R. A significant toxic Event: The Union Carbide Pesticide Plant Disaster in Bhopal, India,1984. www.tropmed.org/rreh/vol1_10.htm accessed 7 February 20068 Boybeyi Z, Raman S. Zanetti P. Numerical investigation of Possible Role of Local Meteorology inBhopal Gas Accident. Atmospheric Environment. Vol 29. No 4. Pp479-496. UK 1
  2. 2. temperature and pressure within the tank to rise and releasing a plume of gas through a safetypressure valve. (Other gases may also have been involved.) Of the ~1 million 1984 Bhopalresidents, between 8,000 and 20,000 people are thought to have died in the disaster withpossibly a further 250,000 being exposed9 (estimates vary widely, up to 40,000 dead and400,000 injured10 indicating a fair degree of confusion at the time). Bhopal residents also havehigher than normal rates of miscarriage and cancer, and children born to the victims whosurvived have congenital deformities such as stunted growth and small heads.11 The gas alsoaffected plants and animals in the same area, both wild and agricultural12, entered the lakesand permeated the porous sandstone under the city, entering the aquifer. No data wascollected on the Kolans River.Following the disaster the factory was closed and the site remains untouched. Chemicalsremained stockpiled at the site. The site is not secured – animals graze and children play onthe site. Concerns about past and current soil and water contamination remain. Evaporationponds used for toxic waste disposal were covered in plastic and buried under soil. This coverhas been breached in at least one place.13 Run-off from the site reached the undergroundaquifer (and may have while the site was operational) which supplies water for the city andhinterlands.14This Health Assessment will look at the acute and chronic effects in the population, as well asthe remaining hazards through inter-generational transfer and toxins remaining in the soil andthe uncleaned site, water supplies and foodstuffs such as animals and plants.The Bhopal disaster has been an emotive issue on an international scale, and is used by greengroups as a symbol of the evils of globalisation and the chemical industry generally. A largenumber of highly emotive articles, documents and websites have been dedicated to this cause.Where possible these sources have not been used, nor those of Union Carbide, as the claimsthey contain are difficult to verify. Sources with a known bias are noted as such.9 Cullinan P. Acquilla S. Ramana Dhara V. Respiratory morbidity 10 years after the Union Carbide gasleak at Bhopal: a cross sectional survey. BMJ 1997;314:33810 TED Case Studies: Bhopal disaster. www.american.edu/TED/bhopal.htm Accessed 4 February 200611 Harari F. Time Capsule 03/12/1984 Gas Leak Kills Thousands in Bhopal Tragedy. The WeekendAustralian Magazine 3-4 December 2005 p10.12 Agarwal R. Nair A. Wankhade K. Surviving Bhopal 2002: Toxic present – toxic future. A report onthe human and environmental chemical contamination around the Bhopal disaster site. Srishti. Factfinding Mission on Bhopal. www.bhopal.net/oldsite/documentlibrary/survivingbhopal2002.docaccessed 7 February 200613 Stringer R. Johnston P. Technical guidelines for cleanup at the Union Carbide India Ltd (UCIL) sitein Bhopal, Madya Pradesh, India. Oct 2002. Greenpeace Research Laboratories, University of Exeter,UK.14 Acharya VN, Naik SR, Potnis AV, Bhalerao RA. Sequential study of thiocyanate levels in Bhopalwater following methyl isocyanate gas leakage. Journal of Post-Graduate Medicine. 1986. Vol 32.Issue 4, p192-194. 2
  3. 3. 2. Hazard identification“The process of determining whether an agent can cause an adverse health condition.”15Pesticides are biologically active compounds, designed to kill plants, insects, fungi oranimals.16Approximately 40 empirical tons of methyl isocyanate (MIC), an ingredient in themanufacture of carbaryl and aldicarb pesticides (sold as Sevin and Temik brands),17 18 wasreleased from a storage tank pressure release valve approximately 33m above the ground.Due to prevailing north to north to northwesterly light winds and a temperature inversion overthe city, the gas was taken from the release valve to the residential areas of the city.MIC is an extremely toxic chemical. It is lighter than water but twice as heavy as air, andhence once released into the atmosphere it tends to settle close to the ground. MIC has a veryhigh vapor pressure and may be the most toxic of all isocyanates due to its ability to affectmany systems. Table 1 contains an excerpt of the Cheminfo data on MIC (some of thisinformation may not have been available in 1984).CHEMINFO record No. 164Chemical family Isocyanic acid esterMolecular Formula C2-H3-N-OStructural Formula CH3-N=COAppearance and odour Colourless liquid with sharp unpleasant pungent odour, lachrymator (vapour irritates eyes and causes tears)Odour threshold 2.1 ppm. Three out of 7 people could still smell MIC at 5 ppmEmergency overview ….EXTREMELY FLAMMABLE LIQUID AND VAOUR. Vapour is heavier than air and may spread long distances. Distant ignition and flashback is possible. Can decompose at high temperatures forming toxic gases such as nitrogen oxides and hydrogen cyanide. Closed containers may develop pressure and rupture on prolonged exposure to heat. Reacts violently with water…VERY TOXIC. May be fatal if inhaled or swallowed. Vapour is extremely irritating to eyes and respiratory tract. Causes lung injury – effects may be delayed. CORROSIVE to eyes and skin. Can cause blindness and permanent scarring. SKIN SENSITIZER. May cause allergic skin reaction. MUTAGEN – may cause genetic damage, based on animal information.Carcinogenicity No human information is available on the carcinogenicity of MIC. One animal study provides limited evidence of carcinogenicity after a very brief exposure…... The International Agency for Research on Cancer (IARC) has not evaluated the carcinogenicity of this chemical.Table 1: Excerpt of Cheminfo Data on Methyl isocyanate1915 National Short Cause in Environmental Health Case Study 2005 documents16 Cox C. From Factories and Tank Cars to You: Hazards of Manufacturing and transporting pesticides.Journal of Pesticide Reform. Summer 1993 Vol 13 No2. P6.17 TED Case Studies: Bhopal disaster. www.american.edu/TED/bhopal.htm Accessed 4 February 200618 Cox C. Aldicarb. Journal of pesticide reform. Summer 199. Vol 12, No 2.19 CCOHS Cheminfo database. Methyl isocyanate. 3
  4. 4. Many other toxic compounds, identified and otherwise, are also present on the factory siteand in the local environment. These include, but are not limited to: ingredients used tomanufacture MIC, metabolites and breakdown products of MIC, and other chemicalsmanufactured in the factory.Chemical stockpiles at the site include: Aldicarb (Temik), BHC,20 an organochloride pesticidewhich includes chlorobenzene. DDT isomers have been isolated on the site and nearby,although the factory did not use or produce DDT.21 Heavy metals including mercury havebeen detected.22 The solar evaporation ponds contain high levels of organochlorine.23MIC can be converted into methylamine (methyl carbylamine isocyanatomethane) by cellularenzymes in the human body, or by bacterial enzymes in water or in soil. This breakdownproduct can yield cyanide.24 Studies have shown that the presence of bacteria in soil canaccelerate the breakdown of MIC.MIC can be broken down by pyrolysis and interaction with water. MIC is more toxic than itsbreakdown products.25 MIC is not biopersistent in the environment, although some of itsbreakdown products including thiocyanate, can persist in water.26 Studies comparing Bhopalwater to Bombay water over before and after the leak show that the MIC had reached thelakes and the aquifer providing water to the population of Bhopal and surrounding districts(Bombay water showed no changes over this period). By August 1985, thiocyanate levels inBhopal water had returned to normal. 27 (Bhopal plaintiffs claim studies have shown otherchemicals remain present in the water supply.28) The half-life of MIC in soil is between 2.7and 6.9 days (longer times recorded in river soils), degradation accomplished by microbialand abiotic processes.29As the Bhopal leak was the largest known human exposure, much of the data comes fromstudies of this site. Other relevant studies include:♦ Studies on a MIC leak at Union Carbides aldicarb and carbaryl plant in West Virginia (1985)30 with the same root causes as the Bhopal leak, resulting in 135 people being hospitalised.♦ metam sodium spill in the Sacramento River (1991)31 a derailed freight train which spilled metam sodium in the Sacramento River. (Metam Sodium turns into methol isocyanate in the presence of water.) The chemical affected local residents, fish, ducks, otters, insects and ‘all living things’ for some months. Residents experienced an abnormally high rate of miscarriage which may have been linked to the spill.3220 ibid21 ibid22 ibid23 ibid24 Acharya VN, Naik SR, Potnis AV, Bhalerao RA. Sequential study of thiocyanate levels in Bhopalwater following methyl isocyanate gas leakage. Journal of Post-Graduate Medicine. 1986. Vol 32.Issue 4, p192-194.25 Varma DR. Guest I. The Bhopal Accident and methyl isocyanate toxicity. Journal of Toxicol environhealth. 1993 Dec; (40):513-2926 ibid27 ibid28 Greenpeace. (1999) The Bhopal Legacy. Quoted on www.bhopal.net/oldsite/poisonpapers.html29 Taylor GE. Schaller KB. Geddes JD. Gustin MS. Lorson GB. Miller GC. Microbial Ecology,Toxicology and Chemical Fate of Methyl Isocyanate in Riparian Soils from the Upper Sacramentoriver. Environmental Toxicology and Chemistry. Vol 15. Issue 10. Pp1694-170130 ibid31 ibid32 California Department of Health Services. Environmental Epidemiology and Toxicology Program.Questions and Answers related to the Cantara loop spill: Metam sodium and MITC in the environment.April 1992 4
  5. 5. ♦ spill of 50 gallons of MIC at FMC Corporation facility in Middlepost, New York (1984)33 caused permanent lung damage and asthma in children in a school nearby♦ An invitro model has shown that MIC is cytogenic, causing sister chromatid exchange. These findings were supported by an epidemiological study of exposed persons in Bhopal.34♦ Cheminfo data cites two laboratory studies of human subjects exposed to MIC vapour35 animal studies demonstrated high oral toxicityMIC can cross cell membranes and hence penetrate the body’s defences, accessing organsthroughout the body. (MIC can also cross into breast milk.) It is linked to a number ofsystemic effects, and it is believed its mechanism may be through the formation of areversible conjugate with glutathione. Aldicarb and sevin act through disrupting the normalcommunication between nerve cells.36MIC is converted into methylamine (methyl carbylamine isocyanatomethane) by cellularenzymes in the human body or bacterial enzymes in soil and water.37Reported adverse outcomes from MIC include:• Death • Eye problems• Respiratory problems • Miscarriage• Nervous system problems • Congenital defects• Gastrointestinal symptoms (abdominal • Neuromuscular abnormalities pain, anorexia and diarrhoea) • Immuno-suppressant effects• Non-specific airways irritation • Haematological effects• Reproductive effects • Gene mutation38 39Physical effects were stronger in the very young and very old, the infirm and smokers.Early radiological investigations of Bhopal victims showed lung oedema and over-inflation,enlarged heart, pleural scars and consolidation. Later investigations showed interstitialdeposits40 (these were also discovered in the autopsies of newborns). Cheminfo data statesthat 49% of pregnant Bhopal leak victims did not give birth to live babies, a 3-4 fold increaseof fetal loss.41High levels of psychological distress have been identified in survivors who may have seenlarge numbers of their family and neighbours dying and dead.42 (Of the children identified ashaving been psychologically affected, some were reported to have been thought dead andplaced in morgues only to wake and find themselves surrounded by dead bodies.)4333 Journal of Pesticide Reform 9(1):2-534 Goswami HK. Cytogenic effects of methyl isocyanate exposure in Bhopal. Human genetics.September 1986. Vol 74, No1. p81-84.35 ibid36 ibid37 ibid38 ibid39 Goswami HK. Cytogenic effects of methyl isocyanate exposure in Bhopal. Human genetics. Vol 74No1. Sept 1986. Pp81-8440 Kamat SR, Patel MH, Pradhan PV, Taskar SP, Vaidya PR. Kolhatkar VP. Gopalani JP. ChandaranaJP. Dalal N. Naik M. Sequential respiratory, psychological and immunological studies with relation tomethyl isocyanate exposure over two years with model development. Environ Health Perspectives.1992 Jul;97:241-5341 ibid42 ibid 5
  6. 6. 3. Dose response relationship“The relationship between the dose (amount and/or duration) of an agent and the risk andseverity of an adverse health effect.”44Cheminfo data cites studies exposing human subjects to varying concentrations of MICvapour. At 2ppm, irritation to nose and throat occurred, at 4ppm irritation was stronger and at21ppm exposure was unbearable.45 Given the toxicity of this chemical such studies areunlikely to be repeated in human subjects. The threshold for MIC toxicity in humans is 0.02ppm of air.46 47A definite dose response relationship is evidenced by studies of Bhopal victims. Thoseclosest to the factory leak had a much higher death rate.A study of effects 105 days after the leak compared symptoms in two groups of children, onegroup resided 1/2km to 2 km from the factory, and a second group who resided 8-10 kmsaway from the factory. (It should be noted that due to the low socio-economic status in thearea, over 91% of those affected remained in the area and hence were easily tracked for thesesorts of studies. This also meant their exposure to the contaminated site continued.) A tableof the results is below:Symptom / test result Group 1 Group 2Respiratory abnormalities (rhonchi, rales, wheezing) 48.1% nilRespiratory obstructive disability 28 8Abnormal radiological findings 66.1% 8.1%Conjunctivitis 79.8% nilVision abnormality 10.3% nilTable 2: Dose response: level of symptoms to MIC in childrenIt should be noted that the children living closer to the factory may have been exposed to anumber of other pollutants prior to the MIC leak and hence general worsening of healthrelated to proximity to the factory may not be directly linked to the leak, but may still beattributable to the Union Carbide Factory.Another study looking at the damage to eyes noted a dose response relationship associatedwith the distance from the factory and death rate in the community as a proxy forconcentration of exposure.48 (Meteorological modelling and comparison of vegetationscorching supports distance from the factory as a proxy a measure of concentration gradient –see notes above.) Highest death rate was in JP Nagyar colony, directly south of the factory.(Figure 2)4. Exposure assessment43 Irani SF. Mahashur AA. A survey of Bhopal children affected by methyl isocyanate gas. Journal ofpostgraduate medicine. 1986. Vol 32. Issue 4. P195-9844 ibid45 ibid46 Acharya VN. Potnis AV. Bhopal gas tragedy; Medical Hazards. Science today, May 1985 pp22-2347 Determination of Noncancer Chronic Reference Exposure Levels batch 2B December 2001. ChronicToxicity Summary Methyl Isocyanate. CAS Registry Number: 624-83-948 Andersson N. Muir MK, Mehra V, Salmon AG. Exposure and response to methyl isocyanate: resultsof a community based survey in Bhopal. British Journal or Indian Medicine. 1988 Jul;45(7):469-75 6
  7. 7. “The process of measuring of estimating the intensity, frequency and duration of exposure toa hazardous agent.”49Exposure routes are multiple. Initially exposure was through the respiratory tract and eyes.More long term, exposure is through the GI tract from ingestion of contaminated food andwater. Specific mention of milk from cows being grazed on the old factory site. As MIC isable to cross membrane barriers, these exposure routes potentially open up all organ systemsto adverse effects, particularly as MIC is cytogenic. (A 2002 study found mercury andorganochlorides in breast milk of Bhopal women.50)However, exposure assessment is somewhat confounded by a number of factors. A numberof contaminants remain on site so it would be difficult to link an illness specifically to theMIC leak exposure. Some symptoms do not become apparent until a long time, sometimesdecades, after exposure. Many of the studies on pesticide exposure relate to small numbers ofworkers and hence results are not statistically viable. Often exposures are to multiplechemicals which makes it difficult to compare statistics. (Several relevant studies are listedabove)Union Carbide is not the only chemical factory in Bhopal and other industries may also havecontaminated the local environmental and the aquifer. A number of those most affected wereworkers at the plant and their families (who lived nearby) who may have been exposed atwork previously. Industrial Indian cities like Bhopal often have heavy air pollution. The localpopulation is of low socio-economic status and are probably exposed to a number of the riskfactors associated with this.Smokers and those with existing ill health were particularly affected. Activities beingundertaken at the time also affected exposure – those doing physical activity outside in themorning would have had a high dose than those remaining indoors (although it should benoted that these houses were not by any means hermetically sealed). Some people would beparticularly susceptible to the exposure.Length and intensity of exposure for individuals is difficult to estimate due to the number oflocal climactic factors affecting the dispersion and distribution of the gas plume. The leakitself lasted from 0030 hours to approximately 0200 – 90 minutes, however the gas remainedin the area for many hours afterwards. A nocturnal inversion was present on the night of thegas leak. It’s position 250m above the ground meant that the warmer gas escaping from the33m high vent remained trapped below the inversion as it cooled in the night air.51 While therelative weight of the compound meant it could be expected to settle rapidly as it cooled, thisappears not to have been the case. Winds were calm and initially northwesterly and thenortherly, directing the plume over the populated areas of Bhopal rather than the agriculturalhinterlands.Other local environmental factors also played a part in determining where the strongest doseswere experienced. Heat rising from parts of the city caused localised weak low pressure cellswhich sucked the gas in but funneled it upwards. In some areas these temperature differencesalso “sucked” clean air off the cooler lakes, dispersing the gas. (The average temperature inthe agricultural lands was about 16C, but in the town it rose to 22C.52) The area is also quitehilly, creating funnels directing air flow. However, the urban areas are quite ‘rough’ for thewind to flow over and hence the air slows over the city. A complex model factoring in all of49 ibid50 ibid Murthy ASV. Varghese S. Nocturnal Temperature Inversions under calm clear conditions:51An analytical study. Council of Scientific and industrial research, New Delhi.52 ibid 7
  8. 8. these factors demonstrates the gas plume moving slowly south east from the factory with littlemixing and the concentration mainly at the emission height of 33m, until it reaches theturbulence over the warmer city. Between 210 to 270 minutes after the release the gas ismixed with other air, cooler and descending on the city, still moving downwind.53 The changefrom northwesterly to northerly win direction had the effect of narrowing the gas plume butincreasing the concentration54, meaning fewer people experienced the plume but those whodid received a more toxic dose.Local reports are varied as to the length of exposure: one area was reportedly ‘clear’ by 0530,while JP Nagyar colony next to the factory was still observably in the gas cloud five hoursafter the release concluded (0700). 55 It is important to note that these were by observation ofthe gas cloud – lower (but still toxic) concentrations may have remained in the area althoughnot visible and not causing the acute symptoms.Overall, using the model mentioned above, vegetation scorching and pattern of deaths asindicators, a small area to the southeast of the factory received the most concentrated gasplumes, with the exposure generally lessening in concentration albeit unevenly, as the plumetravelled further from the initial site and was generally dispersed. Death rates coincided withother indicators, and these areas also experienced the highest rate and most serious adverseeffects. JP Nagyar had the highest death rate.While MIC is not biopersistent in the body or in the environment, it does remain for up to 9days in soil and over 3 months in water (discussed previously). The ongoing contaminationsource could be replenishing the exposure of soils, water (particularly in the lakes andaquifers) and locals.5. Risk Characterisation“The process of predicting the incidence of a health effects resulting from exposure to ahazardous agent by combining the dose response relationship with the exposureassessment”56.As noted above the particular local climactic conditions have made accurate characterisationof exposure difficult due to the number of variable factors and the large number of peopleinvolved. Estimates vary between 200,000 and 400,000 people affected by the initial gasplume. Considering the ongoing environmental exposure through contaminated water in theaquifer, contaminated milk from cattle grazing on the factory site, and contaminated localagriculture products, the potential exposure numbers expand to the entire area. Bhopal doesnot seem to have an agricultural export industry, so presumably most if not all agricultureproducts are consumed locally. Any ongoing contamination, particularly the milk from cattlegrazing on the factory site that are subject to ‘fresh’ contamination, will also affect any newresidents who consume this product. The city of Bhopal is now approximately 1.6 million.No data is available on the agricultural hinterland population, who would also draw upon thecontaminated aquifer.Intergenerational effects such as congenital defects and miscarriages / stillbirths also increasethe number of people affected. There is no data on whether a third generation would also beaffected by the exposure but with a genetic-based defect this is entirely probable, providing53 ibid54 ibid55 ibid56 ibid 8
  9. 9. the defects do not affect fertility (studies on the congenital effects seem to focus on smallheads not on infertility other than the high miscarriage rate).Some victims might experience only low-level effects, but considering the low threshold forMIC, it is likely that all who are exposed would have some effects. Sensitive individualswould experience stronger reactions, as would smokers, the unwell (particularly those withrespiratory conditions), the very young especially those exposed dring the first trimester ofpregnancy57 and the elderly.Survivors would also have additional susceptibility to further toxic assaults and infections.6. Risk Management6.1 CostsAlthough Union Carbide’s safety standards at the Bhopal factory were substandard even byAmerican international standards, the Indian government, on behalf of the victims, reached asettlement of $470million USD – depending on estimates this is as little as $1000 per person.This settlement was intended to cover compensation, but with no ongoing funding, it I nowhaving to cover the ongoing health costs for the victims, and the cleanup of the site58. Inaddition, there is the cost to the agricultural land, products and industry, the loss of jobs tolocals, DALYs (including the costs of supporting victims unable to work). Some, but not allof the money was distributed to victims. Greenpeace cites a US legislation, Superfund, whichplaces the responsibility for cleanup with the polluter, and has some limited ‘extraterritorialprovisions’, dependent on agreement between the US government and the government of theaffected country.596.2 Minimising Ongoing RiskWhile the main incident of exposure occurred 22 years ago, there is evidence of ongoing riskand exposure, which can only be addressed by a full-scale clean-up of the site and affectedareas. Even if it were possible to relocate a city of over a million people, the low socio-economics of the affected populace means they are unlikely to be able to relocate and re-establish easily without significant funding.Greenpeace Research Laboratories have written a document detailing specifications forcleanup for the Bhopal site60. (While Greenpeace cannot be considered to be a disinterestedparty, their specifications do draw on previously published standards and studies.)Their conclusions are that an effective cleanup would include:• Closed loop technologies that do not produce further emissions• Inventory, analysis and quantification of stockpiles to determine actual content, using accredited laboratories• Appropriate UN standards for containment, packaging, removal and transport of toxic chemical stockpiles• Chemicals which cannot be destroyed such as heavy metals and metallic compounds should be stabilised and placed in monitored above-ground storage• Recognition that a large number of toxic chemicals are on site and a number of potential toxic combinations could be created through any mixture or cleaning process.57 ibid58 ibid59 ibid60 ibid 9
  10. 10. • Close ongoing evaluation of effectiveness and any potential for hazard production• Remaining buildings will need to be deconstructed. Materials which can be demonstrated to be free from contamination may be disposed of as normal. Contaminated materials will need to be removed and treated or disposed of according to appropriate standards• Workers in the clean-up will need to be appropriately protected. In addition to the chemicals, there may be asbestos on site, and physical danger from the deteriorating structures.• Sludge from drains around the site will need to be dug out, analysed for toxins and dealt with appropriately• Sludge from storage tanks will need to be analysed and dealt with appropriately• Contaminated soils, particularly the lime pit and solar evaporation ponds which were used for waste disposal, and any other landfill waste disposal are present on sit, as well as generally across the factory site. Soils will need to be systematically sampled and analysed using a grid pattern, toxins identified including quantity, concentration and depth, analysis should include metals such as mercury and should be broad spectrum, seeking to identify unknown compounds, not just the chemicals known to have been present on the site. The presence of DDT, a chemical not manufactured onsite indicates the importance of this. Contaminated soils should be removed then remaining soils retested.• Ground water also needs to be decontaminated. Samples from wells and boreholes within 2km of the site should be tested. Where tests are positive in wells and bores near the perimeter of this zone, the testing zone should be extended until no contamination is detectable. Analyses should include heavy metals, solvents, organics and any other toxins present. Water should be pumped from the contaminated wells and treated by a method appropriate to the contaminant, without causing any further contamination (such as evaporation of solvents which would cause further air pollution). Once cleaned, the water could be used to recharge the aquifer.61This clean-up would be a major undertaking, involving many tonnes of soil, chemicals andthousands of litres of water. This will be costly and a long term undertaking, and provisionwill need to be made for the local community to overcome the inconvenience – clean grazingland for the cattle, an alternative playground for the children, alternative water sources whilewells are decontaminated. Cooperation of the local community is necessary on a number oflevels including use of the alternative resources, and the identification of bores and wells,which may not be regulated.At all stages the appropriate international standards should be identified and applied.7. UncertaintiesThere are a number of areas of uncertainty regarding this exposure. Primarily, identificationof the major contaminant does not allow for the large number of identified and potentiallyunidentified contaminants. No history on pre-existing contamination is available. Actualnumbers of people exposed vary considerably and the level of exposure for each individual isestablished by deduced averages for geographical area.Most of the knowledge about MIC toxicity in humans comes from this exposure, so long termeffects, and ongoing intergenerational effects are not yet available. No knowledge isavailable on interactions between the many toxicants in the Bhopal district.Little is available about the toxic effects from ingestion of contaminated agriculture productsor the intergenerational effects on livestock.61 ibid 10
  11. 11. The Bhopal population had a number of pre-existing risk factors including low socio-economic status, poor housing quality and air pollution. They may also have had dietary andlifestyle risk factors such as smoking. There is little general commentary on the pre-existinghealth of the population or access to health services prior to the disaster. There is littlecomparative epidemiological data on rates of various diseases, congenital malformations etcprior to the exposure.Finally, much of what has been written about Bhopal has come from Union Carbide, anti-chemical industry campaigners, lobby groups on behalf of the victims of Bhopal and otherinterested parties. Objective data, particularly for an event that occurred 22 years ago, can bedifficult to identify.8. CommunicationAffected persons must be informed and involved in the planning of any clean-up andrelocation involved. Significant disillusionment has already occurred with the populationover the compensation funding which has been held back for cleanup costs.Significant distrust and fear as been engendered in a population that is largely dependant onlocal industry as their employers.The population would need to be made aware of what health effects can or cannot be linked tothe gas plume and toxins from the factory. They would need to be made aware of what theycan do to minimise their exposure and the harmful effects any damage may already havecaused, ie: don’t graze cattle on the factory site, keep children away from the factory site,don’t drink from affected wells until they have been cleared (which would required theprovision of a viable local alternative source) and try to quit smoking.The population would need to be made aware of what is being done to clean up the area.They would need provision of health facilities adequate for their increasing needs and withthe appropriate equipment to run the screening tests and treatment required, either free or at afee that this low socio-economic population can afford and is willing to prioritise. 11
  12. 12. 9. ReferencesAcharya VN, Naik SR, Potnis AV, Bhalerao RA. Sequential study of thiocyanate levels inBhopal water following methyl isocyanate gas leakage. Journal of Post-Graduate Medicine.1986. Vol 32. Issue 4, p192-194.Acharya VN. Potnis AV. Bhopal gas tragedy; Medical Hazards. Science today, May 1985pp22-23Agarwal R. Nair A. Wankhade K. Surviving Bhopal 2002: Toxic present – toxic future. Areport on the human and environmental chemical contamination around the Bhopal disastersite. Srishti. Fact finding Mission on Bhopal.www.bhopal.net/oldsite/documentlibrary/survivingbhopal2002.doc accessed 7 February 2006Andersson N. Muir MK, Mehra V, Salmon AG. Exposure and response to methyl isocyanate:results of a community based survey in Bhopal. British Journal or Indian Medicine. 1988Jul;45(7):469-75Boybeyi Z, Raman S. Zanetti P. Numerical investigation of Possible Role of LocalMeteorology in Bhopal Gas Accident. Atmospheric Environment. Vol 29. No 4. Pp479-496.UKCalifornia Department of Health Services. Environmental Epidemiology and ToxicologyProgram. Questions and Answers related to the Cantara loop spill: Metam sodium and MITCin the environment. April 1992CCOHS Cheminfo database. Methyl isocyanate.Cox C. Aldicarb. Journal of pesticide reform. Summer 199. Vol 12, No 2.Cox C. From Factories and Tank Cars to You: Hazards of Manufacturing and transportingpesticides. Journal of Pesticide Reform. Summer 1993 Vol 13 No2. P6.Cullinan P. Acquilla S. Ramana Dhara V. Respiratory morbidity 10 years after the UnionCarbide gas leak at Bhopal: a cross sectional survey. BMJ 1997;314:338Determination of Noncancer Chronic Reference Exposure Levels batch 2B December 2001.Chronic Toxicity Summary Methyl Isocyanate. CAS Registry Number: 624-83-9Goswami HK. Cytogenic effects of methyl isocyanate exposure in Bhopal. Human genetics.September 1986. Vol 74, No1. p81-84.Greenpeace. (1999) The Bhopal Legacy. Quoted onwww.bhopal.net/oldsite/poisonpapers.htmlHarari F. Time Capsule 03/12/1984 Gas Leak Kills Thousands in Bhopal Tragedy. TheWeekend Australian Magazine 3-4 December 2005 p10.Irani SF. Mahashur AA. A survey of Bhopal children affected by methyl isocyanate gas.Journal of postgraduate medicine. 1986. Vol 32. Issue 4. P195-98Journal of Pesticide Reform 9(1):2-5 12
  13. 13. Kamat SR, Patel MH, Pradhan PV, Taskar SP, Vaidya PR. Kolhatkar VP. Gopalani JP.Chandarana JP. Dalal N. Naik M. Sequential respiratory, psychological and immunologicalstudies with relation to methyl isocyanate exposure over two years with model development.Environ Health Perspectives. 1992 Jul;97:241-53Madhya Pradesh. Encyclopedia Britannica Online. www.britannica.com/eb/article?tocId=46063 accessed 4 February 2006Muller R. A significant toxic Event: The Union Carbide Pesticide Plant Disaster in Bhopal,India, 1984. www.tropmed.org/rreh/vol1_10.htm accessed 7 February 2006Murthy ASV. Varghese S. Nocturnal Temperature Inversions under calm clear conditions: Ananalytical study. Council of Scientific and industrial research, New Delhi.National Short Cause in Environmental Health Case Study 2005 documentsStringer R. Johnston P. Technical guidelines for cleanup at the Union Carbide India Ltd(UCIL) site in Bhopal, Madya Pradesh, India. Oct 2002. Greenpeace Research Laboratories,University of Exeter, UK.Taylor GE. Schaller KB. Geddes JD. Gustin MS. Lorson GB. Miller GC. Microbial Ecology,Toxicology and Chemical Fate of Methyl Isocyanate in Riparian Soils from the UpperSacramento river. Environmental Toxicology and Chemistry. Vol 15. Issue 10. Pp1694-1701TED Case Studies: Bhopal disaster. www.american.edu/TED/bhopal.htm Accessed 4February 2006Varma DR. Guest I. The Bhopal Accident and methyl isocyanate toxicity. Journal of Toxicolenviron health. 1993 Dec; (40):513-29Weir D. The Bhopal Syndrome: Pesticides, environment and health. Sierra Club Books, SanFrancisco. 1987. P36www.answers.com/tpic/bhopal?method=5 Accessed 4 February 2006www.worldrom.com/pages/cg_bhopal/fastfacts/bhopal_fastfacts.phtml Accessed 4 February2006 13

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