After reading this essay you will learn about:- 1. Characteristics of Major Pesticides 2. Historical Aspect of Pesticides 3. Classification 4. Application 5. Limitation 6. Toxicology 7. Usage 8. Environmental Impact 9. Persistence, Bioaccumulation and Bio magnification 10. Case Study 11. Pesticide Resistance 12. Regulations 13. General Effects.
Contents:
- Essay on the Characteristics of Major Pesticides
- Essay on the Historical Aspect of Pesticides
- Essay on Classification of Pesticides
- Essay on the Application Potential of Pesticide
- Essay on Limitation of Pesticide Uses
- Essay on Toxicology of Major Pesticides
- Essay on Pesticide Usage in India
- Essay on Environmental Impact of Pesticides
- Essay on Pesticide Persistence, Bioaccumulation and Bio magnification
- Essay on Case Study—DDT in the Environment
- Essay on Pesticide Resistance
- Essay on the Regulations in Pesticide Application
- Essay on General Effects of Pesticide Pollutants
Essay # 1. Characteristics of Major Pesticides
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The term ‘Pesticide’ generally indicates any chemical, microbial agent or their mixture used as active ingredients of products for the control of crop pests and diseases, animal ectoparasites and pests in public health.
The Pesticide Manual lists about 600 active ingredients although there may be two or three times as many chemicals labelled as pesticides throughout the world.
The characteristics of major pesticides are given in Table 25.10:
Essay # 2. Historical Aspect of Pesticides:
Roughly, since the 1940s, chemical pesticides of one form or another have become a dominant and essential form of pest control throughout the world. Literally, thousands of different commercial pesticides are available in the market. DDT (dichlorodiphenyl trichloroethane) was first synthesised in 1877, but did not come into use as a pesticide until 1942.
It was used on a broad scale during World War II (1939-1945) by the US Army. Since then it is used as an important insecticide in agriculture and sanitation purposes all over the world. But due to its residual toxicity, use of DDT in the USA is banned by the Environmental Protection Agency.
Essay # 3. Classification of Pesticides:
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Pesticides are classified in a variety of ways – based on physical state, target species, purpose of application, or chemical nature. On the basis of target species they act on, pesticides may be either insecticides, herbicides, fungicides or rodenticides, depending on whether they are designed to kill insects, plants, fungi or rodents, respectively.
a. Organochlorine:
Organochlorine pesticides are hydrocarbon compounds containing multiple chlorine substituents. One of the most widely known organochlorine pesticides is DDT, an insecticide which was widely used during World War II. Because of its low toxicity to humans, DDT powder was widely applied by the US Army to the skin of soldiers to kill parasitic skin insects.
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Because of their low water solubility’s and environmental persistence, DDT and other organochlorine pesticides also found widespread use as poisons for subterranean nests of termites. About 100,000 tons per year were produced in the late 1950s in the United States alone.
b. Organophosphate:
Organophosphate pesticides are used primarily as agricultural pesticides, and contain a chemically reactive phosphate ester side chain, consisting of a central phosphorous atom double bonded to either an oxygen or sulphur atom, and single bonded to two methoxy (-OCH-,) or ethoxy (-OCH2CH3) groups.
c. Carbamate:
Carbamate pesticides generally have the formula RHNCOOR, and are relatively polar, highly soluble in water, and chemically reactive. Some Carbamates of importance are Aldicarb, Carbaryl, Carbofuran, Ferbam, and Captan. Carbofuran, like many Carbamates, is primarily used in agriculture.
Its usage pattern is consistent with general Carbamate pesticide application, since the Midwest and Southeast are the two regions with the greatest need for pesticides in agriculture.
d. Triazine:
Compounds of the s-Triazine family are among the most heavily used herbicides during the past 30 years.
Although most have low acute toxicity in most animal species, chronic exposures to certain s-Triazines have been shown to be animal carcinogens. s-Triazine (for which this class is named) is a six member ring containing alternating nitrogen and carbon atoms. Common product derivatives include Atrazine, Simazine, Terbuthylazine, Ametryne, and Terbutryne.
e. Naturally Occurring Pesticides:
Natural pesticides are the products of plants or minerals. Nicotine (extracted from tobacco), Pyrethrum (extracted from chrysanthemum flowers), and Rotenone (extracted from the tuber of Derris elliptica) are plant derived, while pesticide like Boric acid, cryolite and Diatomamaceous Earth are mineral derived.
Essay # 4. Application Potential of Pesticide:
Most large-scale pesticide use is undertaken for reasons of public health, agricultural production or forestry management. It is well-known that more than a dozen important diseases are transmitted by mosquitoes, including malaria, yellow fever, encephalitis, etc. where DDT is used widely for control of mosquitoes for a considerable period, particularly in the tropics.
Identically, in agriculture, a number of organophosphate, organochloride and carbamate compounds were used for control of disease pests all over the world. In forestry practices, a bulk amount of pesticides was used in the past where plantation forestry was widely practiced.
Essay # 5. Limitation of Pesticide Uses:
There is little doubt that pesticide use harmed non-target species on a significant scale.
A few examples are:
(a) The destination of speckled sea front in the Texas,
(b) Reduction of photosynthesis by the marine phytoplankton’s,
(c) Residue accumulation in living system through food chain and subsequent, destruction of population of birds, mammals, molluscs, etc.
Essay # 6. Toxicology of Major Pesticides:
In general, most of the pesticides are capable of inducing irreversible toxic effects in undesired biological systems. Unfortunately, since toxicity is often non-selective, adverse effects may develop in exposed humans or other non-target species.
There are three categories of chlorinated hydrocarbon insecticides, viz., DDT and its two other analogues. DDT is cheap and the most effective one. DDT has genotoxic and clastogenic functions.
Normally DDT acts on central nervous system (CNS) by interfering with or blocking the transport of ions (Na+ , K+ and Ca++) across the nerve membrane. Identically, cyclodiene insecticides like Aldrin. Dieldrin, Heptachlor etc. are still more toxic than DDT compounds on CNS.
The organophosphorus insecticides is the single largest class of insecticides, accounting for over 40% of total registered pesticides in the world. Some of them are also used as herbicides. The acute toxicity of some organophosphate compounds is very high.
They act by phosphorylating and inhibiting acetyl cholinesterase in nervous tissues of man and insects. Carbamate insecticides have a similar—but not identical-mechanism of action to OP compounds (reversible inhibition of HehL) and, therefore, they induce quantitatively the same chollinergic form of toxicity.
Pyrethrum, the natural insecticide obtained from chrysanthemum flowers, contains at least six active ingredients generally known as pyrethrins. The mechanism of action of pyrethrins and pyrethroids on the nervous system is thought to be similar to that of DDT.
Herbicides differ widely as to their toxicity and selectivity. Some are toxic to plants and animals by different mechanisms, while some share a common mode of action against the two targets. There are three major types of herbicides-chlorophenoxy compounds (2, 4-D; 2-4-5-T), Bipyndylium compounds (paraquat), and Triazines (Atrazine, Simazine)-which are widely used in agriculture.
A summary of major pesticide effects and persistence is given in Table 25.11:
Essay # 7. Pesticide Usage in India:
The use of synthetic pesticides started in 1948-49 with the use of DDT for malaria control and BHC for locust control. The Indian pesticides production industry started with the setting up of a BHC technical plant at Rishra near Kolkata in 1952.
Shortly after, Hindustan Insecticides Ltd. set up two units to manufacture DDT. In 1969, Union Carbide set up a small plant (Union Carbide India Ltd (UCIL)) in Bhopal the capital city of Madhya Pradesh, to formulate pesticides.
The Bhopal facility was part of India’s Green Revolution aimed to increase the productivity of crops. The industry produced various pesticides-mainly seven brand carbaryl insecticide and temikcbrand aldicarb pesticide.
All the pesticides produced at UCIL were sold in the Indian market. The Union Carbide continued pesticide production till 1984 Bhopal disaster. Today, the Indian pesticides industry comprises of more than 125 basic producers of large and medium scale and more than 500 pesticide formulations.
The pesticide formulation produced in the country are mainly of the conventional type currently, dusting powder has a major share (85%) in the market followed by water-soluble dispersible powder (12%) and emulsification concentrates (2%).
The use of granules, which are advantageous in terms of lower drift, ease of application and safety to operate is still in infancy. Most of the units are in small scale industry (SSI) sector.
India is one of the few remaining countries still engaged in the large scale manufacture, use, and export of some of the toxic chlorinated pesticides, such as p.p-dichlorodiphenyltrichloroethane (DDT) hexachlorocyclohexane (HCH) and pentachlorophenol (PCP).
Even in the 1990s more than 70% of the gross tonnage of pesticides used in agricultural applications in India consisted of formulations which are banned or severely restricted in the east and west.
According to a Green Peace Report, India is now producing 90,000 metric tons of pesticides as the largest industry in the whole of Asia and twelfth largest in the entire world (www(dot) greenpeaceindia(dot)org(dot)nopesti(dot)html). The cumulative consumption of the pesticide, hexachlorocyclohexane (HCHs), in India until 1985 was 575,000 tons and since then about 45,000 tons of HCHs has been used annually.
The usage of DDT and HCH continued till recently. Apart from the US, India is the only country which has applied more than 100,000 tons of DDTs since its formulation, mainly in its agricultural and malarial control programmes until it was banned for agricultural use in 1989.
Even though usage of technical HCH was finally banned completely in 1977, the Government of India is encouraging its replacement with Lindane (y-HCH), an isomer which has all the hazardous properties of HCH.
Even though DDT has been banned for agricultural use, India has so light exemption under Stockholm Convention for use of 10,000 tons of DDT for restricted use in the public health sector. The national malaria program (NAMP) used 3,750 tons of DDT in the year 2001, in Ural and peri-urban areas for residual spraying.
The pattern of pesticide use differs significantly between the countries. The worldwide consumption of pesticide is about two million tons per year, of which 24% is consumed in the USA alone, 45% in Europe and 25% in the rest of the world.
The usage of pesticides in India is only 0.5 kg ha–1 while in Rep. Korea and Japan, it is 6.6 and 12.0 kg ha-1, respectively. Among the various pesticides used in India 40% of all the pesticides used belong to organochlorine class of chemical pesticides. The other major category is organophosphate pesticides.
Monocrotophos, phorate, phosphamidon, methyl parathion and dimethoate are some of highly hazardous pesticides that are continually and indiscriminately used in India. The three commonly used pesticides, lindane (y-HCH), DDT, and malathion account for 70% of the total pesticides consumption.
Regarding the usage of technical pesticides, insecticides account for 80% of total pesticides used in the country, followed by herbicides and fungicides. The pesticides commonly used in India is given in Table 25.12. Pesticides used in high quantity in irrigated areas and in few selected crops like cotton, rice, and potato.
Essay # 8. Environmental Impact of Pesticides:
A 1979 report of the United Nations Environment Programme (UNEP) summarised the environmental impact of the indiscriminate use of pesticides in the following words: When carelessly applied, chemical pesticides can result in acute and long-term side-effects, including sickness and death of people, useful animals, fish, birds, and destruction of crops.
Even when properly used chemical pesticides have a number of unavoidable side-effects.
Their persistence and ubiquitous nature combined with a tendency of some compounds to concentrate in organisms as they move up the food chain, may increase their toxicity to fish, birds, and other forms of life including man and cause other harmful effects on man, his health and well-being.
The environmental fate of pesticides used in crop protection and vector control of communicable diseases is represented diagrammatically in Fig. 25.11. Accumulation of pesticides in the environmental compartments is dependent on both the manner of their application and the chemical nature of the compounds used and their formulations.
The most popular technique of application is spraying in the form of dusts, fumes, mists or vapours using manual or mechanical devices or even small aircraft which, while facilitating diffusion of the chemicals over a large area and making them more effective, leads inevitably to the persistence of potentially toxic chemicals in the environment, contamination of the environment relate to their non-degradable nature.
It is apparent that by both precipitation and leaching pesticides may find their way eventually into water bodies. The transport and fate of pesticides in the aquatic environment is influenced by their concentration and degradation by biotic and biotic factors. Indeed, the two most important degradative forces acting on environmental chemicals including pesticides are sunlight and microbes.
Most pesticides used in the agriculture and public health sectors are transferred to soil where their fate is determined not only by soil micro flora and micro fauna but also by the chemical environment of the soil. Very little is known about the interaction between chemical fertilizers and insecticides or the role of microbial flora in the accumulation of residues of persistent pesticides in soil.
The ecological risk inherent to pesticides arises from the differential vulnerability of different biotic communities to their toxic action and the differential response of organisms to their non-lethal but possible long-term effects.
Besides the rapid development of resistance among arthopods, rodents, bacteria, fungi, and weeds, the two problems that have to be faced are the disruption of natural controls and the pesticide treadmill, entailing the use of more and more chemicals for more and more applications, escalating the cost of control.
The estimated annual impacts of pesticides in developing countries are given in Table 25.13:
Essay # 9. Pesticide Persistence, Bioaccumulation and Bio Magnification:
The persistence of pesticides in the environment is one of the important factors that determines their efficiency as pesticides and their impact on non-target species.
If pesticides degraded rapidly to harmless substances through natural processes there would be little opportunity for them to be spread throughout the food web through feeding relationships and their concentrations to increase through biological magnification.
On the other hand, if pesticides degraded rapidly, repeated applications may be necessary to achieve the same level of pest control that could be obtained with one or a few applications of a more persistent pesticide.
Thus, the very characteristic that makes persistent pesticides desirable from the standpoint of pest control makes them undesirable from the standpoint of their impact on non-target species. The persistence of pesticides in the environment varies widely with respect to pesticide types and the nature of substrates on which they are applied.
Essay # 10. Case Study—DDT in the Environment:
DDT is one of many toxic chemical compounds—some simple and some complex—classed as pesticides, substances used to reduce the numbers of an unwanted plant or animal population.
Before the widespread advances in chemical technology accomplished during and after World War II, two types of insecticides were in use:
(a) Inorganic compounds, including compounds of arsenic, sulphur, copper or cyanide,
(b) Complex organic compounds, often referred to as ‘botanicals’, which were obtained from plant tissues.
Use of these compounds was not widespread and, thus, the impact was minimal. In post-War period, however, many new organic compounds were developed with toxic properties suitable for use as pesticides of one sort or another. One large class of pesticides thus developed is the chlorinated hydrocarbons of which DDT is a member.
Besides their apparent low toxicity to humans, the chlorinated hydrocarbons have two general characteristics that make them desirable as insecticides. First, they are toxic to large range of organisms and, therefore, can control many pests at once.
Second, they are relatively long-lasting and, therefore, need to be applied less frequently. Unfortunately, these characteristics also make the chlorinated hydrocarbons all the more dangerous to natural ecosystems.
The danger lies in their biological magnification within the food chain, a phenomenon produced by the high solubility of these compounds in fats and oils and their storage within the fatty tissues of organisms.
A clear example of DDT accumulation on various organisms in salt marsh area of Great South Bay, New York is given in Table 25.14:
DDT enters the marsh by aerial spraying for mosquito control. Because it is highly insoluble in water, most of the DDT remains in the marsh soil or settles to be incorporated in the bottom sediments of channels and pools. A very small amount, however, does dissolve in the water.
The algae, phytoplankton and decomposer bacteria of the marsh are, thus, exposed to very low concentrations of DDT in their environment. Because DDT is much more readily soluble in fats and oils, it tends to accumulate in the bodies of these tiny organisms and reach concentrations may times those of the water itself.
When these organisms are ingested in large numbers by zooplankton or detrital feeders such as clams and tiny crustaceans, the DDT they take in also tends to be retained because of its insolubility in water. In this way, the concentration of DDT in body tissues increase by many orders of magnitude up the food chain, from fingerling fish to larger fish to predatory birds, such as the herring gull and cormorant.
Physically, the DDT molecule is very stable and, unlike many other organic molecules, does not decompose under continued exposure to oxygen, sunlight or other reagents or energy sources available at the earth’s surface. Similarly, from biological standpoint, DDT is also very stable.
Only a few microbes seem to posses the ability to degrade DDT efficiently and the process appears to require anerobic conditions. In animals, DDT is metabolised very slowly by the liver into breakdown products DDE and DDD—both of which are still highly toxic. These factors combine to yield a half-life for DDT in the biosphere estimated at about 15 years.
At the present time, the total amount of DDT in the biosphere is estimated to be over 2 billion metric tons, of which 3/4 is distributed in terrestrial environments and the remaining 1/4 in marine environments. DDT enters the air largely through aerial spraying operations, but significant amounts enter the air by simply evaporating from water surfaces, plant surfaces and soils.
In this fashion, about 1/4 of the total annual production of 100,000 metric tons/year reaches the ocean. Estimates of DDT reaching the ocean in. run-off are very much lower, a result of the very low solubility of DDT in water (Fig. 25.12).
Essay # 11. Pesticide Resistance:
In recent years, pesticide resistance was noticed in different microbes and also in a number of insects. Thus, it appears that the resistant biota develop some mechanisms of resistance.
The probable mechanisms of resistance are shown in Table 25.15:
Essay # 12. Regulations in Pesticide Application:
In the regulation of pesticide application, government bodies have an important and major role because both producers and users are not likely to limit themselves in the sales and use of pesticides (Table 25.16). Quality control of pesticides is ensured through a rigorous registration procedure requiring testing in four different climatic conditions and making available toxicological data in Indian conditions.
The import, manufacture, sale, transport, use, etc. of pesticides is being regulated under a comprehensive statute ‘The Insecticides Act, 1968’ and the rules framed there under, to ensure availability of quality, safe and efficacious pesticides to the farming community, comprehensive regulations to ensure that no part of the pesticide industry operate outside its watchful eye.
Not only every pesticide product is manufactured, imported or used in India required to be registered with the Central Insecticides Board, any body selling, stocking or distributing pesticide products, also requires a license.
The act also allows the Board to ban or restrict the use of any pesticide product. Accordingly, the Government has banned the use of more than 30 pesticides, restricted the use of 7 pesticides including DDT, and refused registration for 18 pesticides.
India also has a BIS standard (Bureau of Indian Standard) for pesticide application equipment. However, implementation of legislations and standards at field level needs to be strengthened to prevent misuse and inappropriate use of pesticides with equipment the does not meet the minimum of quality standards.
Under the Insecticides Act, compulsory registration of pesticides is provided. The use of chemical pesticides can be initiated only after the proper registration by the Registration Committee, after close scrutiny of the data about bio-efficacy and safety of human beings, wildlife, birds, domestic animals, beneficial parasites and predators. The Insecticide Rules takes care of the safety culture in pesticide handling and use.
It covers periodical clothing, respiratory devices, antidotes and first aid medicines, training of workers and disposal of used packages, surplus materials and washing of insecticides.
The Registration Committee reviews the pesticides from time to time and the recommendations are considered by the Ministry of Agriculture. The Committee as a policy has decided not to register WHO Class IA and IB pesticide unless there is sufficient justification.
The Directorate of Plant Protection, Quarantine & Storage (DPPQS) has good schemes for training at the state level. Besides, training is imparted to the doctors of health centers of states by the medical experts of the Directorate of Plant Protection, Quarantine & Storage.
The National Plant Protection Training Institute (NPPTI) at Hyderabad imparts training to the State Plant Protection functionaries. Farmers Field Schools (FFS) are regularly organized under the IPM programme in addition to season-long training for Masters Trainers under which State Extension Functionaries are trained for full cropping period of various crops.
State Agriculture Universities (SAUs), Krishi Vigyan Kendras (KVKs), and State Department of Agriculture (SDA) also organize training to farmers on safe use of pesticides.
For the enforcement of the quality of pesticides, four important functionaries are notified under the provisions of the Insecticides Act/Rules viz., Licensing Officers, Appellate Authority, Insecticide Inspectors and Insecticide Analysts.
A network of 46 pesticides testing laboratories, situated in 18 States and 1 Union Territory across the length and breadth of the country, with an annual analysis capacity of over 55,666 samples of pesticides is available in the country for continuously monitoring the quality of pesticides.
One of the notified functionaries of the Government.
Insecticide Inspectors can enter and search, at all reasonable times and with such assistance as he considers necessary in which he has the reason to believe that an offence under the Insecticides Act, 1968 and the Rules made thereunder has been or is being or is about to be committed, or for the purpose of satisfying himself that the provisions of this Act or the Rules made there under or the conditions of any certificate of registration or license issued thereunder are being complied with.
Insecticide Inspectors also draw samples of pesticides, Insecticide analysts carry out their analysis. Besides, the Central Government has also established two regional pesticides testing laboratories to supplement the resources of the States/UTs, who do not either have a pesticide testing laboratory or adequate analysis capacity or adequate analysis facility for monitoring the quality of pesticides.
Any disputes in the results of analysis are settled by a referral laboratory of the Central Government, called the Central Insecticides Laboratory (CIL).
In order to strengthen the existing laboratories and to set up new pesticides testing laboratories, the Central Government also extends financial assistance to the States/UTs as grants-in-aid. Besides, State Governments also establish additional Pesticides Testing Laboratories with their own resources.
International Scenario:
Pesticides have traditionally being the object of international legislation in several fields (Table 25.17). Laws and regulations on human health, environmental protection, agricultural practices, international trade and border control all address the proper use, manufacture, export, import and application technologies for pesticides.
The international code of conduct and use of pesticides (Code of Conduct), adopted in 1985 by the 23rd session of the main governing body of the Food and Agriculture Organization of the United Nations (FAO), was formulated to provide universal standards of conduct for all parties, but especially national government and pesticide industry.
Since then, the code of conduct has been amended once, in 1989, to include the prior informed consent procedure, and revised in 2002.
Since 1985, several other international instruments, either dealing explicitly with pesticides or indirectly relating to their management, have come into force.
The most relevant include the Rotterdam Convention on the prior informed consent procedure, for certain hazardous chemicals and pesticides in international trade (Rotterdam Convention), the Stockholm Convention on persistent organic pollutants (Stockholm Convention), the Basel Convention on the trans boundary movements of hazardous wastes and their disposal (Basel Convention), the Montreal Protocol on substances that deplete the ozone layer (Montreal Protocol), the International Labour Organization Convention No. 184 on safety and health in agriculture (ILO Convention 184) and numerous standards on pesticide residues in food issues by the Codex Aliment Arius Commission.
Furthermore, a new globally harmonized system of classification and labelling of chemicals (GHS) has been designed to improve the protection of human health and the environment during the handling, transport and use of chemicals.
However, it is very important to note that legislation alone is unlikely to balance effective pesticide management with an environmentally sustainable approach to pest control.
Governments should consider adopting other policies and strategies to improve pesticide management, such as providing farmers with support and training in integrated pest management (IPM), allocating subsidies for the purchase of minimum-risk products and fostering scientific research, public education campaigns and training for both inspectors and professional users.
A solid legislative and regulatory framework, however, underpins all of these.
Poison Gas at Bhopal, India:
Alarm sirens rang at 12:30 a.m. on the morning of December 3, 1984, in Bhopal, India, at a plant owned by Union Carbide. The internal siren was to warn workers at the plant that a toxic gas leak had occurred, and the public siren was to warn people living around the plant.
Not realizing the extent of the emergency, the public siren was almost immediately shut off, and it was not until 45 minutes later that city authorities learned that people were fleeing the area and not until 3:00 a.m. that they learned that some people were already dead.
Ultimately, it was to be recognized as the most deadly industrial accident in history, claiming thousands of lives, permanently disabling tens of thousands, and leaving perhaps as many as 100,000 people with some after-effects.
Why do we not use more precise numbers? Well, perhaps some of the deaths that night or later were partly caused by other accidents or illness, possibly some of those disabled were really not all that badly injured and some of the disabled were not reported or found, and in a large industrial city in a nonindustrial country people are hard to count anyway.
What happened is slightly more clear than the effects. After operating in India for many years, in 1969 Union Carbide built a plant in Bhopal to manufacture pesticides and herbicides based on carbaryl.
The plant was 50.9% owned by Union Carbide in the United States and 49.1% by Indian investors and was placed in Bhopal partly because the Indian Government and State and local authorities wanted to provide jobs and stimulate economic growth in the region.
For the first 10 years of operation Union Carbide imported the major ingredients for pesticide manufacture and simply combined them at the Bhopal plant, but in 1979 the Indian Government overruled objections of authorities in Bhopal and gave Union Carbide permission to manufacture all of the necessary ingredients in Bhopal.
By 1984 the Union Carbide plant was storing large amount of the two key ingredients, alpha naphthol and methyl isocyanate gas (MIC), and making carbaryl by the reaction:
alpha naphthol + MIC → Carbaryl
which, using formulas, is:
C10H9OH + CH3NCO → C10HvOCH2ONHCH3
Unfortunately, for reasons that are still somewhat in dispute, in the early morning of December 3, 1984, water leaked into one of the tanks holding the MIC. This caused an immediate reaction that broke down some of the MIC to various other organic compounds and generated large amounts of CO2 and heat (the reaction was exothermic).
This combination of hot gases ruptured the control system and poured out into the streets of Bhopal. People who inhaled large quantities of the gas died immediately; their internal organs almost dissolved. People receiving lower doses had serious corrosion of their lungs (causing many later deaths), and many were blinded.
The ensuing financial and legal complications are as sickening in their own way as the gases themselves.
They centered around two questions:
Who was responsible for the accident, and who should be compensated for it?
Union Carbide in America offered an immediate $200 million as a humanitarian gesture but disclaimed responsibility because the plant was operated by an Indian subsidiary and not under direct control of the parent company.
The Indian government rejected the offer as insufficient and spent considerably less money to take care of the families of those who had died and those who were too ill to continue working.
Hordes of US lawyers descended on Bhopal, attempting to get victims to let them bring suit in US courts, where any compensation awarded would presumably be larger than in an Indian court and, not incidentally, would pay the lawyers for the efforts.
As we write 27 years later, neither of the two questions has been satisfactorily answered nor have most of the victims received adequate compensation, though Supreme Court asked the Indian Government to distribute the compensation fund to recorded victims of gas tragedy.
Essay # 13. General Effects of Pesticide Pollutants:
Almost every part of the human body is affected by one pollutant. For example, lead and mercury (remember the Mad Hatter) affect the brain; arsenic, the skin; carbon monoxide, the heart; and fluoride, the bones. Wildlife is affected as well.
Risk potential of some of voluntary and accidental exposure is shown in Table 25.18:
Voluntary Exposure:
People sometimes expose themselves to harmful pollutants on purpose. Voluntary exposure to toxins and potentially harmful chemicals is sometimes referred to as exposure to personal pollutants. The most common of these are tobacco, alcohol, and other so-called recreational drugs.
Use and abuse of these substances have led to a variety of human ills, including death and chronic disease, criminal activity such as reckless driving and manslaughter, loss of careers, street crime, and the straining of human relations at all levels.
The lists of potential toxins and affected body sites for humans and other animals is shown in Fig. 25.13:
