ENDOSULFAN'S CRUELTY IN KASARKODE,NORTH OF KERALA.(PEOPLE NEAR A BIG CASHEW FARM AFFECTED MANY TYPE OF DISEASES ) ENDOSULFAN IS APPLIED USING HELICOPTERS FOR A BIG AREA..

Endosulfan is an organochlorine compound that is used as an insecticide and acaricide. This colourless solid has emerged as a highly controversial agrichemical due to its acute toxicity, potential for bioaccumulation, and role as an endocrine disruptor. Banned in more than 63 countries, including the European Union, Australia and New Zealand, and other Asian and West African nations, and soon in the United States, it is still used extensively in many other countries including India and Brazil. It is produced by Bayer CropScience, Makhteshim Agan, and Government-of-India–owned Hindustan Insecticides Limited among others. Because of its threats to the environment, a global ban on the use and manufacture of endosulfan is being considered under the Stockholm Convention.

Uses

Endosulfan has been used in agriculture around the world to control insect pests including whiteflys, aphids, leafhoppers, Colorado potato beetles and cabbage worms. I^[6] Because of its unique mode of action, it is useful in resistance management; however, because it is non-specific, it can negatively impact populations of beneficial insects.^[7] It is, however, considered to be moderately toxic to honey bees,^[8] and it is less toxic to bees than organophosphate insecticides.^[9]

Production

The World Health Organization estimated world wide annual production to be about 9,000 metric tonnes (t) in the early 1980s.^[10] From 1980–89, worldwide consumption averaged 10,500 t per year, and for the 1990s use increased to 12,800 t per year.

Endosulfan is a derivative of hexachlorocyclopentadiene and is chemically similar to aldrin, chlordane, and heptachlor. Specifically, it is produced by the Diels-Alder reaction of hexachlorocyclopentadiene with cis-butene-1,4-diol and subsequent reaction of the adduct with thionyl chloride. Technical endosulfan is a 7:3 mixture of stereoisomers, designated α and β. α- and β-endosulfan are conformational isomers arising from the pyramidal stereochemistry of sulfur. α-Endosulfan is the more thermodynamically stable of the two, thus β-endosulfan irreversibly converts to the α form, although the conversion is slow.^[11][12]

Health effects

Endosulfan is one of the most toxic pesticides on the market today, responsible for many fatal pesticide poisoning incidents around the world.^[31] Endosulfan is also a xenoestrogen—a synthetic substance that imitates or enhances the effect of estrogens—and it can act as an endocrine disruptor, causing reproductive and developmental damage in both animals and humans. Whether endosulfan can cause cancer is debated.

Toxicity

Endosulfan is acutely neurotoxic to both insects and mammals, including humans. The US EPA classifies it as Category I: "Highly Acutely Toxic" based on a LD₅₀ value of 30 mg/kg for female rats,^[9] while the World Health Organization classifies it as Class II "Moderately Hazardous" based on a rat LD₅₀ of 80 mg/kg.^[32] It is a GABA-gated chloride channel antagonist, and a Ca²⁺, Mg²⁺ ATPase inhibitor. Both of these enzymes^[13] Doses as low as 35 mg/kg have been documented to cause death in humans,^[33][13] Farm workers with and many cases of sub-lethal poisoning have resulted in permanent brain damage.chronic endosulfan exposure are at risk of rashes and skin irritation.^[9] are involved in the transfer of nerve impulses. Symptoms of acute poisoning include hyperactivity, tremors, convulsions, lack of coordination, staggering, difficulty breathing, nausea and vomiting, diarrhea, and in severe cases, unconsciousness.

EPA's acute reference dose for dietary exposure to endosulfan is 0.015 mg/kg for adults and 0.0015 mg/kg for children. For chronic dietary expsoure, the EPA references doses are 0.006 mg/(kg·day) and 0.0006 mg/(kg·day) for adults and children, respectively.^[9]

Endocrine disruption

Theo Colborn, an expert on endocrine disruption, lists endosulfan as a known endocrine disruptor,^[34] and both the EPA and the Agency for Toxic Substances and Disease Registry consider endosulfan to be a potential endocrine disruptor. Numerous in vitro studies have documented its potential to disrupt hormones and animal studies have demonstrated its reproductive and developmental toxicity, especially among males.^[9][13] A number of studies have documented that it acts as an anti-androgen in animals.^[35] Environmentally relevant doses of endosulfan equal to the EPA's safe dose of 0.006 mg/kg/day have been found to affect gene expression in female rats similarly to the effects of estrogen.^[36] It is not known whether endosulfan is a human teratogen (an agent that causes birth defects), though it has significant teratogenic effects in laboratory rats.^[37][38] A 2009 assessment concluded that endocrine disruption occurs only at endosulfan doses that cause neurotoxicity.

Reproductive and developmental effects

Several studies have documented that endosulfan can also affect human development. Researchers studying children from an isolated village in Kasargod Ditrict, Kerala, India have linked endosulfan exposure to delays in sexual maturity among boys. Endosulfan was the only pesticide applied to cashew plantations in the hills above the village for 20 years and had contaminated the village environment. The researchers compared the villagers to a control group of boys from a demographically similar village that lacked a history of endosulfan pollution. Relative to the control group, the exposed boys had high levels of endosulfan in their bodies, lower levels of testosterone, and delays in reaching sexual maturity. Birth defects of the male reproductive system including cryptorchidism were also more prevalent in the study group. The researchers concluded that "our study results suggest that endosulfan exposure in male children may delay sexual maturity and interfere with sex hormone synthesis."^[39] Increased incidences of cryptorchidism have been observed in other studies of endosulfan exposed populations.^[40]

A 2007 study by the California Department of Public Health found that women who lived near farm fields sprayed with endosulfan and the related organochloride pesticide dicofol during the first eight weeks of pregnancy are several times more likely to give birth to children with autism. This is the first study to look for an association between endosulfan and autism, and additional study is needed to confirm the connection.^[41]

A 2009 assessment concluded that epidemiology and rodent studies that suggest male reproductive and autism effects are open to other interpretations, and that developmental or reproductive toxicity occurs only at endosulfan doses that cause neurotoxicity.^[38]

Endosulfan and cancer

Endosulfan is not listed as known, probable, or possible carcinogen by the EPA, IARC, or other agencies. There are no epidemiological studies linking exposure to endosulfan specifically to cancer in humans, but in vitro assays have shown that endosulfan can promote proliferation of human breast cancer cells.^[42] Evidence of cancinogenicity in animals is mixed.^[13]

Environmental fate

Endosulfan breaks down into endosulfan sulfate and endosulfan diol, both of which, according to the EPA, have "structures similar to the parent compound and are also of toxicological concern…The estimated half-lives for the combined toxic residues (endosulfan plus endosulfan sulfate) [range] from roughly 9 months to 6 years." The EPA concluded that, "[b]ased on environmental fate laboratory studies, terrestrial field dissipation studies, available models, monitoring studies, and published literature, it can be concluded that endosulfan is a very persistent chemical which may stay in the environment for lengthy periods of time, particularly in acid media." The EPA also concluded that "[e]ndosulfan has relatively high potential to bioaccumulate in fish."^[9] It is also toxic to amphibians: low levels have been found to kill tadpoles.^[43]

Endosulfan is subject to long range atmospheric transport, i.e. it can travel long distances from where it is used. For example, a 2008 report by the National Park Service found that endosulfan commonly contaminates air, water, plants and fish of national parks in the U.S. Most of these parks are far from areas where endosulfan is used.^[44] Endosulfan has also been detected in dust from the Sahara Desert collected in the Caribbean after being blown across the Atlantic Ocean.^[45] In 2009, the committee of scientific experts of the Stockholm Convention concluded that "endosulfan is likely, as a result of long range environmental transport, to lead to significant adverse human health and environmental effects such that global action is warranted."^[46]