The use of DDT has been banned in the United States because of Essay

The use of DDT has been banned in the United States because of environmental damage and human health concerns. However, in malar - Essay Example (Hayes & Laws, 1991). â€Å"Estimated lethal dose for man is 500 mg/kg and in kerosene solution it’s 150 mg/kg. Woodward et al. (1944) have stated the accepted acute mean lethal dose in rats as 250 mg/kg and Gosselin et al. (1984) has mentioned that the same amount would also be fatal for human beings. Baselt (1982) has stated that DDT is comparatively alright with a lethal dose of 30 g in an adult. â€Å"Exposure to an aerosol mist containing 80 mg DDT in a room of 113 m3 on five consecutive days for two hours two times a day showed no evidence of toxic effects†. (DDT, 1990) Studies have also revealed that the young are at no greater risk than adults. The four phases of the disposition of a toxic compound to estimate its toxicity are absorption through membranes in a system, the distribution throughout the system, the excretion and elimination from the system and finally, the metabolic fate of the chemical. Absorption happens from the gastrointestinal tract and throug h inhalation. DDT can also be taken in by intact skin in oily solution. DDT gets distributed in the body and primarily affects the central nervous system causing irritability. Violent agitations might also take place but is less common than with other organ chlorine pesticides. DDT tends to get accumulated in fatty tissues along with metabolites DDD and DDE. It also gets converted to DDA and dispatched through urine. Breathing in fine DDT aerosol or dust can cause problems for the nose, throat and eyes (Hayes & Laws, 1991). Formulations of DDT dissolved in a solvent is also known to cause temporary dermatitis. In most cases, the effect is attributable to the solvent and not DDT itself. Increased urinary excretion of the more polar metabolites is generally compensated for by increased steroid biosynthesis (Gosselin et al. , 1984). ). The effects of DDT on the respiratory system are only minor compared to the effects that it has on the nervous system. Heightened salivation has been ob served in persons who consumed DDT-infested food (Hayes & Laws, 1991). Apart from vomiting, the gastrointestinal system is hardly affected in cases of extreme poisoning and Renal damage has also been observed in people to some extent. Types of Exposure and Responses associated with DDT: Food is the primary way in which the population gets exposed to DDT. And â€Å"due to its low biodegradability and high lyophilise properties, small amounts of DDT are found to have accumulated in adipose tissue. DDT tends to get stored to a lesser extent in other tissue and this amount is proportional to their neutral fat content.†(Data Sheet on Pesticides, 1976, 2.2) Almost 5000 tonnes of DDT is used every year for the control of vector-borne diseases, primarily for malaria and visceral leishmaniasis control. DDT is acknowledged as a persistent organic pollutant(POP). It gets stored in the fatty tissue of animals and humans, makes its way up the food chain and is found in high concentrations in human breast milk(biomagnification). Populations in areas close to countries which make use of DDT and in temperate regions can be indirectly affected by long-range atmospheric transport so that DDT may contaminate environments far from where it is used. Large exposures can result in vomiting. â€Å"The earliest symptoms include par aesthesia of the tongue, dizziness, tremors and vomiting. It is generally believed that long exposure to DDT and its main metabolic product DDE