Abstract
The present paper overviews the global contamination by organochlorines, a representative group of persistent organic pollutants (POPs) and endocrine disrupters, and their ecotoxicological implications on wildlife and humans from Asia. The recent pattern of contamination by organochlorine residues in the coastal environment is prominent in tropical regions due to continuous usage in the low-latitude developing countries. The major emission source of organochlorine insecticides such as DDTs and HCHs is probably located in the tropical belt and large quantities of volatilized contaminants are dispersed through the atmosphere on global terms. Reflecting this, a considerable contamination was observed in open ocean tropical waters as well as in the Arctic and nearby waters. On the other hand, PCBs are mainly released from developed nations and also deposited in open seas and oceans. The study of the mass transfer of organochlorines at the air-water interface suggests that the oceanic water bodies, particularly Arctic waters, act as a sink for persistent contaminants.
Our studies also focus on exposure and toxic effects of POPs, particularly organochlorines, in higher trophic level wildlife from Asia. Endocrine disrupting chemicals, such as organochlorine insecticides, polychlorinated biphenyls (PCBs) etc are found in tissues of a wide variety of wildlife from Asia. In general, water birds and marine mammals accumulated the dioxin-like compounds with much higher concentrations than humans, implying higher risk from exposure to these toxic contaminants in wildlife. The future issues of endocrine disrupting chemicals in humans and wildlife will have to be focused on Asian developing countries.
