Shinsuke Tanabe, Ehime University, Japan

The present paper overviews global contamination by organochlorines, a representative group of persistent endocrine-disrupting chemicals, and their ecotoxicological implications for wildlife and humans in Asia.

The recent pattern of contamination by organochlorine residues in the coastal environment is prominent in tropical regions due to continuous usage in insecticides 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 with a global reach and significance. Reflecting this, considerable contamination was observed in open tropical ocean 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 to POPs, particularly organochlorines, and the related toxic effects in higher trophic level wildlife from Asia. Endocrine disrupting chemicals, such as organochlorine insecticides, polychlorinated biphenyls (PCBs), organotins etc are found in the tissues of a wide variety of wildlife from Asia. In general, water birds and marine mammals have accumulated the dioxin-like compounds with much higher concentrations than humans, implying higher risk from exposure to these toxic contaminants in wildlife.
The future research on issues of endocrine disrupting chemicals in humans and wildlife will have to be focused on Asian developing countries.