MP17 Endangered Species and Environmental Contaminants: Status of Science
Monday, 14 November 2005: 8:00 AM - 6:30 PM in Exhibit Hall

(KAN-1117-747922) Organochlorine Pesticides, Polychlorinated Biphenyls, and Polybrominated Diphenyl Ethers in Irrawaddy Dolphins from India.

Kannan, K. ¹, Ramu, K.², Kajiwara, N.², Sinha, R.³, Tanabe, S.², ¹ Wadsworth Center, New York State Department of Health, Empire State Plaza, PO Box 509, Albany, NY 12201-0509, USA² Center for Marine Environmental Studies, Ehime University, Matsuyama, Ehime, Japan³ Department of Zoology, University of Patna, Patna, UP, India

ABSTRACT- The Irrawaddy dolphin (Orcaella brevirostris) is at risk of extinction throughout its range, as a result of incidental catches, habitat degradation, and pollution. Populations of Irrawaddy dolphins are constrained by the species narrow habitat requirement - lagoons, estuaries, rivers, and lakes and are therefore particularly vulnerable to the effects of human activities. In this study, for the first time, concentrations of organochlorine (OC) pesticides, polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs) were determined in tissues of Irrawaddy dolphins collected from Chilika Lake, India, to understand the status of contamination. DDTs were the predominant contaminants found in Irrawaddy dolphins; the highest concentration found was 10,000 ng/g, lipid weight, in the blubber. HCHs were the second most prevalent contaminants in dolphin tissues. Concentrations of PCBs, chlordanes, HCB, TCPMe, and TCPMOH were in the ranges of few ng/g to few hundreds of ng/g, on a lipid weight basis. In general, concentrations of OC pesticides and PCBs in Irrawaddy dolphins were lower than the concentrations reported for coastal and riverine dolphins collected in Asia. PBDEs were detected in the blubber of Irrawaddy dolphins at concentrations ranging from 0.98 to 18 ng/g, lipid weight. BDE congener 47 accounted for 60-75% of the total PBDE concentrations. Whereas these results establish the baseline levels of persistent organic pollutants in Irrawaddy dolphins, efforts should be made to reduce the sources of contamination by DDT and HCH in Chilika Lake.

Key words: Irrawaddy dolphin, River dolphin, Organochlorines, PBDE