COMPARISON OF ORGANOCHLORINE RESIDUE LEVELS IN THE STRIPED DOLPHIN FROM WESTERN NORTH PACIFIC, 1978-79 AND 1986

Blubber samples of adult male striped dolphins (Stenella coeruleoalba) from Pacific coast of Japan collected during 1978-1979 and 1986 were analysed for persistent organochlorines such as PCB isomers and congeners, DDT compounds, HCH (BHC) isomers and HCB for understanding the long-term changes in the residue levels of these contaminants. Comparison of the organochlorine levels using dolphins of same age revealed that the level of contamination remains unchanged in the case of PCBs and DDTs during the above period. Whereas HCHs and HCB showed a significant decrease. Unlike terrestrial animals contaminated in point source and nearby areas, the striped dolphin which is living in remote area from the contamination source exhibited slow temporal trend of organochlorine residue levels. Present data indicate that persistent organochlorine contamination is still continuing in the remote marine environment. © 1990.