TEMPORAL TRENDS OF PERSISTENT ORGANOCHLORINE RESIDUES IN HUMAN ADIPOSE-TISSUE FROM JAPAN, 1928-1985

Trend monitoring of organochlorine contaminants, viz. PCBs, DDTs, HCHs and CHLs, was carried out by using formalin-preserved adipose tissue of Japanese males from 1928 through 1985 for understanding the long-term trends in their contamination levels. The highest residual concentrations were observed during the periods of maximum production (or import) and usage of these compounds in Japan. Time trends of the contaminants varied with the usage pattern and their physico-chemical properties. Effectiveness of government regulations on the production and use of organochlorines was seen faster in the case of DDTs and HCHs, which showed a prominent declining trend in their residues, whereas PCB levels exhibited a continuing increase and maintained a steady state even after two decades of a ban on their production, indicating that the exposure to PCBs is still prevailing. Generally, in terms of the spatial view, unlike aquatic fauna from the point-source environment (aquatic ecosystem) humans in the non-point-source environment (terrestrial habitat) revealed a slower rate of reduction in organochlorine residue burdens.