Fluctuations of DDT·PCB Content of Yellowtails / 日本農村医学会雑誌

ABSTRACT

It is a well-known fact that the environment has been globally contaminated with the persistent organochlorine insecticides and PCBs, and that all over the world the general populations have been polluted with them in spite of their minute quantity for some decades. These chemicals except PCBs are mainly neuropoison, and according to De Vlieger (1968), DDT and Dieldrin are translocated to human brain, and these concentrations of the tissue are greater than those of the blood. The adverse and ill effects of these residues on human central nervous system can be determined incompletely. In addition, their production and use have not yet been prohibited in some countries. Therefore, according to the previous report (1981), the contents of these compounds have been surveyed about wild yellowtails migrating around the Islands of Japan, and cultured ones fed on a sort of sardine catched near the Islands.<BR>In the case of DDT, the content of wild samples catched in 1983, showed not only low level of total DDT, but the increase of its metabolites, compared with those of two years before i. e., the mean concentration decreased to about one-half (from 0.38 to 0.17 ppm), and the ratio of its meabolites per total DDT inversely increased from 41 to 57%. In addition, the same tendency was also observed in those of cultured samples.<BR>With regard to PCBs content, however, the fish of wild type showed the same level (0.10 ppm) as that of cultured type in 1983, and their peak patterns were observed similar. The PCBs contents have been almost unchanged in these two types since 1980 over a period of 3 years.