Organochlorine residues in human tissues and some foodstuffs, and the role of yellowtails as an index of the residues

Abstract

The general population and the environment are still polluted with residual organochlorine compounds such as DDT, PCB etc., whose production and use were prohibited in Japan more than 10 years ago. At first, 13 species of human autopsy tissues and blood of rural residents were investigated for residues of organochlorine insecticide (OCI) and indications of their transfer from maternal blood to umbilical cord blood at delivery. Some species of marine fishes, fatty foods, chickens and eggs were surveyed for their OCI content. Based on the data of these surveys, wild and cultured yellowtails were selected as indices of a variety of marine fishes. The characteristics of these yellowtails were examined, and their levels of OCI and PCB were investigated during a period from 1979-83. The conclusions are presented as follows: It is suggested that the organochlorine levels of both types of yellowtail have increased approximately in proportion to the increase of lipid content followed by growth. Besides the difference of the young and mature fishes with respect to the qualities of DDT and PCB residues indicates that their metabolic functions are enhanced by their growth. The wild yellowtails caught in the Nagasaki area in 1981 showed high amounts of DDT and high ratios of technical DDT per total DDT. These facts and the GLC patterns of PCBs in these yellowtails indicate a high level of DDT content in the Japan Current. DDT contents of both wild and cultured yellowtails decreased qualitatively in 1983 as compared with two years before. These facts and the fluctuations observed in total DDT are considered to be a sign of the decline of the yellowtail. It is concluded from the standpoint of ecology that the DDT content on lipid basis in the general population is concentrated as compared with that in marine fishes. PCBs GLC pattern of the cultured yellowtail was obviously different from that of the wild type in 1980, and thereafter their patterns have come to be similar. The levels of PCB content were the same and didn't change distinctly from 1980 to '83 in either type.