o clarify the levels of organochlorine compounds (OCs) and the metabolism of OCs in the body of Steller sea lion Eumetopias jubatus migrating along the coast of Hokkaido, OCs in the sea lion's blubbers for each age, sex and reproductive status were determined by gas chromatography linked to ion trap mass spectrometer. In sea lions, the compounds accumulated in the highest concentrations are DDT and its metabolites (DDTs) suggesting these animals are still exposed to DDTs from the surrounding land. The levels of DDTs and polychlorinated biphenyls (PCBs) in sea lions may cause small effects such as the induction of drug metabolizing enzymes. The concentrations of DDTs, PCBs, hexachlorocyclohexanes and chlordanes in the old female sea lions were lower than those in the males and young females. This is most likely due to the loss of these compounds during nursing. In addition, the concentrations of each compound differed in the degree of difference between the young and the old females. This result may reflect ecological and physiological difference between the young and the old females. The proportions of tetrachlorinated biphenyl concentrations with vicinal hydrogen atoms in para- and meta- positions to total tetrachlorinated biphenyl concentrations were found to be higher in older animals implying low “phenobarbital inducible type” enzyme activity.

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The effects of Nonylphenol (NP) on medaka, Oryzias latipes, were examined with histopathological observation. At 2 weeks of NP treatment, various lesions in the kidney appeared and became more prominent with time. These renal lesions were hyaline deposition in Bowman's space, hyaline cast, hyaline droplets in the tubular epithelium, mitosis of proximal tubular epitheliumand glomerular sclerosis with cuboidalization of Bowman's capsule. Moreover, renal tumor was observed at 24weeks. The testis-ova in medaka developed from 16 weeks of NP treatment. These various pathological changes suggested that NP has carcinogenicity rather than endocrine disrupton. Therefore, the carcinogenic effects of NP on the kidney are of a significant problem.

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It is generally recognized that amphibian populations are potentially sensitive to aquatic contaminant such as herbicides. However, studies on the effects of herbicides on amphibian species are very limited in Japan. Thus, the toxicity of herbicides for paddy field to the tadpole of Rana dybowskii was examined by the author. Among the eight herbicides tested, only Fujigrass® has a high toxicity to the tadpole. Moreover, based on a comparison of the components of herbicides between the Fujigrass® and other non-toxic herbicides, it has become apparent that esprocarb (1,2-dimethlpropyl (ethyl)-thiocarbamate), the principal component of Fujigrass®, is the toxic substance to the tadpole of Rana dybowskii.

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Law Concerning the Examination and Regulation of Manufacture, etc. of Chemical Substances (Chemical Substances Control Law) in Japan has revised in 2003. The purpose of this report is to inform the main point of revision on the Law and discuss the tasks for putting into good operation.

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