Changes in benthic macro-invertebrates and concentrations of pesticide residues were surveyed at a station in the Hinuma River from April 1990 to December 1991, focusing especially on the periods before and after transplantation of rice plants into paddy fields bordering the river. Diazinon, fenthion, butachlor and oxadiazon reached their peak concentrations (2.3-3.1 μ g L^-1 for insecticides, 5.2-5.5 μ g L^-1 for herbicides) soon or one month after rice transplantation. The other pesticides (e. g. fenitrothion, pretilachlor) were detected with peak concentrations below 1 μ g L^-1 at the site. The density of Cheumatopsyche brevilineata (Trichoptera) larvae increased markedly, but larvae of Hydropsyche orientalis (Trichoptera) decreased, after diazinon had reached its maximum concentration at the site. The 48-h LC₅₀ values of insecticides and herbicides for the final instar larvae of both species were higher than those of concentrations detected in the river, However, H. orientalis was more sensitive than C. brevilineata to diazinon and fenthion (48-h LC₅₀, 6.8 and 280 μ g L^-1, 4.4 and 420 μ g L^-1, respectively).

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Effects of insecticides (diazinon, fenthion and fenitrothion) on net-spinning Trichopteran, Hydropsychidae (Hydropsyche orientalis and Cheumatopsyche brevilineata) larvae, which were often dominant species in steams in Japan, were investigated in the laboratory. The 48-h EC₅₀ (effects of going out from nests) values of insecticides (diazinon, fenthion and fenitrothion) for the nested final instar larvae of H. orientalis (Trichoptera) were as well as those of concentrations detected in pesticide-contaminated rivers (48-h EC₅₀ values, 3.8 μg L^-1), but C. brevilineata was very insensitive to these three insecticides (48-EC₅₀ values, 280-660 μg L^-1). Then effects of each insecticide on the nested final instar larvae of these two species were investigated using rotary flowing water taps. The 50% individuals of the larvae of H. orientalis easily went out from their nests by 5 μg L^-1 after six days of applications. And also, multiple effects of two (10 μg L^-1) or three (15 μg L^-1) insecticides on the species were recognized. However, very few individuals of the larvae of C. brevilineata went out from their nests even by 15 μg L^-1 of these three insecticides after two weeks of applications.

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Polychlorinated Dibenzo-p-dioxins and Dibenzofurans (PCDD/Fs) in fish (coastal and freshwater), intestinal contents of freshwater fish and water samples from Matsuyama, Japan were analyzed to evaluate the contamination levels and accumulation patterns. PCDD/Fs were detected in all samples investigated. Impurities of 2,4,6-Trichloropheyl 4-nitrophenylether (CNP) as a herbicide for paddy field and polychlorinated biphenyls (PCBs) were thought as PCDD/Fs sources of fish samples expect for formation under combustion process.
Bioconcentration Factors (BCFs) and Biomagnification Factors (BMFs) of PCDD/Fs in freshwater fish were calculated to evaluate accumulation patterns. BCFs and BMFs were ranged from approximately 10 to 100000 and from 0.001 to 0.1, respectively. These values of high chlorinated congeners, such as OCDD, were lower than low chlorinated congeners, such as TeCDD. There was no correlation between the octanol-water partition coefficient and BCFs and BMFs. It was explained by limited membrane permeability in fish.

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We developed a time-resolved fluoro-immunoassay (TR-FIA) for choriogenin (Cg), a precursor of vitelline envelope protein, by using a specific antibody against Cg in marbled sole Pleuronectes yokohamae. Two major proteins, high- and low molecular-weight vitelline envelope proteins (VeH, 61 kDa and VeL, 37 kDa), constituted the vitelline envelope of the mabled sole. We purified Cg (61 kDa) - which showed common antigenicity with VeH ? from the serum of estrogen-treated marbled sole by a combination of ion-exchange and hydroxylapatite chromatography. The specific antibody against Cg immunostained 170 and 61 kDa bands of vitelline envelope and 61 kDa band of the serum of estrogen-treated marbled sole. The dilution curve of purified Cg was parallel to that of the serum of estrogen-treated marbled sole. The standard curve of TR-FIA was almost linear from 61 pg/mL to 31.3 ng/mL. The intra- and inter-assay variations were less than 5.1 and 12.8 %, respectively. The high sensitivity of TR-FIA will be useful in the detection of effect by environmental estrogens.

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