The Salmonella/microsome assay (Ames test) is a useful method for screening mutagens in complex environmental samples such as river water and sediment. However, no quantitative and generalized method to evaluate the mutagenicity of sediment has yet been established. In this study, the simple and effective method for monitoring the mutagenicity in sediment was investigated, and applied to river sediments and drainage sediments collected in Kanagawa prefecture.
The following method was proved to be simple, sensitive and giving good results for the Ames test for various sediment samples : sediment samples were extracted twice using ultrasonic agitation with dichloromethane/ethanol (4 : 1) and then dichloromethane, and crude extracts were dissolved to n-hexane/ethylacetate (95 : 5) and separated to the insoluble fraction, the passing fraction which should be refined by Cu column from a silica-cartridge, and the eluted fraction from the silica-cartridge with ethylacetate/methanol (1 : 1).
Eleven samples in the tested 13 samples showed the mutagenicities to TA98 or TA100 on addition of S9mix, and the ranges were 10-792 net revertants to TA98 and 13-1,990 net revertants to TA100 per g dry sediment. Fractionation procedure was effective not only for reducing interference caused by coexisting substances and lowering the detection limits of mutagenicity but also for getting information on characteristics of the mutagens contained in the sediment. The developed preparation method was confirmed to be adaptable to various sediment samples.

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Two-stage contact oxidation process was used to treat sulfanilamide wastewater containing high salinity and high strength organic matter. The results indicated that the removal of sulfanilamide was changed from the first stage to second stage with the increasing of loading rate, and when the loading rate was increased up to 1.85 kg-TOC·m^-3·d^-1 sulfanilamide was only removed in the second stage. During this period the total removal of BOD was about 96.5%, the removal of sulfanilamide was 94.1% and the turbidity of the treated wastewater was low because of the low concentration of SS in the effluent. In this study the deference of the bacterial structure between the first stage and the second stage was not obvious until TOC loading rate was increased to 1.16 kg-TOC·m^-3·d^-1. However, when TOC loading rate was 1.85 kg-TOC·m^-3·d^-1, in the first stage microorganisms mainly consisted of bacilliform bacteria, in the second stage, microorganisms mainly consisted of filamentous bacteria.

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Horizontal variations of limiting nutrient and size structure of phytoplankton community at estuarine and oceanic stations from Hiroshima Bay to the Pacific Ocean were studied. The following results were obtained :
1) Concentrations of DIN, DIP and chlorophyll a were very high in Hiroshima Bay estuary and decreased toward the south sea area.
2) Limiting nutrient of phytoplankton in the Hiroshima Bay estuary was estimated to be phosphorus, whereas that in other stations was estimated to be nitrogen.
3) Nanophytoplankton dominated total biomass of phytoplankton population in terms of chlorophyll a in Hiroshima Bay. On the contrary, picophytoplankton showed the greatest fraction of total biomass of phytoplankton population in terms of chlorophyll a from the Sea of Iyo to the Pacific Ocean.
4) Cell density of picocyanobacteria was maximum in the Hiroshima Bay estuary, but the lowest was observed in southernmost station of the Pacific Ocean.

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Consumer product compounds are used in the home and disposed in waste water where they typically receive waste treatment. After treatment, sludge and effluent are released to the environment resulting in the potential exposure of terrestrial and aquatic organisms, respectively, to consumer product compounds.
To ensure the environmental safety of these compounds, the environmental risk posed by compounds released into the environment must be assessed. A reasonable, consistent and cost-effective method to conduct environmental risk assessments and to prioritize testing of these compounds is needed which addresses risk to organisms residing in the terrestrial and aquatic compartments of the environment. Risk is evaluated by understanding environmental fate (i.e., exposure) and effects and is quantified in the risk ratio. In addition, the potential transfers through the food web leading to concentrations in food are predicted with an estimate of bioconcentration and bioaccumulation factors. Specifics of the tiered risk assessment approach are discussed and demonstrated using two consumer product compounds : linear alkylbenzene sulfonate (LAS) and alkyl ethoxy sulfate (AES).

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