We developed a liquid chromatography–tandem mass spectrometry (LC/MS/MS) analysis method for the determination of bromate in drinking water. Furthermore, we have conducted a validation test along with 23 organizations to confirm the validity of the analytical method. Recovery tests of bromate spiked into drinking water obtained by each organization were performed with two set points, that is the standard value (0.01 mg L^-1) and 1/10 of the standard value (0.001 mg L^-1) of bromate in the Japanese Waterworks Act. The linearity of calibration curves, selectivity, accuracy (recovery) , repeatability, and intermediate precision of bromate concentrations were calculated by the data of the recovery tests. The linearity of the calibration curves and selectivity were satisfactory. The accuracy, repeatability, and intermediate precision for the two concentrations obtained by the recovery tests satisfied the criteria in the guideline for the validation of the testing method for drinking water. These criteria are provided by the Ministry of Health, Labour and Welfare, Japan. Therefore, we concluded that the analytical method developed in the present study is valid for the analysis of bromate in drinking water.

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Recently, soil contamination resulting from marine sediments has been reported to occur in many sites of Japan. Marine sediments containing framboidal pyrite (FeS₂) cause the soil to gradually become acidic owing to long-term atmospheric weathering; subsequently, various harmful heavy metals such as lead, cadmium, and arsenic are leached into the environment. In this study, low-cost, environment-friendly countermeasures against the risk of long-term contamination of heavy metals in marine sediments containing natural alkaline materials (pieces of scallop shell) were developed. The shell pieces were effectively suppressed the oxidation of pyrite even in atmosphere, upon adding more than 2.5 wt% shell pieces to the marine sediments. This technique can not only prevent the acidification of the soil caused by the oxidation of pyrite to sulfuric acid but can also retain the chemical forms of arsenic and cadmium in marine sediments in the residual state. Therefore, the risk of arsenic and cadmium leaching into the environment can be greatly reduced.

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The objective of this study is to clarify the environmental conditions and evaluate the effect of the restoration of a shallow area constructed of steelmaking slag (filling layer) and dredged sediments of the estuary (covering layer) . We monitored the pH and the turbidity of the bottom layer during construction, and then the pH of porewater (both layers) and the overlying water after the completion of construction. Moreover, benthic faunal surveys were carried out 2 or 3 years after the completion. The pH of seawater remained at a normal level despite increased turbidity at slag disposal sites during construction. After the completion of construction, the pH of the filling layer pore water was often high. However, the covering layer and overlying seawater maintained pH values of approximately eight. Many species of the benthic animals inhabiting the constructed shallow area were the same as those in the natural area. The species number, density, and biomass (wet weight) at the constructed sites have been more than those at the natural site. These results suggest that we have restored a shallow area that is equal or superior to the natural shallow area for benthic animals by using this construction method.

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Total antioxidant responses were investigated by oxygen radical absorbance capacity (ORAC) assay using gills and whole soft tissues of Corbicula japonica exposed to municipal wastewater in order to evaluate water pollution in brackish lakes. Before the response experiments, the shell lengths of bivalves appropriate to ORAC assay were examined. The results showed that the variation in soluble protein was relatively low in individuals with shell lengths between 19–25 mm, which accounted for 67.3% of all sampled individuals. Gills showed approximately four times larger ORAC values than whole soft tissues and higher continuity of ORAC responses. We conclude that gills are more appropriate organs for detecting antioxidant effects caused by municipal wastewater than whole soft tissues.

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