As a new monitoring technique for road-deposit environments, one of main nonpoint sources in urban areas, we present a modeled-stormwater sampling (MOS) technique in which one can easily obtain road deposits under modeled rainy conditions. To simulate a rainy condition using the MOS technique, we first stir water placed on a road surface and collect the water with suspended matter detached from the road surface. We then analyze the quality of the water samples obtained. To confirm the validity of the MOS technique, we conduct a laboratory experiment for the comparison of road-deposit environments measured with the MOS and those measured using other monitoring techniques. The experimental results indicate that the road-deposit environments measured using the MOS technique show the same results as those measured using an artificial rainfall technique, indicating the fundamental high performance of the MOS technique. Using the MOS technique, we perform field measurements of the temporal and spatial variations of road-deposit environments in urban areas. The observed results indicate that rainfall and traffic may cause appreciable variations of road-deposit environments in time and space.

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The objective of this study is to clarify the effect of ulvoid (Ulva spp.) accumulation on the formation of an eelgrass bed on the coast of Iwakuni, Seto Inland Sea, Japan. We monitored eelgrass shoot density and height and ulvoid volume in the study site, and then conducted experiments on the effects of ulvoid canopy on eelgrass using outdoor tanks. Eelgrass shoot density decreased when ulvoid accumulated, and seedling density decreased as ulvoid volume increased. We found no eelgrass seedlings, when the ulvoid canopy height was more than 20 cm. According to the outdoor tank experiments, the survival rate of eelgrass in the 13 cm ulvoid canopy height tank for more than one month differed little from that of eelgrass in the control tank. However, eelgrass in the 25 cm ulvoid canopy height tank died out in 38 days. Eelgrass leaves elongated 5-7, 3-6 and 2-3 cm per day in the control tank and in the 13 and 25 cm ulvoid canopy tanks, respectively. The difference between the initial and final (after 30 days) carbon contents in eelgrass leaves and rhizomes in the control tank was not significant, but that in the 25 cm ulvoid canopy height tank was significant. The carbon content in eelgrass 25 cm ulvoid canopy height tank was lower than that in the control tank (without ulvoid).

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The first nationwide simultaneous survey of familiar water environments was conducted on June 6, 2004, the standard measurement day. There were 2,545 survey points and 531 groups of participants (approximately 4,000 people), mainly volunteers. The survey items were atmospheric temperature, water temperature, and chemical oxygen demand (COD). The COD measurement used a commercial water quality test kit for samples with a relatively low COD (COD(D)), and was standardized using an original manual and common tools to improve the measurement precision of simple water analysis. The number of COD(D) measurements was set at three per sample. The three measurements performed at 90% of all the survey points showed a good agreement of 94%. It was observed that the frequency of the measurements differed between those that were indicated and not indicated by the standard colors of the test kit used. The COD(D) value that is the median of the three measurements for each sample, was assumed to represent the COD(D) of the survey point. The mean of the statistical ranges of the three measurements, which was derived for each COD(D) value, distributed with a peak at 6 mgO · l^-1. When the range was large, the use of the median was effective in rejecting outliers.

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Bromate ion concentration in groundwater was determined for 572 non chlorinated wells and 16 springs in Tama district, Tokyo. Bromate ions were detected in 30.9% of shallow wells, 21.6% of deep wells and 56.2% of springs. Their concentrations ranged from 0.1 to 5.6 μg·l^-1. In five shallow wells, bromate ion concentrations of 2.1 μg·l^-1 or higher were detected. We also determined bromate ion concentration in chlorinated groundwater samples (from 85 wells and 86 tap water supplies from groundwater). Bromate ions were detected in 38.8% of the wells and 74.4% of the tap water samples. Their concentrations ranged from 0.1 to 57.7 μg·l^-1 (well water) and 0.2 to 13.8 μg·l^-1 (tap water). A follow-up survey of bromate ions in seven wells (4 non chlorinated and 3 chlorinated) was performed. Bromate ion concentration in non chlorinated well water hardly changed during the survey period. Of the 3 chlorinated wells, 2 showed no rechlorination in the second sampling; bromate ion concentrations in these two wells decreased.

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On-site water purification facilities have been employed to reduce suspended solid or organic pollutant concentration in river water, but their potential for removing micropollutants such as endocrine-disrupting chemicals (EDCs) has not yet been extensively investigated. Water quality tests on influent and effluent from treatment facilities using gravel contact oxidation were conducted. The removal ratios for nonylphenol and bisphenol-A exceeded 50%, with removal efficiency depending on operating conditions. Specifically, removal efficiency increased when longer hydraulic retention time (HRT) and aeration were applied. In addition to trapping a proportion of the suspended solids, adsorption and biodegradation in the facilities resulted in reducing the concentration of environmental endocrine disruptors.

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