To clarify the behavior of 1,4-dioxane in a water environment, concentrations and loads of 1,4-dioxane in water in the Tama River and its inflow rivers were investigated. Contamination of 1,4-dioxane was observed at every sampling point. The level of 1,4-dioxane in the river increased because of the inflow of the branches and especially inflows of those carrying effluent from sewage treatment plants. The cumulative load of 1,4-dioxane from catchments along the river stream from Nagata Bridge, as the uppermost point in this study, closely resembled the measured load at each sampling point in the Tama River. These results indicate that 1,4-dioxane was scarcely degraded, volatilized, or absorbed during flow down the river. The respective contribution rates of the loads of the branches and the sewage were estimated as 25 % and 75 %. Furthermore, the measured load of inflow was 30 times higher than the estimated loads based on Pollutant Release and Transfer Register system (PRTR) in the Tama River Basin. These findings suggest that the present PRTR has never covered the 1,4-dioxane emission sources completely.

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The purpose of the present study was to elucidate the characteristic accumulation patterns of the Polycyclic Aromatic Hydrocarbons (PAHs) in various organisms inhabited in the typical eutrophic lake “Lake Suwa”. We also calculated the Biota Sediment Accumulation Factors (BSAF) of each organism to estimate the difference in the pattern of PAHs accumulation among their tropic levels or habitat.
We showed that the concentrations of Σ₁₁PAHs was highest in phytoplankton (mainly Aphanizomenon sp.) (36,900±2,800 ng/g-lipid), followed by chironomid (3, 130±380 ng/g-lipid), catfish (1,720±1,360 ng/g-lipid), zooplankton (mainly Bosmina sp.) (890±170 ng/g-lipid), cherry salmon (270±70 ng/g-lipid), freshwater prawn (240±70 ng/g-lipid), largemouth bass(130±20 ng/g-lipid), Japanese smelt (140±30 ng/g-lipid), crucian carp (120±4 ng/g-lipid), and common carp (50±16 ng/g-lipid). We also analyzed dioxins (DXNs) in largemouth bass.The concentration of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), non-ortho dioxin like-PCBs, and mono-ortho-substituted dioxin-like PCBs (dioxin-like PCBs) were 7±1, 3±1, 117±13 ,and 3,770±930 ng/g-lipid, respectively. Based on these data, we calculated the BSAF of each organism. Σ₁₁PAHs BSAF exceeded 1.0 only in phytoplankton (18.7 g-ignition loss/g-lipid) and chironomid (1.6 g-ignition loss/g-lipid), and other organisms, especially fish, were below 1.0. These results indicated that PAHs were the substances mainly accumulated in primary consumers but not in higher tropic level consumers. On the other hand, BSAF of PAHs and dioxin like-PCBs in largemouth bass had large difference. This may due to the high metabolic rate of PAHs compared to dioxin like-PCBs. These results indicated that ability to metabolize PAHs is important to estimate accumulation pattern of PAHs.
From our results, different accumulation pattern of PAHs in invertebrate and fish were observed. Invertebrates accumulate high Kow PAHs compared to fish. These results may also due to the difference in the ability to metabolize PAHs between fish and invertebrates.

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A macroporous diatomaceous earth column was applied to the separation and simultaneous determination of pesticides in soil on a golf course. Two analytical procedures were used for this technique. One was GC/MS determination of cyproconazole, propiconazole, tetraconazole and triflumizole, and the other was HPLC/UV determination of azoxystrobin, flazasulfuron, halosulfuron-methyl and siduron. One enormous advantage of this column technique was the fact that surfactants sprayed together with pesticides produced no emulsion formation. It also made the separation process very simple and rapid in comparison with liquid-liquid extraction technique with a separating funnel. The recoveries of the pesticides spiked to the soil of a golf course were 84.4∼93.5 %, and the relative standard deviations were 0.7∼5.8 % by the proposed methods.

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Water quality problems have been studied in the Naka River run through Saitama to Tokyo from April 1994 to September 2004 at Saitama, Japan. Mobility inhibition test using D. magna of the Naka River water made clear that acute toxic chemicals remained in the river waters in the mid-1990s. The pollution by the chemicals acute toxic to D. magna remained until 2000, but after 2001 the pollution decreased remarkably. Several river waters polluted by organophosphate insecticides were examined by D. magna test battery with and without piperonyl butoxide (PBO) and the D. magna test battery of the Naka River waters were also performed. These results indicate that the mobility inhibition test battery with and without PBO is an effective tool to identify whether organophosphate insecticides are responsible for the toxicity of complex polluted river waters or not and the mobility inhibition of D. magna in the Naka River waters was shown to be caused by organophosphate insecticides. We also discuss what the serious organophosphate insecticide pollution of the river waters was improved by after 2001.

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Effects of the application with adsorbent made of amorphous iron oxide (Fe₂O₃) on reducing the cadmium (Cd) transfer to paddyfield rice were comfirmed in field examinations. By sprinkling the adsorbent at the rate of 0 to1.0 weight percent per plowlayer (15 cm) into paddyfield before cultivation, Cd transfer from soil to rice was restricted with increase of sprinkling rate. In the case at 1.0 percent, the concentration of Cd in rice (0.07 ppm) was approximately equal to average concentration (0.06 ppm) at investigation of Japan in comparison with 0.16 ppm at no sprinkling case in this experiment. These observations suggest that sprinkling amorphous iron oxide into paddyfield before cultivation is effective for reducing the Cd transfer to rice.

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