| Budget Amount *help |
¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 2000: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1999: ¥900,000 (Direct Cost: ¥900,000)
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| Research Abstract |
The state of polycyclic aromatic hydrocarbons (PAHs) in the nature is one of the important issues from the viewpoints of environmental chemistry. When PAHs are transported into environmental water from atmosphere, they adsorb quickly to the suspended solids (SS) because of their hydrophobic property. In this study, we investigated the state of PAHs in natural water obtained from three rivers and Lake Kojima in Okayama Prefecture, Japan. First, SS was separated by glass fiber filter in accordance with the JIS K0102. Subsequently, the amounts of PAHs in SS and in filtrate were measured separately.
The average concentrations of SS in the rivers were 1-2 mg/L, and benzo[a]pyrene in SS (p-BaP) were 1-4 ng/L.The mass ratios of p-BaP to total benzo[a]pyrene (t-BaP = p-BaP+d-BaP) were ca. 60%.
On the other hand, the average concentrations of SS at three different points in L.Kojima were 20-30 mg/L.However, the t-BaP concentrations in water of the lake were the same as those of the rivers. It was also clarified that the ratios of p-BaP to t-BaP of the lake were >90%. Other PAHs, fluoranthene and perylene seem to be adsorbed to SS, too.
The mutagenicity assay of extracts from SS and filtrate was performed according to the preincubation technique of Yahagi et al.. However, no positive ewsult was observed from 300 mL equivalent sample.
The results obtained in this study show that the PAHs amounts in the rivers and the lake are ppt level, and SS adsorbs the most of these chemicals. Therefore, the amounts of PAHs in SS and in filtrate have to be measured simultaneously to evaluate the problems such as endocrine disruption.
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