特集　「地球環境および地域環境と化学」　周防灘西部海域海底堆積物中の多環芳香族炭化水素の起源の推定と評価

In order to estimate the origin of polycyclic aromatic hydrocarbons (PAHs) in surface and core sediments from The Western Sea of Suo, the horizontal and the vertical distributions of PAHs and the composition ratio of PAHs (BkF/BaP) in sediments were investigated. Moreover, the topographic factor of this sea area and the relationships between heavy metals concentrations and PAHs concentrations have been investigated. Two compossition ratios of PAHs (BaP/BghiP, BkF/BaP) in atmospheric suspended particulate matter that were admitted a difference to these composition ratios with each emission sources, were util ized to estimate of the origin of PAHs in sediments. On the vertical distribution, an evide nt change appeared in the composition ratio of PAHs (BkF/BaP) in 4045 cm layer, corresponds to about 1920 by <SUP>210</SUP>Pb-chronology, at Site 23(Fig.2). On the other hand, surface sediments except for Sites 10, 15, 23 were classified into 2 groups (Cluster A and B) by the Cluster analysis. Significant difference in the composition ratio of PAHs (BkF/BaP) at each Cluster were found (Cluster A: 0.425, Cluster B: O.355). Furthermore, the difference was admitted to the slope of the regression line between Pb concentration and BaP concentration in each Cluster (Cluster A: 0.114, Cluster B: 0.054) (Table 3). At Cluster A, the relationship between Fe concentration and BaP concentration was linear (r=0.829), and PAHs concentrations in sediments correlated negatively with the depth of water (Fig.4). However, the correlation was not admitted between the distance from Site 20 and PAHs concentrations in sediments. On the other hand, the negative correlation was admitted between the distance from Site 20 and PAHs concentrations in sediments at Cluster B (except site 8) (Table 5). As these results, it was estimated that the origin of PAHs at sea area of Cluster A was mobile source and at sea area of Cluster B were both mobile source and industrial source, respectively.