Distribution of Parent and Alkylated PAHs in Bivalves Collected from Osaka Bay, Japan

Abstract

To compare the distributions of polycyclic aromatic hydrocarbons （PAHs） and alkylated PAHs （alkPAHs） in sessile marine organisms, bivalves were collected from 20 sites along the coastal areas of Osaka Bay in Japan. Both PAHs and alkPAHs in bivalve tissues were determined by GC/MS. Total PAHs （ΣPAHs） were 87.3-361, 212-214 and 70.9-351 ng/g dry weight （dw） in blue mussels, green mussels and oysters, respectively. Meanwhile, total alkPAHs（ ΣalkPAHs） were 466-3293, 950-1788 and 286-2787 ng/g dw in blue mussels, green mussels and oysters, respectively. When compared to their reported concentrations in sediments, ΣPAH were much lower while ΣalkPAH were higher in bivalves. Moreover, ΣalkPAHs in bivalves of each samling site were 1.8-9.8 times higher than ΣPAHs although ΣalkPAHs in sediment of each sampling site were 1.2-4.5 times lower than ΣPAHs. On the other hand, of the PAHs, naphthalene showed the highest concentration in bivalves for most of the sampling sites. Fortunately, benzo（a）pyrene and PAH4 concentrations in bivalves from Osaka Bay were within the EU criteria. For individual alkPAHs in bivalves, the naphthalene, dibenzothiophene, and phenanthrene/anthracene groups were accumulated at relatively high concentrations. These results suggest that the low molecular weight alkPAHs have higher tendency to pollute water columns.