Hydrocarbons of Oysters and Short-necked Clams in Hiroshima Bay

Abstract

The n-alkane distributions of oysters Crassostrea gigas and short-necked clams Tapes japonica collected from Hiroshima Bay were examined. An absence of any biogenic odd-carbon predominance of n-alkanes was found. After 30 days of starvation of the clams in artificial sea water, considerable amounts of hydrocarbons were found to be retained, but the n-alkane distribution showed a preferential disappearance of shorter chain odd-carbon n-alkanes. Furthermore, the fecal hydrocarbons of the clams showed an even-carbon predominance of the n-alkanes. Although petroleum oil was not detected by taste or smell, the values of carbon preference index and n-C₁₆ ratio indicated some low-level oil pollution of the bivalves. Moreover, the presence of non-biogenic alkylated benzenes also indicated that some oil pollution of the oysters had occurred.