琵琶湖水および琵琶湖周辺河川水におけるＰＦＯＳおよびＰＦＯＡの濃度調査および琵琶湖への河川流入負荷量の推定

Abstract

A survey of PFOS and PFOA concentrations was performed for surface water in Lake Biwa (14 sites) and 31 rivers (35 sites) around Lake Biwa in May and June 2009. The concentrations were 0.8∼5.3 ng/L for PFOS and 8.7∼26ng/L for PFOA in Lake Biwa and ND∼10 ng/L for PFOS and ND∼32 ng/L for PFOA in the rivers. The loading amounts of PFOS and PFOA from the rivers flowing into Lake Biwa were 2∼582 mg/day (n=19) and 8∼7084 mg/day (n=25), respectively. There were no wide differences among the 12 sites except the two sites (8C and 168) for the PFOS and PFOA concentrations in the Lake Biwa surface water. The differences of PFOS and PFOA concentrations among the rivers were probably because of the differences of their loading amounts in the basin areas of the rivers. The concentrations of PFOS in Lake Biwa were lower than those in Lake Suwa or Lake Kasumigaura but the concentrations of PFOA were reverse. On the other hands, The PFOS and PFOA concentrations in the rivers around Lake Biwa were relatively low in the recent river survey data in Japan.