抄録
The sum of 9 PFCs concentrations in water of Lake Biwa was 10.6 ～13.5 ng/L and little differences among 4 sites of northern basin of Lake Biwa (12B, 17A, 17B, 17C') in August 2011. The order of average PFCs composition in 7 sites of all over the Lake Biwa was PFOA ＞PFNA ＞PFHpA ≧PFHxA ＞PFOS ＞PFDA ＞PFHxS ＞PFUnDA ≧PFBS, little differences among the sites. The concentration range (average) in water of 12 rivers around Lake Biwa was 0.48 ～59.2(26.4) ng/L and large differences among the 12 rivers. The order of average PFCs composition in water of the 12 rivers was PFOA ＞PFNA ＞PFOS ＞PFHxA ≧PFHpA ＞PFDA ＞PFBS ＞PFHxS ＞PFUnDA, slightly different from that in Lake Biwa. Seasonal changes of PFCs concentrations and compositions in water of 3 sites of Lake Biwa (6B, 12B, 17B) were little in May, August, November 2012 and February 2013. The sum of 15 PFCs concentration range (average) in sediment of Lake Biwa was ND ～4.42 (1.51) ng/g dry wt. in May ～December 2013. The PFCs concentration was high in clay-like sediment of deep central area of northern basin of Lake Biwa. There were no differences between southern and northern basins of Lake Biwa in the PFCs composition of the water and the order of PFCs composition was PFOA ＞PFHxA ≧PFBA ≧PFNA ≧PFHpA ＞PFPeA ＞PFOS. However, there were differences for the PFCs composition of the sediment and the order was PFDoDA ＞PFTrDA ＞PFOS ＞PFDA in the southern basin and PFUnDA ＞PFTrDA ＞PFDoDA ＞PFOS in the northern basin. The ratio of short-middle chain carbon (C4 ～C9) PFCs was high and long chain carbon (C12 ～C14) PFCs were not detected in the water of Lake Biwa. However, the ratio of middle-long chain carbon (C10 ～C13) PFCS and PFOS was high and short-middle chain carbon (C4 ～C7) PFCs were not detected in the sediment of Lake Biwa.
