TIME TRENDS OF PERFLUORINATED COMPOUNDS IN THE SEDIMENT CORE OF TOKYO BAY, JAPAN (1950s-2004)

摘要

The time trend of perfluorinated compounds (PFCs) was determined in sediment core samples collected in Tokyo Bay. The core sample deposited during 1950s-2004 was divided into two- to three-year intervals. Perfluorocalboxylates (PFCAs), perfluoroalkylsulfonates (PFSAs), perfluorooctane sulfonamidoacetic acids (FOSAAs), fluorotelomer calboxylates (FTCAs), fluorotelomer unsaturated carboxylates (FTUCAs), branched isomers of PFCs, and other compounds were measured. Perfluorooctane sulfonate (PFOS) decreased gradually from the early 1990s while N-ethylperfluoro-1-octanesulfonamidoacetic acid (N-EtFOSAA) and N-methylperfluoro-1-octanesulfonamidoacetic acid (N-MeFOSAA) decreased rapidly in the late 1990s. Perfluorooctanoic acid (PFOA) increased during 1990s. The observed trends were regarded as a reflection of the shift from perfluorooctyl sulfonyl fluoride (POSF)-based products to telomer-based products after 2001 due to the phase out of POSF-based products. Several other characteristics of the PFC trend were obtained: "rapid increase after the early 1970s" for long-chain PFCA (C11 - C13); "gradual increase from the 1950s" for middle-chain PFCA (C9 - C10); and others. This study revealed that the sediment core can serve as a tool to reconstruct the past pollution trend of PFCs with longer than eight-carbon chain and provides interesting evidence concerning their environmental dynamics.