Temporal trends of PFOS and PFOA in guillemot eggs from the Baltic Sea, 1968--2003.

Perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) have recently been identified as ubiquitous environmental contaminants. Although they have been produced for 50 years, little is known about when they first appeared in the environment and how their concentrations have changed over time, particularly in response to the phase-out of PFOS, which began in 2000. In this study temporal trends in the concentrations of PFOS and PFOA in the Baltic Sea marine environmentwere measured using archived guillemot eggs. Samples collected from Stora Karlsö (Sweden) between 1968 and 2003 were received from an environmental specimen bank and concentrations of PFOS and PFOA were analyzed using HPLC coupled to ESI-MS/MS. PFOA was not detected in any of the samples (LOD 3 ng/g), but there was an almost 30-fold increase in PFOS concentrations in the guillemot eggs during the time period, from 25 ng/g in 1968 to 614 ng/g in 2003 (wet weight). Regression analysis indicated a significant trend, increasing on average between 7 and 11% per year. A sharp peak in PFOS concentrations was observed in 1997 followed by decreasing levels up to 2002, but this cannot be linked to the PFOS phase-out, which occurred at the end of this period.