Accumulation of perfluorooctane sulfonate (PFOS) in the food chain of the Western Scheldt estuary: Comparing field measurements with kinetic modeling.

The environmentally persistent perfluorooctane sulfonate (PFOS) is a perfluoroalkylated acid (PFA), which has been found to accumulate and biomagnify through food webs all over the world. In the present investigation, the accumulation kinetics of PFOS was explored using the bioaccumulation model OMEGA. As accumulation behavior of PFOS may show similarities to fatty acids as well as to neutral organic compounds, different modeling approaches were used. Accumulation kinetics of PFOS was modeled similar to (1) moderately and (2) highly hydrophobic compounds, (3) metals and (4) as a combination of hydrophobic compounds and metals. Modeled elimination and uptake rate constants were compared to empirical rate constants from literature. Subsequently, model predictions were compared to field-based biota-suspended solids accumulation ratios (BSAF) in the estuarine food chain of the Western Scheldt, The Netherlands. Results show that uptake of PFOS is comparable to moderately hydrophobic compounds and elimination is best described by elimination kinetics of metals. These observations indicate that the accumulation behavior of PFOS is comparable to that of short and medium chained fatty acids.

Exposure patterns of perfluorooctane sulfonate in aquatic invertebrates from the Western Scheldt estuary and the southern North Sea.

Over the past decades little research has been conducted on the environmental behavior and effects of fluorinated organochemicals (FOCs). Recently it has been reported that perfluorooctane sulfonic acid (PFOS) is occurring worldwide. Little is known about the PFOS levels in organisms originating from the southern North Sea and the Western Scheldt estuary. In this study, we determined, for the first time, the PFOS-exposure levels in Crangon crangon, Carcinus maenas, and Asterias rubens from these ecosystems. Concentrations on a wet-weight basis in soft tissues of shrimp, crab, and starfish ranged from 19 to 520 ng/g, from 24 to 877 ng/g, and from 9 to 176 ng/g, respectively. These results show the existence of a PFOS pollution gradient in organisms along the Western Scheldt estuary, with the highest concentrations near Antwerp. The range of PFOS levels in shrimp and crab are slightly higher in coastal regions compared with sampling sites in open water. This study shows widespread distribution of PFOS in the Belgian and Dutch marine and estuarine environment at rather high concentrations.