The potential threat of PFAs accumulation in the Phocoena phocoena: the North Sea food web.

Abstract

This study present an overview on the contamination of poly- and perfluoroalkyl substances in the harbour porpoise and its foodweb of the North Sea. Perfluorooctane sulfonic acid (PFOS) is found to be the predominant compound in the harbour porpoise and in other marine apex predators globally. Studies in the North Sea suggest that PFOS remains stable in the food web or might even be decreasing in the last few years after regulations have been taken to limit the release and use of PFOS. However, long-chain Perfluoroalkyl carboxylates seem to be increasing in the harbour porpoise and other marine apex predators globally. The most important pathway that leads to contamination of PFAs into the North Sea are rivers that flow through urban, highly industrial and agricultural areas. The harbour porpoise feeds at a lower trophic level than other marine mammals in the North Sea but due to them being coastal foragers they might be more susceptible. Contamination is solely through their diet but there is a knowledge gap on trophic transfer in the harbour porpoise food web in the North Sea. New born porpoises and juveniles are the most contaminated of all life-stages, probably due to placental transfer and exposure through lactation. This makes the harbour porpoise particularly vulnerable, in laboratory animals is seen that exposure to high levels of PFOS results in developmental problems and reproductive failure. Recommendations on future research are given.