Priority and emerging micropollutants in sediments of Capbreton Canyon (SW France)
Résumé
Priority substances set by the Water Framework Directive (WFD) are of major interest to evaluate the quality of coastal and marine systems, the final receptors for pollutant emissions. Emerging substances not regulated by the WFD, i.e. personal care products and pharmaceuticals, are of high concern since only scarce information of their occurrence, reactivity and impact are available in themarine environment.A large screening of micropollutants has been achieved in surface sediments collected in the Canyon of Capbreton (Gulf of Biscay). Twenty-four stations have been sampled within the first 30 km of the canyon in July 2017. Occurrence andconcentrations of priority (PAHs, PCBs, OCPs and trace metal) and emerging micropollutants (synthetic musks and sunscreens compounds) have been determined. In addition, sediments collected at three different depths were used to perform incubation experiments with a synthetic musk (HHCB) or a sunscreen compound (OD-PABA). Experiments have been performed at 12°C in the dark, controls have been also conducted with sterilized sediments. Some priority substances were lower than the detection limits whereas PAHsand PCBs exhibited high concentration levels ranging from 199 to 7,116 ng.g-1 and from 0.1 to 18.6 ng.g-1, respectively. Emerging micropollutants were measured at low concentrations. Musk compounds (HHCB, AHTN and MK) concentrations were up to 3.6, 2.3 and 7.0 ng.g-1, respectively. Sunscreens (3-BC, 4-MBC, EHMC and OC) concentrations were up to 6.2, 9.2, 31.8 and 29.2 ng.g-1, respectively. Highest concentrations were observed for offshore stations. Sediments from terraces or slopes of the canyon exhibited higher levels compared to those from the continental shelf. Degradation potentials have been only observed under biotic condition for OD-PABA suggesting the involvement of biologically mediated mechanisms