Anthropogenic platinum contamination in blue mussels (Mytilus edulis) and sediments from a coastal system (Toulon Bay, France)

Platinum group elements (PGEs), i.e. Pt, Pd, Rh, Ir, Ru and Os, are among the least abundant elements present in the environment. However, due to the intensification of anthropogenic activities, the concentrations of PGEs in the natural environment have increased. In this study, platinum concentrations of two sediment cores and historical mussel samples collected from the Toulon Bay (France) were analysed using adsorptive catalytic stripping voltammetry (AdCSV) technique. The results showed a clear increase of Pt contamination in wild mussels during the past 30 years. Platinum concentrations in wild mussels were of 0.10 ng.g-1 in 1984 and reached 0.79 ng.g-1 in 2014. Similarly, a generally increasing trend was found in Pt sediment profiles with generally higher Pt concentrations and more heterogeneous Pt profile in the inner Toulon Bay. The temporal Pt concentration profiles in both sets of historical samples clearly suggest increasing the presence of PGEs in the contemporaneous natural environment, probably linked to intense anthropogenic activities. These results reflect human pressure which has largely changed the biogeochemical cycle of PGEs, in various environmental compartments. This emerging and ongoing contamination reaches the marine biota including wild bivalves, such as mussels, which might serve as biomonitors of environmental Pt exposure. At the present stage, one cannot exclude that such Pt contamination may affect the trophic web implying the risk of effects on marine ecosystems and even on human beings.