Occurrence and contents of trace metals and rare earth elements on plastic pellets

We determined the occurrence of pellets (2-5 mm) and their composition in terms of trace metals and rare earth elements (REE) on nine sandy beaches of the coast of Bahia, northeastern Brazil. We compared the occurrence of pellets between oceanic and sheltered beaches and the effect of fluvial contribution on the occurrence of these microplastics. The number of pellets found was surprisingly low (i.e., max 45 pellets per m² in an oceanic beach without fluvial river inputs). Thus, the studied beaches exhibited a very low pollution index. Concentrations of ∑REE in pellets varied between 0.36 and 1.74 mg kg^-1 and were ~5-fold higher in white/transparent pellets than in brown pellets. The sum of trace metals (i.e., Fe, Cd, Cu, Ni, Pb, and Zn) was also highest in the white pellets (357 ± 12 mg kg^-1). Plastic pellets are a potentially important vector of REE exposition to biota.