Organic pollutants in marine plastic debris from Canary Islands beaches

Given their capacity to adsorb chemical pollutants, microplastics represent a growing environmental concern in the oceans. The levels of 81 chemical compounds in two types of beached microplastic (pellets and fragments) were monitored across the Canary Islands (Spain). The highest concentrations were found for polycyclic aromatic hydrocarbons (PAH) (52.1-17,023.6ng/g and 35.1-8725.8ng/g for pooled pellets and fragments, respectively). The polychlorinated biphenyl (PCB) concentrations were 0.9-2285.8 and 1.6-772.5ng/g for pooled pellets and fragments, respectively, whereas organochlorine pesticides (OCP) ranged from 0.4-13,488.7 and 0.4-3778.8ng/g, respectively. The sum of polychlorinated biphenyls and diphenyl-dichloro-ethane (DDT) metabolites was significantly higher in beaches on Gran Canaria, which is the most populated and industrialized island. The sum of ultraviolet filters (UV-filters) was higher in those beaches more frequented by tourists (Famara and Las Canteras), than in occasionally or very rarely visited beaches (Cuervitos and Lambra), with values ranging from 0 to 37,740.3ng/g and 3.7-2169.3ng/g for pellets and fragments, respectively. Furthermore, the sum of brominated diphenyl ethers (BDE) (0-180.58ng/g for pooled pellets and 0.06-3923.9ng/g for pooled fragments) and organophosphorus flame retardants (OPFR) (20.0-378.0ng/g for pooled pellets, and 22.6-7013.9ng/g for pooled fragments) was significantly higher in an urban beach (Las Canteras) than in the rest of the studied beaches. Finally, the concentrations of the pesticide chlorpyrifos were much higher on Gran Canaria beaches than in the rest. In this research we provide further evidence of the important role of plastic debris in the adsorption of a wide range of marine pollutants. The regional pattern of chemical contamination of plastics reveals that the sorption of many compounds probably occurs in coastal waters. Further investigation is necessary to understand the relationship between plastic types and adsorption of different pollutants, especially for emerging pollutants.