Microplastic occurrence in La Paz Bay (Mexico) and phthalate esters concentration in two resident filter-feeder species

Release of hazardous chemicals from floating plastic debris may cause toxicological effects on marine species. Phthalate esters (PAEs) are suggested to act as endocrine disruptors even at low concentrations. Large filter-feeding species, characterized by a long life span and a continue feeding activity, are potentially chronically exposed to these contaminants both leaching from ingested plastics and from their degradation and through the food chain. In this study, we evaluate the abundance and the polymer characterizations by FTIR spectroscopy of microplastics collected through surface-trawling plankton nets in the Bay of La Paz, Mexico. The increasing human pressure in this area is giving rise to chemical pollution from urban wastewaters, agriculture and maritime activities. Presence of six PAEs as plastic tracers has been assessed in neustonic samples and in skin biopsy samples of fin whales (Balaenoptera physalus) and whale sharks (Rhyncodon typus) by GC-qMS. Sixty six per cent of the net tows contained plastics with a maximum of 0.22 items/m3. Neustonic samples showed different fingerprint of PAEs, indicating heterogeneous levels and spatial patterns in the investigated area. Diethylhexyl phthalate presented the highest values in all samples analyzed, with a concentrations ranged from