Exploring microplastics in commercial bivalve species and in bivalve aquaculture waters: Insights from the southern Pacific

Microplastics pose a significant potential threat to marine biota, with filter feeders among the most susceptible species. Bivalves are an important source of animal protein and micronutrients, therefore microplastic concentrations in marine ecosystems can raise concerns for consumers and producer countries. Although Chile is a major bivalve exporter, there is limited data on microplastic levels in commercially valuable species and areas related to aquaculture activities. Here we explored microplastic contents, characteristics, and types in three commercial bivalve species from areas with contrasting levels of anthropogenic impact. We additionally assessed microplastics in surface waters from marine areas where bivalve aquaculture takes place in southern Chile. Results show a consistent presence of microplastics in low magnitude for all species and in waters surrounding aquaculture facilities. Higher concentrations were observed in more anthropized sites. Microplastics consisted mainly of fibers, with polyamide, polyester, and polyethylene being the most common polymers. Also, probably due to different feeding behaviors, interspecific differences were found. These exploratory results underscore the need to enhance monitoring of, and develop mitigation strategies for, microplastic pollution in aquaculture industry. • Microplastic pollution was analyzed in bivalves and water from varying anthropized areas. • Levels of microplastics were higher in bivalves from anthropized sites and differed among species. • Water samples showed higher microplastic levels in key aquaculture production zones. • Findings highlight the need for monitoring and mitigation of microplastics in aquaculture practices.