Microplastic occurrence and distribution in the Gulf of Guayaquil, Ecuador

Microplastics (MPs) were assessed in water and sediment samples along the Salado Estuary, an estuarine system composed of a complex river drainage network in Guayas, Ecuador. MPs were quantified and categorized according to shape, size, and composition. Pellet morphology (237,490 MP/L) and transparent color MPs (252,990 MP/L) were the most common in water, while fragments (27,330 MP/m³) and silver color MPs (25,310 MP/kg) were the most common in solid samples (river sediments, mangrove mud, and sand). MPs made of Polycarbonate, Polyestyrene, and Polypropylene were the most common in all samples. Giving MPs characteristics, likely mapped sources were wastewater from Guayaquil and surrounding towns, boats, and shrimp farms. The samples with the highest MPs were found near Guayaquil, and those with the least were found in the estuary mouth. Monitoring and managing plastic disposal in estuaries are fundamental, as we report a small part of an undocumented issue here.