Impact of Microplastic in Mexican Coastal Areas Using Mussels (Mytilus spp.) as Biomonitors

Microplastics (MP) are plastic fragments smaller than 5 mm found in water columns and sediments, posing a threat to marine life due to their toxicological potential for the absorption and release of harmful compounds such as heavy metals. Mussels exhibit high filtration rates with the ability to bioaccumulate microplastics and are considered bioindicators of environmental contamination. The present study aims to evaluate the impact of microplastics in different geographical areas to identify their effects on ecosystems and potential damage to human health, focusing on the bioaccumulation capacity of MP in mussels. Samples of water, sediment, and mussels (Mytilus) from the Central Mexican Pacific were analyzed using optical microscopy and contamination indices. The levels of heavy metals detected at the sampling sites suggest low contamination, according to the Heavy Metal Evaluation Index (HEI). In Juluapan Lagoon, 93% of the MP particles found were fibers, with similar results in Barra de Navidad (75%). In Puerto Interior, Laguna Valle de Garzas, and Juluapan Lagoon, fibers accounted for 100% of the identified MP in water. The concentration of MP in water reached up to 7 MP/L, and 13 MP/mussel in Barra de Navidad. The presence of associated contaminants and MP suggests potential harmful effects on environmental health due to the high bioaccumulation of microplastics in mussels.