Microplastics in the Barra Norte and Mocambo Beach Sediments, Gulf of Mexico, Mexico

The abundance and characteristics of microplastics (MPs) in the Barra Norte and Mocambo beach sediments in the Gulf of Mexico were investigated. The number of MPs was higher in the Barra Norte (5865 MPs · kg-1) than in the Mocambo (4315 MPs · kg-1) beach sediments. The size of MPs in the Barra Norte and Mocambo beaches was varied between 0.6 - 1.30 mm and 0.91 - 1.25 mm, respectively, and all MPs were fiber. In both beaches, the predominant color of fiber was transparent. The Scanning Electron Microscopy (SEM) images showed that the fibers were fragmented, with surface features such as fissures, cracks, holes, degradation and adhered particles, indicating polymer aging, mechanical weathering, chemical dissolution, and their exposure to UV radiation. Cellophane (CP) and polyethylene terephthalate (PET) were the polymer types detected by the Fourier-Transform infrared (FTIR) Spectroscopy, which were possibly sourced from the textile products and disposable plastic bags, respectively. It was inferred that the abundance of MPs in the Barra Norte beach was due to coastal industrial activities related to the Adolfo López Mateos Thermoelectric Plant. Similarly, MPs in the Mocambo beach was attributed to an inadequate management of urban solid waste in the coastal zone. This study provided an awareness to the scientific community on the threat of MPs contamination in the coastal sediments of the Gulf of Mexico.