Microplastics in sediments from the southern Gulf of Mexico: Abundance, distribution, composition, and adhered pollutants

Approximately 23 Mt of plastics reaches the ocean each year, fragmented into microplastics (MP). MPs are widely dispersed in the sea, becoming deposited in sediments. MPs are considered carriers of pollutants such as heavy metals and polycyclic aromatic hydrocarbons and, when ingested by biota, pose a high health risk. This study determined metals and PAHs in sedimentary microplastics from the southern Gulf of Mexico (GOM). One hundred twenty-four sediment samples were collected, covering an area of 26,220 km2. The mean (±SD) of MPs in sediments was 16.46 ± 17.76 MPs/kg. The most abundant polymers were cellophane (CE), polyvinylidene fluoride (PVDF), polyethylene (PE), polyamides (PA), and nylon (NYL). A strong correlation (r: 0.83) was found between MP density and sediment depth. PA and PE were found near shorelines and PVDF near oil platforms. Aluminum, arsenic, and tin had the highest concentration (89.6 ± 94.6, 23.1 ± 70.3, and 19 ± 29.2 μg g-1, respectively), and acenaphthylene was the PAH with the highest concentration (3.4 ± 12.6 μg g-1). This study shows that MP with a higher density is found at greater depths, and this research is one of the first to cover a large area of the Gulf of Mexico.