Maritime and lagoon beaches sediments mineral phases and potentially toxic elements characterization and evaluation of microplastics retention

The present study aimed to characterize the texture, mineral phases, and geochemical composition of sixteen sediment samples of beaches in Portugal, from maritime and Ria de Aveiro lagoon environments. Additionally, the presence of Microplastics (MPs) in these sediments was estimated. Sediments from both environments were classified as sands, with a quartz content ranging ∼70–90 %. The physicochemical parameters showed neutral conditions, with pH between 6.16 and 7.05, typically of this type of setting. The concentration of As, Cr, and Zn was above sediment guidelines, suggesting anthropogenic contamination, particularly in one location, posing a risk to beach users. Contamination indices and toxicological assessment confirmed anthropogenic contamination, particularly by Cr on the maritime beaches, highlighting pollution and toxicity risk. This may be linked to industrial, domestic, and agricultural activities, population density, traffic, as well as traditional fishing practices. MPs were identified in both sediments and water samples from maritime and Ria de Aveiro beaches, ranging 38 to 958 MP/kg. The more abundant identified MPs were PUR, ABS, and PE, mainly in the form of fibers, with different colors.