Microplastics of marine sediments of the Colombian Caribbean

Plastic pollution is understudied in some regions of the world, that is the case of Colombian Caribbean. As a consequence, it was aimed to quantify and characterize the microplastics (MP) in marine sediments in two sectors influenced by the Magdalena and Sinú rivers. Sediment samples collected during the 2021 rainy season and 2022 dry season were dried (60 °C) and processed with aqueous sodium hexametaphosphate solution at 4.6 g/L in order to wet sieve them through two mesh sizes (0.3 mm and 1.4 mm) and manually extract the plastic particles. The microplastics extracted were classified by size (0.3 mm to <1.4 mm and 1.4 mm to 5 mm), shape (fibers, films, fragments, foams) as well as analyzed via FTIR spectroscopy in order to identify the polymers present in the samples. Moreover, the relationship of grain size and MP concentration explored by taking a fraction of the sediment samples into a granulometry analysis. Concentration of MP are reported in number of particles per kg of dry weight sediment.