Influence of environmental conditions on distribution and types of microplastics in surface waters of Tumaco Bay, Colombian Pacific

Abstract

Microplastics (MP) pose a major environmental problem for estuaries areas, as they are exposed to multiple sources of plastic waste. In this study, the spatiotemporal influence of environmental variables on the abundance, distribution and types of MP in surface waters of Tumaco Bay were assessed. The samples were collected in the rainy and dry seasons of 2020, in the inner and outer estuary, and were processed by density separation. MP abundance was higher in dry season (11.40 ± 2.60 ítems/m3) and in the inner estuary (8.42 ± 4.91 items/m3). Fibers were the most abundant type of MP (53.89 %). Salinity and TDS were significantly correlated with fibers, and precipitation with fragments, films and total MP. These results demonstrate high contamination (8.13 items/m3) and an increase in MP concentration in Bay. This could be related to the exposure of waste carried by the rivers. On the other hand, the higher abundance of MP in the dry season could be due to a decrease in dispersion for an entrance fewer of water to system and an increase in density of water, related to the increase in salinity, which favors the buoyancy of MP.