Microplastics in the Surface Waters and Sediment in an Agrarian Part of Vembanad-Kol Wetlands, the Largest Ramsar Site—Southwest India

The degradation from larger plastic to tiny pieces permits its extensive allocation in different trophic levels and readily persists in the aquatic marshy food web. This first baseline research attempt focused on the distributional profile of Microplastic (MP) and the in-situ variation with the biochemical composition of Kol sediment residue. The density-separation method was adopted for MPs dissociation, visually counted and categorized them through a compound microscope to account for size, type and color. Further, the chemical characterizations and confirmation were done through Fourier Transform Infrared (FT-IR) spectroscopy and SEM-EDAX analysis. In all the examined samples micro debris was observed as prioritized complex moieties. Major MP shapes were represented as: filament (78%), thread (20%) and pellet (2%). Filament-shaped Polyethylene (PE) and Polyvinyl chloride (PVC) have been the dominant types of polymer components in the recorded MP particles. The red filament-shaped PVC has been the presiding type in the Northern Kol water of the second wet season. In the first sampling, white-colored PE filaments were prominent in the Central Kol region of the sediment with a high organic matter deposition. The multivariate statistical analyses noted the biochemical composition of Kol wetland sediment residue has an allochthonous origin and was correlated with MP morphological characters. The present investigation serves as the initial scientific data bank on MPs in the renowned agrarian, Ramsar wetland ecosystem. The relation between the MPs and sediment organic matter enhances the accumulation of small MPs threads, which could easily be injected into the residing aquatic biota.