Characterization of micro-plastics in water and sediments in Batticaloa lagoon at Kattankudy

Abstract

Micro-plastics (mps) are a globally ubiquitous contaminant and the occurrence and accumulation of mps in the aquatic environment is nowadays an undeniable fact. The present study intends to address morphological characterization and quantification of micro-plastics at Batticaloa lagoon near Kattankudy municipal dumping sites during the period of September 2019 to February 2020. A one-liter backet and Ekman grab sampler were utilized to collect water samples and sediments, respectively. Density separation was carried out using Nacl solution and all floating solids were subject to a wet per-oxidation method and observed under a stereomicroscope. All the recovered micro-plastics were sorted into categories based on the size (1 mm, 1-2 mm, 2-4 mm) shapes (film, fragment, filament, foam, pellet, microbeads) and colour (white, black, transparent and other colours). Kattankudy sample stations showed mps of 1638.83 ±71.69 items kg^{− 1} in sediment and 1028.33 ± 73.73 items per liter in surface water. Lagoon-shore sample site showed highest number of mps (surface water 691.10 ±28.50 items per liter, sediments 1033.00 ±28.80 items kg^{− 1}) than lagoon sample sites. Overall abundance of mps was statistically significant (p<0.05; one-way Anova) among the study sites. Fragments were the most abundant particle shapes found within the sediments (~33%) and a greater number of films were overwhelmed in surface water (~47%) from both study sites. Less than 1 mm size fraction was the most common in sediments while somewhat larger sizes 2-4 mm was dominant in surface water. An assortment of colors was found in the mps gathered from both surface water and sediment among that in shore ~51% white colour and inside the lagoon ~27% were transparent. This study indicates evidence of micro-plastics pollution present in Kattankudy stations, which calls urgent precautionary measures to mitigate mps pollution. Further research is expected to address real impacts of these micro-contaminants on the lagoon environment in future.