Characterization of microplastics and its Pollution load index in freshwater Kumaraswamy Lake of Coimbatore, India

Abstract Mass production, consumption, and disposal of plastics pollute the freshwater environment. Microplastics are small plastic particles less than 5mm in diameter that enter the ecosystem as a result of the breakdown of large plastic particles or the direct release of small plastic particles by climate and human activities. This study focused on investigating the spatial, and seasonal dispersal of microplastics in the surface water of Kumaraswamy Lake, Coimbatore which is located at the Latitude of 110’00.52'' N, Longitude of 76056’42” E. In different seasons, such as summer, pre-monsoon, monsoon, and post-monsoon samples were taken from the inlet, centre, and outlet. Microplastics made of linear low-density polyethylene, high-density polyethylene, and polypropylene were found in all sampling points. From the water samples, fibre, thin, fragments, and film shapes of microplastics were identified and most of them were black, pink, blue, white, transparent, and yellow in colour. The lake's microplastic pollution load index values were less than 10, which implies the risk I category. Microplastic concentration over four seasons was 8.77 ± 0.27 particles per liter and a high distribution was observed in the outlet area (10.70 ± 0.25 particles/L). Seasonally, the highest microplastic concentration was found in the monsoon season followed by pre-monsoon, post-monsoon, and the lowest in the summer season. These results emphasize that the distribution of microplastics spatially and seasonally wise may cause harmful effects on the fauna and flora that live in lake habitats.