Quantification of microplastic in Red Hills Lake of Chennai city, Tamil Nadu, India

Inevitable use of plastic materials in our day-to-day life has led to the entry of microplastic into aquatic environments, which are plastics less that than 5 mm. Microplastic is of great concern in recent years due to its impact on humans and aquatic organisms since they absorb organic contaminants and pathogens from the surrounding media due to higher surface and volume ratio. This is the first study attempted to study the distribution and source of microplastic contamination in Red Hills Lake which is one of the freshwater systems supplying water to the North of Chennai city. Thirty-two sediment samples and six water samples were collected covering an area 18.21 km². The presence of microplastic was analyzed in water and sediment as per the National Oceanic and Atmospheric Administration (NOAA) protocol. The mean concentration of microplastic in water samples was 5.9 particles/L and 27 particles/kg in sediment. In both sediments and water, the most commonly found microplastic types are as follows: fibers (37.9%), fragments (27%), films (24%), and pellets (11.1%). Based on the FTIR, the common types of microplastic were of high-density polyethylene, low-density polyethylene, polypropylene, and polystyrene. Further samples were evaluated for surface elemental composition in order to understand whether heavy metals get adhered to the surface of microplastic using energy-dispersive X-ray. Our results indicated the presence of microplastic in water and sediments which will lead to further study of microplastic presence in biota and microplastic pollution in freshwater systems.