Microplastic pollution – a rising threat along an urban lake in the Vellore district of Tamil Nadu, India: abundance and risk exposure

ABSTRACT

Lake ecosystems provide vital services, but face escalating threats from synthetic microplastic (MP) pollution driven by human activities, necessitating urgent action. This study investigates MP contamination in Dharapadavedu Lake, Tamil Nadu, India, characterizing its presence and distribution. MPs in water and sediment were assessed using NOAA's standardized protocol. The results indicate that mean concentration of MPs in lakeshore sediment and water was 2.46 ± 1.06 particles/kg and 1.26 ± 0.88 particles/L, respectively. Significantly, medium-sized MPs (500–1,000 μm) were most abundant, comprising predominantly white, red, and green colors with fragments and fiber morphotypes. Attenuated total reflection Fourier transform infrared spectroscopy revealed valuable insights into the polymer composition of MPs in the lake, identifying four primary types: nylon (polyamide), high-density polyethylene, low-density polyethylene, and polypropylene. Pollution load index data reveals that MP pollution levels of 2.26 in sediment and 1.46 in water indicate a moderate to high level of risk. These findings reveal that the repercussions of recreational activities, anthropogenic activities, and fishing practices around the lake contributed to the accumulation of MPs in the lake. This study fills a research gap by investigating MP pollution in Dharapadavedu Lake for the first time, establishing a baseline contamination estimate.