Characterization and seasonal distribution of microplastics in the nearshore sediments of the south-east coast of India, Bay of Bengal

In view of increasing Microplastics (MPs) contamination in the marine environment and dearth of baseline data, a study was conducted on the abundance, characterization, and seasonal distribution of MPs in the nearshore sediments of the south-east coast of India. Sediment samples (n = 130) were collected at a distance of 1 km and 10 km from the shore region at varying depths (8-45 m) along the Chennai to Puducherry coast (165 km stretch), representing two seasons, i.e., south-west (July 2019 and July 2020) and north-east (January 2020) monsoons. The average abundance of MPs at the 22 offshore sites along the Chennai to Puducherry coast varied from 9 +/- 4.3 to 19 +/- 12.9 particles/50 g dry weight, in July 2019 and January 2020, respectively. July 2020 had an average abundance of 10 +/- 4.5 particles/50 g dry weight. Spatially, high levels of MPs were found at 1km stations and transects in proximity to the river inlets, and temporally, the north-east month recorded the maximum concentration. The dominant morphotype was the filament, and the major polymers were polyethylene and polypropylene. Scanning Electron Microscope (SEM) images revealed the surface irregularity and degradation of MPs due to weathering. The study highlights that high sediment contamination by MPs occurs during heavy rainfall and accumulates closer to river inlets. Eventually, this study suggests that appropriate management of plastic wastes on the landside will reduce MP contamination in the marine environment (C) Higher Education Press 2022

Automated summary

The study investigated the abundance, characterization, and seasonal distribution of microplastics (MPs) in nearshore sediments along the southeast coast of India, finding that MPs accumulate at higher levels during heavy rainfall, especially near river inlets. Filament was the dominant morphotype, with polyethylene and polypropylene as major polymers. Proper management of land-based plastic waste can reduce MPs contamination in the marine environment.