Distribution, characteristics and ecological risk of microplastics in beach sediments along the Northern coast of Andhra Pradesh, India

Abstract

Microplastics (MPs) are among the most important emerging contaminants found in marine habitats globally, mandating to comprehend the nature and extent of its pollution in coastal environments before suggesting any mitigation measures. This study aims to investigate the level of MPs contamination in the sediments of 31 beaches along the Northern coast of India's second-longest coastline, the Andhra Pradesh coastline. The sediment samples were analysed to determine the presence of MPs and to investigate their abundance, morphology, spatial distribution, and polymer composition. An aggregate of 346 MP particles were recovered from all the 31 locations by analysing a 20 g sample from each site, with size ranging from 50 to 2000 μm. The average abundance estimated was 564 particles/kg with fibres (89.667 %) as the dominant shape followed by films (8.17 %), fragments (1.88 %) and foam (0.31 %). Transparent, black and blue coloured particles were majorly observed while, other colours identified were brown, red, yellow, pink and green. The predominant polymer type identified by ATR-FTIR and µ-Raman Spectroscopy was polyethylene terephthalate, followed by polypropylene, polystyrene, ethylene vinyl acetate, polyvinyl chloride, and polyester. Further this study also performed a preliminary ecological risk assessment of MPs for the northern Andhra Pradesh coast using PLI and RQ. The PLI computed was >1, indicating pollution. Additionally, 15 of the locations examined have RQ values greater than 1, indicating potential threat to the ecosystem. The findings have provided insights into the risks that can be posed by MPs throughout the Northern coast of Andhra Pradesh, highlighting the absolute necessity of creating effective plans for their control and reduction.