Search

Microplastics (MPs; particles <5 mm) are widely distributed in various habitats from the land to the oceans. They have even reached the remotest of places, including the deep seas and Polar Regions. Although research on MPs pollution in the marine environment has received widespread attention in recent years, the distribution, sources and ecological risks of MPs in coastal areas remain unclear. This study assessed the abundance, characteristics, sources and ecological risk of MPs in surface waters and sediment of the mainland coast and four island groups comprising the coral reef environment of the Gulf of Mannar (GoM), southeast India. Mean MPs abundance across all 95 sampling sites ranged from 28.4 to 126.6 items L−1 in water and from 31.4 to 137.6 items kg−1 in sediment. MP fibers <2 mm dominated the water, while fragments >3 mm were predominant in sediments. Polyethylene (PE) and polypropylene (PP) were the most common polymers in both matrices. The major proportion of MPs in the GoM derived from land-based sources, with distance to the mainland, coastal population density and improper handling of solid waste being the main factors influencing the abundance of MPs. Polymer Hazard Index (PHI), Pollution Load Index (PLI) and Potential Ecological Risk Index (PERI) were used to assess current levels of MPs. While the GoM has high PHI values (>1000) resulting from MPs with high hazard scores (e.g. polyamide, polystyrene, polyvinyl chloride), the PLI values (1.46 and 1.51) indicate low MPs pollution levels in GoM waters and sediments, and the PERI values (31.7 and 24.4) indicate that this represents a minor ecological risk. The results from the current study enhance our understanding of the characteristics, sources, and associated environmental risks of MPs to marine ecosystems. This data may provide a baseline for future monitoring and the formulation of environmental policy. [Display omitted] • MP abundance, size, shape and polymer type vary between water and sediment matrices. • Mainland shores and shoreward sides of islands have higher MP concentrations. • Polymer type abundances in solid wastes on shore and islands are closely related. • Distance to mainland, population density and waste handling influence MP abundance. • Pollution indices indicate MP are currently a minor ecological risk in the GoM. [ABSTRACT FROM AUTHOR]

This study investigated the microplastic (MPs) contamination of the mussels, P. viridis and P. perna of different sizes, and their environment viz. water and sediment. MPs were recovered from the soft tissues of both species. The mean abundance of MPs ranges from 0.87 ± 0.55 to 10.02 ± 4.15 items/individual; 0.1 ± 0.03 to 2.05 ± 0.33 items/g; 31.57 ± 7.63 to 59.25 ± 14.32 items/l in water, and 79.54 ± 18.66 to 108 ± 40.36 items/kg in sediment. Smaller mussels (3–6 cm) are capable of ingesting higher quantities of MPs per gram of tissue weight, and the rate of MP uptake decreases when the mussels grow in size. These might be due to the faster filtration rate in smaller mussels. MPs of fiber type and blue color in the size range of 500 μm to 1 mm are predominant in mussels. Eleven different polymeric groups were identified, of which PE is the most common, followed by PP. The distribution patterns of MP abundance, shape, size, color, and polymer in mussels more closely resemble those in water. There is no significant difference in MP quantities between P. perna and P. viridis (p > 0.05). FTIR-ATR spectroscopy and SEM analysis show that most of the MPs have been strongly weathered. EDAX analysis detects heavy metals like As, Ni, Fe, Zn, and Cd associated with MPs. This study shows that the MPs contents of both the mussel species are transferred from seawater to their edible meat. This study again proved that mussels can act as bio indicator of MPs pollution. [Display omitted] • Microplastics were assessed in east and west coast mussels and their ecosystems. • MP numbers in mussels vary from 0.1 to 4.6 items/g and 1.5 to 7.6 items/individual. • MP abundance in mussel reflects that in water but is inversely related to body size. • Mussels are more likely to ingest blue MPs and PE fibers of size from 500 μm–1 mm. • FTIR-ATR reveals 11 polymers and SEM-EDX shows weathered MPs with pollutants. [ABSTRACT FROM AUTHOR]