Characteristics and risk assessment of microplastic mediated heavy metal transport in black clam Villorita cyprinoides from a Ramsar wetland of South India

The synergetic and interactive effects of microplastics (MPs) as potential carriers of pollutants and pathogens have a manifold impact on human health and aquatic biota. The present study delineates the role of MPs in transporting heavy metals to the black clam, Villorita cyrpinoides of Vembanad Lake in South India. MPs in water (3.41 ± 1.87 items/L), sediment (154.6 ± 45.4 items/kg) and within clams (0.87 ± 0.34 items/g tissue) showed considerable variation based on their physical and chemical characteristics, which in turn reflected its differential potential to carry heavy metals. Though the levels of heavy metals (Al, Fe, Mn, Zn, Cr, Pb) within the clam and those carried by MPs were less than the hazardous limits, the concentration of Cd within the clam and MP was found to have a positive correlation. Though the present levels of heavy metal pollution in the lake do not pose a direct threat to humans, anthropogenic interventions and reduced water flow have turned the lower reaches of the lake into a sink of heavy metals. Hence with MP concentration increasing it is worth investigating how their future interactions with heavy metals and other pollutants would pose a risk to living organisms.