Microplastics occurrence in commercial crab Scylla serrata from Kaveri River of Tamil Nadu: An emerging concern for community health.

Abstract

Microplastic (MPs) pollution has engulfed global aquatic systems, and the concerns about MPs translocation and bioaccumulation in fish, crabs, and other marine organisms are now an unpleasant truth. In the past few years, MPs pollution in freshwater systems, particularly rivers, and subsequently in freshwater organisms, especially in crabs, has caught the attention of researchers. Rivers provide livelihood to approximately 40% of the global population through food and potable water. Hence, assessment of emerging contaminants like MPs in waterways and the associated fauna is crucial. This study assessed MPs in crab S. serrata across the largest riverine system of south India, the Kaveri River. The MPs were characterized by optical microscopy, and field emission scanning electron microscopy-energy dispersive X-ray (FESEM-EDX) analysis for their number, shape, size, and color. Polymer composition was analyzed using attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR) and Raman spectroscopy. Polypropylene (PP), polystyrene (PS), polyamide (PA), and polyvinyl chloride (PVC) were the dominant plastic polymers in the crab intestine. Additionally, the FE-SEM analysis revealed that the MPs have differential surface morphology with rough surfaces, porous structures, fissures, and severe damage. Most MPs comprised Na, Si, Mg, Cl, K, and Ca, according to EDX analyses. The findings might provide insight into the status of MPs in S. serrata at Kavery river that could help in formulating regulations for MPs reduction and contamination in rivers eventually to protect the environment and human health. PRACTITIONER POINTS: The first findings on the identity and properties of MPs in crabs from the Kaveri River at Mettur Dam. A simple and cost-effective approach for extracting microplastics from crab samples from Mettur Dam, Kaveri River, Salem District, Tamil Nadu, India. Microplastics were detected using optical microscopy, ATR-FTIR, and FE-SEM.