Microplastics and associated polycyclic aromatic hydrocarbons in surface water and sediment of the Bay of Bengal coastal area, India: sources, pathway and ecological risk

In the aquatic environment around the world, microplastic contamination has been a common and ongoing issue. Particularly, the ability of microplastics to absorb persistent organic pollutants (POPs) and then transmit these POPs to aquatic creatures has attracted a lot of interest. A stereomicroscope was used to detect the size, shape, and color of the microplastics (MPs), and Fourier Transform Infrared (FTIR) spectroscopy was used to identify the polymer composition of the MPs. To address MP transit, destiny, and mitigation, a study of MP pollution coastal areas is required. In the current study, MP pollution in the collected sample from upper layer of water and sediment of the Digha and Puri beaches along the coast of BOB was evaluated. The average concentration with SD of MPs observed in water was 5.3 ± 1.8 items/L whereas, in sediments, it was 173.4 ± 40.1 items/kg at Digha beach. The mean MPs abundance in the Puri beach was 6.4 ± 1.7 items/L in the water and 190.4 ± 28.0 items/kg in the sediments. The investigated total 16-PAHs concentrations were 164.7 ng/g, 121.9 ng/g, 73.6 ng/g, and 101.3 ng/g on the MPs surface of foam, fragment, fibers, and film respectively in the studied MPs sample. Smaller than 1000 µm size of MPs are distributed in the largest concentration. Fibers, films, fragments, and foam were the most common shapes of MPs. The molecular structure of MPs in water and sediment samples was analysed i.e., polyesters (PEs), polypropylene (PP), polyethylene (PE), polymethyl methacrylate (PMMA), polystyrene (PS), polyamide (PA), polycarbonates (PC), and polyurethane (PU). The obtained result offers an accurate assessment of the PLI, and the investigated polymer facilitates determining the polymer hazard levels, which emphasizes the risk associated with it.