Study on microplastic pollution in the coastal seawaters of selected regions along the northern coast of Kerala, southwest coast of India

Coastal areas are one of the most significant ecosystems, sustaining rich bioresources. Coastal seawaters are subjected to human interferences that lead to pollution and pose serious environmental issues. The current study attempts to categorize and quantify microplastics from selected regions of the northern coast of Kerala, located in the Southwest coast of India. In this study, surface seawater samples were collected from five sampling sites for three months. The five sampling regions selected were marked with GPS (Global Positioning System) and replicates of surface seawater samples (top ⁓10 cm) were collected from the selected transects by using a zooplankton net of mesh size 240 μm that was hauled in water for 20 min. In this study, deep coloured fibres (< 2 mm in size) were predominant and these were observed in the range of 0.80–6.99 items/m3. An analysis of the chemical composition of the microplastic particles by micro-Raman Spectroscopy (HORIBA Scientific LabSpec 6) revealed that polypropylene (PP) was the dominant (31–52% of the randomly selected subset (10%) of total fibre particles) among the five polymer types collected. Poly (ethylene-co-vinyl acetate) or PEVA, polyamide (PA), polybutadiene (BR) and polyethylene (PE) were the other polymer types observed and the presence of these particles in the coastal seawaters causes a lot of harm as these areas comprise rich fauna that plays a significant role in the food web. The current study will provide the impetus to conduct similar studies in seawaters and other aquatic environments in India and the threat microplastic particles impose on the ecological community could also be better estimated by understanding their status. This quantitative study opens the door for further research on the distribution of microplastic particles in the system and the adsorption of organic pollutants and their leaching effects on fauna. [Display omitted] •Characteristics of microplastics in surface seawater off the northern coast of Kerala were revealed.•MPs were plenteous with predominance of fibres (≤ 2 mm) in all the seawater samples observed.•Polypropylene (PP) was the prevalent polymer type.•Polybutadiene (BR), a characteristic component of tyres was observed from the coastal waters of drive-in beach.•Dominance of secondary MPs indicated the increased manipulation of coastal zones.