Potential Ecological Risk Assessment Studies Based on Source and Distribution of Microplastics from the Surface Sediments of Tropical Backwaters, Kerala, India

The aim of this investigation is to comprehend the ecological risk of microplastics in surface sediments of selected estuaries (Kadinamkulam, Anchuthengu and Kappil-Hariharapuram estuaries) along the southwest coast of Kerala, India. The studied tropical estuaries of Kerala found totally 407 microplastic particles in the surface sediments. Among these, 117 MPs found from the Kadinamkulam estuary, 182 MPs found from the Anchuthengu estuary and 108 MPs found from the Kappil-Hariharapuram estuary. The sediments were dominated by colour microplastics followed by white verities (Colour microplastic – Kadinamkulam: 80.34 %, Anchuthengu - Kappil- Hariharapuram: 78 %). The Polymer hazard index (PHI) of the study area reveals that the value of PHI exceeds > 1000 due to the presence of hazard scores polymers such as polystyrene (PS) and polypropylene (PP). The outcome of the PHI and PERI suggest that the estuarine sediments were falling under high ecological risk and these microplastics were primarily derived from river inflow and urbanized areas around the estuarine system.