Quantification and characterisation of microplastic pollution and its ecological risk in the coastline of Tuticorin, India

Abstract

Microplastics (MPs) are present practically everywhere in the coastal ecosystems, including the sediment of beaches and wetlands as well as the columns of surface and subsurface waters. Marine MPs are most frequently found in the near shore zones. Due to their potential negative impact on ecosystem functions, MPs have become a significant environmental problem worldwide. Contamination by microplastics has been well-documented around the world and it has drawn the attention of the scientific community, governmental and international organisations and the general public. In the present study, involving the isolation, assessment and characterisation of MP debris collected from six coastlines with recreation and fishing activities in Tuticorin district, the most common MP polymers identified are polypropylene, polyethylene, polyamide and polystyrene. The maximum number of MPs are found in the sediment samples of Tiruchendur (with an average of 8.33 5.3), and the least number of MPs are observed in the water samples of Aalanthalai (2 1.0). To assess the quality of water and sediment, we calculated the polymer hazard index (PHI), pollutant load index (PLI) and potential ecological risk index (PERI). Because of the presence of high-hazard polymers like polyamide (PA) and polystyrene (PS), the study areas have high PHI values (>1000). According to PLI values, water and sediment samples from Tiruchendur and Manapad are highly contaminated with MPs (PLI: 6.98 to 13.85), whereas samples from Aalanthalai, Kayalpattinam and Roche Park are less contaminated (PLI: 1.87 to 3.43). The PERI values of sediment samples from Tiruchendur show the highest ecological risk (PERI: 416.783). On the basis of anthropogenic activities, centres with recreational activities have substantially greater MP concentrations than the fishing locations, and the sediment samples are considerably more polluted with MPs than the water samples taken from the same locations, according to PLI values.