Hidden Pollution in Irrigation Systems: Microplastics in Surface and Groundwater of the Pazhayar River Basin, South India

Microplastic (MP) contamination from anthropogenic sources has been repeatedly proposed as an environmental threat based on its possible ecological and human health impacts, due to its persistent nature. The research aimed to explore the occurrence, distribution, characteristics and polymer composition of microplastics at the groundwater and surface water level of Pazhayar River basin, Kanyakumari District. Fifty-two water samples (35 groundwater and 17 surface water) were collected and analyzed by means of wet peroxide oxidation, vacuum filtration, stereomicroscopy, and Fourier Transform Infrared (FTIR) spectroscopy. All locations where sampling was conducted contained detected microplastics, noting higher abundances in surface waters than groundwater — a record of anthropogenic signals. Morphologically, fibres predominated; and polypropylene (PP) and polyethylene (PE) were the dominant polymers detected. Higher microplastic levels were again reported for urbanized areas such as around Nagercoil and Suchindram, suggesting the impact of population density and effluent discharge. Our findings reveal the extent of microplastic pollution across coastal ecosystems in southern Tamil Nadu and indicate a pressing need for ongoing monitoring, enhanced plastic waste management measures and more efficient water resource protection strategies.