Assessing the geospatial distribution and association of microplastics with water quality in the lakes of Vellore, Tamil Nadu, India
摘要
Microplastics (MPs) are emerging contaminants which of global concern impacting water quality of an aquatic ecosystem. However, the investigation on the MPs is uncommon as compared to the water quality parameter analysis particularly in South India. This study analysed the MPs abundance, their polymer characterisation and physicochemical parameters of water quality in five lakes fed by the River Palar in South India. Water samples were collected from the lakes to analyse 14 physico-chemical parameters to determine the Water Quality Index (WQI)MPs were extracted from the water samples using density separation, and their polymer characterisation was performed using light microscopy, SEM & FTIR spectroscopy. The concentration of MP ranged from 89 to 637 mg/L across the five lakes with the highest concentration from Lake Saduperi showing (673 mg/L). Nine major Polymer types were identified, which includes Polyamide (Nylon), Polyethylene (PE), Polyethylene Terephthalate (PET), Polytetrafluoroethylene (PTFE), Polyvinyl Chloride (PVC). SEM micrographs revealed irregular, surface-cracked microplastic structures with co-contaminants. Geospatial analysis of water quality parameters indicated sharp regional variations in water quality, showing higher contamination around urban settlements, solid waste disposal sites, and from agricultural runoff zones. The estimation of Pearson correlation revealed a statistically significant correlation (r = 0.9) between the concentration of MP and Phosphate (r = 0.98, FDR-adjusted p = 0.0496)—which clearly indicates a direct effect of MP on water. An overall WQI comparison of the five lakes highlighted that the water quality was poor and unsuitable for drinking in all lakes except one i.e., Lake Sathyamangalam. This study provides novel insights on the MP- Phosphate co-occurrence in the study area. A targeted monitoring of phosphate-MP and polymer-specific source tracking is recommended to prevent contamination in the freshwater systems. This study also supports regional water management, and aids urban planners in environmental management and policy modifications.