CHENNAI: A study conducted across five lakes in Vellore district has found widespread microplastic contamination and poor water quality, with researchers warning that urban discharge, agricultural runoff and improper waste disposal are affecting freshwater ecosystems linked to the Palar river basin.
The study, published in Scientific Reports, was carried out by researchers from the School of Bioscience and Technology and the School of Agricultural Innovations and Advanced Learning at Vellore Institute of Technology (VIT), Vellore.
The study covered Gopal Samuthram Lake, Saduperi Lake, Melkavanur Lake, Sathyamangalam Lake and Sedhuvalai Lake, all of which are connected to the Palar river system and serve as important sources for irrigation, groundwater recharge and domestic needs in the region.
Researchers analysed 100 water samples collected during the pre-monsoon season between January and May 2024. The samples were examined for 14 physicochemical parameters, including pH, dissolved oxygen, nitrate, phosphate, turbidity and total dissolved solids, alongside microplastic concentration.
The study found microplastic concentration ranging between 89 mg/L and 637 mg/L across the lakes, with Saduperi Lake recording the highest levels.
Laboratory analysis identified polymer types such as polyethylene, polyethylene terephthalate (PET), polyvinyl chloride (PVC), nylon and PTFE.
The researchers said the water quality index assessment showed that water in most of the lakes was either poor or unsuitable for drinking purposes. Sathyamangalam Lake was the only water body that showed relatively better quality compared to the others.
The study also found a strong correlation between microplastic concentration and phosphate levels, indicating a link between plastic pollution and nutrient contamination in freshwater bodies.
According to the paper, phosphate levels in four of the five lakes exceeded permissible limits, while nitrate concentration was high in lakes located near agricultural zones.
Several lakes also recorded high salinity, elevated dissolved solids and low dissolved oxygen levels, which affect aquatic life and water usability.
The researchers said contamination levels were higher near urban settlements, drainage channels, waste disposal locations and agricultural runoff zones.
The paper called for regular monitoring of freshwater microplastics, improved sewage treatment, scientific solid waste management and stricter pollution control measures in lake ecosystems connected to the Palar basin.
The study further said the findings could support water resource management and environmental planning in rapidly urbanising regions of Tamil Nadu.
* Study conducted in five lakes linked to the Palar river basin in Vellore district
* 100 water samples analysed between January and May 2024
* Microplastic concentration ranged from 89 mg/L to 637 mg/L
* Saduperi Lake recorded the highest contamination
* Most lakes classified as poor or unsuitable for drinking
* Strong link found between microplastics and phosphate pollution
* Urban waste, sewage discharge and agricultural runoff cited as key causes
* Study calls for continuous monitoring and stricter waste management measures