Lifeline of Dakshina Kannada polluted with microplastics: Study

MANGALURU: A study conducted by researchers found shocking amounts of microplastics in the water, sediments, and soil samples collected from the Nethravathi River catchment area. The samples were collected from the catchment area of the river on July 2019. Packaging materials and cloth fibres were sources for most of the microplastic materials obtained during the study, which is mainly due to the mismanaged solid waste and lack of effective waste water treatment facilities, noted the researchers.
Dr Anish Kumar Warrier, associate professor, geology, and coordinator, Centre for Climate Studies, said, “All the samples showed the presence of microplastics.We found 288 pieces of microplastics per cubic metre of water, 96 pieces per kg of sediment, and 84.5 pieces per kg of soil. Fibres, films, and fragments are the main categories obtained from the catchment area. The microplastics present in the samples were mostly transparent and white in colour, which are due to the decay of plastic carry bags, packing materials, and fishing lines,” he said.
Microplastics are plastic pieces that are less than 5mm in size, that are more harmful than large plastic debris. The world’s oceans contain large amounts of these particles, and their presence is severely affecting marine organisms.
Fragmentation of larger plastic materials which is due to mismanaged solid waste and washing garments, are the primary sources of these materials in the catchment area of the river. Moreover, the sampling sites near to important pilgrim centres like Dharmasthala and Subrahmanya, register a higher concentration of fibres released due to the washing of clothes.
The study was published online in the scientific journal, ‘Science of the Total Environment’, recently. The study concludes that the river is contaminated with microplastics from its origin to the sink.
“However, our data suggest that microplastic pollution is less in the Nethravathi River, when compared with other global rivers,” said Dr Anish. Researchers from Manipal Institute of Technology (MIT), Manipal Academy of Higher Education(MAHE) conducted a detailed investigation on the river. Dr Anish along with K Amrutha, DST Inspire PhD Scholar, department of civil engineering, conducted the source-to-sink characterization of microplastics for the Netravathi River, which debouches into the Arabian Sea. The team is expanding this work to other aquatic ecosystems in the region and is joined by Prof. Vishnu Unnikrishnan, faculty, Civil Engineering, MIT.