A government-funded Anna University study has found that Cauvery, one of India’s major rivers, carries the highest level of toxins despite having lowest discharge into the sea, as per a report by Ram Sundaram in the Times of India.
Cauvery river’s annual discharge is only 8 cubic kilometres but the amount of total dissolved solids is 753 mg per litre, which is nearly six times that of the Ganga.
The study’s final report was released on December 9. It was conducted with financial support from the Indian Space Research Organisation.
“The higher the chemical load of the river is generated due to geologic conditions and mostly by the pollution induced by the people. Though the river has a high amount of TDS, it transports very low amount of dissolved load to the oceans because of lower discharge,” L Elango, professor of geology who headed the study, told Deccan Chronicle.
Groundwater in parts of Tamil Nadu and Karnataka, including Mekadatu, Sriramasamuthiram, Kandiyur, Appakudathan, Rudrapatna and Pannavadi, has been contaminated due to the high level of pollutants, making it unfit for irrigation and drinking.
Several textile, cement and chemical industries located along the river have discharge large amounts of toxic effluents, the ToI report says.
"The presence of major ions such as sodium and chlorine was much higher in the Cauvery, particularly near industrial areas, coast and confluence of tributaries, compared to the other rivers studied,” Elango told ToI.
Abnormal levels of sodium can lead to hypertension and reproductive toxicity in humans.
“The groundwater samples collected in Erode and Karur districts indicated that it was not suitable for drinking and in some areas it was deteriorated so much that it was not suitable for irrigation too,” R. Ramapriya, co-author of the paper and a research scholar at Anna University, told Deccan Chronicle.
In December 2016, a New Indian Express report had pointed out how pollution levels in the river were rising consistently over the years and had classified the river water as ‘grade B’, which can be used for drinking after purification.
District Pollution Control Board officer Ganeshan had then told NIE, “Due to soil erosion and chemicals being let into the river, Cauvery water is being polluted on a daily basis. It is really alarming that the river is polluted just after flowing 100 km from Talacauvery.”