CHENNAI: In a first, a team of researchers from the Indian Institute of Technology Madras (IIT-M) has found in the Cauvery river high concentrations of emerging contaminants, including the less-studied pharmaceutically active compounds, which pose a serious threat to humans and the ecosystem.
Although several studies in the past have shown the deteriorating quality of Cauvery water, this is the first time a study has quantified the concentration of pharma contaminants. At least 15 such pollutants, including anti-inflammatories such as ibuprofen and diclofenac, anti-hypertensives such as atenolol and isoprenaline, enzyme inhibitors like perindopril, stimulants like caffeine, and antidepressants and antibiotics were detected in high concentration, the study stated.
The concentration of a few of these contaminants in the Cauvery is several times higher than in the Ganges or other rivers. For instance, 3,330.73 nanograms per litre of carbamazepine was detected in the Cauvery, which is 273 times the levels in the Thamirabarani. Researchers said Kanakpura in Bengaluru and Mettur in Salem are the most polluted stretches. The results were published in the peer-reviewed journal, Science of the Total Environment.
‘Effect of contaminants on humans unknown’
The study authored by Jayakumar Renganathan, Insamam Ul Huq S, Kamaraj Ramakrishnan, Manthiram Karthik Ravichandran, and Ligy Philip was jointly funded by the Department of Science and Technology, Government of India, and the UK Natural Environment Research Council.
“We monitored water quality for two years to assess seasonal variation of emerging contaminants, especially pharmaceutically active compounds,” said Dr Philip, Institute Chair Professor, department of Civil Engineering, IIT-M, adding the observations are alarming. “Not much is known about how pharmaceutical contaminants affect human health and the ecosystem over time.
The team’s environmental risk assessment shows pharmaceutical contaminants pose medium to high risk to selected aquatic lifeforms of the riverine system,” she said. The team collected water from 22 locations along the entire river. The quality of water at catchment sites was also monitored. Some contaminants like isoprenaline, perindopril and topiramate have been quantified for the first time in Indian rivers.
The water is also polluted with other emerging contaminants such as personal care products, plastics, flame retardants and heavy metals. The study recommends regular monitoring of rivers and their tributaries for contamination by pharma products. Also, wastewater treatment systems need to be upgraded to reduce the levels of emerging contaminants in receiving water bodies such as rivers. Tamil Nadu Pollution Control Board chairman Supriya Sahu said she will ask district environmental engineers to look into the issue. An action plan on rejuvenation of the Cauvery notes the river is highly polluted near Mettur.