The Cauvery river water is polluted by a range of contaminants including pharmaceutically active compounds, personal care products, plastics, flame retardants, heavy metals and pesticides among many others, the Indian Institute of Technology (IIT) Madras researchers have found in a two-year study.
"Our observations are alarming. So far, not much is known about how pharmaceutical contaminants affect human health and the ecosystem over time," said Civil Engineering professor at IIT Madras, Dr Ligy Philip.
The team's environmental risk assessment has shown that pharmaceutical contaminants pose medium to high risk to the selected aquatic lifeforms of the riverine system. These drug compounds, when released even in minuscule amounts into water bodies, can harm human beings and the ecosystem in the long run, an IIT release said.
Dr Philip led a team of researchers who monitored the water quality of the river for two years to assess the seasonal variation of emerging contaminants, especially pharmaceutically active compounds, and contaminants and pollutants were quantified.
The study found significant contamination by metals such as arsenic, zinc, chromium, lead and nickel. Freshwater intake points were also found to be loaded with extraordinarily high concentrations of pharmaceutical contaminants.
These pharmaceutical contaminants included anti-inflammatory drugs like ibuprofen and diclofenac, anti-hypertensives such as atenolol and isoprenaline, enzyme inhibitors like perindopril, stimulants like caffeine, antidepressants such as carbamazepine, and antibiotics such as ciprofloxacin.
The team collected water from 22 locations along the entire stretch of the river, setting up 11 sampling stations near discharge points of partially treated or untreated wastewater and 11 locations near intake points of water supply systems. The quality of water in the catchment sites was also monitored.
The research team found that water quality and levels of pharmaceutical contaminants in Cauvery are influenced by monsoon season.
The post-monsoon period showed an increased level of various types of contaminants including pharmaceuticals due to reduced riverine flow and continuous waste discharge from multiple sources.
There was also a need to upgrade wastewater treatment systems to reduce the levels of contaminants.
The results of the study, carried out with joint funding from water technology initiatives of the Centre's department of Science and Technology, and the UK Natural Environment Research Council have recently been published in the peer-reviewed journal, ''Science of the Total Environment.''
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