IIT Madras study reveals presence of ‘forever chemicals’ in Chennai lakes, drinking water

High levels of pre- and polyfluoroalkyl substances, that could potentially cause significant health issues, have been found in the Buckingham Canal, Adyar River and Chembarambakkam lake

Updated - April 07, 2024 11:07 am IST

Published - April 06, 2024 11:41 am IST - CHENNAI

Samples from the Adyar River were also found to contain high levels of PFAS in the IIT Madras study.

Samples from the Adyar River were also found to contain high levels of PFAS in the IIT Madras study. | Photo Credit: SRINATH M

For Chennai residents, the dismal state of the city’s lakes is hardly surprising news. Yet, a recent study by IIT Madras reveals the pervasive presence of ‘forever chemicals’ — pre- and polyfluoroalkyl substances (PFAS) — in Buckingham Canal, Adyar River and Chembarambakkam Lake.

PFAS are a vast family of synthetic chemicals found in everyday products such as non-stick cookware, upholstery, food packaging, water or stain resistant coatings, and industrial materials. These chemicals do not degrade easily in the environment. According to the study, conductedby Professor Indumathi M. Nambi and researcher G. V. Koulini of IIT-M, these emerging contaminants are persistent in the environment, and could lead to adverse health effects such as liver damage, low infant birth weights, hormonal imbalance, fertility issues, immune system effects, and even cancer. 

The findings, published in Environmental Sciences Europe, revealed high levels of PFAS in groundwater samples from Chennai. While groundwater samples were collected from in and around the Perungudi dumpsite, surface level samples were taken from different points along the Buckingham Canal, Adyar river, and Chembarambakkam lake. Samples from a water treatment plant (WTP) near the lake were also tested. All the samples were quantified for eight target PFAS.

Chemicals also found in treated water

The researchers also found that the concentrations of all eight target PFAS increased in the treated water of the water treatment plant, compared to the raw water. This is likely due to the presence of unidentified precursors that transform into more stable PFAS end products during treatment, the study notes.

The target PFAS’ concentration ranged in varying quantities up to 136.274 ng/L in the groundwater; 59. 838 ng/L in Adyar river; 60.174 ng/L in Buckingham canal, up to 33.316 ng/L n Chembarambakkam lake, and up to 23.952 ng/L in the raw water of the water treatment plant.

When compared to the United States Environmental Protection Agency’s health advisory levels in drinking water, the measured amounts of PFOA (77.61 ng/L) and L-PFOS (8.12 ng/L) are each around 19,400 times and 400 times higher. The advisory limits are 0.004 ng/L and 0.02 ng/L.

“It is necessary to have an advanced polishing treatment system that can remove PFAS from water because conventional water treatment does not reduce these chemicals, rather, makes them more prevalent,” the study says.

Industrial emissions, untreated domestic wastewater discharge, and open dump sites have been suspected to be significant sources of contamination, highlighting the need for further investigation to fully assess the extent of PFAS contamination in Chennai.

The study also specifically points out the risk to Pallikaranai marshland, a Ramsar site, due to its proximity to the highly contaminated Perungudi dumpyard.

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