Polyfluoroalkyl substances (PFAS) are synthetic chemical compounds that contain multiple carbon-fluorine bonds. PFAS materials are used in coatings, textiles, and several industrial products. They are also notorious for resisting degradation and can contaminate the environment for a very long time.
Many studies from different parts of India have already found PFAS in water sources. Conventional water treatment systems that can remove these compounds are not yet commercially available even as the extent of PFAS contamination across India remains unclear.
In a 2025 review in the Journal of Hazardous Materials Advances, scientists examined monitoring and regulations across Gujarat, Maharashtra, Tamil Nadu, and West Bengal. The review’s first author, Rajneesh Kumar Gautam, of the Swedish University of Agricultural Sciences, said the evidence establishes that PFAS contamination in India is a legitimate concern but that its national extent is poorly defined, thanks in part to differences in the way different research groups test and analyse PFAS.
This particular lacuna has been identified in multiple studies of late.
For example, in a 2024 paper in Environmental Sciences Europe, researchers from IIT-Madras reported the analysis of 14 water samples collected between 2022 and 2023 from groundwater, surface water, and the four stages of a water treatment plant in Chennai. The teamfound that groundwater from residential wells in the vicinity of garbage dumps had the highest PFAS levels.
At the treatment plant, concentrations of all eight target PFAS were 5% to 103% higher in treated water than in raw water. Study coauthor Indumathi M. Nambi, a professor of environmental engineering, suggested the increase may reflect unidentified precursors that turned into more stable PFAS inside the plant. The study did not quantify those precursors.
The eight target PFAS, Dr. Nambi said, represented only a fraction of the potentially diverse fluorinated compounds that may be present. She recommended that testing should thus include other PFAS materials that may be present in the water, rather than relying only on a fixed list.
Resolving mixed sources
On July 16 this year, researchers from GITAM (Deemed to be) University, Hyderabad, and from Canada and the U.S. reported the results of testing 77 kinds of PFAS in seawater and sewage from around Visakhapatnam. The findings, published in npj Emerging Contaminants, showed the presence of 38 compounds, with concentrations in sewage ranging from low to very high.
The team also used a model to estimate that sewage accounted for about 41% of median PFAS concentrations along the coast. GITAM assistant professor and study coauthor Manoj Rayaroth said distinguishing municipal sewage from industrial inputs would require systematic sampling around the mixing points.
Nejumal Kannankeril Khalid, a coauthor from the University of Montreal, said source-specific sampling together with targeted, suspected, and non-target PFAS analysis, chemical fingerprints, and machine-learning approaches could improve source discrimination and help resolve mixed sources.
Testing for a fixed list of PFAS means substances not indicated on that list may not be detected. Precursors can also change into other PFAS. Dr. Rayaroth said high-resolution mass spectrometry can help identify PFAS beyond a fixed list, but care is needed because PFAS can enter samples during collection and analysis. Removing PFAS from treated wastewater presents another challenge.
Abhradeep Majumder, assistant professor in the Department of Civil Engineering at BITS Pilani-Hyderabad, said conventional biological wastewater treatment cannot remove PFAS. He noted that adsorption-based treatment, which can remove PFAS from water, has shown potential but that low-cost materials designed to capture PFAS still need to be developed.
From detection to exposure
Finding PFAS in water does not, by itself, tell us how much of a health risk it poses. That depends on the type of PFAS, the dose, duration of exposure, and route of exposure. In its 2025 monograph, the International Agency for Research on Cancer classified perfluorooctanoic acid (PFOA) as ‘carcinogenic to humans’ and perfluorooctanesulfonic (PFOS) as ‘possibly carcinogenic to humans’. Both PFOA and PFOS are types of PFAS materials.
In a study published in February this year a team that included Dr. Nambi found that a mix of 24 PFAS-compounds — including long- and short-chain PFAS molecules and their precursors — delayed the hatching of zebrafish eggs, inhibited the offspring’s growth, accumulated in their blood, and reduced their heart rates.
Chirag Dhara, assistant professor at Krea University in Sri City, said incomplete exposure data should not delay controls on PFAS whose hazards are already well established.
Anbumani Sadasivam, principal scientist at the CSIR-Indian Institute of Toxicology Research, Lucknow, said India lacks sufficient baseline data to reliably estimate PFAS exposure. He said CSIR-IITR is participating in a UNEP-funded National Implementation Plan to build baseline data on PFAS in environmental matrices and consumer products, and has developed capabilities to detect 50 multi-class PFAS molecules across different matrices.
Where regulation falls short
The Environment Ministry has said there is no specific regulation banning PFAS manufacturing. India has no PFAS-specific drinking-water limit under the current IS 10500:2012 standard.
But the standard is now under revision. The Bureau of Indian Standards said a dedicated Working Group on Emerging Contaminants and Forever Chemicals is examining PFAS limits and associated contaminants.
The scope and number of PFAS to be included have not yet been finalised, while analytical methods for PFAS in drinking water are also being considered. Dr. Anbumani said India should first establish which PFAS are being manufactured, imported, and used, alongside baseline monitoring, toxicological studies, and enforceable limits.
Girija K. Bharat, a former Scientist at CSIR-CIMFR, said that, to her knowledge, there is currently no clear regulatory pathway for penalising a source responsible for PFAS contamination sources.
Dr. Dhara warned that a named-chemical approach could leave precursors and transformation products outside regulation.
Dr. Gautam also said India has enough evidence to introduce precautionary interim limits for well-studied PFAS. He called for harmonised monitoring and broader screening for precursors and other fluorinated compounds.
Rohan Singh is an independent science journalist in Lucknow.
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