Per and polyfluoroalkyl substances in marine aquatic systems in Visakhapatnam, India

Per- and polyfluoroalkyl substances (PFAS) are persistent pollutants with limited documentation in India. We targeted 77 PFAS in seawater and sewage water from the Visakhapatnam coastal zone, Bay of Bengal. Thirty-eight compounds were detected; total PFAS ranged from 12 to 597 ng/L in seawater and 140 to 1324 ng/L in sewage water, with short-chain PFAS dominating (up to 93% of total concentration). PFBS, PFOA, PFHxA, and PFHxS showed the highest detection frequencies, and the elevated prevalence of the fluorotelomer sulfonate precursor 6:2-FTS suggests direct industrial and municipal wastewater influence. A two-end-member mixing model estimated that sewage discharge contributes approximately 41% of median coastal PFAS concentrations. Multivariate analysis identified two chemically distinct sewage source signatures (AFFF-associated perfluoroalkyl sulfonates and residential precursor transformation products) and a compound-level fingerprint correlation (Spearman r = 0.71, p = 0.004) confirmed that the coastal PFAS profile mirrors that of sewage water. Ecological risk assessment against US EPA (2024) chronic aquatic life criteria indicated low ecological risk at current concentrations (PFOS RQ = 0.042). However, human health risk via seafood consumption warrants cautionary alertness: the estimated median PFOS fish tissue concentration of 11.2 ng/g wet weight exceeds the EU Regulation 2022/2388 maximum level for fish muscle (2.0 µg/kg ww) by 5.6-fold. These findings provide the first systematic characterization of PFAS sources, distributions, and risks in the Visakhapatnam coastal zone and highlight the urgent need for fish biomonitoring and a national PFAS regulatory framework for Indian coastal environments.