Spatial distribution, compositional profile, sources, ecological and human health risks of legacy and emerging per- and polyfluoroalkyl substances (PFASs) in freshwater reservoirs of Punjab, Pakistan

• Published in: The Science of the total environment 2023-01, Vol.856, p.159144-159144, Article 159144
• Main Authors: Riaz, Rahat, Junaid, Muhammad, Rehman, Muhammad Yasir Abdur, Iqbal, Taimoor, Khan, Jawad Aslam, Dong, Yanran, Yue, Linxia, Chen, Yupeng, Xu, Nan, Malik, Riffat Naseem
• Format: Article
• Language: English
• Subjects: Ecological risk; Emerging compounds; Freshwater reservoirs; Per- and polyfluoroalkyl substances; Positive matrix factorization
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2022.159144

Per- and polyfluoroalkyl substances (PFASs) are a large group of chemicals reported in global environment and are responsible for various adverse impacts on humans and environment. We report a comprehensive study on occurrence of PFASs, including legacy, substitute and emerging ones, from Pakistan. Surface water samples were collected from five ecologically important freshwater reservoirs in Pakistan, namely, Head Panjnad (HP), Head Trimmu (HT), Chashma Barrage (CB), Head Blloki (HB), and Head Qadirabad (HQ). The detection frequencies of PFASs ranged between 37 %–100 %. The highest concentration of ∑15PFASs was detected at HP (114.1 ng L−1), whereas the lowest at HQ (19.9 ng L−1). Among the analyzed PFASs, 6:2 fluorotelomer sulfonic acid (6:2 FTS) and perfluorooctanoic acid (PFOA) showed maximum mean concentrations of 9.1 ng L−1 and 7 ng L−1 at HP, followed by Perfluorooctane sulfonic acid (PFOS) with level of 0.99 ng L−1 at HT. The ecological risk assessment for selected species i.e., daphnid, mysid, fish and green algae showed that PFOS, perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA) exhibited moderate risk i.e., Hazard Quotients (HQs) < 1 to the modeled organisms, whereas perfluorobutane sulfonic acid (PFBS) showed the high risk to green algae (HQs = 8.6) and PFOA presented a high risk to all the organisms (HQs ranged between 1.04 and 7.38). The level of ∑PFASs at HP (114.1 ng L−1) exceed the EU guideline value of ∑PFASs in water (100 ng L−1), however the risk quotient (RQmix) values of all age groups were < 1 implying that the detected PFASs in water do not pose risk to human health. Source apportionment through Positive Matrix Factorization (PMF) showed that industrial effluent is the main source of PFASs in freshwater reservoirs. Comparable concentrations of legacy and substitute PFASs in this study indicate that legacy PFASs are still in use adjacent to ecologically important water reservoirs. [Display omitted] •Maximum concentration of ∑15PFAS was found at Head Pajnad (114.1 ng L−1).•Legacy (PFOS), substitute (6:2 FTS) and emerging (6:2 diPAP) PFASs were detected.•PFOA, PFOS, 6:2 FTS, PFBS and 6:2 diPAP were detected more frequently.•Wastewater, municipal effluents, and agricultural runoff were the main PFASs sources.•PFBS and PFOA presented the elevated ecological risks in freshwater reservoirs.