Occurrence and profiles of perfluoroalkyl substances in wastewaters of chemical industrial parks and receiving river waters: Implications for the environmental impact of wastewater discharge

Abstract

A total of 17 groups of wastewaters from the chemical industrial parks and matched receiving river waters were collected in the east of China. The measured total concentrations of 21 analyzed PFAS analogues (∑21PFAS) in the influents and effluents of the wastewater treatment plants (WWTPs) were in the range of 0.172–20.6 μg/L (mean: 18.2 μg/L, median: 3.9 μg/L) and 0.167–93.6 μg/L (mean: 10.8 μg/L, median: 1.12 μg/L), respectively, which were significantly higher than those observed in the upstream (range: 0.0158–7.05 μg/L, mean: 1.09 μg/L, median: 0.482 μg/L) and downstream (range: 0.0237–1.82 μg/L, mean: 0.697 μg/L, median: 0.774 μg/L) receiving waters. Despite the concentrations and composition profiles of PFAS varied in the water samples from different sampling sites, PFOA was generally the major PFAS analogue in the research areas, mainly due to the history of PFOA production and usage as well as the specific exemptions. The calculated concentration ratios of the short-chain PFCAs and PFSAs to their respective predecessors (PFOA and PFOS) in most of the samples far exceeded 1, indicating a shift from legacy PFOA and PFOS to short-chain PFAS in the research areas. Correlation network analysis and the calculated concentration ratios of PFAS in the effluents versus influents indicated transformation may have occurred during the water treatment processes and PFAS could not be efficiently removed in the WWTPs. Wastewater discharge of chemical industrial parks is a vital source of PFAS dispersed into the aquatic environment.