High-resolution temporal wastewater treatment plant investigation to understand influent mass flux of per- and polyfluoroalkyl substances (PFAS)

Drew Szabo; Jaye Marchiandi; Subharthe Samandra; Julia M Johnston; Raoul A Mulder; Mark P Green; Bradley O Clarke

doi:10.1016/j.jhazmat.2023.130854

High-resolution temporal wastewater treatment plant investigation to understand influent mass flux of per- and polyfluoroalkyl substances (PFAS)

J Hazard Mater. 2023 Apr 5:447:130854. doi: 10.1016/j.jhazmat.2023.130854. Epub 2023 Jan 22.

Authors

Drew Szabo¹, Jaye Marchiandi², Subharthe Samandra², Julia M Johnston², Raoul A Mulder³, Mark P Green³, Bradley O Clarke⁴

Affiliations

¹ Australian Laboratory for Emerging Contaminants, School of Chemistry, University of Melbourne, Victoria 3010, Australia; Department of Materials and Environmental Chemistry, Stockholm University, Stockholm 11418, Sweden.
² Australian Laboratory for Emerging Contaminants, School of Chemistry, University of Melbourne, Victoria 3010, Australia.
³ School of BioSciences, University of Melbourne, Victoria 3010, Australia.
⁴ Australian Laboratory for Emerging Contaminants, School of Chemistry, University of Melbourne, Victoria 3010, Australia. Electronic address: brad.clarke@unimelb.edu.au.

PMID: 36701979
DOI: 10.1016/j.jhazmat.2023.130854

Abstract

This study aims to identify sources of per- and polyfluoroalkyl substances (PFAS) to wastewater treatment plants (WWTPs) and reveals previously undescribed variability in daily PFAS concentrations by measuring their occurrence in WWTP influent each hour over the course of a week. ∑₅₀PFAS concentrations ranged between 89 ± 38 on Monday and 173 ± 110 ng L^-1 on Friday, where perfluoroalkyl carboxylic acids (PFCAs), disubstituted phosphate esters (diPAPs), and perfluoroalkyl sulfonic acids (PFSAs) contributed the largest proportion to overall weekly concentrations 37%, 30%, and 17% respectively. Simultaneous pulse events of perfluorooctanesulfonic acid (PFOS; 400 ng L^-1) and perfluoroheptanesulfonic acid (PFHpS; 18 ng L^-1) indicate significant industrial or commercial waste discharge that persists for up to 3 h. The minimum number of hourly grab samples required to detect variation of PFOS and PFHpS concentrations are 7 and 9 samples respectively, indicating a high degree of variability in PFAS concentrations between days. Overall, the risk of sampling bias from grab samples is high given the variability in PFAS concentrations and more frequent sampling campaigns must be balanced against the cost of analysis carefully to avoid the mischaracterisation of mass flux to receiving surface waters.

Keywords: Autosampling; Cost-benefit analysis; Pulse event, source identification; Statistical power.