Oral Presentation Society of Environmental Toxicology and Chemistry Australasia 2021

The Fate of Per- and Polyfluoroalkyl Substances (PFAS) in Wastewater and Coastal Waters of New Zealand (#99)

Swadhina Priyadarshini Lenka 1 , Melanie Kah 2 , Lokesh P. Padhye 1
  1. Department of Civil and Environmental Engineering, The University of Auckland, Auckland, New Zealand
  2. School of Environment, The University of Auckland, Auckland, New Zealand

A comprehensive review of the literature indicated the prevalence of PFAS in global wastewaters owing to their extensive use in the manufacturing of a wide range of consumer and industrial products [1]. PFAS are also detected in coastal waters due to their discharge in the ocean from nearby wastewater treatment plants (WWTPs) and industries. In this study, the fate of 38 short-chain (C3-C6), long-chain (C>6), and precursor PFAS in a WWTP and coastal waters of New Zealand was assessed. The concentrations of perfluoroalkyl carboxylic acids (PFCAs) increased after secondary treatment, as observed previously [1]. A simultaneous increase (~40%) and decrease (~50 %) in the effluent concentrations of perfluorohexanoic acid (C6) and precursor 6:2 fluorotelomer sulfonate, respectively, indicated a possible transformation of precursors into short-chain PFCAs during biological treatment. The fate of ultra-short chain perfluoropropionic acid in a WWTP was studied for the first time and concentration results indicate 38% removal between influent and effluent. Long and short-chain PFAS were detected in coastal water samples collected downstream of the WWTP outlet (C1), an industrial zone (C2), and a recreational bay (C3). ∑PFAS decreased 20 times between C1 and C3, which were located 6 km apart, and halved between C2 and C3, which were located 9 km apart. It is noteworthy that the concentrations of regulated PFOS + PFHxS and PFOA were significantly below the guideline values for drinking water (70 and 560 ng/L) and recreational water (2,000 and 10,000 ng/L) as per National Environmental Management Plan, Commonwealth Australia. This study confirmed the incomplete removal of PFAS by advanced WWTPs and provided evidence for the PFAS contribution of WWTPs to coastal waters.

  1. [1] Lenka, S.P., Kah, M., Padhye, L.P., 2021. A Review of the Occurrence, Transformation, and Removal of Poly- and Perfluoroalkyl Substances (PFAS) in Wastewater Treatment Plants. Water Res. 117187. https://doi.org/10.1016/j.watres.2021.117187