Calibration and application of passive sampling for per- and polyfluoroalkyl substances in a drinking water treatment plant

Abstract

The aim of this study was to calibrate and apply polar organic chemical integrative samplers (POCIS) to examine 26 per- and polyfluoroalkyl substances (PFASs) in a drinking water treatment plant (DWTP). As a first step, the sampling rates (R_s) of 14 PFASs were determined in a laboratory calibration study for POCIS-WAX (weak-anion exchange) and POCIS-HLB (hydrophilic-lipophilic balance) (each with a surface area per mass of sorbent ratio of 227 cm² g^-1). While most PFASs were still in the linear uptake phase during the 28-day calibration study, R_s ranged from 0.003 to 0.10 L d^-1 for POCIS-WAX and 0.00052 to 0.13 for POCIS-HLB. It is important to note that POCIS-WAX had higher R_s for short-chain perfluoroalkyl carboxylates (PFCAs) with a perfluorocarbon chain length of C₃-C₆ and perfluorobutane sulfonate (PFBS) compared with POCIS-HLB. Furthermore, R_s was significantly positively correlated with the sorbent-water partition coefficient (K_pw) for POCIS-WAX and POCIS-HLB (p < 0.0001). Use of POCIS-WAX and POCIS-HLB in the DWTP showed good agreement with composite water sampling. No removal of PFASs was observed in the full-scale DWTP. Overall, this is the first study of PFAS monitoring in a DWTP using two types of POCIS. The results demonstrate high suitability for future applications.

Keywords: Drinking water; PFASs; POCIS; Passive sampling; Sampling rates.