Complementarity of Passive Sampling and Composite Aqueous Sampling to Assess PFAS Emissions in Industrial Wastewater

This study evaluates the capability of three passive samplers (PS) to enhance the monitoring of per- and polyfluoroalkyl substances (PFAS) in industrial wastewater. Effluent from a textile manufacturer, an industrial laundry, and a semiconductor facility (all ≥10,000 m³/a discharge) was sampled over the course of two work weeks. Passive sampling included a polar organic chemical integrative sampler (POCIS), a Speedisk sampler (SD), and a flow-through tube passive sampler (TPS), while an automated aqueous sampler obtained continuous composite wastewater samples. Composite samples revealed fluctuating concentrations of up to 18 different PFAS (varying by site) with total loads from 0.12 mg/day (semiconductor manufacturer) to 8.8 mg/day (industrial laundry). Notably, the PS detected up to 19 additional PFAS compared to aqueous samples, revealing multiple representatives of legacy PFAS as well as precursor compounds (6:2 FTAB, 6:2 FTS), differing by site. Quantitative assessments from PS in the complex industrial matrices remained inconclusive and need further examination. This study highlights the in situ enrichment potential of PS as sensitive and low-maintenance qualitative tools. When applied in parallel, PS and continuous composite aqueous sampling offer complementary advantages and improved insight in qualitative and quantitative monitoring of PFAS emissions from industrial sources, with relevance for regulatory surveillance.