Wastewater-Based Epidemiology for Tracking Human Exposure to Per- and Polyfluoroalkyl Substances

Abstract

Per- and polyfluoroalkyl substances (PFAS), ubiquitous contaminants due to environmental persistence and bioaccumulation, necessitate novel approaches for population-level exposure assessment. Here, wastewater-based epidemiology (WBE) was applied to evaluate PFAS exposure across two Chinese coastal cities (Haikou and Sanya). Twenty-seven PFAS were analyzed in wastewater from 16 treatment plants using solid-phase extraction-LC-MS/MS, with 20 compounds detected (ΣPFAS: 21.06–99.04 ng/L). Short-chain PFAS (CF2 units < 7) dominated (>60%), exceeding long-chain analogs. Positive Matrix Factorization (PMF) resolved six contamination sources: household pollutants (22.81%), atmospheric deposition (19.01%), human metabolism (15.4%), textiles (14.99%), aqueous film-forming foams (AFFF, 14.94%), and cosmetics (12.84%). Population-normalized mass loads varied regionally (Haikou: 5.14–25.75 mg/day/1000 inhabitants; Sanya: 1.69–35.89 mg/day/1000 inhabitants). To bridge wastewater data with human exposure, endogenous PFAS contributions (e.g., metabolic excretion) were isolated via PMF analysis, enabling differentiation from exogenous sources. By correlating wastewater concentrations with population-specific excretion rates, blood-equivalent PFAS levels were estimated, revealing spatial disparities consistent with biomonitoring trends. This WBE framework bypasses traditional biomonitoring limitations—high costs, ethical barriers, and delayed results—while providing real-time, population-wide exposure insights. Our findings establish a scalable tool for identifying contamination hotspots and prioritizing source-specific interventions, critical for mitigating PFAS-related health risks.

Keywords: PFAS, Sewage epidemiology, Environmental monitoring, Exposure assessment, PMF