Vapor Intrusion Risk Prioritization of Emerging Contaminants in Contaminated Soils: An Integrated Framework Combining Physicochemical Screening, Toxicity Assessment, and Johnson–Ettinger Modeling

Emerging contaminants (ECs) in contaminated soils pose increasing challenges for environmental management due to their diverse physicochemical properties, limited regulatory standards, and uncertain exposure pathways. Although vapor intrusion (VI) assessment has been extensively developed for conventional volatile organic compounds (VOCs), the applicability of existing approaches to structurally diverse ECs remains poorly understood. This study developed an integrated risk-based framework to prioritize ECs with potential VI concerns by combining contamination occurrence characterization, physicochemical property screening, toxicity evaluation, and Johnson–Ettinger (J&E) modeling. Results showed substantial variability in vapor migration potential among EC groups. This suggests that conventional VI assessment methods may not be directly transferable to all ECs. Differences in volatility, partitioning behavior, degradation, and toxicity can strongly influence VI risk. PFAS precursors, particularly fluorotelomer alcohols, exhibited greater vapor-phase mobility than terminal perfluoroalkyl acids, highlighting the importance of compound-specific evaluation rather than class-based assumptions. The proposed framework provides a practical tool for prioritizing ECs requiring detailed VI investigation and supports more efficient allocation of monitoring and remediation resources. This study highlights the need to expand conventional VOC-focused VI assessments toward integrated, risk-based approaches capable of addressing increasingly complex contaminated sites.