Airborne PCB Concentrations in Portland, Oregon: Emissions and Contributions from the Portland Harbor Superfund Site

We investigated airborne concentrations of polychlorinated biphenyls (PCBs) near the Portland Harbor Superfund Site (PHSS), a historical and culturally significant location. In collaboration with residents, we measured airborne PCBs using polyurethane foam passive air samplers (PUF-PAS) deployed for 6 weeks. Additionally, we estimated PCB emissions based on the flux calculations from Portland Harbor (PH) water using PCB concentrations reported by the U.S. EPA to predict airborne PCB concentrations with an atmospheric dispersion model (AERMOD). Measured airborne total PCB concentrations ranged from 70 to 910 pg m^-3 with a geometric mean of 330 pg m^-3, which is lower than concentrations observed in other known PCB-contaminated areas in the U.S. Air congener distributions resembled commercial Aroclor mixtures 1016 and 1242, and estimated PCB flux from the water averaged 450 ± 120 ng m^-2 d^-1. Predicted airborne PCB concentrations ranged from 1 to 124 pg m^-3, with enrichment in non-Aroclor congeners when PH water is the sole source. However, all predicted concentrations were lower than measured values and exhibited different congener distributions, suggesting that PCB flux from PH water contributes only a minor portion (∼2%) of Portland's airborne PCB burden, and that additional PCB sources exist within the community.