| Total accumulation and subsequent washoff of surface films derived from gas- and particle-phase atmospheric deposition on seven different impervious surface types (glass, galvanized steel, PVC, PTFE, asphalt, brick, concrete) was investigated. Total accumulation (SigmaPAH 515--31 715 ng/m2; SigmaPCBs 9--86 ng/m2), washoff yields and proportions removed varied among surface types. PAH washoff yields were related to antecedent dry days and static electrification, particularly for PVC and PTFE. PAH and PCB washoff profiles were similar among surface types, with enrichment of particle-phase PAH relative to air. PAH and PCBs from film on all surfaces were washed off independently of aqueous solubility. As surface films concentrate and subsequently release atmospherically-derived PAH and PCBs with washoff, the importance of film washoff as a contributor of contaminants to urban surface waters should be considered. |
