Chemical fate is a concern at environmentally contaminated sites, but characterizing that fate can be difficult. An important component of characterizing fate is identifying and quantifying the movement of chemicals at the air-water interface. Superfund sites are often suspected sources of air pollution due to legacy sediment and water contamination. A quantitative assessment of polycyclic aromatic hydrocarbon (PAH) and oxygenated PAH (OPAH) diffusive flux in a river system that contains a Superfund Mega-site, and passes through residential, urban and agricultural land, has not been reported before. Here, passive sampling devices (PSD) were used to measure 60 polycyclic aromatic hydrocarbons (PAHs) and 22 oxygenated PAHs (OPAHs) in the air and water. Human health risk associated with inhalation of vapor phase PAHs and dermal exposure to PAHs in water were assessed. Excess lifetime cancer risk estimates show potential increased risk at sites within and in close proximity to a Superfund Mega-site. Specifically, estimated excess lifetime cancer risk associated with inhaling PAHs was above 1 in 1 million within the Superfund Mega-site. We show the majority of PAHs and some OPAHs in the water are from airborne sources. The majority of PAHs detected in both environmental compartments, 16 out of 26, the direction of mass transfer at all five study sites was deposition. This suggests that the river water in this Superfund site is predominantly a sink for airborne PAHs and OPAHs, rather than a source.