Heterogeneous Atmospheric Chemistry of Lead Oxide Particles with Nitrogen Dioxide Increases Lead Solubility: Environmental and Health Implications.

The heterogeneous chem. of NO2 with Pb-contg. particles was examd. to better understand Pb metal mobilization in the environment. In particular, PbO particles, a model Pb-contg. compd. due to its widespread presence as a Pb paint and as naturally-occurring mineral (massicot, and litharge) component, were exposed to NO2 at different relative humidities. XPS showed that upon exposure to NO2, the PbO particle surface reacts forming adsorbed NO3- and Pb(NO3)2 thin films; the extent of NO3- formation was relatively humidity dependent. NO2-exposed PbO particles had an increased amt. of Pb which dissolved in aq. suspensions at circumneutral pH vs. unexposed particles. Results identified the potential importance and impact that heterogeneous chem. with trace atm. gases can have on increasing soly. and hence the mobilization of heavy metals such as Pb in the environment. Results also showed that surface intermediates which form, such as adsorbed Pb(NO3)2, can yield higher Pb concns. in water, including drinking, estuary, and lake water, and groundwater. [on SciFinder(R)]