Speciation of atmospheric mercury at two sites in northern Nevada, USA

Gaseous elemental mercury (Hg0), reactive gaseous mercury (RGM), and mercury bound to particles (Hgp) were measured during seasonal 1- or 2-week data collection campaigns at two Mercury Deposition Network sites (NV02 and NV99) in northern Nevada, USA. The sites are rural but are located in an area of diverse natural and anthropogenic mercury sources that include undisturbed and mining mercury-disturbed enriched substrates, coal-fired power plants, ore processing facilities, and industrial facilities. Concentrations of Hg0 averaged over all campaigns were 3.0±1.7 ng m−3 at NV02 and 2.5±3.1 ng m−3 at NV99, higher than has been reported for other rural sites. Hg0 concentrations at the sites were found to be influenced by both local substrate emission and transport from regional source areas. Concentrations of RGM and Hgp were within ranges reported for other rural sites (13±18 and 9±7 pg m−3 at NV02, 7±8 and 13±12 pg m−3 at NV99, respectively). Mercury wet deposition rates measured over 3 years (2003–2005) were similar to other sites in the arid West (3.0±0.7 μg m−2 yr−1 at NV02, 3.9±0.4 μg m−2 yr−1 at NV99).