Passive Monitoring of Ambient Reactive Gaseous Mercury in the Four Corners Area and Eastern Oklahoma

Mark E. Sather1, Shaibal Mukerjee, Ph.D.2, Johnson Mathew3, Bob Brunette4, Jason Karlstrom4, Nathan Lewis4 and Gerard van der Jagt4

This presentation summarizes the first year of a two year air monitoring project estimating reactive gaseous mercury (RGM, a.k.a. gaseous oxidized mercury, GOM) dry deposition rates in the Four Corners area and eastern Oklahoma. The project collaborators include the U.S. Environmental Protection Agency (EPA) Region 6, EPA' Office of Research and Development (ORD), Frontier Global Sciences, Alion, the New Mexico Environment Department (NMED), the National Park Service (NPS), the Bureau of Land Management (BLM), the Jemez Pueblo, and the Cherokee Nation. Ambient monitoring began in August, 2009, and will run through August, 2011, at six sites in the Four Corners area (i.e., NW New Mexico and SW Colorado) and one site in eastern Oklahoma. The two years of ambient monitoring enables robust field testing of the new Frontier Atmospheric Dry Deposition (FADD) surrogate surface device for passive monitoring of RGM, and will enable assessment of inter-annual and spatial variability of the RGM data. This project also provides firsttime RGM dry deposition flux estimates for 24 consecutive months at six sites in the Four Corners area and one site in eastern Oklahoma to set a valuable ambient mercury deposition estimate baseline in those areas. Five of the seven sites are collocated with wet deposition mercury measurements to evaluate total mercury deposition impacts. Project site types include regional background, power plant, rural, urban, and elevated mountain sites. The eastern Oklahoma site houses a continuous Tekran mercury instrument, which provides continuous RGM measurements to compare to the collocated passive RGM measurements from the FADD samplers. FADD samples are deployed for two-week integrated time periods, and include duplicate field and blank samples. In the first year of the study significant dry deposition rate estimates are being detected at all of the project sites, with a predominance of the highest flux estimates measured at the Mesa Verde National Park site. This abstract of a proposed presentation does not necessarily represent EPA policy.

1 Air Quality Analysis Section, U.S. EPA Region 6, 1445 Ross Avenue, Dallas, TX 75202, , (214) 665-8353
2 National Exposure Research Laboratory, U.S. EPA ORD, Research Triangle Park, NC 27711, , (919) 541-1865
3 Houston Laboratory, U.S. EPA Region 6, 10625 Fallstone Road, Houston, TX 77099, , (281) 983-2132
4 Frontier Global Sciences, 414 Pontius Ave. N., Seattle, WA 98109, , (206) 957-1461