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Atmospheric Mercury Measurements in the Gulf of Mexico and Mid-Atlantic Regions:
Early Results from an Emerging Monitoring Network

Winston Luke*, Mark Cohen, Paul Kelley
NOAA/Air Resources Laboratory (R/ARL), SSMC3, Rm. 3316, 1315 East West Hwy., Silver Spring, MD

Steve Brooks
Canaan Valley Institute, P.O. Box 673, Davis, WV 26260

Jake Walker
Grand Bay National Esturarine Research Reserve, 6005 Bayou Heron Rd., Moss Point, MS 39562


The presence of mercury in the environment, its wide distribution and cycling in coastal and aquatic ecosystems, and risks to human health constitute a major environmental resource management issue. The majority of mercury emitted to the environment is injected into the atmosphere through the combustion of fossil fuels, incineration of mercury-containing waste, and metallurgical processes (e.g., smelting). Wet and dry atmospheric deposition delivers mercury to sensitive aquatic ecosystems, where it can be converted to more toxic and bio-available forms such as methylmercury. Human exposure to methylmercury, which adversely affects the nervous system, results from consumption of contaminated fish and other organisms in the aquatic food web.

Despite mercury’s importance, however, many of the complex processes controlling its movement through the environment are poorly understood, and there is debate over the efficacy of emission controls in reducing mercury concentrations in estuarine and marine fish. In 2006 the National Atmospheric Deposition Program (NADP) introduced the Atmospheric Mercury Initiative to address many of these uncertainties. The initiative seeks to establish a network of sites to “…measure event-based mercury wet deposition, air concentrations of mercury in its gaseous and particulate forms, and meteorological and land-cover variables needed for estimating dry deposition fluxes [NADP, 2006].”

We present early results from two such sites in the emerging network: a rural site at the Grand Bay National Estuarine Research Reserve (NERR) in Moss Point, MS, and a suburban site on the campus of the Beltsville Agricultural Research Center (BARC) in Beltsville, MD. The measured atmospheric mercury concentrations at the sites (elemental Hg(0), reactive gaseous mercury, and fine particulate mercury) will be summarized, and will be interpreted using ancillary measurements of primary (CO, NO/NOY, SO2) and secondary (O3) trace gases at each site; prevailing meteorology; and back trajectory analysis. Results of quality assurance exercises, designed to estimate the precision of co-located mercury measurements and to better characterize instrument response variations under a variety of conditions, will also be discussed.