HR: 0800h
AN: B11B-0396    [Abstracts]
TI: In Situ Micrometeorological Mercury Fluxes From Tidally-Exposed Wetland Sediments
AU: * Smith, L M
EM: lsmith@envsci.rutgers.edu
AF: Rutgers University, 14 College Farm Rd., New Brunswick, NJ 08901, United States
AU: Reinfelder, J R
EM: reinfelder@envsci.rutgers.edu
AF: Rutgers University, 14 College Farm Rd., New Brunswick, NJ 08901, United States
AB: Major research efforts have examined the influx of mercury to estuaries from point and non-point sources. However, little is known about the efflux of gaseous elemental mercury (Hgº) from tidally-exposed estuarine sediments back to the atmosphere, a potentially important re-distribution pathway of mercury on watershed to global scales. In the New Jersey Meadowlands in northeastern New Jersey, U.S.A., this route may be particularly important due to the high degree (sediment mercury concentrations up to 51 ug g-1 dry weight) and large areal extent of mercury contamination, coupled with the vast sediment surface area exposed to the atmosphere at low tide. Sediment-air vertical fluxes of mercury were studied at a tidal salt marsh within the New Jersey Meadowlands, Hudson County, NJ) in August 2005, May 2006, and June 2007. Vertical fluxes were estimated from in situ measurements of vertical concentration gradients of total gaseous Hg (>95% elemental Hg) coupled with vertical wind speed profiles and atmospheric stability correction factors for momentum and water vapor. Sediment-air mercury fluxes ranged from -461 to +253 ng m-2 h-1 and were highest during periods of peak solar radiation. Laboratory flux chamber studies with sediments from the New Jersey Meadowlands, and from the nearby Raritan and Passaic River estuaries demonstrate the importance of UV light and sulfide as controlling factors in mercury volatilization from tidally exposed sediments.
DE: 0414 Biogeochemical cycles, processes, and modeling (0412, 0793, 1615, 4805, 4912)
DE: 0438 Diel, seasonal, and annual cycles (4227)
DE: 0442 Estuarine and nearshore processes (4235)
DE: 0489 Trace element cycling (4875)
DE: 0497 Wetlands (1890)
SC: Biogeosciences [B]
MN: 2007 Fall Meeting