Estimation of annual trace element deposition to the Chesapeake Bay watershed
- Maryland Dept. of Natural Resources, Annapolis, MD (United States)
The mid-Atlantic region of the Chesapeake Bay watershed is subject to wet deposition of atmospherically released contaminants from mid-western US and comparable deposition from the southeastern region as well. Deposition from events originating in the mid-western sector are dominated by emissions strength while those originating in the southeastern sector are most strongly influenced by meteorology. Trace element concentrations precipitation and aerosol in weekly integrated samples at rural sites adjacent to Chesapeake Bay are highly variable in space and time. Influence of regional coal combustion appear to peak in aerosol samples during winter and mean concentrations of Cu, Ni, Pb and Zn in precipitation samples were 50-100% higher at the southern site (Haven Beach, VA). Annual atmospheric loads of Al, Cd, Cr, Pb and Zn deposited to the surface of Chesapeake Bay are within 2-fold quantities of the dissolved fluvial loads delivered by the Susquehanna river. The atmospheric load of Cd, Pb, Cr, Zn and Cu directly to the Bay below the fall line is comparable in magnitude to point sources below the fall line and the contribution of erosion. Atmospheric deposition (wet + dry) of Fe, Al, Mn, Cr, Cu, Ni, Cd, Zn and Pb to the Susquehanna, Potomac and James sub-basins were calculated from existing data. The atmospheric load to the watershed for crustal elements (Fe, Al, Mn) was less than the fluvial export and up to 40x greater than fluvial export for non-crustal elements (Ni, Cd, Zn, Pb).
- OSTI ID:
- 617699
- Report Number(s):
- CONF-9610359--
- Country of Publication:
- United States
- Language:
- English
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