Environmental Pollution and Biogeochemical Cycles
Mercury
Mercury (Hg) is a toxic metal that occurs in natural systems at very
low levels. However, mercury (and particularly methylmercury) is strongly
bioaccumulated in the food chain; pristine waters having total Hg concentrations
well below 1 ng L-1 (sub part per trillion) can produce fish with Hg concentrations
approaching 1 mg kg-1 (1 part per million), well above most state and federal consumption guidelines.
Our research
program is focused on the biogeochemistry (fate and behavior)
of mercury in natural systems with particular emphasis on the terrestrial
portions of the landscape and their interactions with both the atmosphere
and surface waters. Research to date has focused on Hg deposition in open air and forested systems; determination of the hydrologic mass balance of Hg in forested upland-peatland watersheds; determination
of the Hg content of wood fuels; and Hg volatilization from soils.
Current research is focused on determination of the causes of enhanced
methylation of Hg in upland and peatland portions of the watershed and
on the development of a micrometeorological method for determination of ambient
Hg surface--atmosphere fluxes from non-polluted surfaces.
Biogeochemistry
Numerous chemicals of concern are involved in complex biogeochemical
cycles. Examples include CO2, SOx, nitrogen, mercury, pesticides, PAHs,
and many other chemicals of concern. These biogeochemical cycles are often characterized
by having both natural and anthropic sources; large pools and small fluxes;
numerous and often complex physical transport pathways; and often by relatively
rapid transformations among several chemical species having widely different
toxicities, mobilities, solubilities, and other properties.
Research in the department has focused on various biogeochemical pathways
and transformations for a number of these chemicals of concern. While
many are recognized as pollutants, they may also have major roles in agricultural
productivity, ground and surface water quality issues, and even global
climate change.
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