PATHWAYS OF MERCURY EVASION FROM CONTAMINATED WETLANDS: A GLOBALLY IMPORTANT SOURCE OF ATMOSPHERIC MERCURY?
Impact/Purpose:
Two pathways exert primary control over the release of Hg0 from estuarine environments: the abiotic reduction of Hg(II) to Hg0(aq) as moderated by complex interactions of UV radiation, DOC, salinity, and pH in the water column, and by the diffusive release of bacterially reduced Hg0 from plant leaf surfaces during transpiration.
Our objectives are to: 1) determine the relative importance of these two different evasion pathways; 2) investigate the fundamental processes governing chemical interactions within each pathway; and 3) evaluate the net contribution of evasion from Hg contaminated wetlands to the global Hg budget. These objectives will be studied by experimentally and empirically testing hypothesized relationships between measured environmental parameters and Hg behavior in a wetland.
Description:
Mercury (Hg) is a globally occurring pollutant that bioaccumulates and persists in the environment. The global Hg cycle is highly dependant on air/water exchange, as it is one of the primary pathways to deliver Hg to the atmosphere. Although open water systems appear to be net sinks for Hg sequestration (e.g. Chesapeake Bay), nearshore wetland systems may be significant sources of Hg emission due to 1) biogenic release from plant leaves and 2) the increased quantity and quality of dissolved organic carbon. Because estuarine environments are naturally and anthropogenically enriched in Hg, we hypothesize that the evasion of Hg from contaminated wetlands, particularly estuaries, may be a critically important and currently underestimated flux of Hg to the atmosphere.
Record Details:
Record Type:PROJECT(
ABSTRACT
)
Start Date:01/15/2005
Completion Date:01/14/2008
Record ID:
118738
Keywords:
ESTUARY, METALS, INTEGRATED ASSESSMENT, ENVIRONMENTAL CHEMISTRY, ATMOSPHERE, ECOLOGY, GEOLOGY, BIOAVAILABILITY, AIR QUALITY, ATMOSPHERIC SCIENCES,
Related Organizations:
Role
:OWNER
Organization Name
:LEHIGH UNIVERSITY
Mailing Address
:27 Memorial Dr
Citation
:Bethlehem
State
:PA
Zip Code
:18015
Project Information:
Approach
:A Hg contaminated estuary in the Meadowlands complex (NJ) will be the site of extensive field measurements. The high productivity, freshwater/marine transitional environment of the estuarine study area enables us to fully examine a matrix of environmental variables including UV transparency, DOC quantity and quality, salinity, pH, and plant communities. Laboratory experiments (e.g laboratory solar simulator) conducted using samples obtained from the field sites will test specific hypothetical relationships. We plan to investigate the use of stable Hg isotopes to label and trace different pathways and also the natural mass-dependant fractionation of Hg isotopes along evasion pathways to ascertain its utility for future studies.
Cost
:$298,907.00
Research Component
:Hazardous Waste/Remediation
Approach
:A Hg contaminated estuary in the Meadowlands complex (NJ) will be the site of extensive field measurements. The high productivity, freshwater/marine transitional environment of the estuarine study area enables us to fully examine a matrix of environmental variables including UV transparency, DOC quantity and quality, salinity, pH, and plant communities. Laboratory experiments (e.g laboratory solar simulator) conducted using samples obtained from the field sites will test specific hypothetical relationships. We plan to investigate the use of stable Hg isotopes to label and trace different pathways and also the natural mass-dependant fractionation of Hg isotopes along evasion pathways to ascertain its utility for future studies.
Cost
:$298,907.00
Research Component
:Health Effects
Project IDs:
ID Code
:GR832214
Project type
:EPA Grant