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Mercury Methylation and Demethylation in a Contaminated Urban Watershed

The major goals and objectives of this project were to:   1) complete the development of and validate a new analytical method   for measuring MeHg, as well as inorganic Hg, in environmental   samples;  2) identify sites of high methylating activity in a contaminated   watershed in the Lake Michigan drainage basin (Grand Calumet River,   IN),   3) test whether Hg methylation and demethylation rates exhibit non-  linear dependencies on Hg contamination levels.    This project entailed two major tasks aimed at improving our   capabilities to measure MeHg in environmental systems. The first   task was to complete the development of a new analytical method for   measuring MeHg and inorganic Hg in environmental samples. The new   method, whose central ideas and potential applications were laid out   in our initial proposal, has been refined to the point where we are   now able to routinely use it to make difficult environmental   measurements of MeHg in sediments and biota.    The second task was to use the system to analyze MeHg in sediments   of a contaminated urban watershed, i.e., the Grand Calumet River   watershed in northwestern Indiana. Using the new method, we   investigated spatial and seasonal variations in MeHg levels in   wetland sediments. Marked differences were found, with late   summer/early fall sediment samples having the highest levels of   MeHg. As has been observed elsewhere, MeHg becomes an increasingly   smaller fraction of the Hg(-T) as Hg(-T) increases.    (methylmercury); (Hg); (MeHg); (mercury); (toxic metal); (toxic   metals); (human health); (Lake Michigan); (Indiana); (methylation);   (demethylation); (fish consumption); (fish consumption advisory);   (fish consumption advisories); (chemicals of concern); (chemical of   concern)

In progress
Start Date
End Date
Scope of Study
Field Investigation
Laboratory Investigation
Scale of Phenomena
Impact of Pollutants
Toxic Metals
Toxic Organics
Lake Basin Connecting Channels
Lake Michigan
State Province
Region Being Monitored
Coastal Wetlands
Nearshore Terrestrial
Resource Being Monitored
Bottom Sediment
Human Health
Suspended Sediments
Beneficial Use Impairment Assessments
Compliance with Environmental Quality Objectives
Degradation of Benthos
Restrictions of Fish and Wildlife Consumption
Tainting of Fish and Wildlife Populations
Annex Numbers
Persistent Toxic Substances
Remedial Action Plans and Lakewide Management Plans
  • Annex Numbers
    Annex Numbers
    Persistent Toxic Substances
    Remedial Action Plans and Lakewide Management Plans
  • Annex 17

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