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The Role of Hg(II) Reduction and Chemical Speciation in Controlling the Concentration of Mercury and its Methylation in Natural Waters

EPA Grant Number: R824778
Title: The Role of Hg(II) Reduction and Chemical Speciation in Controlling the Concentration of Mercury and its Methylation in Natural Waters
Investigators: Morel, Francois M.
Institution: Princeton University
EPA Project Officer: Levinson, Barbara
Project Period: November 1, 1995 through October 31, 1998 (Extended to October 31, 1999)
Project Amount: $349,950
RFA: Water and Watersheds (1995)
Research Category: Water and Watersheds

Description:

According to our understanding of the mercury cycle in natural waters, two distinct processes determine the rate of formation of methylmercury and its eventual accumulation in fish: 1) mercury reduction and volatilization control the overall concentration of mercury in many natural water bodies; 2) mercury uptake and methylation by bacteria control the transformation of inorganic mercury into its biologically accumulated organic form. The ultimate aim of this project is to elucidate the parameters that control the concentration and bioaccumulation of methylmercury.

Building on the preliminary research described in the proposal to EPA/NSF, rapid progress has been made on both the chemical and microbiological aspects of the project. In particular, the rates of oxidation and reduction of dissolved mercury and the rate of dissolution of mercuric sulfide under various conditions have begun to be quantified. Contrary to what is generally reported in the experimental literature, the oxidation of Hg(0) in oxic waters is relatively rapid (hours to days). This process, should effectively decrease the net rate of Hg(0) volatilization and maintain higher mercury concentrations in many aquatic systems.

In addition, preliminary data have been obtained in support of the hypothesis that the presence of polysulfides increases the solubility of mercury sulfide and enhances many fold the rate of microbial methylation of mercury under anoxic conditions. If these preliminary results are confirmed, they will constitute a breakthrough in our understanding of the mechanisms of Hg methylation in anaerobic sediments and of the factors that control it.

Publications and Presentations:

Publications have been submitted on this project: View all 7 publications for this project

Journal Articles:

Journal Articles have been submitted on this project: View all 7 journal articles for this project

Supplemental Keywords:

atmosphere, water, sediments, exposure, bioavailability, heavy metals, aquatic, environmental chemistry, analytical. , Ecosystem Protection/Environmental Exposure & Risk, Water, Scientific Discipline, Waste, RFA, Water & Watershed, Ecology, Bioavailability, Mercury, Chemistry, Fate & Transport, Hydrology, Watersheds, Environmental Chemistry, Contaminated Sediments, heavy metals, natural waters, aquatic, fate and transport, methylmercury, mercury uptake, bioaccumulation, microbiological aspects, methylation, bacteria control, lake sediment, contaminated sediment, fish consumption, mercury loading, mercuric sulfide, chemical speciation, mercury concentrations, Hg2 reduction

Progress and Final Reports:
1998 Progress Report
Final Report

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The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.

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