April 2019 Meeting

Monday, April 8, 2019
6:00 - 7:30 pm

Pellissippi State Technical Community College
10915 Hardin Valley Road, Knoxville
J.L Goins Administration Building
Faculty/Staff Dining Room


Metal, Liquid, Gas, God? - Mercury Forms and Transformations that Impact Fate, Transport, Uptake and Remediation


David Watson
Senior Research Scientist, Oak Ridge National Laboratory (Retired)


The impact of mercury on human and ecological health has been known for decades. Although inorganic mercury is the predominant form initially introduced into the environment, conversion of the mercury to the neurotoxin methylmercury and bioaccumulation poses the greatest risk. Localized spills of elemental mercury can result in highly contaminated soils that are sources of Hg to the atmosphere and aquatic systems. Chemical transformations, which can lead to changes in mercury speciation and mobility and increase the potential for groundwater and surface water releases, are poorly understood. Between 1950 and 1963, 11 million kg of elemental mercury was used at the Oak Ridge DOE Y-12 National Security Complex, and it has been estimated that 193,000 kg of Hg was lost to soils. Hg-contaminated soils are found at multiple historical spill locations within the approximately 800 ac. Y-12 industrial facility but the exact locations and the extent of contamination are not fully characterized. Elevated levels of Hg are present within and around historical Hg-use buildings, in storm drains, and within the main channel and floodplain of East Fork Poplar Creek (EFPC), which originates within the Y-12 facility. Many past studies have focused primarily on quantifying the concentration of total mercury present. However, through various research programs, Oak Ridge National Laboratory (ORNL) has more recently been 1) developing techniques for characterizing and delineating the extent of mercury spills 2) determining the forms of mercury present 3) assessing the impact of subsurface materials and water chemistry on mercury transformations and mobility and 4) determining the primary sources of mercury in the lower reaches of EFPC and mechanisms for methylation. An overview of ORNL's findings from some of these research programs will be provided in this presentation.


Senior Research Scientist, Oak Ridge National Laboratory (Retired). Mr. Watson is a hydrogeologist with over 30 years of experience working with DOE, DOD, EPA, State agencies and industry, characterizing, assessing the risk and remediating a wide variety of contaminants at hazardous waste sites. He has an M.S. in Hydrology from the New Mexico Institute of Mining and Technology (1983) and a B.A. in Geology with a minor in Environmental Studies from the University of Vermont (1978). He is co-author on ~100 peer review journal publications. Mr. Watson was the Field Site Manager for the DOE Oak Ridge Field Research Center conducting research on new and innovative characterization methods, contaminant fate and transport, modeling and remediation of groundwater, surface water and source zones. His research, focused on the complex relationships between contaminants, hydrology, geology, chemistry, microorganisms and heterogeneity at multiple scales, has led to the development of new and innovative tools for investigating and remediating contaminated sites. On the DOE Oak Ridge Reservation (ORR), Mr. Watson has led projects demonstrating the use of emulsified vegetable oil for the sustained bioremediation of uranium contamination in groundwater, the installation and testing of permeable reactive barriers for the removal of radionuclides, and developed new methods for the characterization of Hg contaminant source zones. In recent publications Mr. Watson has documented how Mn-oxides in soils creates coatings of soluble, mobile Hg-oxides on the surface of mercury beads and how mercury soil vapor mapping can be used to locate and map the extent of Hg source zones.


Page updated March 11, 2019