Grantee Research Project Results
Final Report: Assessment of Natural Source (Geologic and Vegetation) Mercury Emissions: Speciation, Mechanisms and Significance
EPA Grant Number: R829800Title: Assessment of Natural Source (Geologic and Vegetation) Mercury Emissions: Speciation, Mechanisms and Significance
Investigators: Gustin, Mae Sexauer , Zehner, Richard E. , Rytuba, James J. , Johnson, Dale W. , Hatchett, Ben , Sedinger, Ben , Hanson, Brian , Peterson, Christianna , Weaver, Coty , Zhang, Hong , Stamenkovic, Jelena , Ericksen, Jody , Fay, Laura , Martindale, Lindsey , Engle, Mark , Xin, Mei , Markee, Melissa , Weisburg, Peter , Pillai, Rekha , Lyman, Seth , Lindberg, Steve , Kuiken, Todd , Ellis, Tyler
Institution: University of Nevada - Reno , Tennessee Technological University , United States Geological Survey , University of Tennessee , Desert Research Institute
Current Institution: University of Nevada - Reno , Desert Research Institute , Tennessee Technological University , United States Geological Survey , University of Tennessee
EPA Project Officer: Chung, Serena
Project Period: January 1, 2003 through December 31, 2005 (Extended to December 31, 2007)
Project Amount: $891,545
RFA: Mercury: Transport, Transportation, and Fate in the Atmosphere (2001) RFA Text | Recipients Lists
Research Category: Heavy Metal Contamination of Soil/Water , Air Quality and Air Toxics , Safer Chemicals , Air
Objective:
The major objective of this project was to develop data sets and process level information on natural mercury (Hg) fluxes between soil, vegetation and air that would allow us to assess the significance of natural versus anthropogenic sources of atmospheric for the United States. We worked towards this major objective by way of 5 sub-objectives:
- Quantify Hg emissions from representative sources that have significant terrestrial coverage including geologically naturally Hg enriched areas, background areas, and biotic sources (plants and forest fires).
- Develop process level information on gaps in our understanding of micrometeorological parameters and substrate characteristics controlling Hg emission and deposition to and from soils.
- Quantify the potential for deposition and re-emission of elemental and reactive Hg associated with soil surfaces.
- Investigate the speciation of atmospheric Hg associated with naturally enriched sites.
- Use a GIS framework to estimate natural source Hg emissions for the United States.
Summary/Accomplishments (Outputs/Outcomes):
This project has resulted in ~30 plus papers published in the peer review literature that provide data, discussion, and important information building the framework for better understanding natural sources and sinks of mercury (Hg). Information developed has been used by our research team and others to develop regional and global estimates of Hg sources and sinks allowing us to understand the impact of anthropogenic Hg emissions on the environmental fate and distribution of Hg, as well as the potential efficacy of regulatory controls. The peer reviewed publications have been cited in many other works in the peer reviewed literature as well as in reports. The information developed in this project was also disseminated through ~35 formal presentations at local, regional, national and international meetings.
Through this project information was developed on emissions of Hg from natural geologic sources. Data was collected from representative areas of geologic Hg enrichment and these data, along with that previously developed, was applied to develop area emission estimates. These estimates were built using empirically derived fluxes as well as information on the factors controlling emissions and our understanding of atmospheric Hg deposition and re-emission. It is estimated that 10 to 20 Mg/y are emitted from areas identified as being naturally mercury enriched in the western U.S. This is an underestimate for naturally enriched area emissions given that there are other types of mineralization that have Hg enrichment that were not considered and naturally enriched areas outside of the western U.S. were not considered. This information has been used to understand the relative contribution of natural versus anthropogenic sources to the atmospheric Hg pool as well as to revise global and regional Hg models.
Through development of empirical data at representative areas of geothermal activity, and using a heat flux map for the U.S., we developed a current estimate of ~ 3 Mg/y emitted from geothermal areas. We also reported that there is little emission from volcanic sources due to the fact that there are no active volcanoes in the U.S. These estimates could change significantly as crustal heat flux and volcanic activity change.
Most terrestrial land surface area is not geologically enriched in Hg, therefore it is important to understand the role of natural systems with background Hg concentrations as sources, sinks or temporary resting sites for atmospheric Hg. In this project extensive data sets representing broad spatial and temporal scales were developed for low Hg soils, litter covered surfaces and vegetation. It appears that soils are a temporary resting place for Hg deposited directly from the air by wet and dry process, with elemental Hg being deposited and re-emitted on short time steps and reactive Hg deposited in precipitation being sequestered and re-emitted gradually over time.
Plant foliage is a significant sink for gaseous elemental Hg and globally could account for uptake of 2500 Mg or more per year from the atmosphere. Mercury transferred from the air-to-soil by way of plants may be accumulated in soils over time. Plants also exert a significant impact on terrestrial ecosystem flux by the way of plant shading and litter cover of soil, both of which reduce emissions. Since plant foliage is a large sink for atmospheric Hg it is clear that forest fires would act as a means of re-introduction of sequestered Hg back into the atmosphere. Data developed provided an estimate of 2 to 6 g of Hg lost per hectare of forest burned and 0.4 g/ha if the ecosystem was a desert shrub system. These estimates are similar to those developed by others and have been used to scale up fire Hg emissions for the U.S. and other areas.
In order to develop models that allow us to predict Hg cycling in ecosystems we must have process level information. The second objective of this project focused on filling data gaps in our understanding of factors controlling air-soil Hg exchange and clearly demonstrated that soil moisture, atmospheric oxidants, air Hg concentrations and specific wavelengths of light are important in influencing Hg emissions. Since these parameters, along with temperature, incident light and precipitation, all vary with space and time understanding the relative forcing potential on Hg flux is important. Detailed laboratory and field data developed in this project provide algorithms and discussion of the relative importance of factors in influencing flux from soils, litter and foliar surfaces.
Air Hg speciation was measured at rural, urban and sites naturally enriched in Hg. In areas enriched in Hg, ambient background concentrations of gaseous Hg were elevated relative to unenriched areas, and exhibited diel patterns reflecting local enriched sources. Reactive gaseous Hg concentrations were typically <10% of total Hg concentrations and in most cases <2% and exhibited a diel pattern indicative of local production.
We are in the final process of using the empirical data developed in this project to scale Hg flux from three different types of areas with background Hg concentrations (Stamenkovic et al., in preparation). Empirically derived Hg fluxes and environmental parameter data are being used to develop a multiple regression and a rule-based model (classification and regression tree approach) of air Hg exchange for three biomes with background Hg concentrations: tall grass prairie from central Oklahoma (data collected in the field and inside large environmentally-controlled growth chambers), forested areas on the East Coast, and a semiarid area in Nevada. Other scaling activities have developed emission estimates for geothermal, geologically Hg enriched and volcanic areas in the U.S. These areas emit at the least 20 Mg/y. Natural background soils are temporary resting places for atmospheric Hg with background emissions roughly being equal or slightly less than inputs estimated for direct wet and dry deposition. Foliar uptake however results in vegetated ecosystems being a net sink for atmospheric Hg.
Journal Articles on this Report : 29 Displayed | Download in RIS Format
| Other project views: | All 78 publications | 31 publications in selected types | All 29 journal articles |
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Engle MA, Gustin MS, Lindberg SE, Gerler AW. Investigation of the effect of tropospheric oxidants on Hg emissions from substrates. Materials and Geoenvironment 2004;51(3):1546-1549. |
R829800 (2004) R829800 (Final) |
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Engle MA, Gustin MS, Lindberg SE, Gertler AW, Ariya PA. The influence of ozone on atmospheric emissions of gaseous elemental mercury and reactive gaseous mercury from substrates. Atmospheric Environment 2005;39(39):7506-7517. |
R829800 (2004) R829800 (2005) R829800 (Final) |
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Engle MA, Gustin MS, Johnson DW, Murphy JF, Miller WW, Walker RF, Wright J, Markee M. Mercury distribution in two Sierran forest and one desert sagebrush steppe ecosystems and the effects of fire. Science of the Total Environment 2006;367(1):222-233. |
R829800 (2005) R829800 (2006) R829800 (Final) |
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Engle MA, Gustin MS, Goff F, Counce DA, Janik CJ, Bergfeld D, Rytuba JJ. Atmospheric mercury emissions from substrates and fumaroles associated with three hydrothermal systems in the western United States. Journal of Geophysical Research 2006;111, D17304, doi:10.1029/2005JD006563. |
R829800 (2004) R829800 (2006) R829800 (Final) |
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Ericksen JA, Gustin MS, Lindberg SE, Olund SD, Krabbenhoft DP. Assessing the potential for re-emission of mercury deposited in precipitation from arid soils using a stable isotope. Environmental Science & Technology 2005;39(20):8001-8007. |
R829800 (2004) R829800 (2005) R829800 (Final) |
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Ericksen JA, Gustin MS, Xin M, Weisberg PJ, Fernandez GCJ. Air-soil exchange of mercury from background soils in the United States. Science of the Total Environment 2006;366(2-3):851-863. |
R829800 (2004) R829800 (2005) R829800 (2006) R829800 (Final) |
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Fay L, Gustin M. Assessing the influence of different atmospheric and soil mercury concentrations on foliar mercury concentrations in a controlled environment. Water, Air, & Soil Pollution 2007;181(1-4):373-384. |
R829800 (2006) R829800 (Final) |
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Fay L, Gustin MS. Investigation of mercury accumulation in cattails growing in constructed wetland mesocosms. Wetlands 2007;27(4):1056-1065. |
R829800 (2006) R829800 (Final) |
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Gustin MS, Stamenkovic J. Effect of watering and soil moisture on mercury emissions from soils. Biogeochemistry 2005;76(2):215-232. |
R829800 (2004) R829800 (2005) R829800 (Final) |
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Gustin MS, Engle M, Ericksen J, Lyman S, Stamenkovic J, Xin M. Mercury exchange between the atmosphere and low mercury containing substrates. Applied Geochemistry 2006;21(11):1913-1923. |
R829800 (2005) R829800 (2006) R829800 (Final) |
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Gustin MS, Lindberg SE, Weisberg PJ. An update on the natural sources and sinks of atmospheric mercury. Applied Geochemistry 2008;23(3):482-493. |
R829800 (Final) |
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Gustin MS, Kolker A, Gardfeldt K. Preface: transport and fate of mercury in the environment. Applied Geochemistry 2008;23(3):343-344. |
R829800 (Final) |
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Gustin M, Zehner R, Stamenkovic J. Experimental examination of the influence of precipitation and moisture content on mercury emissions from soils. Materials and Geoenvironment 2004;51(3):1592-1595. |
R829800 (2004) R829800 (Final) |
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Kuiken T, Gustin M, Zhang H, Lindberg S, Sedinger B. Mercury emission from terrestrial background surfaces in the eastern USA. II. Air/surface exchange of mercury within forests from South Carolina to New England. Applied Geochemistry 2008;23(3):356-368. |
R829800 (2006) R829800 (Final) |
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Kuiken T, Zhang H, Gustin M, Lindberg S. Mercury emission from terrestrial background surfaces in the eastern USA. Part I: Air/surface exchange of mercury within a southeastern deciduous forest (Tennessee) over one year. Applied Geochemistry 2008;23(3):345-355. |
R829800 (Final) |
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Lohman K, Seigneur C, Gustin M, Lindberg S. Sensitivity of the global atmospheric cycle of mercury to emissions. Applied Geochemistry 2008;23(3):454-466. |
R829800 (Final) |
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Lyman SN, Gustin MS, Prestbo EM, Marsik FJ. Estimation of dry deposition of atmospheric mercury in Nevada by direct and indirect methods. Environmental Science & Technology 2007;41(6):1970-1976. |
R829800 (2006) R829800 (Final) |
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Lyman SN, Gustin MS. Speciation of atmospheric mercury at two sites in northern Nevada, USA. Atmospheric Environment 2008;42(5):927-939. |
R829800 (Final) |
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Millhollen AG, Gustin MS, Obrist D. Foliar mercury accumulation and exchange for three tree species. Environmental Science & Technology 2006;40(19):6001-6006. |
R829800 (2005) R829800 (2006) R829800 (Final) |
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Millhollen AG, Obrist D, Gustin MS. Mercury accumulation in grass and forb species as a function of atmospheric carbon dioxide concentrations and mercury exposures in air and soil. Chemosphere 2006;65(5):889-897. |
R829800 (2005) R829800 (2006) R829800 (Final) |
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Nacht DM, Gustin MS, Engle MA, Zehner RE, Giglini AD. Atmospheric mercury emissions and speciation at the Sulphur Bank Mercury Mine Superfund Site, Northern California. Environmental Science & Technology 2004;38(7):1977-1983. |
R829800 (2004) R829800 (Final) R827634 (Final) |
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Nacht DM, Gustin MS. Mercury emissions from background and altered geologic units throughout Nevada. Water, Air, & Soil Pollution 2004;151(1-4):179-193. |
R829800 (2004) R829800 (Final) R827634 (Final) |
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Obrist D, Gustin MS, Arnone III JA, Johnson DW, Schorran DE, Verburg PSJ. Measurements of gaseous elemental mercury fluxes over intact tallgrass prairie monoliths during one full year. Atmospheric Environment 2005;39(5):957-965. |
R829800 (2004) R829800 (2005) R829800 (Final) |
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Peterson C, Gustin M. Mercury in the air, water and biota at the Great Salt Lake (Utah, USA). Science of the Total Environment 2008;405(1-3):255-268. |
R829800 (Final) |
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Stamenkovic J, Lyman S, Gustin MS. Seasonal and diel variation of atmospheric mercury concentrations in the Reno (Nevada, USA) airshed. Atmospheric Environment 2007;41(31):6662-6672. |
R829800 (Final) |
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Stamenkovic J, Gustin MS, Arnone III. JA, Johnson DW, Larsen JD, Verburg PSJ. Atmospheric mercury exchange with a tallgrass prairie ecosystem housed in mesocosms. Science of the Total Environment 2008;406(1-2):227-238. |
R829800 (Final) |
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Weiss-Penzias P, Gustin MS, Lyman SN. Observations of speciated atmospheric mercury at three sites in Nevada: evidence for a free tropospheric source of reactive gaseous mercury. Journal of Geophysical Research 2009;114, D14302, doi:10.1029/2008JD011607. |
R829800 (Final) |
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Xin M, Gustin M, Johnson D. Laboratory investigation of the potential for re-emission of atmospherically derived Hg from soils. Environmental Science & Technology 2007;41(14):4946-4951. |
R829800 (Final) |
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Xin M, Gustin MS. Gaseous elemental mercury exchange with low mercury containing soils: investigation of controlling factors. Applied Geochemistry 2007;22(7):1451-1466. |
R829800 (Final) |
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Supplemental Keywords:
mercury, natural Hg sources, geothermal Hg sources, natural Hg biogeochemical cycling, vegetation-air-soil Hg exchange,, Scientific Discipline, Air, INTERNATIONAL COOPERATION, Waste, TREATMENT/CONTROL, Ecosystem Protection/Environmental Exposure & Risk, POLLUTANTS/TOXICS, Air Quality, air toxics, Treatment Technologies, Environmental Chemistry, Chemicals, Fate & Transport, Environmental Monitoring, Bioremediation, Chemistry and Materials Science, fate and transport, contaminated sediments, air pollutants, Hg, mercury, mercury emissions, modeling, mercury cycling, hazardous waste, chemical kinetics, contaminants in soil, bioremediation of soils, atmospheric mercury chemistry, mercury chemistry, phytoremediation, atmospheric chemistry, atmospheric mercury cycling, atmospheric deposition, contaminant transport models, heavy metals, mercury vapor, atmospheric mercuryProgress and Final Reports:
Original AbstractThe 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.
Project Research Results
- 2006 Progress Report
- 2005 Progress Report
- 2004 Progress Report
- 2003 Progress Report
- Original Abstract
29 journal articles for this project