Redox Processes and Water Quality of Selected Principal Aquifer Systems
Tóm tắt
Reduction/oxidation (redox) conditions in 15 principal aquifer (PA) systems of the United States, and their impact on several water quality issues, were assessed from a large data base collected by the National Water‐Quality Assessment Program of the USGS. The logic of these assessments was based on the observed ecological succession of electron acceptors such as dissolved oxygen, nitrate, and sulfate and threshold concentrations of these substrates needed to support active microbial metabolism. Similarly, the utilization of solid‐phase electron acceptors such as Mn(IV) and Fe(III) is indicated by the production of dissolved manganese and iron. An internally consistent set of threshold concentration criteria was developed and applied to a large data set of 1692 water samples from the PAs to assess ambient redox conditions. The indicated redox conditions then were related to the occurrence of selected natural (arsenic) and anthropogenic (nitrate and volatile organic compounds) contaminants in ground water. For the natural and anthropogenic contaminants assessed in this study, considering redox conditions as defined by this framework of redox indicator species and threshold concentrations explained many water quality trends observed at a regional scale. An important finding of this study was that samples indicating mixed redox processes provide information on redox heterogeneity that is useful for assessing common water quality issues. Given the interpretive power of the redox framework and given that it is relatively inexpensive and easy to measure the chemical parameters included in the framework, those parameters should be included in routine water quality monitoring programs whenever possible.
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Tài liệu tham khảo
Abacus Concepts, 1996, StatView Reference
Back W. andI.Barnes.1965.Relation of electrochemical potentials and iron content to groundwater flow patterns. U.S. Geological Survey Professional Paper no. 498‐C. Reston Virginia:USGS.
Bradley P.M, 2003, History and ecology of chloroethene biodegradation: A review, Bioremediation Journal, 7, 81, 10.1080/713607980
Dzombak D.A., 1990, Surface Complexation Modeling—Hydrous Ferric Oxide
Kölle W., 1985, Formation of sulfate by microbial denitrification in a reducing aquifer, Water Supply, 3, 35
Lapham W.W. P.A.Hamilton andD.N.Myers.2005.National water‐quality assessment program—Cycle II regional assessments of aquifers. U.S. Geological Survey Fact Sheet 2005‐3013. Reston Virginia:USGS.
Lovley D.R., 1988, Hydrogen concentrations as an indicator of the predominant terminal electron‐accepting reactions in aquatic sediments, Geochimica et Cosmochimica Acta, 52, 2993, 10.1016/0016-7037(88)90163-9
Lovley D.R., 1983, Sulfate reducers can outcompete methanogens at freshwater sulfate concentrations, Applied and Environmental Microbiology, 45, 187, 10.1128/aem.45.1.187-192.1983
Paschke S.S., 2007, Hydrogeologic Settings and Ground‐Water Flow Simulations for Regional Studies of the Transport of Anthropogenic and Natural Contaminants to Public‐Supply Wells—Studies Begun in 2001, 17
Ruddy B.C. D.L.Lorenz andD.K.Mueller.2006.County‐level estimates of nutrient inputs to the land surface of the conterminous United States 1982–2001. U.S. Geological Survey Scientific Investigations Report 2006‐5012 17. Reston Virginia:USGS.
Straub K.L., 1996, Anaerobic, nitrate‐dependent microbial oxidation of ferrous iron, Applied and Environmental Microbiology, 62, 1458, 10.1128/aem.62.4.1458-1460.1996
Tiedje J.M, 1988, Biology of Anaerobic Microorganisms, 179
USGS.2006a.National Water‐Quality Assessment (NAWQA) Program.http://water.usgs.gov/nawqa/index.html(accessed September 29 2007).
USGS.2006b.National Water‐Quality Assessment (NAWQA) Program method sampling and analytical protocols.http://water.usgs.gov/nawqa/protocols/methodprotocols.html(accessed September 29 2007).
USGS.2003.Principal aquifers of the 48 conterminous United States Hawaii Puerto Rico and the U.S. Virgin Islands.http://www.nationalatlas.gov/mld/aquifrp.html(accessed September 29 2007).
Warner K.L. andT.L.Arnold.2005.Framework for regional synthesis of water‐quality data for the glacial aquifer system in the United States. U.S. Geological Survey Scientific Investigations Report 2005‐5223 6. Reston Virginia:USGS.