HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (23) Citing Articles via Google Scholar Google Scholar Articles by Puckett, L. J. Articles by Cowdery, T. K. Search for Related Content PubMed PubMed Citation Articles by Puckett, L. J. Articles by Cowdery, T. K. GeoRef GeoRef Citation Agricola Articles by Puckett, L. J. Articles by Cowdery, T. K. Related Collections Ground Water Quality Water Pollution Nitrogen

TECHNICAL REPORTS
Ground Water Quality

Transport and Fate of Nitrate in a Glacial Outwash Aquifer in Relation to Ground Water Age, Land Use Practices, and Redox Processes

^a U.S. Geological Survey, 413 National Center, Reston, VA 20192
^b U.S. Geological Survey, 2280 Woodale Road, Mounds View, MN 55112

* Corresponding author (lpuckett{at}usgs.gov)

Received for publication February 8, 2001. A combination of ground water modeling, chemical and dissolved gas analyses, and chlorofluorocarbon age dating of water was used to determine the relation between changes in agricultural practices, and NO^-₃ concentrations in ground water of a glacial outwash aquifer in west-central Minnesota. The results revealed a redox zonation throughout the saturated zone with oxygen reduction occurring near the water table, NO^-₃ reduction immediately below it, and then a large zone of ferric iron reduction, with a small area of sulfate (SO^2-₄) reduction and methanogenesis (CH₄) near the end of the transect. Analytical and NETPATH modeling results supported the hypothesis that organic carbon served as the electron donor for the redox reactions. Denitrification rates were quite small, 0.005 to 0.047 mmol NO^-₃ yr^-1, and were limited by the small amounts of organic carbon, 0.01 to 1.45%. In spite of the organic carbon limitation, denitrification was virtually complete because residence time is sufficient to allow even slow processes to reach completion. Ground water sample ages showed that maximum residence times were on the order of 50 to 70 yr. Reconstructed NO^-₃ concentrations, estimated from measured NO^-₃ and dissolved N gas showed that NO^-₃ concentrations have been increasing in the aquifer since the 1940s, and have been above the 714 µmol L^-1 maximum contaminant level at most sites since the mid- to late-1960s. This increase in NO^-₃ has been accompanied by a corresponding increase in agricultural use of fertilizer, identified as the major source of NO^-₃ to the aquifer.

Abbreviations: PVC, polyvinyl chloride • DOC, dissolved organic carbon • DO, dissolved oxygen • CFC, chlorofluorocarbon

This article has been cited by other articles:

				D. A. Saad Agriculture-Related Trends in Groundwater Quality of the Glacial Deposits Aquifer, Central Wisconsin J. Environ. Qual., September 2, 2008; 37(5_Supplement): S-209 - S-225. [Abstract] [Full Text] [PDF]

				L. M. Debrewer, S. W. Ator, and J. M. Denver Temporal Trends in Nitrate and Selected Pesticides in Mid-Atlantic Ground Water J. Environ. Qual., September 2, 2008; 37(5_Supplement): S-296 - S-308. [Abstract] [Full Text] [PDF]

				B. A. Browne, G. J. Kraft, J. M. Bowling, W. M. DeVita, and D. J. Mechenich Collateral Geochemical Impacts of Agricultural Nitrogen Enrichment from 1963 to 1985: A Southern Wisconsin Ground Water Depth Profile J. Environ. Qual., June 23, 2008; 37(4): 1456 - 1467. [Abstract] [Full Text] [PDF]

				C. T. Green, L. J. Puckett, J. K. Bohlke, B. A. Bekins, S. P. Phillips, L. J. Kauffman, J. M. Denver, and H. M. Johnson Limited Occurrence of Denitrification in Four Shallow Aquifers in Agricultural Areas of the United States J. Environ. Qual., May 1, 2008; 37(3): 994 - 1009. [Abstract] [Full Text] [PDF]

				L. J. Puckett and W. B. Hughes Transport and Fate of Nitrate and Pesticides: Hydrogeology and Riparian Zone Processes J. Environ. Qual., November 7, 2005; 34(6): 2278 - 2292. [Abstract] [Full Text] [PDF]

				C. Conan, F. Bouraoui, N. Turpin, G. de Marsily, and G. Bidoglio Modeling Flow and Nitrate Fate at Catchment Scale in Brittany (France) J. Environ. Qual., November 1, 2003; 32(6): 2026 - 2032. [Abstract] [Full Text] [PDF]

				S. J. Kalkhoff, K. E. Lee, S. D. Porter, P. J. Terrio, and E. M. Thurman Herbicides and Herbicide Degradation Products in Upper Midwest Agricultural Streams during August Base-Flow Conditions J. Environ. Qual., May 1, 2003; 32(3): 1025 - 1035. [Abstract] [Full Text] [PDF]