Sources and Concentrations of Nitrate‐Nitrogen in Ground Water of the Central Platte Region, Nebraska^a

Abstract

During 1976‐1977 nitrate‐nitrogen (NO3‐N) concentrations exceeded 10 mg/1 in 183 of the 256 ground‐water samples collected from parts of Buffalo, Hall, and Merrick counties in Nebraska. Comparison of the isotopic values with those of potential nitrate sources suggested that the primary source of contamination in most wells was fertilizer and that a small percentage of the wells contained significant concentrations of NO3‐N derived from animal wastes. A combination of two or more sources of contamination was assumed for those samples for which the source could not be identified. Significant negative correlations between δ15N and NO3‐N (‐0.35 in Buffalo and Hall Counties) and between δ5N and depth to water (–0.55 in Merrick County) indicate that denitrification is the major factor in isotopic fractionation of nitrogen from the nitrate sour

Occurrence of sulfonamide antimicrobials in private water wells in Washington County, Idaho, USA

“…A δ 15 N between +5‰ and +10‰ can also indicate a mixed source, such as the combination of animal wastes and fertilizer (Tesch and Carlson, 2003b). In addition, bacterial denitrification in groundwater results in significant enrichment of nitrate from both fertilizer and animal waste (Gormly and Spalding, 1979;Kendall and McDonnell, 1998). Wells 2, 3, 4, and 6 are all down gradient from the CAFO, with three of those four locations having nitrate levels greater than 18 mg/l and, assuming the effect of denitrification is minimal, all exhibited δ 15 N characteristic of animal or human waste sources.…”

“…Samples for nitrogen isotope analysis were prepared and analyzed using the steam distillation method (Bremner and Keeney, 1965) with modification of Gormly and Spalding (1979). Nitrate and ammonium concentrations were determined during sample preparation by titration with standardized acid.…”

Assessing the Effect of a Dumpsite to Groundwater Quality in Payatas, Philippines

“…The discharge of domestic sewage may have contributed to the production and occurrence of NO 3 -N in the well waters of the study areas [11] indicated that NO 3 -N concentrations in the groundwater might result from point sources such as sewage disposal. The range of results obtained for NO 3 -N in both study areas did not vary, although certain stations showed high levels of NO 3 -N in the well waters of the with dumpsite area.…”

Kansas Case Study Applications of Nitrogen-15 Natural Abundance Method for Identification of Nitrate Sources

“…Work by Kreitler ( , 1979, Kreitler and Jones (1975), Shearer et al (1978), Kohl et al (1971), Heaton (1986), Mariotti et al (1988), Korom (1992), and Kendall (1998), and others, has contributed to development and use of the method. Examples of a few studies that illustrate the usefulness of the method include Gormly and Spalding (1979) in Nebraska, Mariotti et al (1988) in France, Mitchell et al (2003) in Canada, and Townsend et al (1994) in Kansas.…”