Richard Lowrance Donald C. Obenhuber 1991 <p><span>Aquifer microcosms were used to examine the effects of NO</span>⁻₃<span> and C amendments on groundwater from the Claiborne aquifer. Nitrate concentrations of 12.17 mg L</span>⁻¹<span> in aquifer microcosms were reduced 0.92%/d to 5.84 mg L</span>⁻¹<span> by the addition of 10 mg C L</span>⁻¹<span> for 35 d. Nitrate disappearance correlated with increases in number of denitrifiers and dissolved N</span>₂<span>O concentration and decreases in dissolved oxygen, suggesting biological denitrification. Nitrate/chloride ratios decreased in microcosms with 10 mg C L</span>⁻¹<span> added and then increased when the C addition was removed. Carbon additions of 0.4 mg C L</span>⁻¹<span> had no effect on the microbial or chemical properties of the microcosms. Nitrous oxide levels in wells sampling the Claiborne aquifer showed an increase with depth, indicating N</span>₂<span>O production within the aquifer. Microcosms are useful tools to examine biological transformations of chemical contaminants in unconsolidated aquifer material. The remediation of NO</span>⁻₃<span> contaminated aquifers by organic infusion is possible and appears to be a function of microbial denitrification.</span></p> application/pdf 10.2134/jeq1991.00472425002000010041x en Alliance of Crop, Soil, and Environmental Science Societies Reduction of nitrate in aquifer microcosms by carbon additions article