| Abstract: | Little is known about nitric oxide (NO) production or consumption in the subsurface, an environment which may be conducive to NO accumulation. A study conducted in a nitrogen-contaminated aquifer on Cape Cod, Massachusetts assessed the occurrence and turnover of NO within a contaminant plume in which nitrification and denitrification were known to occur. NO (up to 8.6 nM) was detected in restricted vertical zones located within a nitrate (NO 3-) gradient and characterized by low dissolved oxygen (<10 ??M). NO concentrations correlated best with nitrite (NO 2-) (up to 35 ??M), but nitrous oxide (N2O) (up to 1 ??M) also was present. Single-well injection tests were used to determine NO production and consumption in situ within these zones. First-order rate constants for NO consumption were similar (0.05-0.08 h-1) at high and low (260 and 10 nM) NO concentrations, suggesting a turnover time at in situ concentrations of 10-20 h. Tracer tests with 15N[NO] demonstrated that oxidation to 15N[NO2-] occurred only during the initial stages, but after 4 h reduction to 15N[N2O] was the primary reaction product Added NO 2- (31 ??M) or NO3- (53 ??M) resulted in a linear NO accumulation at 2.4 and 1.0 nM h-1 for the first 6 h of in situ tests. These results suggest that NO was primarily produced by denitrification within this aquifer. ?? 2008 American Chemical Society. |
| Genre: | Article |
| ProdID: | 70032911 |
| Citation Author: | Smith, R. L.; Yoshinari, T. |
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| Citation End Page: | 8251 |
| Citation Issue: | 22 |
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| Citation Language: | English |
| Citation Larger Work Title: | Environmental Science and Technology |
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| Citation Number Of Pages: | 7 |
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| Citation Search Results Text: | Occurrence and turnover of nitric oxide in a nitrogen-impacted sand and gravel aquifer; 2008; Article; Journal; Environmental Science and Technology; Smith, R. L.; Yoshinari, T. |
| Citation Start Page: | 8245 |
| Citation Volume: | 42 |
| Citation Year: | 2008 |
| Type: | citation/reference |
| Text: | Occurrence and turnover of nitric oxide in a nitrogen-impacted sand and gravel aquifer; 2008; Article; Journal; Environmental Science and Technology; Smith, R. L.; Yoshinari, T. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| URL (DIGITAL OBJECT IDENTIFIER): | http://dx.doi.org/10.1021/es801290v |
| Date Other: | Tue, 1 Jan 2008 00:00 -0600 |
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