| Abstract: | We examined the temporal and vertical distribution of total ammonia nitrogen (TAN) and un-ionized ammonia nitrogen (NH3-N) in sediment pore water and compared the temporal patterns of TAN and NH3-N concentrations in overlying surface water with those in pore water. Pore water was obtained by core extraction and subsequent centrifugation. We measured TAN concentrations and calculated NH3-N concentrations from February through October 1993 at four sites in Pool 8, upper Mississippi River, at depths of 0 to 4, 4 to 8, and 8 to 12 cm below the sediment-water interface. Total ammonia nitrogen and NH3-N concentrations were significantly different among sampling dates (p = 0.0001) and sediment depths (p = 0.0001). Concentrations of TAN and NH3-N in surface water were significantly less than those in pore water from all sediment depths (p < 0.05). Concentrations in pore water ranged from 0.07 to 4.0 mg TAN/L and less than 1 to 20 I?g NH3-N/L in winter, and from 0.07 to 10.0 mg TAN/L and 1 to 175 I?g NH3-N/L in summer; greatest concentrations were usually found in sediments 8 to 12 cm deep. Annual mean TAN concentrations were positively correlated with silt and volatile solids content and were negatively correlated with sand content. Because of the high variability of TAN and NH3-N concentrations in pore water, sediment toxicity studies should take into account the season and the depth at which sediments are obtained. The annual mean NH3-N concentration in pore water at one site (55 I?g/L) exceeded the concentration (30 I?g/L) demonstrated to inhibit growth of fingernail clams in laboratory studies. However, these concentrations apparently were not lethal, as evidenced by the presence of fingernail clams at this site. |
| Genre: | Article |
| ProdID: | 1002893 |
| Citation Author: | Frazier, Bradley E.; Naimo, Teresa J.; Sandheinrich, Mark B. |
| Citation Contributing Office: | Upper Midwest Environmental Sciences Center |
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| Citation End Page: | 99 |
| Citation Issue: | 2 |
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| Citation Language: | English |
| Citation Larger Work Title: | Environmental Toxicology and Chemistry |
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| Citation Number Of Pages: | 8 |
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| Citation Phsyical Description: | pp. 92-99 |
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| Citation Search Results Text: | Temporal and vertical distribution of total ammonia nitrogen and un-ionized ammonia nitrogen in sediment pore water from the upper Mississippi River; 1996; Article; Journal; Environmental Toxicology and Chemistry; Frazier, Bradley E.; Naimo, Teresa J.; Sandheinrich, Mark B. |
| Citation Start Page: | 92 |
| Citation Volume: | 15 |
| Citation Year: | 1996 |
| Type: | citation/reference |
| Text: | Temporal and vertical distribution of total ammonia nitrogen and un-ionized ammonia nitrogen in sediment pore water from the upper Mississippi River; 1996; Article; Journal; Environmental Toxicology and Chemistry; Frazier, Bradley E.; Naimo, Teresa J.; Sandheinrich, Mark B. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Mon, 1 Jan 1996 00:00 -0600 |
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