Spatial and temporal variations in aluminum chemistry of a dilute,acidic lake |
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Authors: | Gary C Schafran Charles T Driscoll |
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Institution: | (1) Department of Civil Engineering, Syracuse University, Syracuse, NY 13244, USA |
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Abstract: | Elevated concentrations of Al have been observed in acidic surface waters. An assessment of the chemistry of aqueous Al is of interest because of its role as a toxicant to aquatic organisms, a pH buffer, and an adsorbent of orthophosphate and organic carbon. In this investigation we evaluated the spatial and temporal fluctuations of Al forms in an acidic drainage lake.High concentrations of NO
3
–
(51.0 ± 11 mol l–1), H+ (14.9 ± 3.5 mol l–1), and Al (19.6 ± 3.5 mol l–1) were introduced to Dart's Lake through drainage water during the snowmelt period. During low flow periods microbially mediated depletions of nitrate served to neutralize H+ and aluminum base neutralizing capacity. Thus in Dart's Lake, NO
3
–
transformations were extremely important in regulating short-term changes in pH and subsequent changes in the inorganic forms of Al. During stratification periods Al appeared to be non-conservative within the lake system. Although we know very little about the character and transformations of alumino-organic solutes, these substances were correlated with dissolved organic carbon (DOC) concentrations. Alumino-organic substances appear to be introduced to the lake from both drainage water and sediments. |
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Keywords: | aluminum acidic deposition lake fluoride dissolved organic carbon |
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