Aluminum control of phosphorus sorption by lake sediments.

Abstract

Release of reactive (phosphate-like) phosphorus (P) from freshwater sediments represents a significant internal P source for many lakes. Hypolimnetic P release occurs under reducing conditions that cause reductive dissolution of ferric hydroxide [Fe(OH)3]. This hypolimnetic P release may be naturally low or artificially reduced by sediment with naturally high or artificially elevated concentrations of aluminum hydroxide [Al(OH)3]. We presentfield and laboratory data for a common extraction analysis of sediments from 43 lakes differing in trophic status, pH regime, climate, and P loading. The results indicate that a simple sequential extraction of sediment may be a useful predictor of sediment's ability to release P. Sequential extractions of sediment P, Al, and Fe by water (H2O), bicarbonate-dithionite (BD), and NaOH (at 25 degrees C) showed that negligible amounts of P would be released from lake sediments during hypolimnetic anoxia if either (1) the molar Al(NaOH-25):Fe(BD) ratio is > 3 or (2) the molar Al(NaOH-25):P(H2O+BD) ratio is > 25. These ratios can be used as operational targets for estimation of sediment P release potential and Al dosing of P-rich sediment to prevent hypolimnetic P release under anoxic conditions.

• Authors: Jirí Kopácek, Jakub Borovec, Josef Hejzlar, Kai-Uwe Ulrich, Stephen A Norton, Aria Amirbahman
• Journal: Environmental science & technology (Environ Sci Technol) Vol. 39 Issue 22 Pg. 8784-9 (Nov 15 2005) ISSN: 0013-936X [Print] United States
• PMID: 16323777 (Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, Non-P.H.S.)

Chemical References

• Bicarbonates
• Ferric Compounds
• Water
• Dithionite
• Phosphorus
• ferric hydroxide
• Sodium Hydroxide
• Aluminum Hydroxide

Topics

• Aluminum Hydroxide (analysis, metabolism)
• Bicarbonates
• Dithionite
• Europe
• Ferric Compounds (analysis, metabolism)
• Fresh Water
• Geologic Sediments (analysis)
• North America
• Phosphorus (chemistry, metabolism)
• Sodium Hydroxide
• Water