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United States Department of Agriculture

Agricultural Research Service

Research Project: DEVELOPING TOOLS TO ENHANCE WATER QUALITY FROM AGRICULTURAL ENTERPRISES IN SOUTH FLORIDA Title: Adsorption/desorption of phosphorus on limestone from the Biscayne Aquifer under freshwater and seawater conditions.

Authors
item Jolicouer, J. - FLORIDA INTERNATIONAL UNI
item Price, Rene - FLORIDA INTERNATIONAL UNI
item Savabi, M

Submitted to: Annual American Geophysical Union Hydrology Days
Publication Type: Abstract Only
Publication Acceptance Date: December 4, 2007
Publication Date: March 7, 2008
Citation: Jolicouer, J., Price, R., Savabi, M.R. 2008. Adsorption/desorption of phosphorus on limestone from the Biscayne Aquifer under freshwater and seawater conditions.. Annual American Geophysical Union Hydrology Days.

Interpretive Summary: Understanding the flow of water in the limestone aquifer (Karst) is important in south Florida. Furthermore, concentration of the phosphorus in the ground water is a concern for the restoration of the Everglades project plan. Once in the groundwater, phosphorus can be transported to the coastal zone with the discharging groundwater. This study reports the results of laboratory leaching tests of varying concentrations of P through limestone.

Technical Abstract: Areas of seawater intrusion are known geochemically active regions particularly in limestone aquifers, where carbonate mineral dissolution and ion exchange reactions are important. Both of these processes can lead to a release of phosphorus from the aquifer matrix to the groundwater as seawater intrudes the coastal carbonate aquifer. Once in the groundwater this phosphorus can be transported to the coastal zone with the discharging groundwater. This presentation reports the results of laboratory leaching tests of varying concentrations of P through limestone in both a deionized water and seawater matrix. Early results indicate that P is significantly retarded in the deionized water effluent relative to chloride, and that the limestone has a strong affinity to adsorb P dissolved in deionized water. In the seawater matrix, however, phosphorus was not retarded relative to the deionized water, and even higher than expected concentrations of P were observed in the effluent at low concentrations of P. The resulting effluent chemistry will be input to geochemical models to decipher the dominant geochemical reactions most likely occurring within the limestone rock with the seawater matrix.

Last Modified: 10/24/2014
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