Geochemistry of the Floridan aquifer system in Florida and in parts of Georgia, South Carolina, and Alabama
The chemical quality of the groundwater in the Floridan aquifer system is determined primarily by mineral-water interaction. However, some changes in water quality have been imposed by development, particularly near coastal pumping centers. A total of 601 chemical analyses, all from different wells, most completed in the upper part of the aquifer system, were used to describe the variations in water chemistry and to study the processes responsible for observed changes. The Floridan aquifer system is a vertically continuous sequence of Tertiary carbonate rocks that are of generally high permeability and are hydraulically connected in varying degrees. Dissolved solids concentrations in water from the Upper Floridan aquifer generally range from < 25 mg/L near outcrops to > 25,000 mg/L along the coasts. The dominant cations in the groundwater are Ca(2+), Mg(2+), and Na(+); the dominant anions are HCO3({minus}), Cl({minus}), and SO4(2{minus}). The concentration of Ca(2+) is controlled primarily by calcite saturation. Concentrations of Mg(2+), Na(+), and Cl({minus}) are highest where mixing of freshwater and saltwater occurs. Concentrations of HCO3({minus}) reflect the control of calcite solubility. The concentration of SO4(2{minus}) is highest where gypsiferous rock units are present in the aquifer system. The major geochemical processes that occur in the Upper Floridan aquifer, based on water quality maps and computations using a geochemical model are: (1) dissolution of aquifer minerals toward equilibrium; (2) mixing of groundwater with recharge, leakage, or seawater; (3) sulfate reduction; and (4) cation exchange between water and aquifer minerals.
- OSTI ID:
- 5379764
- Country of Publication:
- United States
- Language:
- English
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540320* -- Environment
Aquatic-- Chemicals Monitoring & Transport-- (1990-)
ACID CARBONATES
ALABAMA
ALKALI METAL COMPOUNDS
ALKALINE EARTH METAL COMPOUNDS
ANIONS
AQUIFERS
CALCIUM COMPOUNDS
CATIONS
CHARGED PARTICLES
CHEMICAL ANALYSIS
CHEMISTRY
CHLORIDES
CHLORINE COMPOUNDS
CONTAMINATION
DEVELOPED COUNTRIES
ECOLOGICAL CONCENTRATION
FLORIDA
GEOCHEMISTRY
GEORGIA
GROUND WATER
HALIDES
HALOGEN COMPOUNDS
HYDROGEN COMPOUNDS
ION EXCHANGE
IONS
MAGNESIUM COMPOUNDS
MONITORING
NORTH AMERICA
OXYGEN COMPOUNDS
POLLUTION
REGIONAL ANALYSIS
SODIUM COMPOUNDS
SOUTH CAROLINA
SULFATES
SULFUR COMPOUNDS
USA
WATER
WATER CHEMISTRY
WATER POLLUTION