Chemical quality of water in the upper part of the Floridan aquifer, Duval County, Florida

The Floridan aquifer is the principle source of freshwater in Duval County (fig. 1). Most water-supply wells penetrate only the upper 600 feet of the aquifer because highly mineralized water is found in the deeper zone. Earlier investigations have shown that within the upper 600 feet of the aquifer, the water quality varies considerably. In most areas the water contains very low concentrations of inorganic constituents whereas in other areas the concentrations are much higher. 

In order to determine the areal distribution of the inorganic constituents in the upper part of the aquifer, water samples were collected from selected wells throughout Duval County and analyzed for common chemical constituents.