Chemical and isotopic composition and potential for contamination of water in the upper Floridan Aquifer, west-central Florida, 1986-89

Abstract

Relatively little is known about the processes controlling the fate and transport of the many toxic compounds associated with industrial wastes, and even less is known about how various inorganic and organic compounds interact once havi.ng entered the groundwater system. A more thorough understanding of the processes affecting contaminants in the subsurface is needed to assess future problems of contamination and to effectively contain and clean up contaminated ground waters. Analysis and selection of appropriate and cost-effective remedial measures to contain and restore contaminated ground water reJ.ies on a thorough understanding of the many •factors that affect the fate, transport, and transformation of contaminants once having entered an aquifer. To improve understanding of these factors, the U.S. Geological Survey, Office of Hazardous Waste Hydrology, is conducting three major research demonstration efforts addressing hazardous waste contamination of ground water. These national interdisciplinary field studies have developed important applied, developmental, and theoretical research findings which have expanded our knowledge of groundwater contamination transport processes. This series of technical papers presents the research conducted at a creosote works site in Pensacola, Florida. The papers were originally presented at a Toxic Waste-GroundWater Contamination Program symposium in Tucson, Arizona, in March 1984.

Evaluating Complex Hydrogeological Settings in a Constructed Wetland: An Isotopic/Chemical Mass Balance Approach

“…The isotopic composition of treated effluent (EF) discharging into the CP ranged from −8.3‰ to −9.2‰ for δD and −1.67‰ to −1.74‰ for δ 18 O. These values were close to the Upper Floridan groundwater line reported by Swancar and Hutchinson (1995). In contrast to the CP, the isotopic composition of wetland water collected from a pump (WP) at the end of the flow path showed seasonal variation.…”

“…6A). The groundwater and rainwater sources were combined in one as "GW" because the local meteoric water line had a tendency to approach the Upper Floridan groundwater line (Swancar and Hutchinson 1995;Kendall and Coplen 2001;Kish et al 2009). When these water sources are considered as endmembers to the wetland water (i.e., have unique chemical composition compared to the mixture), it is possible to estimate mixing proportions between them waters using a mass-balance approach (e.g., Christophersen and Hooper 1992;Clark and Fritz 1997;Doctor et al 2006).…”

“…Kendall and Coplen (2001) reported that the local meteoric water line for Florida was δD=5.4 δ 18 O+1.3 (R 2 = 0.96). The regression equation for the Upper Floridan groundwater line published by Swancar and Hutchinson (1995) was δD=5.4 δ 18 O+1.5 (R 2 =0.97). The distribution of δD and δ 18 O for the WP is very similar to the reported water lines but slightly lower in slope and intercept.…”

Hydrogeology and results of tracer tests at the old Tampa well field in Hillsborough County, with implications for wellhead-protection strategies in west-central Florida

“…In northern Hillsborough and Pasco Counties, the top of the aquifer is about 50 ft below land surface. The aquifer is at risk from sources of contamination at land surface because the sediments that overlie the aquifer do not prevent downward movement of water (Swancar and Hutchinson, 1992). The Florida Department of Environmental Protection (FDEP) has enacted regulations that limit the amount and type of land use near well fields to protect public water supplies.…”

Geochemical Determination of the Fate and Transport of Injected Fresh Wastewater to a Deep Saline Aquifer

“…In south Florida, research has been conducted on the fate and transport of effluent waste in the Florida Keys, primarily from septic tanks and small wastewater treatment plants Griggs et al, 2003), and in central Florida with regards to agricultural nitrate contamination (Tihansky and Sacks, 1997 Isotope hydrology of south Florida has been extensively studied in the SAS (Swart et al, 1989;Price, 2001;Meyers et al, 1993;Price and Swart 2006;Price et al, 2008), and in the Floridan Aquifer in central and west Florida (Swancar and Hutchinson, 1992;Sacks, 1995;Katz et al, 1997;Rectenwald, 2000;Morrissey et al, 2010 (Swart et al, 1989). The δ 18 O data from wells sampled from depths of 240 m and 490 m ranged from -2.6 ‰ to -1.8 per mil (Rectenwald, 2000).…”