AN INVESTIGATION INTO CONTROLS ON ARSENIC CONCENTRATIONS IN GROUNDWATER AT A FORMER GOLF COURSE IN BOCA RATON, FLORIDA

Arsenic is a naturally-occurring metallic element that has been used by humans for thousands of years as a pesticide. It is the primary contaminant of concern at the maintenance area of the former Ocean Breeze Golf Club in Boca Raton, Florida. Initial sampling showed Arsenic up to 490 ug/L in groundwater. Elevated concentrations of Arsenic have persisted in on-site monitor wells since 2011. Though alleged, dumping by vandals was later shown to be unlikely based on the persistent, yet moderate concentrations and depth of impacted groundwater (8-12 feet below land surface), but without intervening soil impacts. Previous assessment revealed a plume of Arsenic-contaminated water in the direction of the natural groundwater flow, but no upgradient source has been identified in monitoring wells, surface water, or sediment in a nearby pond. Thus, available data have not been sufficient to determine the source of Arsenic contamination. Here we present the historical data on the site as well as preliminary results from our ongoing study, which focuses on 1) confirming the source of the Arsenic contamination, and 2) characterizing controls on the distribution and transport of Arsenic at the site. Primary methods for the ongoing study include geophysical investigations to confirm the plume dimensions, and use geophysics to better characterize the hydrostratigraphy.