The first study which detected and quantified submarine groundwater discharge on a regional basis was done by Moore (1996) in the South Atlantic Bight off South Carolina. He measured enhanced radium-226 concentrations within the water column near shore and up to about  from the shoreline. Radium-226 is a decay product of thorium-230, which is produced within sediments and supplied by rivers. However, these sources could not explain the high concentrations present in the study area. Moore (1996) hypothesized that submarine groundwater, enriched in radium-226, was responsible for the high concentrations. This hypothesis has been tested numerous times at sites around the world and confirmed at each site.