Wells sampled for groundwater-age dating in New Hanover County, North Carolina

Sulfur hexafluoride (SF6) is a trace atmospheric gas that is primarily of anthropogenic origin but also occurs naturally in fluid inclusions in some minerals and igneous rocks, and in some volcanic and igneous fluids. SF6 has been used as a dating tool of groundwater because atmospheric concentrations of SF6 are expected to continue increasing (Busenberg and Plummer, 1997). SF6 samples were collected in 30 wells in New Hanover County, North Carolina in May 2017. The results of these samples were input into a spreadsheet calculator developed by the USGS Groundwater Dating lab in order to estimate groundwater age based on SF6 concentrations. The wells sampled include monitoring, domestic, and large water user wells within the surficial, [...]