Groundwater age dating with chlorofluorocarbons
CFCs and tritium can be used in a similar manner for tracing modern water. CFCs have certain advantages over tritium because CFCs are detectable in lower concentrations than tritium, and are, therefore, more sensitive indicators of modern water where modern and old water mix. Apparent CFC ages are obtained by converting measured CFC concentrations in groundwater to equivalent air concentrations using known solubility relationships (Warner and Weiss, 1985; Bu and Warner, 1995) and the recharge temperature. Inferring shallow groundwater flow in saprolite and fractured rock using environmental tracers. Corrections for excess air are made if appropriate (Busenberg and Plummer, 1992). Environmental tracers for age dating young ground water.
Lesage (Editors), Groundwater Contamination and Analysis at Hazardous Waste Sites, Marcel Dekker, New York, pp.
Sorption of CFCs to aquifer materials may cause CFC velocities to be lower than water velocities in some aquifers, resulting in apparent CFC ages which are older than groundwater ages (Cook et al., 1995; Busenberg and Plummer, 1993).
However, sorption of CFCs does not appear to be important processes in low organic carbon aquifers. The transport of atmospheric trace gases to the water table: implications for groundwater dating with chlorofluorocarbons and krypton 85.
Source of text: This review was assembled by Eric Caldwell, primarily from Solomon et al.
Comparison of Chlorofluorocarbon-Age Dating with Paticle-Tracking Results of a Regional Ground-water Flow Model of the Portland Basin, Oregon and Washington.