Investigating Gas-Water-Rock Carbon Isotope Exchange in the Field

Extensive investigations of isotope content and hydrochemical parameters in soil gas, soil material, groundwater and seepage water from a Quaternary aquifer show a good correlation between 14C concentration of the groundwater and its mean residence time in the unsaturated zone. The initial 14C concentration varies between 100 and 50% modern. It decreases through solution and dissolution of carbonates to 50% of the 14C concentration of atmospheric CO2.