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Photo from U.S. Geological Fact Sheet 134-99

Concentrations of CFC-11, CFC-12, and CFC-113 in water recharged in equilibrium with air between the years 1940 and 2000 at temperatures of 5 to 25C. The CFC analysis determined that concentrations of CFC-11, CFC-12 and CFC-113 were 493, 203, and 28 pg/kg in the water sample to be dated. The recharge temperature of 10C was determined from analysis of dissolved nitrogen and argon in the water sample.


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