Full range determination of ²²²Rn at the watershed scale by liquid scintillation counting.

(222)Rn has been increasingly used to identify groundwater contribution to surface water. Particular attention has been paid to analytical protocols and counting parameters used for liquid alpha scintillation measurements over a range of activities covering river and groundwater domains. Direct measurements and Rn-extraction protocols are optimized, and scintillometer efficiency is calibrated using international standards over the 0.5-35 Bq/L range. The interval of activities was performed in surface water and groundwater from a small Canadian watershed.