LUNG DOSE ESTIMATES FROM RN-222 IN ARIZONA GROUNDWATER BASED ON LIQUID SCINTILLATION MEASUREMENTS

Since August 1989, Rn-222 groundwater samples from across the state of Arizona have been collected and analyzed using liquid scintillation. Of the 253 specimens acquired, 65% have Rn-222 concentrations above 11 Bq L(-1) (300 pCi L(-1)), while 16% have Rn-222 activities over 37 Bq L(-1) (1,000 pCi L(-1)). The geometric mean Rn-222 concentration for all the wells tested is 13 Bq L(-1 x) divided by 4; the arithmetic mean is 37 +/- 122 Bq L(-1). Using the geometric mean, it is estimated that an additional tracheobronchial lung dose equivalent of 0.19 mSv y(-1 x) (divided by) 13.9 is delivered to Arizona residents from the well water to home pathway.