Southeastern Section - 58th Annual Meeting (12-13 March 2009)

Paper No. 36
Presentation Time: 8:30 AM-12:30 PM

COMPARISON OF URANIUM AND RADON STUDIES FOR THE STONE MOUNTAIN, GEORGIA GRANITE AND THE ELBERTON GRANITE


FREEMAN, Joelle M., Department of Geology, University of Georgia, 210 Field Strreet, Athens, GA 30602, SWANSON, Samuel E., Department of Geology, University of Georgia, Athens, GA 30602, JORDAN, Thomas R., Geography, University of Georgia, 210 Field Street, Room 204, Athens, GA 30602, CHENHALL, Rebecca M., Walton County Cooperative Extension, University of Georgia, 100 North Broad Street, Monroe, GA 30655 and ATILES, Jorge H., Housing & Consumer Economics, University of Georgia, College of Family and Consumer Sciences, 224 Dawson Hall, Athens, GA 30602, joelle@uga.edu

The Georgia Radon Education Program is funded by a US EPA grant via the Georgia Department of Community Affairs (DCA) and is administered through the College of Family and Consumer Sciences and the University of Georgia Cooperative Extension. The program educates the public regarding radon health risks, testing, and mitigation, and distributes complimentary radon test kits. The data collected from the return of the complimentary test kits is reported in picocuries per liter of air (pCi/L) and is the basis for this study. The US Environmental Protection Agency (EPA) recommends that homes with radon levels at or above 4 pCi/L be remediated.

The purpose of this study is to compare the measured radon concentration in homes built on granite to adjacent homes built on metamorphic rocks of the Georgia Piedmont. Rocks in the Georgia Piedmont were categorized as high in uranium by the National Uranium Resource Evaluation (NURE) program conducted in the 1970's by the US Department of Energy. Two post-metamorphic granite plutons (Elberton and Stone Mountain) in the Georgia Piedmont were selected for this study. The Stone Mountain and the Elberton granites lie within counties classified as having high radon potential on the EPA Map of Radon Zones.

Two areas that include outcrops of the Elberton and Stone Mountain granites were selected for study. Radon test results (n > 800) from within these areas were plotted using GIS software. Radon results from surrounding areas (n > 2600) were also tabulated. Homes on the Elberton granite have elevated radon levels (17% above 4 pCi/L) compared to adjacent homes not on granite (14% with results above 4 pCi/L). Homes on the Stone Mountain granite have lower radon levels (9% above 4 pCi/L) than adjacent homes not on the granite (13% with results above 4 pCi/L). The results for the Elberton granite fit the model of higher radon (and uranium) in the granite relative to the host rocks. Results from the Stone Mountain area may indicate abnormally low uranium content for the Stone Mountain granite, high uranium content of host rock (Lithonia gneiss), or regional variations in home construction. Further analysis of the data include study of the geochemistry of the Elberton and Stone Mountain granites (and their host rocks) and the pattern of home construction in the area around Stone Mountain.