DISTRIBUTION OF INDOOR RADON CONCENTRATIONS AND URANIUM-BEARING ROCKSIN TEXAS

The purpose of this study was to compare regional patterns of indoor r adon concentration with uranium-bearing rock zones and county populati ons in Texas. Zones yielding radon concentrations that are relatively high for Texas include shale and sandstone in northwest Texas; red bed s in north-central Texas; felsic volcanic rocks in west Texas; and san dstone, limestone, and igneous rocks in central Texas. Located in nort hwest Texas, only five of the 202 counties evaluated have mean indoor radon concentrations above 4.0 pCi I-1. Two of those counties have pop ulations above the state median of 20115. The highest county mean conc entration is 8.8 pCi I-1. Results of this study suggest that (1) regio nal geology influences indoor radon concentrations in Texas, (2) state wide, the radon concentrations are relatively low, (3) highly populate d counties do not coincide with regions of high indoor radon concentra tion, and (4) regions that may warrant further monitoring include nort hwest Texas and, to a lesser degree, west and central Texas.