|Duex reported that indoor air pollution from radon in 1994 has been identified by the U.S. Environmental Protection Agency as a serious health problem; estimates indicate that radon is the second-leading cause of lung cancer (after smoking) and that high levels of radon may cause as many as 20,000 to 40,000 lung cancer deaths per year in the United States. Studies of the potential risk in the Gulf Coast have been few. This report summarizes more than 7,000 previously unreported radon analyses and relates them to geological information in order to identify possible problem areas for the Gulf Coast region of Louisiana, Texas, Mississippi, Alabama, and Florida. |
High levels of indoor radon are generally associated with older crystalline igneous and metamorphic bedrock. Thus, most areas of the Gulf Coast are relatively low risk because they are underlain by Cenozoic sedimentary rocks and unconsolidated deposits. However, some types of sedimentary deposits, such as black shale and phosphate-rich rocks, can be areas of high risk.
According to the U.S. EPA indoor radon survey results the percentage of houses with screening levels greater than 4 pCi per 1 (picocuries per liter) for given states is as follows... AL= 6.0%, LA= 0.8%, MS= 2.0%, and TX= 4.0% (no data available for FL).
The data developed in the current study indicated that the percentages of houses with greater than 4 pCi/l for given states are as follows ... AL= 6.1%, LA= 0.60%, MS= 2.0%, TX= 1.6%, and FL= 4.5%. The areas that appear to have the greatest risk are parts of northern Alabama and Mississippi, central Texas, and some areas in Florida.
Radon is a naturally occurring radioactive gas that is part of the U and Th decay series. The most common isotope is 222Rn, hereafter referred to simply as radon, and it occurs in the 238U to 206Pb decay chain. The immediate parent of radon is 226Ra, but it is radon is daughter products that cause the main health problems.