RADON CONCENTRATIONS IN HOMES IN AN AREA OF DOLOMITE BEDROCK - DOOR COUNTY, WISCONSIN

A statewide survey by the Wisconsin Department of Health and Social Se rvices with U.S.E.P.A. assistance reported an anomalously high percent age of homes in Door County with radon concentrations in excess of 20 pCi/L. The results were of interest because the county is underlain by marine sedimentary rocks rather than the igneous and metamorphic crys talline types usually associated with elevated radon concentrations. A voluntary population of 55 homes was tested for radon using activated charcoal canisters. This population was also asked to provide questio nnaire response data on family, home, and socioeconomic aspects. The d ata were separated into socioeconomic, energy efficiency, radon access , and karst level categories and statistically analyzed. A subpopulati on was selected from the larger population for detailed site investiga tion, which included additional in-home air testing and, at some sites , water supply analysis and in-ground testing for radon. The field inv estigations collected information on the geology, soil, topography, an d home construction and use. The results of the investigation verified and characterized the radon occurrences iu Door County. The presence or absence of karst features is shown to be statistically significant to radon levels.