Radon Risk Mapping Using Uranium Series Geochemistry and Social Vulnerability in the North Carolina Coastal Plain

Radon (222Rn) is a colorless, odorless, inert radioactive gas that emits alpha radiation, making radon inhalation the leading cause of lung cancer among non-smokers. Based on previous low-resolution radon hazard maps, the Mid-Atlantic Coastal Plain is broadly generalized as low risk, yet indoor radon tests in the coastal plain of North Carolina show measurements as high as 54 pCi/L, approximately 18 times the U.S. Environmental Protection Agency’s action level. Here I combine uranium-series radionuclide measurements from sediment cores with social vulnerability data to create higher resolution radon hazard maps. Using ultra low background high resolution gamma spectrometry, I measure 238U, 226Ra, and 210Pb in sediment cores within Nash and Edgecombe Counties in the North Carolina Coastal Plain. Radon disproportionately affects socially vulnerable and historically excluded populations, and thus the effects of radon gas cannot be generalized across a county’s population. I overlay demographic data relating to the themes of socioeconomic status, household composition/disability, and race/ethnicity/language from the Center for Disease Control’s Social Vulnerability Index (SVI) with measured values of 226Ra in core sections. In addition to high indoor radon levels, my study area shows a high vulnerability with regards to these three SVI themes. My results indicate the presence of elevated 226Ra in sediment in Nash and Edgecombe counties, as well as the need for further mapping efforts in the Mid-Atlantic Coastal Plain to direct radon mitigation, testing, and public health efforts