Assessment of Radon and Naturally Occurring Radionuclides in the Vredefort Meteorite Crater in South Africa

Despite elevated uranium concentrations in the Vredefort Crater's impact rings, indoor radon levels were unexpectedly low, averaging 113 Bq/m³. This finding contrasts with expectations based on geological uranium content (50 Bq/kg) and defunct mine tunnels in the area, which showed significantly higher radon levels (364 Bq/m³). The study, conducted during the COVID-19 pandemic and colder months—conditions typically associated with increased indoor radon—attributes this discrepancy to surficial deposits, bedrock composition, and architectural features that mitigate radon accumulation. Soil samples confirmed uranium activity at 30 Bq/kg, aligning with global averages (35 Bq/kg). The research combines soil sampling, radionuclide surveys across three impact rings, and indoor measurements to assess the relationship between natural radionuclides and radon exposure in this unique meteorite crater.

Le Roux, R., & Bezuidenhout, J. (2023). Assessment of Radon and Naturally Occurring Radionuclides in the Vredefort Meteorite Crater in South Africa. Atmosphere, 14(12), 1826. https://doi.org/10.3390/atmos14121826