Granite commonly contains high concentrations of uranium, with subsequent high exhalation of radon gas. The geology of the West Coast Peninsula of South Africa is dominated by granite. No measurements of radon gas has, however, been undertaken in, or near the towns of the peninsula and a recent article predicted potentially high indoor radon concentrations in the town of Saldanha. This article sets out to validate the predicted results by measuring the indoor radon concentration for the two largest settlements on the West Coast Peninsula: Vredenburg and Saldanha. Measurements were conducted during the summer months with houses typically being more open due to the warm weather. The data was found to exhibit lognormal behavior, with the I-type granite formation of Vredenburg yielding a higher indoor radon concentration than the ignimbrite formation of Saldanha. The average indoor radon concentration of Vredenburg was 34% higher than that of Saldanha, with 58.7 Bq/m³ and 38.6 Bq/m³ respectively.

South Africa has rich coal deposits concentrated in the northeast of the country, and as a result, most of the country’s coal mining is located in this region. Two of the principal coalfields exploited are the Witbank and Highveld coalfields, located in the Mpumalanga province. Coal contains trace quantities of the naturally occurring radionuclides whose mass concentration can be enhanced by anthropogenic activity. The radioactive fallout from these activities could lead to elevated radon concentrations indoors. Two towns, Secunda and eMalahleni, were identified due to their proximity to coal-based industries. A previous study investigated whether these industries caused elevated radon levels in Secunda homes but found a lower-than-expected average concentration of 76.4 ± 7.6 Bq m⁻³. This was attributed to either the prevailing wind depositing the radioactive fallout to neighboring towns, such as eMalahleni, or the type of industrial activity. This paper builds on this study by investigating whether elevated radon levels are found in homes in eMalahleni. Measurements were performed in 22 homes during December 2019, and the average indoor radon concentration was calculated as 122.1 ± 8.5 Bq m⁻³. The cause of these elevated levels was then investigated, and it was found that even though the coal industry contributes to elevated radon levels, the town’s underlying geology seems to be the primary contributor.

Secunda is a town built amid the coalfields of the Mpumalanga province of South Africa. Surrounding the town are 11 coal-fired plants (CFPs) contributing around 59% of the country’s energy needs. It is also home to Sasol Synfuels, which produces synthetic gas through coal gasification and natural gas reforming. Coal, like most materials found in nature, contains trace elements of the naturally occurring primordial radionuclides ⁴⁰K, ²³⁸U, ²³²Th, and their decay products. The milling and combustion of coal in a CFP increases the mass concentration of these trace elements, and the residuals end up on ash heaps as fly ash, bottom ash, and boiler slag. A small percentage of fly ash also ends up in the atmosphere. This paper sets out to determine the anthropogenic impact of the industrial activity on indoor radon in the town of Secunda in the Mpumalanga region of South Africa. Measurements were done in 37 homes during July when higher indoor radon levels are expected due to homes typically being closed due to the low temperatures. The average indoor radon concentration was found to be 76.4 Bq m⁻³. This indicates that the fallout from the industrial activity surrounding Secunda does not enhance the emanation of radon. This may be due to the type of activity or the climate and prevailing winds mitigating its indoor build-up. Measurements during the warmer months and in neighboring towns with different industrial activities are required to confirm the trends established by this research.

Geographic Information Systems (GIS) consists of various tools to perform spatial analyses in a wide variety of disciplines, including radiometric analysis to characterize the distribution of natural radionuclide concentrations. Recently, open‐source GIS has become popular among geospatial users because it can be freely used, and powerful tools are constantly developed to enhance software capabilities. Gamma‐ray spectroscopy was used to measure the concentrations of these natural radionuclides by dragging a Delta Underwater Gamma System (DUGS) among the sediment in the Berg River estuary located in Velddrif, South Africa. In this study, QGIS was used to visually illustrate and interpret the distribution of natural radionuclides, that is, potassium (K⁴⁰), thorium (Th²³²), and uranium (U²³⁸). These concentrations can be used to investigate various geographical and geological phenomena, which include sediment processes. The data were then interpreted to derive sediment characteristics. Various features of tidal estuaries were demonstrated by the results.

Sedimentation can cause numerous problems in rivers, estuaries, harbors, and coastal areas. It is therefore important to trace and model the movement of sediments. The natural physical, chemical, and biological components of the aquatic sediment generally relate to these features in its terrestrial catchment area. It consequently contains the naturally occurring radionuclides of thorium, uranium, and potassium, which can be used as tracers. To achieve this aim, a delta underwater gamma system (DUGS) was developed to map the radionuclides in aquatic sediments. Though the system has been tested for radiometric accuracy, the low concentrations of natural radionuclides in aquatic sediments and the attenuation by the water and detector enclosure necessitated an evaluation to determine the detection efficiency of the detector along with optimal operational parameters. These included spectra accumulation time and underwater speed. The DUGS was consequently used to determine and optimize these parameters for mobile measurement of aquatic sediments. The acquired gamma spectra were also analyzed using full spectrum and energy window analysis to determine the optimal method for extracting the activity concentrations of the nuclides in the sediments.