Measurements of radon concentrations in groundwaters from Swaziland using CR-39 nuclear track detectors

Several studies have shown that water-borne 222Rn contributes to indoor air concentrations. A passive radon measurement method was employed to determine radon activity concentrations in groundwater in wells of Swaziland. Concentrations ranged between 1.8 ± 0.1 and 152.9 ± 4.8 Bq L−1, with only slight variations (maximum 2.4σ from the mean) over 1 yr in a typical well. The arithmetic mean 222Rn concentration measured in groundwater supplies was 25.2 Bq L−1; geometric mean 13.5 Bq L−1. Fifty-four percent of the wells had 222Rn water concentrations in excess of the U.S. Environmental Protection Agencyʹs proposed limit of 11 Bq L−1 (300 pCi L−1) for public drinking water supplies.