Uranium in hot water tanks: a source of TENORM.
Uranium deposits were detected inside hot water tanks using gamma-ray spectroscopic techniques and corroborated by the difference in the uranium concentration of the groundwater entering and leaving the hot water tanks. In-situ gamma-ray spectroscopy was performed using a transportable high-purity germanium (HPGe) gamma-ray spectrometer to estimate the mass of uranium in the hot water tanks. Gamma-ray spectroscopic analyses of hot water tanks in four residences with groundwater uranium concentration between 732 and 7,667 mug L revealed an estimated 3.5 to 69 g of uranium in each hot water tank. The uranium deposit within the tanks was indicated by the 143.8, 163.4, and 185.7 keV gamma rays of U and confirmed with the 63.3, 92.3, and 92.8 keV gamma rays of Th as well as the 1,001 keV peak of Pa. An average decrease in uranium concentration of 23% was observed in the groundwater that passed through the hot water tanks. Additionally, once "uranium free" water entered the hot water tanks, the uranium deposits within the tanks resulted in an increase in the uranium concentration in the effluent water. The groundwater had an alkalinity in the range of 46-96 mg L as CaCO3 and a pH range of 7.3-8.1. The accumulation of uranium in these hot water tanks results in them being classified as technologically enhanced naturally occurring radioactive materials (TENORM).
DeVol
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Environmental Engineering & Science Department, Clemson University, Clemson, South Carolina 29634-0919, USA. tim.devol@ces.clemson.edu
Woodruff
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D014501:Uranium / Q000032:analysis*; D014875:Water Pollutants, Radioactive / Q000032:analysis*; D014881:Water Supply / Q000032:analysis*
D014875:Water Pollutants, Radioactive; D014501:Uranium