Really hot water
Janet Raloff
Sometimes, water heaters do more than the obvious. While they heat water, they also collect a little uranium, creating deposits of radioactive scale inside their tanks. That's what South Carolina researchers have discovered in a community with the dubious distinction of having water that's naturally laced with among the highest concentrations of uranium ever reported in groundwater: 10,000 micrograms per liter.
Uranium concentrations in 50 residential wells near Simpsonville exceed federal drinking water standards by a factor of 300, Van Price of the University of South Carolina in Columbia and his colleagues reported in Denver at a meeting of the Geological Society of America last November.
In homes receiving some of the most contaminated water, uranium concentrations fell by about 23 percent as water passed through heaters, Timothy A. DeVol and Richard L. Woodruff Jr. of Clemson University now find.
Their calculations, presented in the December 2004 Health Physics, indicate that residues from the water left each heating tank with up to 69 grams of uranium, depending on the tank's age and the household's water use.
Although the radioactive tank deposits pose little or no risk to homeowners, DeVol says, they do justify classifying the water heaters as naturally occurring radioactive waste (SN: 10/26/91, p. 264). Such materials can pose hazards if the tank's metal is later scrapped and recycled. For now, they're not subject to regulation by the federal government or most states.
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References:
Committee on Alternatives for Controlling the Release of Solid Materials from Nuclear Regulatory Commission Licensed Facilities, National Research Council. 2002. The Disposition Dilemma: Controlling the Release of Solid Materials from Nuclear Regulatory Commission-Licensed Facilities. Washington, D.C.: National Academy Press. Available at http://www.nap.edu/catalog/10326.html.
DeVol, T.A., and R.L. Woodruff Jr. 2004. Uranium in hot water tanks: A source of TENORM. Health Physics 87(December):659–653. Abstract.
Price, V., et al. 2004. Investigations of high uranium contents in domestic water wells, South Carolina Piedmont (Abstract 99–12). Geological Society of America meeting. Nov. 7–10. Denver. Abstract available at http://gsa.confex.com/gsa/2004AM/finalprogram/abstract_79996.htm.
Warner, R. … V. Price, et al. 2004. Petrography and uranium mineralogy of SC DHEC well core, Jenkins Bridge Road, near Simpsonville, South Carolina. Geological Society of America meeting. Nov. 7–10. Denver. Abstract available at http://gsa.confex.com/gsa/2004AM/finalprogram/abstract_77524.htm.
Further Readings:
2002. Division of Health Assessment and Consultation Exposure Investigation, Simpsonville/Fountain Inn, South Carolina. Agency for toxic substances and Disease Registry report. Feb. 26. Available at http://www.atsdr.cdc.gov/NEWS/simpsonvillefinalei.html.
Chepesiuk, R. 2002. Unwell water in South Carolina. Environmental Health Perspectives 110(April):182. Available at http://www.ehponline.org/docs/2002/110-4/forum.html#unwe.
Kurttio, P., et al. 2002. Renal effects of uranium in drinking water. Environmental Health Perspectives 110(April):337–342. Available at http://www.ehponline.org/docs/2002/110p337-342kurttio/abstract.html.
Raloff, J. 1991. NORM: The new hot wastes. Science News 140(Oct. 26):264–267.
Sources:
Timothy A. DeVol
Environmental Engineering and Science Department
Clemson University
Clemson, SC 29634-0919
Van Price
School of Environment
University of South Carolina
Columbia, SC 29208
From Science News, Volume 167, No. 3, January 15, 2005, p. 46.
