Radium and radon are naturally occurring radioactive elements that result from the radioactive decay of uranium, which is present in small levels in common rocks and minerals.
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Radium is present in the confined part of the Ozark aquifer. However, the levels of radium seldom exceeded the U.S. Environmental Protection Agency drinking-water standard. |
Water samples collected from 20 randomly selected municipal-supply wells in the confined part of the Ozark aquifer were analyzed for the presence of radium (Adamski, 1997c). Radium levels ranged from 0.1 to 14 picocuries per liter (pCi/L). One sample had a level exceeding the interim U.S. Environmental Protection Agency (EPA) maximum contaminant level (MCL) of 5 pCi/L. No levels exceeded the proposed MCL of 20 pCi/L for radium in drinking water.
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Radon levels exceeded a proposed (but withdrawn) U.S. Environmental Protection Agency drinking-water standard in nearly one-half of the samples. Radon can enter homes through their water systems. Homes served by private domestic wells and small public waterworks using ground water can be particularly vulnerable. |
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Water samples were collected from 53 domestic wells in the unconfined parts of the Springfield Plateau and Ozark aquifers, and 20 municipal supply wells in the confined part of the Ozark aquifer (Adamski, 1997c). In samples from these 73 wells, radon levels ranged from 99 to 2,065 pCi/L with a median of 269 pCi/L. A proposed MCL of 300 pCi/L was recently (1997) withdrawn by the EPA, pending further review. Radon levels exceeded that level in nearly 44 percent of the samples but are lower than levels in many other aquifers in the Nation (p. 20). |
Radon levels exceeded 300 picocuries per liter in almost one-half of the water samples from domestic and municipal-supply wells. |
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Exposure to radon has been recognized as a health risk, primarily as a cause of lung cancer. One pathway by which radon can enter a home is through its water system, especially if ground water is the water source. Small public water systems and private domestic wells often have closed systems and short transit times that do not remove radon from water or permit it to decay. Exposures can occur from water used for drinking, showering, and other common household purposes. Radon gas also can enter buildings from surrounding rock and soil through foundation cracks. |
Radon entering a home through a water system (modified form Otton and others, 1993). |
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Radon levels are greater in the Springfield Plateau aquifer and the unconfined part of the Ozark aquifer than in the confined part of the Ozark aquifer. | |
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Hydrogeology appears be significant in determining radon levels. Levels in the samples from unconfined aquifers (Springfield Plateau aquifer and part of the Ozark aquifer) were substantially higher than levels in samples from the confined part of the Ozark aquifer. |
Radon levels are lowest in the confined part of the Ozark aquifer. |
