The U.S. Geological Survey has reported that naturally occurring radionuclides in the groundwater of southeastern Pennsylvania may pose a health hazard to some residents, especially those drinking water from wells drilled in the Chickies Quartzite. Water from 46% of wells sampled in the Chickies Quartzite and 7% of wells sampled in other geologic formations exceeded the USEPA maximum contaminant level (MCL) for total radium. Radon-222 may pose a health problem for homeowners by contributing to indoor air radon-222 levels. The radon-222 activity of water from 89% of sampled wells exceeded 300 pCi/L (picocuries per liter), the proposed USEPA MCL, and water from 16% of sampled wells exceeded 4,000 pCi/L. Uranium does not appear to be present in elevated concentrations in groundwater in southeastern Pennsylvania.
The concentration of radium in water from the Chickies Quartzite is inversely related to pH but directly related to dissolved organic carbon, total dissolved solids, barium, and sulfate. The activities of radium in all water samples from the Chickies Quartzite with a pH less than 4.7 exceeded the USEPA MCL of 5 pCi/L. Low pH decreases the adsorption of radium onto the aquifer matrix and thus increases the amount of radium in groundwater. Uranium does not appear to be present in elevated concentrations in groundwater in southeastern Pennsylvania. Water samples from only 2 of 362 wells sampled (0.6%) exceeded the proposed USEPA MCL for uranium.
Concentrations of uranium in water samples from 45% of the wells sampled were below reporting limits. Methods for removal of uranium from a water supply are summarized in other documents cited. Search the I2M Web Portal for recent reports of uranium in the groundwater used for drinking water in other States.
Original working URL: https://pa.water.usgs.gov/reports/fs012-00.html
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