Survey of 226Ra/228Ra and inorganic constituents in Iowa private drinking water wells

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Thursday, November 3, 2022
Margaret E. Carolan
Richard J. Langel
Dustin May
Anthony DeSalvo
Humberto E. Gonzalez-Ribot
Alyssa J. Mattson
Michael D. Schueller
Darrin A. Thompson
David M. Cwiertny
Tori Z. Forbes
Journal Title: 
AWWA Water Science

Radium is a naturally-occurring radioactive element found in Upper Midwest aquifers, yet exposure risks for unregulated water sources in this region are unknown. A survey of 226/228Ra and other inorganic constituents in 94 private wells was conducted in 2019 across 10 Iowa counties. Within private wells, 53% measured below minimum detectable activity whereas 6.3% have 226/228Ra levels above the United States Environmental Protection Agency Maximum Contaminant Level. 226/228Ra occurrence was not associated with well-depth or chemical surrogates, but were generally consistent with the lithology and historical water quality trends for aquifers. In 2020, 11 of the 226/228Ra-impacted wells were re-sampled to assess the efficacy of in-home water treatment. Water softeners reduced 226/228Ra to non-detectable activities, but other inorganic constituents persisted and their removal required more advanced treatment. This study suggests that 226/228Ra occurrence in private wells can reasonably be anticipated from public water supply data if reliable information is available to identify the source aquifer.


Carolan, M. E., Langel, R. J., May, D., DeSalvo, A., Gonzalez‐Ribot, H. E., Mattson, A. J., ... & Forbes, T. Z. (2022). Survey of 226Ra/228Ra and inorganic constituents in Iowa private drinking water wells. AWWA Water Science, 4(6), e1311. DOI: