A study supported by the University of Iowa’s (UI) Center for Health Effects of Environmental Contamination (CHEEC) has detected the naturally-occurring radioactive element radium in private well water.

Radium isotopes 226 and 228are regulated under the Safe Drinking Water Act (SDWA) with a United States Environmental Protection Agency (U.S. EPA) enforceable Maximum Contaminant Level (MCL) of 5 picocuries per liter (pCi/L) for combined radium. Private wells are not regulated under SDWA, and the burden of monitoring and treating contaminants in private drinking water wells falls entirely on the consumer.

“From 2001 to 2020, combined radium was one of the most common violations for public water systems regulated under SDWA in the state of Iowa,” said David Cwiertny, CHEEC’s Director.  “Private wells in this region have not been studied and the exposure risks were largely unknown”

The element is of concern because exposure to elevated concentrations in drinking water has been associated with increased risk of developing blood, bone, lung, breast, and bladder cancers.

In 2019, the study measured radium and several other inorganic constituents such as arsenic and manganese in 94 private wells across ten Iowa counties – Allamakee, Carroll, Cherokee, Emmet, Greene, Johnson, Kossuth, Palo Alto, Woodbury, and Wright.

 “We mapped radium occurrence data from public groundwater monitoring wells and MCL violations in public water systems across Iowa from the last 20 years,” said Tori Forbes, CHEEC’s Professor in UI’s Department of Chemistry. “We selected these counties because they had elevated Ra activity. We wanted to assess whether private wells were impacted because they likely draw water from the same aquifers as the public systems.”

Radium was detected in 46.8% of the samples (44 wells) drawn from outdoor well hydrants. Six wells had concentrations exceeding the EPA’s MCL, with a maximum concentration of 12 pCi/L. The highest levels of radium were mostly localized to northwest Iowa, where private wells more often source their water from aquifers known to contain radium.

Follow-up sampling in 2020 was then conducted among 12 households in four counties to assess the efficacy of in-home water treatment. Water softeners reduced ^226/228Ra to non-detectable activities.

“We found that radium concentrations had the greatest reduction when drinking water was treated with an in-home water softener or under counter reverse osmosis,” Forbes said.

Researchers also tested for 14 distinct metals and metalloids – including arsenic, manganese, and uranium. Concentrations above EPA’s MCL for arsenic and manganese were found in 17% and 61% of the 2019 samples. Four samples in Cherokee County had uranium concentrations close to or above the EPA MCL of 30 μg/L for total uranium.

Several of these inorganic constituents were also found to persist to the consumer’s tap unless advanced treatment like reverse osmosis was used.

“This study is really important. It highlights the risks of inorganic chemical exposures to public health from private well water and suggests we may want to start monitoring for a wider number of potential contaminants in private wells in Iowa ,” said Cwiertny. “The study also shows that it is possible to identify and prioritize vulnerable wells using data from public water supply if reliable information is available to identify the source aquifer.”

This study is published in the journal AWWA Water Science. The full results can be read here .

CHEEC supports and conducts environmental health research relating to environmental toxins. Its mission is ‘to determine the levels of environmental contamination which can be specifically associated with human health effects”.

Since 1989, CHEEC has awards $3.3 million for seed grant research. This investment has attracted more than $24 million in external funding for additional research.

CHEEC provides support for environmental educational programs organized by non-profit organizations, government entities, professional associations and educational organizations.  The program provides funding for activities geared towards exposure prevention, assessment and awareness, and improvement of environmental health. 

For more information, visit https://cheec.uiowa.edu/outreach/education-grants or email cheec@uiowa.edu.