EPA Monitoring Radium Concentrations in Silex, Missouri, Public Water System
LENEXA, KAN. (SEPT. 29, 2023) – The U.S. Environmental Protection Agency (EPA) Region 7 is aware that the city of Silex, Missouri, has declared a city-wide emergency regarding the presence of naturally occurring radionuclides in the city’s groundwater source for its water supply. EPA is aware that this declaration has caused concern among members of the community regarding the safety of the public drinking water.
EPA is working with the Missouri Department of Natural Resources (MoDNR), Missouri State Emergency Management Agency (SEMA), and Missouri Department of Health and Senior Services (MoDHSS) to address the elevated radionuclides in the Silex Public Water System by providing the community with information about the potential risks associated with radium. EPA has also directed the city to prepare a plan to provider residents with alternative water.
The city of Silex has a history of radionuclide violations. The most recent Notice of Violation, issued Aug. 11, 2023, was for a radionuclide running annual average of 5.75 picocuries per liter (pCi/L). The Maximum Contaminant Level (MCL) for the radionuclides – radium-226 and radium-228 (combined) – for drinking water is 5 pCi/L. All MCL violations require public notice.
EPA’s risk associated with this level of radionuclides in the Silex PWS is not an immediate threat, but rather one that could come from consistent, long-term exposure.
As the levels of radionuclides in the Silex PWS have been persistently elevated for numerous years, EPA encourages members of the Silex community who are concerned about their water to use alternative sources of drinking water, such as bottled water, for drinking and cooking. Our goal is to work with the city to find other long-term solutions as quickly as possible.
The Toxicological Profile of radium from the Agency for Toxic Substances and Disease Registry (ATSDR), notes that there are no known health effects of radium from dermal exposure. Therefore, activities like bathing, washing dishes, and laundry do not pose a risk or require bottled water.
Water Distribution by SEMA
SEMA routinely works with its partners to coordinate distribution of alternate drinking water upon request by local communities, on a temporary basis.
Twenty-four pallets of bottled water (approximately 5,760 gallons) were delivered to Silex today, and SEMA is assisting the Mayor’s Office in coordinating a point of distribution for residents. SEMA staff are also working closely with local emergency management partners to assess any ongoing needs.
What is radium?
Radium is a naturally occuring radioactive metal that can exist in several different forms, called isotopes. Radium is formed when uranium and thorium break down in the environment. Small amounts of uranium and thorium are found in most rocks and soil.
High concentrations of naturally occurring radium are found in some areas of the United States.
According to ATSDR, populations at greatest risk of exposure from the consumption of drinking water with a high radium content are located in the Piedmont and Coastal Plain province in New Jersey, North Carolina, South Carolina, and Georgia and parts of Minnesota, Iowa, Illinois, Missouri, and Wisconsin.
Additionally, the U.S. Geological Survey (USGS) has reported that oxygen levels and dissolved minerals are among the factors responsible for high concentrations of radium in untreated water from an aquifer that underlies six states, including Missouri.
What are the risks associated with exposure to radium?
There is no immediate risk from consumption of water from the Silex public system. However, radium is a known human carcinogen and drinking water with levels of radium above MCLs for numerous years can increase the risk of developing certain cancers.
What can I do to protect myself, my family, and my friends from radium?
Radium in water, at levels above the MCL, poses a potential hazard to human health when the water is used for drinking or cooking over many years. EPA recommends that residents use alternative sources of water, such as bottled water, for drinking and cooking.
Points of Contact
EPA Region 7
- Kellen Ashford
- 816-610-2132
- ashford.kellen@epa.gov
Missouri Department of Natural Resources (MoDNR)
- Brian Quinn
- 573-751-1010
- brian.quinn@dnr.mo.gov
Missouri Department of Health and Senior Services (MoDHSS)
- Lisa Cox
- lisa.cox@health.mo.gov
Missouri State Emergency Management Agency (SEMA)
- Katy Linnenbrink
- 573-751-6294
- katy.linnenbrink@sema.dps.mo.gov