Strontium contamination in drinking water is a serious but often overlooked public health concern. Unlike uranium or radium, which regularly make headlines, strontium receives far less media attention despite being regulated by the EPA with the same urgency and a strict maximum contaminant level (MCL) of 8 picocuries per liter (pCi/L). For homeowners in affected regions, particularly the Midwest and Southwest, understanding strontium's health risks and removal options is essential for protecting your family's long-term health.
What Is Strontium and Where Does It Come From?
Strontium is a naturally occurring radioactive element found in soil and rock formations across North America. When water percolates through these geological layers, it dissolves strontium and carries it into groundwater supplies that feed wells and municipal water systems. Strontium is chemically similar to calcium, which is why it bonds easily with water molecules and persists in the environment for decades.
The primary sources of strontium in drinking water are:
- Geological deposits: Certain rock and mineral formations naturally contain radioactive strontium isotopes, particularly strontium-90, a byproduct of uranium decay and historical nuclear weapons testing fallout.
- Groundwater wells: Private wells and some municipal water systems that rely on deep groundwater are more likely to encounter strontium than surface water sources.
- Regional prevalence: Strontium contamination is most common in the Midwest (particularly Kansas, Nebraska, and Iowa), parts of the Southwest, and some areas of Texas and Oklahoma, though it can occur anywhere with specific geological conditions.
Strontium-90, the radioactive isotope of primary concern, has a half-life of approximately 29 years, meaning it remains dangerous in the environment and in human tissue for centuries.
EPA Regulations and Maximum Contaminant Levels
The U.S. Environmental Protection Agency (EPA) classifies strontium as a radioactive contaminant and has established a maximum contaminant level (MCL) of 8 pCi/L for combined radium (radium-226 and radium-228) and a separate standard for gross alpha particle activity of 15 pCi/L, which includes strontium-90. This means that water suppliers are legally required to keep strontium levels below these thresholds.
Public water utilities are required to test for radioactive contaminants, including strontium, and notify customers if levels exceed the MCL. However, many private well owners have no obligation to test, leaving them vulnerable to undetected strontium exposure. The Safe Drinking Water Act mandates that municipal water systems provide annual Consumer Confidence Reports (also called water quality reports) detailing any contaminants found, which may include strontium levels.
It's important to note that the EPA's MCL is based on cancer risk assessments and bone toxicity data, meaning even small amounts of strontium in drinking water may pose health risks, particularly to vulnerable populations.
Health Effects of Strontium Exposure
How Strontium Affects the Body
Strontium behaves similarly to calcium in the human body. When ingested through drinking water, it is absorbed into the bloodstream and accumulates in bones and teeth over time. This bioaccumulation is the primary concern: strontium doesn't leave the body quickly, but instead concentrates in skeletal tissue where the radiation exposure is most damaging.
Health Risks Associated with Strontium
Bone and skeletal damage: Chronic strontium exposure damages bone cells and can weaken bone density, increasing fracture risk and leading to conditions similar to osteoporosis. Children are particularly vulnerable because their bones are still developing and they consume more water relative to body weight than adults.
Cancer risk: As a radioactive isotope, strontium-90 emits beta particles that can damage DNA in bone marrow, the tissue responsible for producing red and white blood cells. The EPA's MCL is based on a cancer risk level of 1 in 10,000 over a lifetime, suggesting that exposure at or near the legal limit carries a measurable cancer risk.
Leukemia and blood disorders: Studies of populations exposed to strontium-90 fallout from nuclear testing have shown increased rates of childhood leukemia and other blood cancers, suggesting a direct link between strontium exposure and bone marrow damage.
Children at higher risk: Young children face greater health risks from strontium exposure because they drink more water relative to body weight, their bones are still mineralizing (making them more susceptible to strontium substitution for calcium), and their developing immune systems are more vulnerable to radiation damage.
Pregnant women: Strontium can be transferred to the fetus through the placenta and to infants through breast milk, potentially affecting fetal bone development and increasing lifetime cancer risk for the child.
Testing for Strontium in Your Water
Public Water System Testing
If you receive water from a municipal water utility, your water supplier is required to test for radioactive contaminants including strontium at least once every four years (or more frequently in some cases). You can find these results in your annual water quality report, which utilities are required to provide to all customers by July 1 each year. You can also request a copy directly from your water utility or check your utility's website.
To locate your water supplier's report and see if strontium has been detected in your area, use a free tool like ClearWater's ZIP code lookup (checkclearwater.com), which aggregates EPA data and provides easily understandable summaries of your local water quality, including any radioactive contaminants.
Private Well Testing
If you have a private well, testing for strontium is your responsibility. The EPA does not mandate testing for private wells, but the agency strongly recommends that private well owners test at least once for radioactive contaminants. Here's how:
- Contact your local or state health department: Ask for a list of certified laboratories that can test for radioactive contaminants. Many states maintain lists of approved testing facilities.
- Request a radioactive contaminant panel: Ask for testing that specifically includes strontium-90 or gross alpha particle activity, which includes strontium.
- Collect samples properly: The laboratory will provide instructions for collecting water samples in sterile containers. Improper collection can invalidate results.
- Review results within context: If strontium is detected above 8 pCi/L, your water exceeds the EPA's safe drinking water standard and treatment is strongly recommended.
Testing typically costs between $100 and $300 for a radioactive panel, depending on your location and the laboratory. Some state environmental agencies offer subsidized or free testing programs for private well owners.
When to Test
If you have a private well and live in a strontium-prone region (Midwest, Southwest, parts of Texas and Oklahoma), testing should be a priority. Even if you don't live in a historically high-strontium area, if your home is on a private well, consider testing at least once. New construction or significant drops in water quality are also reasons to test.
Water Removal Methods for Strontium
Reverse Osmosis (RO) Systems
Reverse osmosis is one of the most effective methods for removing strontium from drinking water. These systems use a semi-permeable membrane to force water through tiny pores, blocking dissolved minerals and radioactive particles while allowing pure water to pass through. RO systems typically remove 90-95% of strontium.
Advantages: High removal efficiency, relatively simple operation, and improved taste and odor as a side benefit.
Disadvantages: RO systems produce wastewater (typically 3-4 gallons of waste for every 1 gallon of treated water), require regular filter replacement, and reduce water pressure in the home.
Best for: Drinking water and cooking water from under-sink or countertop systems; generally not practical for whole-house treatment due to waste water concerns.
Ion Exchange Systems
Ion exchange softeners, often used to remove calcium and magnesium hardness, can also remove strontium through a chemical process where resin beads exchange strontium ions for sodium or potassium ions. However, strontium removal effectiveness varies depending on water hardness and other dissolved minerals.
Advantages: Can treat whole-house water supplies, reduces water hardness simultaneously, and doesn't produce wastewater during filtration.
Disadvantages: May add sodium to treated water (a concern for people on sodium-restricted diets), requires periodic resin recharging with salt, and effectiveness depends on specific water chemistry.
Best for: Homes with moderately hard water seeking a dual-purpose system that removes both hardness and radioactive contaminants.
Granular Activated Carbon (GAC) Filters
Standard activated carbon filters are not effective at removing strontium or other radioactive contaminants. While these filters excel at removing chlorine taste and odor, they do not bind radioactive particles and should not be relied upon as a strontium treatment method.
Distillation Systems
Distillation involves boiling water and collecting the steam condensate, which leaves behind dissolved minerals including strontium. This method is highly effective (removes 99%+ of strontium) but is slow, energy-intensive, and impractical for large household water needs. Distillation is best used as a supplemental treatment for drinking water only.
Selecting a Treatment System
The best treatment method depends on your water test results, household size, budget, and whether you want to treat your entire home's water or just drinking and cooking water. A water test showing strontium levels will help guide your choice. Consulting with a water treatment professional or your state's drinking water program can help you select the most appropriate system for your situation.
Steps You Can Take Today
If you're concerned about strontium in your water, here are immediate actions to protect your health:
- Check your local water quality: If you have municipal water, retrieve your water supplier's latest water quality report or use a free online tool to see if strontium or other radioactive contaminants have been detected. Use ClearWater (checkclearwater.com) to search by ZIP code and get a plain-language summary of your water quality.
- Test private wells: If you have a private well, contact your state health department to find a certified laboratory and schedule testing for radioactive contaminants.
- Install a point-of-use treatment system: If testing confirms strontium above safe levels, consider installing a reverse osmosis system under your sink to treat drinking and cooking water immediately. This is the fastest way to reduce exposure.
- Reduce water consumption from contaminated sources: While treatment is being arranged, use bottled water for drinking and cooking if strontium has been confirmed in your water supply.
- Inform your family: Ensure household members, especially children, understand the importance of using treated water for drinking and cooking.
- Stay informed: Request updated water quality reports annually and remain aware of any changes in your water supply, particularly if you live in a region historically affected by strontium contamination.
Key Takeaways
Strontium is a radioactive contaminant regulated by the EPA with a maximum safe level of 8 pCi/L, yet it remains underrecognized compared to other water quality threats. The element accumulates in bones and teeth, with the potential to cause bone damage, weaken immunity, and increase cancer risk, particularly in children and pregnant women. Regions in the Midwest, Southwest, and parts of Texas and Oklahoma face elevated risk, though strontium can occur anywhere.
Testing is the first step: municipal water customers should review their water quality reports, while private well owners should contact their state health department to arrange testing with a certified laboratory. If strontium is present above safe levels, reverse osmosis and ion exchange systems offer effective removal options.
By taking action today, you reduce your family's lifetime exposure to this silent contaminant and protect long-term health. Use every resource available, including your water utility's reports and tools like ClearWater, to stay informed about what's in your tap water and make informed decisions about treatment.