US drinking water is among the safest in the world, but not when it comes to chromium. One of the world’s largest producers of this powerhouse metal, we do a better job making it than disposing of it safely.
Now, like so many chemicals, it’s turning up in the water supply, and the health effects aren’t pretty. What exactly is chromium, and how do you remove it from your drinking water? Find out here.
Key Takeaways:
- Chromium can enter tap water through naturally occurring sources, such as rocks and soils in the water supply.
- It can also enter tap water through industrial waste from certain factories, including steel and paper mills.
- Industrial spills have been known to cause higher levels of chromium in drinking water as well.
- Reverse osmosis filtration systems are one of the best methods for removing chromium from drinking water.
What is Chromium?
Chromium is a colorless, odorless and tasteless metallic element that occurs naturally in rock and soil. There are two forms — trivalent chromium-3 (Chromium III), an essential nutrient found in many vegetables, fruits and grains — and hexavalent chromium-6 (Chromium IV), a more toxic form of chromium ore used in manufacturing.
Chemically, the difference between them is minor. But when it comes to your health, they’re worlds apart.
How Does Chromium Get into Tap Water?
Trivalent chromium comes from two natural sources — volcanic dust and the erosion of natural chromium deposits. Less common in urban areas, small amounts are present throughout the environment. It’s carried from place to place in runoff.
Hexavalent chromium also occurs naturally, but it’s oxidized for use as an industrial chemical. Present in a wide range of consumer products from inks to paint, it’s used in factories as a corrosion inhibitor and to weld or electroplate metals.
Poor storage practices at hazardous waste sites are largely to blame for Chromium VI contamination. It seeps into the soil and groundwater supplies.
Is Chromium in Drinking Water Dangerous?
If you guessed that the hexavalent form of chromium is toxic, you’re right. According to the National Institute of Environmental Health Sciences, exposure in animals and humans is linked to a broad range of health effects from rashes to cancer.
Staff exposed to high levels of chromium dust in workplace air are more likely to develop lung cancer. Other health risks of long-term chromium exposure:
- Kidney and liver disease
- Asthma
- Eye irritation
- Stomach ulcers
- Reproductive damage
- Sinus, nasal and gastrointestinal cancers
- Allergic dermatitis and more
And although hexavalent chromium is a more toxic form of this hazardous contaminant, even trivalent chromium has adverse health effects in higher-than-necessary amounts. When exposed to hexavalent chromium in air, soil or drinking water, the human body converts it to trivalent chromium, leading to total chromium toxicity.
Does the Government Regulate Chromium in Water Supplies?
The Environmental Protection Agency (EPA) regulates drinking water contaminants as a matter of public health. Under the Safe Drinking Water Act, public water systems must test for total chromium levels and keep concentrations below the EPA’s Maximum Contaminant Level (MCL) of 0.1 mg/L or 100 parts per billion (ppb).
Because the body processes Chromium VI into Chromium III, there is no specific drinking water standard for hexavalent chromium. But the EPA continues to monitor scientific developments under the Unregulated Contaminant Monitoring Rule.
States, of course, can set their own drinking water standards. In 2014, the California government set the maximum acceptable concentration of hexavalent chromium at 10 ppb after a lengthy environmental health hazard assessment.
But public water systems pushed back, saying the cost of compliance was prohibitive. A Sacramento Superior Court agreed, overturning the rule until the California State Water Board can prove it’s economically feasible.
Until then, California’s adopted a 50-ppb limit in line with other world agencies including Health Canada. And EPA’s MCL for total chromium remains an enforceable standard that carries penalties for non-compliance.
Should You Test Your Water for Chromium?
Chromium occurs naturally in most water supplies. But if you drink city water, you have an advantage. All municipalities test for total chromium levels, and some test for both trivalent and hexavalent chromium. Look no further than your annual consumer confidence report for information or go online and check chromium levels on your water supplier’s website.
If you drink well water, however, you’re out of luck. Testing for chromium is up to you. We recommend sending a water sample to Tap Score, an independent water testing company with a network of certified laboratories nationwide.
Their Essential Well Water Test checks for 52 contaminants including total chromium. You can also add a hexavalent chromium test to assess well contamination risks.
How To Remove Chromium from Drinking Water
Chromium is notoriously difficult to get rid of — a garden-variety carbon filter won’t cut it. So, let’s explore your filtration options.
Reverse Osmosis
Reverse osmosis systems filter water through a semi-permeable membrane that removes molecules larger than water. Powerful treatment technology, it’s used by water treatment plants to remove stubborn contaminants. See our recommended Reverse osmosis brands.
Undersink systems fit neatly in a cabinet where they produce up to 125 gallons per day of chromium-free water. Three to five gallons of treated water are held in a storage tank for immediate availability, and more is made on demand.
Countertop systems are equally effective, removing up to 99 percent of total chromium and a host of other contaminants from drinking water. Affordable and effortless to install, they’re a much more cost-effective and environmentally friendly option than resorting to bottled water.
Ion Exchange
Ion exchange is the same technology used in water softeners. Filters pull chromium out of your drinking water and flush it away. The best models are as effective as reverse osmosis systems, removing up to 99 percent of chromium plus hard minerals.
Unlike undersink and countertop filters that treat only drinking water, ion exchange filters are plumbed into your main water line where they treat water throughout your home, including in the shower.
The benefits of whole-home filtration for chromium, however, are often outweighed by the cost. Reverse osmosis systems start at $300 — ion exchange filters can run thousands with professional installation.
So-called lime softening — the addition of soda ash or other compounds to water to increase the pH level — is an equally costly way to eliminate chromium. Systems are complex and rarely used at the residential level. Factories and water treatment facilities use it to treat incoming water and wastewater discharge.
Why Do Some Carbon Filters Claim to Remove Chromium?
Ordinary activated carbon doesn’t remove chromium. But some filters that use carbon also contain other filtration media that does.
Brita filters, for example, use ion exchange resin in some of their models while other brands contain KDF 55 — a copper-zinc filtration media that neutralizes chromium through a chemical reaction.
All-KDF filters are rare — it’s better as a carbon booster. Part of proprietary media blends, it rarely gets the attention it deserves. But it can remove as much chromium as reverse osmosis or ion exchange filters. Still, you have to know what you’re buying.
As hybrid filtration technology improves, it’s becoming more difficult to classify filters — manufacturers don’t want to give away their trade secrets. The best way consumers can protect themselves is by purchasing an NSF-certified unit.
Filters certified by the National Sanitation Foundation (NSF) are independently tested and guaranteed to meet performance claims. They may cost a little extra because the certification process is costly. But when it comes to contaminants as harmful as chromium, it’s worth it for the peace of mind.
Evaluate claims carefully. Filters that eliminate “up to” 99-percent of chromium could remove as little as 20, 30 or 40 percent. No amount of hexavalent chromium in water is safe, so models that remove “at least” 99 percent are a better bet. And don’t be shy about asking for test results. Reputable companies aren’t shy about backing their products.
Chromium in Water — FAQs
Are children at greater risk of chromium toxicity?
Chromium is less imminently harmful to children than lead but far more hazardous than many of the contaminants we worry about in drinking water. According to the Centers for Disease Control and Prevention (CDC), children may experience the same adverse health effects as adults.
Are pets at risk for chromium poisoning?
They are. In fact, many of the studies used to understand the human health effects of chromium were done with animals.
Exposure for pets occurs primarily through the grain sources found in bargain-brand commercial pet foods and contaminated drinking water. Both children and pets may be at higher risk of exposure if they play in or consume contaminated soil.
Can I water my garden with chromium-contaminated water?
The North Carolina State University Extension Service says that chromium is not easily taken up by most common garden plants. Direct contact with contaminated soil through inhalation or ingestion, however, is a cause for concern. Take precautions if your water test is positive.
Are there other ways to reduce exposure to chromium?
Yes. The chromium level in cigarettes is high, so don’t smoke and avoid secondhand fumes. And although the chromium in vitamin pills is safe, it adds to your cumulative exposure.
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