Wendy Spicer, M.S.  |  Scientific Contributor
***Updated 10/27/2022 to include recent health studies and regulatory status. 

If you have seen the movie Erin Brockovich, you are familiar with chromium 6 (also known as hexavalent chromium and chromium VI). The film tells the story of a legal clerk turned activist who uncovers that a California utility company, Pacific Gas and Electric (PG&E), was knowingly dumping chromium 6 waste and contaminating the local water supply. Brockovich’s law firm, Masry and Vititoe, represented over 600 clients in a lawsuit against PG&E which settled for $333 million dollars in 1993. Despite the success and fame of this story, chromium 6 water contamination remains largely unregulated and problematic across the United States. The Environmental Working Group estimated that in 2015, water supplies serving over 218 million Americans were contaminated with chromium 6.

What Is Chromium?

It is important to note that there are 2 very different forms of chromium that are often grouped together when reporting contaminant levels. These two different types vary based on their oxidation states, meaning that they differ in the number of electrons surrounding the atom’s nucleus. Chromium (III), or trivalent chromium is a naturally occurring element that is an essential nutrient, and is beneficial, not toxic to humans. In fact, chromium(III) plays a role in glucose, fat, and protein metabolism by increasing the effect of insulin.

However, chromium 6 is the highly-toxic form of chromium. Industrial discharge is the largest source of chromium 6 in our environment and is released into air and wastewater by metal processing facilities, tannery facilities, chromate production, stainless steel welding, ferrochrome production, and pigment production. The major way that most people are exposed to chromium 6 is through contaminated food and water.

What Are The Adverse Health Effects Of Chromium in Water?

There is strong evidence that chromium 6 is a human carcinogen. The most recent EPA draft toxicity review states "Cr(VI) is likely to be carcinogenic to humans by the oral route of exposure.” 

Specifically, this study suggests that chromium 6 causes stomach cancer in humans, consistent with previous tumor results reported in rodent studies. Chromium 6 exposure is also known to cause multiorgan toxicity such as kidney damage, allergy, and asthma. This study compared the toxicity of chromium 3 to chromium 6 in kidney cells, and scientists observed toxic effects in cells treated with chromium 6 but not with chromium 3.

In addition to being a likely carcinogen, the most recent EPA draft toxicity review discusses negative health effects affecting organ systems  including gastrointestinal, liver, immune, hematologic, as well as the male reproductive system. In addition, the developing fetus is considered especially susceptible because Chromium 6 was determined as a likely cause of developmental toxicity in humans. 

Chromium 6 is also a known endocrine-disrupting chemical, and this study documented that environmental exposure to chromium 6 caused detrimental reproductive effects in women and negative health effects in infants in California. In fact, the scientists reported that women with occupational chromium 6 exposure experienced infertility, pregnancy loss, spontaneous abortion, and stillbirth.

Breathing high levels of chromium 6 can cause irritation to the lining of the nose, and nose ulcers. Lung and respiratory cancers are more common in industrial workers (where it is more likely to be inhaled) while gastrointestinal tumors are more common in humans and animals exposed to chromium 6 in drinking water. Accidental or intentional ingestion of extremely high doses of chromium 6 compounds can cause acute respiratory, cardiovascular, gastrointestinal, hematological, hepatic, renal, and neurological distress which may result in death.

Is Chromium 6 Regulated?

Chromium 6 in drinking water is not currently regulated by any State or at the Federal Level. However, the California Water Resources Control Board’s Drinking Water Program is the first in the nation to unveil a proposal to set a “maximum contaminant level” (MCL) of 10 parts per billion, or ppb, in water. The board is also proposing to set the “detection limit,” which would trigger reporting, at 0.05 ppb. The current Public Health Goal in California (the level below which there is no expected health issues) for Chromium-6 is 0.02 ppb.

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Eric Roy, Ph.D.  |  Scientific Founder

Since the lead crisis in Flint put lead contamination in the national spotlight, our Tech Support Team is frequently asked questions about testing a home’s water for lead.   Many who reach out to us do so after having been duped by "testing companies" looking to make a quick buck.  This article discusses how to test your home's water for lead accurately & cost-effectively.  

Check For Free City Programs

Some large cities (like Washington DC, NYC, Chicago) have programs in place where residents can submit samples to the city for free lead testing.  We strongly encourage people to take advantage of this free service if it's available to them.  

Ignore Marketing Gimmicks And Find An Accredited Laboratory For Lead Testing

Most of the consumer “test kits” you find at hardware stores or large online retailers are almost always for low cost “screening” tests that are notorious for false alarms and inconclusive results, which allows the lab to upsell you on a more sensitive and accurate test.  Don't be fooled by marketing claims that a kit is "EPA Recognized" or "Tests to EPA Standards"... they don't mean anything.  With lead, you should simply find an accredited water quality lab in your area, and request their test kit.   We recommend finding a lab that uses EPA Method 200.8, which is an Inductively Coupled Plasma, Mass Spectrometry (ICP-MS) based method that gives accurate results at low concentrations.  

Sample Properly From The Faucet 

Because lead contamination occurs when water sits in lead-containing plumbing pipes, solder, and connections, it’s important that you sample from the faucet and collect at a time when your home’s water has not been used for at least 6 hours (like first thing in the morning)

We recommend collecting 3 samples:  one as soon as you turn on the faucet (also known as a "first draw"), and separate samples after the water has been running for 30 seconds, and 2 minutes.   The reason for collecting multiple samples in this interval is to sample water that sat overnight in different parts of the home’s plumbing and service line. 

Get Help Interpreting Lead Test Results

If all samples come back at zero, you’re probably in the clear for lead.  This is a good thing!

If any of the samples come back above zero, the interpretation gets quite a bit more complicated because EPA’s statements on lead toxicity and regulations are not in alignment.  On one hand, EPA states that there is no safe level of lead, which would imply that lead concentrations should be zero.  However, EPA has established a 15 ppb “Action Level” for lead… which most people (and some media outlets) interpret to mean “if my water is under 15 ppb, it’s safe.”  Unfortunately, that’s simply not true, because the 15 ppb Action Level threshold was established to tell whether or not city-wide corrosion control measures are having problems, not if a single sample contains too much lead.  Furthermore, the EPA allows for up to 10% of samples collected under the Lead and Copper Rule to test above the 15 part per billion Action Level (with no upper limit), and the city remains in compliance.

The reality is, if your water has lead in it after letting water sit in pipes for 6 hours or more, we highly recommend taking steps to reduce exposure, whether it's using a point of use water filter that is rated to remove lead, or allowing your water to run for 2 minutes before using it for drinking, cooking, or washing food.  

We encourage everyone to take advantage of Hydroviv’s “Help No Matter What” approach to Technical Support when it comes to water.  Even though we do not offer lead testing, our water quality experts are happy to give advice through all stages of the lead testing process, free of charge, to make sure that you get answers in the most efficient way possible.  We do not take money from test labs for referrals.

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