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

***Updated to include 2021 water quality data***

For Hydroviv’s assessment of Washington, D.C. drinking water, we aggregated water quality test data from D.C. Water (the public utility provider) and the U.S. Environmental Protection Agency (EPA), as well as from samples that we collect and analyze. We cross reference these data with toxicity studies in the scientific and medical literature, and look at upcoming regulatory changes. The custom water filters that build and sell for Washington, D.C. are optimized with these factors in mind.

Lead In DC Tap Water

Washington, D.C. is an old city with a lot of lead service lines, so it's not a huge surprise that D.C. has had such a big problem with lead in drinking water. Lead leaches from lead-containing pipes, solder, and fittings, unlike most contaminants which are found at the source. D.C. Water uses two sampling periods when testing for lead: January-June and July-December. In the 107 samples pulled during January-June period, the 90th percentile concentration for lead was 2 parts per billion, and 3 samples were above the 15 part per billion Action Level (AL). In the 105 samples pulled from the July-December sampling period, the 90th percentile concentration was 3 parts per billion, and one of the collected samples exceeded the action level. Although these results indicate that D.C. is in citywide compliance with federal water quality standards, it's important to point out that EPA, CDC and the American Academy of Pediatrics all agree that there is no safe level of lead for children. The bottom line is that the federal standards allow up to 10% of sampled taps to have lead concentrations over 15 parts per billion.

We highly recommend that Washington D.C. residents take a look at this map to see if their home has a lead service line, because those homes (and homes with plumbing that predates 1986) are most susceptible. We also highly recommend taking advantage of D.C. Water's free lead testing program, and any families with small children take steps to remove any lead from their water, even if they don't use a Hydroviv filter. It's important to remember that most pitchers and fridge filters do NOT remove lead from water. Hydroviv Undersink filters are NSF/ANSI 53 certified to remove lead from drinking water.

Detectable Levels of Unregulated Contaminants In DC Tap Water

One thing that has caused quite a bit of alarm from several people in this year's report is that several herbicides, VOC's and synthetic compounds were all found at detectable levels in D.C. drinking water. Herbicides such as Dalapon, shouldn't be a huge surprise seeing that D.C. draws water from near at the end of a river, so there is opportunity for agricultural runoff to enter the river. For anyone who is interested, The Maryland DEP has made the Source Water Assessment for the Potomac River (404 pages) publicly available. 

DC's Water Source: Potomac River

The Washington Aqueduct (operated by the Army Corps of Engineers) draws water from the Potomac River for treatment. District of Columbia Sewer and Water Authority (aka D.C. Water) purchases treated water from the Washington Aqueduct, and is responsible for distributing it throughout D.C. We also have a stand-alone article that entirely focuses on the Potomac River.

Left Out Of The Report: Chromium 6

We were a bit surprised to see Chromium 6 left out of the 2019 water quality report for Washington, D.C. Even though it's a known human carcinogen, chromium 6 is categorized as an "Emerging Contaminant" by EPA but is not regulated on its own. D.C. Water (and 6000 other municipalities) participate in the Unregulated Contaminant Monitoring Rule (UCMR3), which is a nationwide testing program to study "emerging" contaminants. UCMR acknowledges that contaminants on the list most likely cause adverse health effects, including cancer. The concentration in D.C. water average 86 parts per trillion. For perspective, these levels are roughly 4-5x higher than what The State Of California set as a public health goal. We believe that people should not wait for EPA to begin regulating chromium 6 on its own, and filter their water, even it they aren't using our product. It's important to remember that most pitchers and fridge filters do NOT remove chromium 6 from water.

Per and Polyfluoralkyl Substances (PFAS) In Washington, D.C. Drinking Water

PFAS are a category of chemicals found in various non-stick/stain resistant products, as well as fire fighting foam. PFAS are considered to be "emerging contaminants" because they are not currently regulated by EPA, but are known to be toxic and persistent in the environment. PFAS have been detected at surrounding military installments that are in close proximity to the Potomac River (DC's source water). Most municipalities are not required to test for, or remove, PFAS from drinking water. Not all filters are designed to remove PFAS from drinking water. If you'd like find water filters that remove PFAS from tap water, check out this Duke/NC State study.

Disinfectant

The primary disinfectant used to treat Washington DC's tap water is chloramine, except for a few weeks in the spring when DC switches over to chlorine. D.C. (and a growing number of municipalities) use chloramine instead of chlorine for a few reasons: for one, chloramine is more persistent than chlorine, so it maintains its ability to disinfect the water further away from the source. On the other side, chloramine does not quickly dissipate from water if left in a jug overnight. If you want to get it out of the water, you'll need a filter designed to remove chloramine, because a regular charcoal filter doesn't do a great job removing it.

If you want to learn more about Hydroviv's water filters, check out www.hydroviv.com, or drop us a line through live chat or email (hello@hydroviv.com). Even though we sell our products nationwide, Hydroviv is a DC company and we take care of our own backyard!

As always, feel free to take advantage of our "Help No Matter What" approach to technical support. We will answer your questions about water quality even if you have no desire to purchase one of our products. 

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What Are Heavy Metals?

Chemists categorize heavy metals as elements that are at least five times denser than water. Examples of heavy metals include: cobalt (Co), copper (Cu), chromium (Cr), iron (Fe), magnesium (Mg), manganese (Mn), molybdenum (Mo), nickel (Ni), selenium (Se), zinc (Zn), arsenic (As), mercury (Hg), and lead (Pb). Some heavy metals are essential minerals for healthy biochemical and physiological functions. Others, such as lead, chromium, arsenic, and mercury are toxic even when ingested in very small quantities. Elemental density and toxicity are interrelated. Arsenic, which is technically categorized as a metalloid (think of a metalloid as metal-like), is quite dense and is extremely toxic in very small quantities. Thus, toxicologists typically categorize arsenic as a heavy metal. Due to their shared high degree of toxicity, lead, cadmium, chromium, mercury, and arsenic are cause for significant public concern.

How Are We Exposed To Heavy Metals?

People can be exposed to heavy metals through ingestion, inhalation, or contact with skin. The severity of the health effects of heavy metals is related to the type and chemical form of each particular contaminant, and is also depends on the exposure time and dose.

Heavy metals have industrial, domestic, agricultural, medical and technological applications, and as a result they are now widespread in our environment. Heavy metal pollution in water is very high in areas where mining, smelters, metal processing refineries, wood preservation, and paper processing facilities are located. Human exposure to heavy metals as well as public concern for the associated health risks have both risen dramatically as a result of an exponential increase of their use in these various applications.

If Heavy Metals Are Toxic, Why Are They Found In Multi-Vitamins?

Some heavy metals including cobalt (Co), copper (Cu), chromium (Cr), iron (Fe), magnesium (Mg), manganese (Mn), molybdenum (Mo), nickel (Ni), selenium (Se) and zinc (Zn) are essential minerals that are necessary for various biochemical and physiological functions. They serve as components of several key enzymes and play important roles in various oxidation-reduction reactions in our bodies. Many of these metals are found naturally in the food we eat, while other foods are fortified with these minerals. For example, almost all grain products (cereal, bread, crackers, etc) are fortified with iron. Inadequate supply of these minerals can result in a variety of deficiency diseases. For example, anemia (red blood cell deficiency) can result from low iron. Supplements can prevent or treat diseases resulting from mineral deficiency.

Not all heavy metals are toxic in low quantities, however all heavy metals (yes, even the good ones) can be toxic if too much is ingested. Each heavy metal’s toxicity depends on dosage, method of exposure, age, gender, genetics, and nutritional status of the exposed individual. An excess amount of any particular heavy metal produces cellular and tissue damage leading to a variety of adverse effects and human diseases. For some including chromium and copper, there is a very narrow range of concentrations between beneficial and toxic effects, so be careful when taking supplements. Other metals such as aluminium (Al), antimony (Sb), arsenic (As), barium (Ba), beryllium (Be), bismuth (Bi), cadmium (Cd), gallium (Ga), germanium (Ge), gold (Au), indium (In), lead (Pb), lithium (Li), mercury (Hg), nickel (Ni), platinum (Pt), silver (Ag), strontium (Sr), tellurium (Te), thallium (Tl), tin (Sn), titanium (Ti), vanadium (V) and uranium (U) have no established biological functions and are considered non-essential metals in our diet.

What Is Heavy Metal Toxicity Or Heavy Metal Poisoning?

Each metal differs in how it behaves in our bodies, and exposure alone does not always cause disease or harm. Heavy metal-induced toxicity and carcinogenicity involves many biochemical processes, some of which are not clearly understood. The human body’s natural response to heavy metal exposure is to store them and slowly excrete them over time to minimize organ damage.

Acute heavy metal poisoning usually occurs when people are exposed to large amounts of one particular metal at a time. For example, a child swallowing a lead bullet can cause a large amount of lead exposure all at once. Acute exposures can quickly cause serious health effects or death.

Chronic or long-term exposure to lower levels of heavy metals can also cause health problems. The symptoms of chronic heavy metal poisoning can be severe, but are often less obvious and develop much more slowly over time than the symptoms caused by acute exposure. This is a topic of growing scientific evidence that needs to be better researched to clarify all the possible health implications. Chronic heavy metal poisoning can be challenging for both health care providers and patients because there are often many more questions than answers. Symptoms of chronic heavy metal toxicity can include but is not limited to headaches, fatigue, muscle and joint pain, and weakness. However, these same symptoms can be caused by many other health problems unrelated to heavy metal toxicity. True chronic heavy metal poisoning is rare but also difficult to diagnose.

What Are The Health Effects Of Heavy Metal Toxicity?

Even in very low quantities, lead, cadmium, chromium, mercury, and arsenic are known to induce cardiovascular diseases, developmental abnormalities, neurologic and neurobehavioral disorders, diabetes, hearing loss, hematologic and immunologic disorders. These heavy metals are also classified as human carcinogens (known or probable) according to the U.S. Environmental Protection Agency, and the International Agency for Research on Cancer.

Although the acute and chronic effects are known for some metals, little is known about the health impact of mixtures of heavy metals. Studies have shown that toxic heavy metals can interfere with absorption and use of nutritionally essential metals such as iron, calcium, copper, and zinc. However, the research on the combined effects of heavy metal exposure is very limited.

How Can I Minimize Exposure To Heavy Metals?

The best way to reduce heavy metal pollution is prevention. Identify sources of heavy metals in your home and remove them. Here are some helpful suggestions:

• Be aware of local fish advisories for mercury contamination.
• Test the water in your home for heavy metals and install a home water filtration system if necessary.
• Read labels on products coming in to your home.
• Store products containing heavy metals out of reach of children.

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Rebecca Labranche | Laboratory Director, A&L Laboratory

How Is Drinking Water Regulated?

The Environmental Protection Agency (EPA) sets regulatory limits for over 90 contaminants in water provided by public water systems. The EPA sets these limits in accordance with the Safe Drinking Water Act to protect public health in the communities that are using this water. The EPA limits are divided into two main categories. National Primary Drinking Water Regulations are legally enforceable standards that apply to public water systems. Primary standards protect public health by limiting the levels of contaminants in drinking water that negatively affect human health. National Secondary Drinking Water Regulations are non-enforceable guidelines regulating contaminants that may cause cosmetic effects (such as skin or tooth discoloration) or aesthetic effects (such as taste, odor, or color) in drinking water. EPA recommends secondary standards for water systems but does not require systems to comply. In addition to the federal EPA standards, The Safe Drinking Water Act (SDWA) gives individual states the opportunity to establish their own drinking water standards if they are not more lenient than those set by the EPA's national standards.

So how do these federal and state regulations affect private well-owners? These same limits and guidelines used for public water are also adopted by most institutions and lenders for home water testing as a way to determine if the property provides potable, safe water. When a home goes up for sale, if the buyer is financing, they will likely be required to test the water. While lenders may be concerned about a potable water source in order to protect their investment, there are no official rules or regulations for determining potability of private wells. Many states and towns do not even require sampling of private wells after installation. It is the responsibility of the homeowner to maintain their well and water supply. 

How Often Should Home Water Testing Be Conducted?

Private well water should be tested a minimum of once per year. Drinking water supplies obtained from shallow dug wells and surface water sources should be tested more frequently as they are more susceptible to contamination. Annual testing of both dug and drilled wells should check for the most common contaminants which are bacteria, nitrates and nitrites. Even if your water has consistently been safe to drink in the past, these parameters could change without you knowing, and affect the safety of your water. New drilled wells should be tested with a more comprehensive water test which includes bacteria, nitrates, nitrites, metals, minerals and radon. This test identifies many common primary and secondary contaminants typically found in the bedrock surrounding the well. This comprehensive test should be repeated every 3 – 5 years to ensure the well is still providing safe water.

What Are The Most Common Types Of Drinking Water Contaminants?

Drinking water contaminants can be divided into several categories: Inorganic Chemicals, Organic Chemicals, Radionuclides and Microorganisms. Testing for every possible analyte would be prohibitively expensive but we have put together a comprehensive test package which covers common problems found in our area.

Laboratories throughout the United States will offer similar packages based on the geology in their area.

What Is The Process For Analyzing Drinking Water?

The process of analyzing drinking water varies by laboratory and their methods used. However, the basic premise is the same for all of them. The first step is to obtain a water test kit from the certified drinking water laboratory that you intend to use for the analysis. Home water testing kits are specific to each laboratory and their methods so it is important not to use another laboratory’s bottles. These test kits come with all the information that is needed to collect the sample and get it back to the laboratory in the required time frame. The sampling instructions are usually step by step and easy to follow. Once the water is received by the laboratory it will be analyzed for the requested parameters and a report will be generated and sent back to the client. The typical turn-a-round time for a comprehensive water test is 2-3 business days.

Using a certified laboratory is very important. They are monitored by their state and undergo periodic inspections to ensure that they are producing the highest quality data. During these inspections their instruments, standard operating procedures, lab technicians, quality control documentation and reporting procedures are reviewed and evaluated. If anything is found to be out of compliance certification for the laboratory can be revoked. In addition to inspections, they also have to complete proficiency tests for each method they conduct to prove that they can perform the method properly and obtain results within the specified limits.

What Are The Risks Associated With Consuming And/Or Using Contaminated Water?

The risks vary greatly depending on which contaminants you have in your water. Common health effects include gastrointestinal illness, reproductive problems, neurological disorders and cancer. These health problems pose a greater threat to young children, pregnant women, the elderly, and people with compromised immune systems. The health effects of drinking contaminated water can range from no physical impact to severe illness or even death.

Some of the effects of drinking contaminated water are known almost immediately. Immediate health related issues generally stem from contamination by pathogens such as total coliform and E.coli. Symptoms include gastrointestinal and stomach illnesses such as nausea, vomiting, cramps, and diarrhea.

Other contaminants pose health effects that may not be observed for many years. Some of the most common ones are:

Arsenic in water occurs naturally as well as from industrial activities. Studies have shown that chronic or repeated ingestion of water with arsenic over a person’s lifetime is associated with increased risk of cancer (of the skin, bladder, lung, kidney, nasal passages, liver or prostate) and non-cancerous effects (diabetes, cardiovascular, immunological and neurological disorders).

Lead can occur due to corrosion of lead containing household plumbing and by industrial pollution. Major toxic effects include anemia, neurological dysfunction/damage and renal impairment.

Uranium is a tasteless, colorless, odorless contaminant. Drinking water with uranium amounts exceeding 30ug/L can lead to increased cancer risk, liver damage, or both.

Copper has both long term and short term effects. Some people with short term exposure, experience gastrointestinal distress, and with long-term exposure may experience liver or kidney damage. It is typically introduced into the water from household plumbing systems.

Fluoride has been shown to reduce tooth decay in children's teeth if they receive an adequate level. The optimal concentration, as recommended by CDC is approximately 1.1 mg/L. In the range of 2.0-4.0 mg/L of fluoride, staining of tooth enamel is possible. Above 4.0 mg/L, studies have shown the possibility of skeletal fluorosis, as well as the staining of teeth.

Radon is the second leading cause of lung cancer. High levels of radon gas occur naturally in Maine soil and water, and can move up into a house from the ground. The house then traps the radon in the air inside. Radon gas can also dissolve into well water, which is then released into the air when you use the water.

What Should I Do If The Laboratory Finds Something In My Water?

If tests on your water indicate problems, the next step is to determine what type of system you need to treat the water. This can be a difficult decision because there is a wide variety of water treatment devices on the market today. Water purifiers range from relatively low-cost, simple filter devices for a kitchen faucet to more expensive, sophisticated systems that treat water from its point of entry into a home. Keep in mind, no one water treatment device can solve every problem.

Rebecca Labranche is the Laboratory Director for A & L Laboratory. A & L Laboratory specializes in drinking water analysis for both public systems and private wells throughout the State of Maine.

Editor's Note: Since this article was first written, more drinking water contaminants have gained attention in the news.These include Per and Polyfluoroalkyl Substances (PFAS), which have recently become Federally regulated in drinking water. If you want to get your water tested and are unsure of what to request, feel free to contact our Water Nerds at hello@hydroviv.com. We can discuss your water concerns and help you prioritize which contaminants to test for.

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Eric Roy, Ph.D.  |  Scientific Founder

Since The Environmental Working Group recently released a report about the prevalence of chromium-6 in drinking water supplies, our email and support line have been filled with questions about the toxic heavy metal. The purpose of this article is to address a lot of these FAQs, including the answer to "what is chromium-6?," and to discuss how to remove chromium 6 from drinking water.

Is Chromium-6 the Same Thing as “Regular” Chromium?

No. So what is chromium-6? Chromium comes in a variety of chemical “flavors.” Most forms of chromium (e.g. chromium metal, trivalent chromium) are not toxic. These are the types of chromium used to make stainless steel and are found in dietary supplements. There is no reason to be throwing away stainless steel cookware!

Chromium-6 (or hexavalent chromium), on the other hand, is an extremely toxic form of chromium, and is known to cause cancer, even at very low concentrations. In popular culture, chromium-6 is the chemical that was at the center of the Erin Brockovich story, which was made into a movie starring Julia Roberts.

Where Does Chromium-6 Come From?

Unfortunately, chemicals containing chromium-6 are useful in a number of industrial processes, which means that chromium-6 can enter drinking water supplies through waste streams that enter rivers and ground water. Industries that generate chromium-6-containing waste include: steel production, leather tanning, textile manufacturing, wood preservation, and electroplating.

How Is Chromium-6 Regulated?

It's not. In 1991 EPA set a Maximum Contaminant Level (MCL) for total chromium (all kinds) in drinking water of 200 parts per billion. The structure of this regulation is flawed because it treats non-toxic forms of chromium in the same manner as highly toxic chromium-6. To put it in perspective, California (which has tighter regulatory conditions that the EPA) has set a proposed limit of 20 parts per trillion for chromium-6, a level that is 10,000 times lower than what the current EPA regulation is for total chromium. Part of the challenge in formulating a proper regulation is that advanced detection procedures and equipment are required to measure things at part per trillion concentrations.

Are the Recent News Articles the Result of a Recent Spike in Chromium-6 Concentrations?

No. There is no sudden rise in chromium-6, the media coverage is just shining light on an existing situation.

What Can I Do To Reduce Exposure To Chromium-6?

Unlike lead, which leaches into water from pipes, chromium-6 comes from the source water itself, so flushing pipes does not reduce concentrations of chromium-6 in drinking water. Boiling water also does not reduce/remove chromium-6.

If you want to remove chromium-6 from your water, you need to filter it using a high end water filter. Filtration pitchers and common fridge filters DO NOT filter chromium-6 from water. A new generation of water filters that use chromium 6 removal media are extremely effective at filtering chromium-6 (and other contaminants) from water. Reverse osmosis is also a viable way to remove chromium 6 from water for people who are willing to accept the drawbacks, including low flow rate. We recently wrote a more in depth article on how to filter chromium 6 from water.

If you have any questions about filtering chromium-6 from your water, we encourage you to take advantage of Hydroviv’s “Help No Matter What” approach to technical support, where we will help you select an effective water filter system, even if it’s not one that we sell. This free service can be reached by emailing support@hydroviv.com

Update April 23, 2017: We have published an article specifically on how to filter chromium 6 from drinking water. See it HERE

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