Did you know that over 200 million Americans across all 50 states have been exposed to chromium-6 in their drinking water? That's according to an Environmental Working Group (EWG) analysis from 2016, and the problem hasn't disappeared. This widespread contamination often flies under the radar, but it's a chemical with a notorious past, brought into the spotlight by the tireless work of Erin Brockovich. For years, the story of chromium-6's presence in Hinkley, California, and the ensuing legal battle, captivated the nation. What many don't realize is that Hinkley was not an isolated incident; chromium-6 is a contaminant that continues to affect communities nationwide.
I’m here to tell you about chromium-6, often called hexavalent chromium, and why you should care about it. This isn't just a story about a movie; it's about your water, your health, and your right to know what's coming out of your tap. We’ll break down where it comes from, what it does to your body, and most importantly, what you can do to protect yourself and your family.
Most often, when we talk about chromium in water, we're talking about two main forms: trivalent chromium (chromium-3) and hexavalent chromium (chromium-6). Chromium-3 is actually an essential nutrient, playing a role in glucose metabolism. Chromium-6, however, is a different beast entirely. It’s a known carcinogen when inhaled, and increasingly, evidence points to its dangers when ingested through drinking water. The distinction between these two forms is incredibly important, as their health impacts are dramatically different.
The story of chromium-6 is inextricably linked with the efforts of Erin Brockovich and the residents of Hinkley, a small desert community in southern California. For decades, Pacific Gas & Electric (PG&E) used chromium-6 as a rust inhibitor in its natural gas compressor station in Hinkley, discharging wastewater directly into unlined ponds. This allowed the highly toxic chemical to seep into the groundwater, contaminating drinking water wells throughout the community.
Residents of Hinkley began experiencing a range of severe health problems: cancers, reproductive issues, and various other ailments. Brockovich, then a legal clerk, began investigating these illnesses and found a direct link to the contaminated water. Her relentless work, alongside attorney Ed Masry, led to a landmark class-action lawsuit against PG&E. In 1996, the utility was ordered to pay a record-breaking $333 million settlement to over 600 Hinkley residents. This case brought the dangers of chromium-6 to national attention, solidifying its place in environmental health history. It also highlighted the often-difficult path communities face when confronting corporate polluters.
However, the Hinkley clean-up continues to this day, decades later. The plume of contamination has spread, and nearby communities are still grappling with the legacy of PG&E's actions. What happened in Hinkley serves as a potent reminder of how long-lasting and complex environmental contamination can be, even after legal battles are won and settlements are paid. The human cost of such contamination is immeasurable, extending far beyond initial medical bills and property losses.
Chromium-6 doesn't just appear in our water out of nowhere. It has several primary sources, both natural and industrial. Naturally, it can occur in certain geological formations, leaching into groundwater. However, the vast majority of chromium-6 contamination we see in drinking water today is a result of industrial processes.
Industries that commonly use chromium-6 include: Electroplating and metal finishing: This is a major source, as chromium-6 is used for corrosion protection and to give a shiny finish to metals. Tanning: Chromium compounds are used in the tanning of leather. Textile manufacturing: Dyes and pigments often contain chromium. Wood preservation: Some wood preservatives contain chromium. Pulp and paper production: Chromium can be used in various steps of the papermaking process. Stainless steel production: Chromium is a key component of stainless steel. * Cooling towers: As seen in Hinkley, chromium-6 was historically used as a corrosion inhibitor in industrial cooling towers.
When these industries release their wastewater improperly or dispose of chromium-containing waste without adequate safeguards, the chemical can migrate into soil, surface water, and groundwater. Old industrial sites, landfills, and even spills can create long-lasting sources of contamination. The U.S. Environmental Protection Agency (EPA) acknowledges these industrial discharges as significant contributors to chromium-6 presence in water supplies across the country. Understanding these sources is the first step in prevention and mitigation efforts.
The health impacts of chromium-6 are what truly make it so alarming. While chromium-3 is benign, and even beneficial in small amounts, chromium-6 is a known human carcinogen when inhaled, causing lung cancer according to the National Toxicology Program (NTP) and the International Agency for Research on Cancer (IARC). But what about when we drink it?
For years, there was debate about whether ingested chromium-6 posed the same cancer risk. Accumulating research now strongly suggests that it does. The NTP conducted a two-year study, published in the Environmental Health Perspectives journal in 2008, which found clear evidence of cancerous tumors in rats and mice that consumed chromium-6 in their drinking water. Specifically, the study linked ingested chromium-6 to tumors in the mouth and small intestine.
Beyond cancer, chromium-6 exposure has been linked to a range of other serious health issues:
Gastrointestinal problems: Stomach ulcers, irritation, and damage to the digestive tract are common symptoms of exposure. Liver and kidney damage: These organs are responsible for filtering toxins, and chromium-6 can impair their function. Reproductive issues: Some studies suggest a link between chromium-6 and adverse reproductive effects in both men and women. Developmental problems: Pregnant women exposed to chromium-6 may face risks to their developing fetuses. * Skin irritation and allergies: Direct contact with chromium-6 can cause dermatitis and allergic reactions.
It's important to remember that these effects can vary depending on the level and duration of exposure. Long-term, low-level exposure, the kind most people might experience through contaminated drinking water, is a particular concern because the effects might not be immediately obvious, slowly accumulating over years. The Centers for Disease Control and Prevention (CDC) provides extensive documentation on the acute and chronic effects, emphasizing the need for precautionary measures.
One of the most frustrating aspects of chromium-6 contamination is the lack of a specific federal drinking water standard. While the EPA has a maximum contaminant level (MCL) for total chromium (which includes both chromium-3 and chromium-6) set at 100 parts per billion (ppb), this standard was established in 1991 and doesn't differentiate between the two forms. This is a significant loophole, as the vast majority of the health risks come from chromium-6.
Many environmental and public health advocates argue that the 100 ppb standard for total chromium is inadequate to protect public health from chromium-6. In fact, California became the first state to set an MCL specifically for chromium-6 in 2014, establishing a standard of 10 ppb. However, even this standard has faced challenges and debates, with some scientists and organizations advocating for an even lower limit. The state's Office of Environmental Health Hazard Assessment (OEHHA) had previously proposed a public health goal (PHG) for chromium-6 of 0.02 ppb, a figure 500 times lower than the adopted MCL, highlighting the scientific consensus on its extreme toxicity.
The absence of a specific federal MCL for chromium-6 means that many water utilities across the country are not explicitly required to test for it or remove it, as long as their 'total chromium' levels are below 100 ppb. This leaves millions of Americans unprotected, relying on state-level regulations or voluntary actions by their water providers. This regulatory vacuum makes it challenging for consumers to know the actual risk in their tap water and makes it difficult for affected communities to demand action from their local authorities.
Given the widespread nature of chromium-6 and the regulatory gaps, you might be wondering how to know if your drinking water is safe. Here are the steps you can take:
Don't assume your water is safe just because it tastes fine or looks clear. Many dangerous contaminants are odorless and tasteless, and chromium-6 is one of them. Proactive investigation is your best defense.
Once you know your chromium-6 levels (or if you simply want to be proactive), what can you do? Fortunately, there are effective strategies for reducing exposure.
#### 1. Water Filtration
The most direct way to protect yourself is through water filtration. Not all filters are created equal, so it's essential to choose one specifically designed to remove chromium-6.
Reverse Osmosis (RO) Systems: These are highly effective at removing a wide range of contaminants, including chromium-6, heavy metals, and PFAS. RO systems work by forcing water through a semi-permeable membrane that traps impurities. They can be installed under the sink to treat drinking and cooking water or as whole-house systems. Keep in mind that RO systems can be slow and generate some wastewater, but their effectiveness is unparalleled. Anion Exchange Filters: These filters use a specialized resin that attracts and binds to negatively charged ions, including hexavalent chromium. They are a good option for point-of-use filtration, like a faucet filter or a pitcher filter, though their capacity might be limited compared to RO systems. * Activated Alumina Filters: While not as common for residential use, activated alumina can also be effective at removing chromium-6. However, its effectiveness can be dependent on pH and other water chemistry factors.
When selecting a filter, always check for certifications from organizations like NSF International (e.g., NSF/ANSI Standard 58 for RO systems or specific certifications for chromium-6 removal). These certifications ensure that the product performs as advertised.
#### 2. Advocate for Better Regulations and Utility Action
Individual action is important, but systemic change is even more powerful. You can become an advocate for stronger regulations and better water quality in your community.
Contact Your Elected Officials: Reach out to your local, state, and federal representatives to express your concerns about chromium-6 and demand stronger drinking water standards. Let them know you support a federal MCL specifically for hexavalent chromium, independent of total chromium. Attend Local Water Board Meetings: Get involved with your local water utility's board meetings. Ask questions, voice your concerns, and encourage them to conduct specific chromium-6 testing and implement treatment technologies if necessary. Public records are public for a reason, attend these meetings and make your voice heard. Join or Support Environmental Groups: Organizations like the Environmental Working Group (EWG), Clean Water Action, and local environmental advocacy groups are constantly working to push for cleaner water and stricter regulations. Lending your support, whether through donations or volunteering, amplifies these efforts. Share Your Knowledge: Talk to your neighbors, friends, and family about chromium-6. The more people who are aware of the issue, the more pressure can be put on decision-makers to act.
The battle against chromium-6 contamination is far from over. Despite the scientific evidence and growing public awareness, strong federal action has been slow. However, the pressure from states like California, ongoing scientific research, and persistent advocacy from groups like the EWG continue to push the needle.
The EPA periodically reviews its drinking water standards, and there is hope that a specific MCL for chromium-6 will eventually be established at the federal level. This would be a monumental step, providing a consistent level of protection for all Americans, regardless of where they live. Until then, remember that knowledge is your most powerful tool. Understanding your exposure and taking proactive steps are crucial for safeguarding your health.
Start by checking your local water quality reports on Know Your Exposure. Enter your zip code or city to get an instant overview of your area's water situation. If you suspect chromium-6 might be an issue, follow up with your utility or consider independent testing. Educate yourself, filter your water, and get involved in advocating for clean, safe drinking water for everyone. Your health, and the health of future generations, depends on it.
### What is Chromium-6 and why is it dangerous? Chromium-6, or hexavalent chromium, is a highly toxic form of the element chromium. While small amounts of trivalent chromium (chromium-3) are essential for health, chromium-6 is a known carcinogen when inhaled and has been linked to various cancers and other serious health problems when ingested through drinking water. It primarily enters water supplies through industrial pollution from industries like metal finishing and electroplating.
### How does chromium-6 get into drinking water? Chromium-6 can enter drinking water from various sources, both natural and industrial. Naturally, it can leach from certain geological formations. However, the main source of contamination is industrial discharge from processes like electroplating, textile manufacturing, leather tanning, and historically, its use as a corrosion inhibitor in cooling towers. Improper disposal of industrial waste is a significant contributor.
### Is there a federal drinking water standard for chromium-6? Currently, there is no specific federal drinking water standard (MCL) for chromium-6. The EPA has a standard for "total chromium" (100 parts per billion), which includes both chromium-3 and chromium-6. This is considered inadequate by many experts, as it doesn't account for the vastly different toxicity of chromium-6. California is the only state with a specific MCL for chromium-6, set at 10 ppb.
### How can I find out if my drinking water has chromium-6? You can check your water utility's annual Consumer Confidence Report (CCR), search online databases like Know Your Exposure using your zip code, or contact your water provider directly. For private wells, or if you want definitive results, consider independent water testing by a certified laboratory.
### What can I do to remove chromium-6 from my drinking water? Effective ways to remove chromium-6 include installing a reverse osmosis (RO) filtration system, which is highly effective for a broad range of contaminants. Anion exchange filters are another option. Always look for filters certified by organizations like NSF International to ensure they meet performance standards for chromium-6 removal.
Check your water quality by zip code to see if this contaminant has been detected near you. Find water filters that remove PFAS that are certified to reduce common contaminants. For information on PFAS specifically, see our PFAS contamination guide.
Check your water now. Enter your zip code at KnowYourExposure.com to see what contaminants have been detected in your local water supply – including PFAS, lead, and other regulated compounds.