Nearly 6 million Michigan residents drink, cook with and otherwise use tap water with an unregulated heavy metal, hexavalent chromium, at levels above where scientific study shows a cancer risk exists, a database compiled by an environmental nonprofit organization shows.
It's the same contaminant made famous in the 1990s, when law clerk Erin Brockovich investigated Pacific Gas & Electric's contamination of groundwater over decades with hexavalent chromium in the Mojave Desert near Hinkley, Calif. Average levels of the chemical in the town were more than 50 times higher than the public health guideline limit established now, and far above the levels found in Michigan tap water.
Brockovich — whose crusade was chronicled in the 2000 movie, "Erin Brockovich," starring Julia Roberts — helped spearhead a lawsuit that led to a $333-million settlement from PG&E to about 600 Hinkley residents, the largest toxic tort injury settlement in U.S. history.
Millions of Michigan tap-water users are also exposed to trihalomethanes, a group of organic chemicals that often occur in drinking water as a result of chlorine disinfecting. The U.S. Environmental Protection Agency sets maximum allowable levels of those chemicals at 80 parts per billion, but some scientific studies show a cancer risk develops at levels 100 times less, at 0.8 parts per billion. Many state water agencies are below the regulatory limit, but exceed the public health guideline.
"We don't want to scare, but we want to make people aware," said Nneka Leiba, director of healthy living science for the Environmental Working Group, which released the study today.
"When you talk to the utilities, they are going to say, 'Our water is legal.' But most people now realize, legal doesn't necessarily mean safe — especially when it comes to water."
The Working Group's national drinking water database, www.ewg.org/tapwater/, compiles water quality data from nearly 50,000 public water systems in every U.S. state and the District of Columbia. It shows thousands of municipal water supplies across the nation with what at least some scientists say are unsafe levels of chemicals arising from industrial pollution, naturally occurring sources, even water treatment itself.
Federal and state regulators set acceptable limits of tap water contaminants not just on public health thresholds, but factors including the costs and feasibility of removing the chemicals. But the Working Group's database looks at municipal water supply contaminants not just in comparison to regulatory limits, but also to the lowest scientific limit determined to represent a potential health risk.
The group encourages water users to use the database, which is searchable by ZIP code, to examine what contaminants in their water exist at levels of concern, and to consider buying an appropriate home water filter to screen the contaminant. Reverse-osmosis and charcoal-filter systems are effective on some common contaminants.
"Annual water quality reports from utilities compare their levels of various chemical contaminants to legal, regulatory limits. But the reports typically don't include chemicals that may be of concern, but for which no regulatory limit has been set, Leiba said. And legal limits aren't solely concerned with health effects, she said.
"If a chemical is harder to remove from water, or costs more, that legal limit moves up," she said. "It's no longer about health; it's a compromise between health and feasibility."
The database shows that the Great Lakes Water Authority system, serving 3.9 million people in the metropolitan Detroit region, has levels of hexavalent chromium above a health guidance level, but below state and federal averages. The water also contains trihalomethanes at levels well below federal regulatory standards, but above a health guideline standard. Also found were naturally occurring radiological contaminants Radium-226 and Radium-228. Water systems in Flint, Ann Arbor, and other locations in the state had similar detections.
Officials with both the Great Lakes Water Authority and the City of Ann Arbor emphasized that their water systems meet and surpass regulatory standards.
"The drinking water treatment process is a complex science and can vary greatly from state to state depending on source water," said water authority spokeswoman Amanda Abukhader in an e-mail. "This is why we follow federal guidelines, which are formed with the diverse input of communities, clinicians, allied health professionals, environmental advocates, and other engaged stakeholders. It is these federal guidelines that help ensure that all Americans are receiving clean, safe water."
Existing drinking water regulatory standards involve reaching scientific consensus, said City of Ann Arbor spokesman Robert Kellar.
"You can’t cherry pick a study and say, 'Let’s change what everybody’s doing based on this one set of findings,'" he said.
"We run 140,000 tests a year on the city’s drinking water, and we always try to utilize new technologies to address emerging contaminants."
But the regulatory process is "stalled," Leiba said.
"EPA has not added a chemical to the regulated list since 1996 — despite knowing about chromium-6; despite knowing about perchlorates," she said.
"Databases like ours show how ubiquitous these chemicals are. The regulatory process is such that it can be heavily influenced by industry. And industry has the ability to stymie new regulations."
Hexavalent chromium, or chromium-6, can result from industrial processes such as metal plating, steel and pulp mills, but can also occur naturally.
The health advisory guidelines cited by the Working Group for both chromium-6 and trihalomethanes were set by the California Office of Environmental Health Standard Assessment. The office conducts scientific study to determine public health goals based on a one-in-a-million lifetime cancer risk level, meaning for every million people who drank two liters of water with that level of chromium-6 daily for 70 years, no more than one person would be expected to develop cancer from being exposed to it.
The office, by California law, can't consider the feasibility of removing a contaminant, or other, non-health-related issues, said Sam Delson, a spokesman for the agency.
"We have a separation of risk assessment from risk management," he said. "We provide scientific guidance when the state Water Resources Control Board starts working on the maximum contaminant level. That board has to factor in both technical feasibility — is it feasible to achieve — and economic — would the cost be prohibitive? Obviously, in the real world, there are other factors that need to be considered."
But Leiba said the Working Group still sees value in showing water-users the unvarnished health assessments — particularly when there are things they can do about it, such as installing appropriate home water filtration systems.
"We know America has some of the best water in the world," she said. "There are areas of the world with far worse contamination problems. But that shouldn't be our comparison. The U.S. has more resources, and the ability to say, 'Here is what we're drinking now; how can we make it better?'"
Contact Keith Matheny: 313-222-5021 or firstname.lastname@example.org. Follow him on Twitter @keithmatheny.
What's in our water?
The Environmental Working Group's database, www.ewg.org/tapwater/, searchable by ZIP code, shows contaminant levels in local drinking water supplies — including those that some scientific study has shown are potentially harmful but that are not regulated by the federal EPA or states. Other contaminant levels are listed that comply with existing regulations, but that research shows lower levels could be health-harming.
Michigan's water contaminants
The stuff showing up in water systems in metro Detroit, Flint, Canton, Bay City, Midland and other water systems most frequently:
Hexavalent chromium (chromium-6): A heavy metal that can result from industrial processes such as metal plating, steel and pulp mills, but that can also occur naturally.
The risk: Has been found to cause cancer in laboratory animals.
The levels: At 0.116 parts per billion in Detroit; 0.226 parts per billion in Ann Arbor, with similar detections elsewhere.
Regulatory limit: There is no regulatory standard for chromium-6 in drinking water.
Public health guideline: A California agency's research set the one-in-a-million cancer risk from drinking chromium-6 tainted water over a lifetime at 0.02 parts per billion.
Trihalomethanes: A group of organic chemicals that often occur in drinking water as a result of chlorine treatment for disinfectant purposes.
The risk: Cancer and harm to reproduction.
The levels: 26.6 parts per billion in Detroit; 4.55 parts per billion in Ann Arbor.
Regulatory limit: Up to 80 parts per billion.
Public health guideline: A California agency's research set the one-in-a-million cancer risk from drinking water with trihalomethanes over a lifetime at 0.8 parts per billion.
What you can do
Local water agencies assure the public that their water is safe and surpasses all regulatory requirements. But those concerned about the contaminants that exceed health guidelines identified by the Environmental Working Group can buy home water filtration systems, such as a reverse-osmosis or charcoal filter system, that effectively reduce or eliminate certain contaminants.
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