gfrphoto/Flickr

An environmental advocacy group tested tap water in Bend and found hexavalent chromium, a natural mineral and manufacturing byproduct that the EPA says "is likely carcinogenic in humans" though utilities are not specifically required to test for it in the water supply.

The Portland Water Bureau has sent out a response to the Environmental Working Group’s tests showing hexavalent chromium in drinking water across the country to reassure its customers that Portland water is safe to drink. The bureau says it will follow the Environmental Protection Agency’s new recommendations for how utilities can monitor the probable carcinogen and let customers know how much of it is in their drinking water.

Portland’s drinking water comes from the protected Bull Run and Columbia South Shore Wellfield watersheds, and the Portland Water Bureau tests Bull Run water for total chromium three times a year. Since 2000, 30 of 33 samples from Bull Run have shown no trace of chromium. The highest level detected was 3 parts per billion, which is more than 30 times below the federal limit for total chromium.

Note, however, that’s total chromium.

Hexavalent chromium is one of two key types of chromium that can be found in drinking water. Trivalent chromium is another kind, and it can actually have beneficial health effects. Hexavalent chromium, or chromium-6, is carcinogenic when inhaled, and the EPA has said it is a “likely carcinogen” when ingested. But the EPA doesn’t have specific drinking water limits for chromium-6 yet, so water utilities are not required to test for it. New standards for how much chromium-6 is safe to drink are still underway, but in the meantime, the Portland Water Bureau says it is developing a testing plan that will meet the EPA’s latest recommendations.

Any word from your utility on how they handle chromium-6? I’d be interested to hear about any new action on hexavalent chromium at other utilities around the state.

The EPA released the new recommendations today, saying they respond to emerging scientific evidence that chromium-6 could pose health concerns if consumed over long periods of time. They also follow a Environmental Working Group report that their volunteers found hexavalent chromium in the tap water of cities across the country – including Bend.

Details about the new recommendations, from the EPA:

“The enhanced monitoring guidance provides recommendations on where the systems should collect samples and how often they should be collected, along with analytical methods for laboratory testing. Systems that perform the enhanced monitoring will be able to better inform their consumers about any presence of chromium-6 in their drinking water, evaluate the degree to which other forms of chromium are transformed into chromium-6, and assess the degree to which existing treatment affects the levels of chromium-6 in drinking water.”

Three things to know (in addition to the fact that some experts say we shouldn’t worry about the low levels detected):

1. The water sample containing chromium-6 was taken from a tap served by private water utility Avion Water Co. (one of three that serve the city).
2. Avion serves 12,000 customers in central Oregon, including roughly 6,000 in Bend city limits and 6,000 in the area north of Redmond and West of La Pine.
3. Avion said because the sample was collected at the tap instead of at the source or main waterline, it’s harder to tell where the chromium-6 came from.

“EPA absolutely has a drinking water standard for total chromium, which includes chromium-6 (also known as Hexavalent Chromium), and we require water systems to test for it. This standard is based on the best available science and is enforceable by law. Ensuring safe drinking water for all Americans is a top priority for EPA. The agency regularly re-evaluates drinking water standards and, based on new science on chromium-6, had already begun a rigorous and comprehensive review of its health effects. In September, we released a draft of that scientific review for public comment. When this human health assessment is finalized in 2011, EPA will carefully review the conclusions and consider all relevant information, including the Environmental Working Group’s study, to determine if a new standard needs to be set.”

Background, also from the EPA:

• Currently, the total chromium standard is 0.1 mg/L (100 parts per billion).

• Our latest data shows no U.S. utilities are in violation of the standard.

• More information on chromium

• Track the status of the ongoing risk assessment

The group found the probable carcinogen chromium-6 in Bend’s drinking water – the only city in Oregon that was tested. But it’s still unclear what level is safe to ingest. California has a public health goal of .06 parts per billion (not binding), and Bend’s water sample showed levels of .78 parts per billion. Should Bend residents be worried (or maybe just investing in reverse-osmosis water filtration systems)?

From NYT:

“The chemical has been linked to increased cancer risk. But Allan Smith, a professor of epidemiology at the School of Public Health at the University of California, Berkeley, said the concentrations reported by the Environmental Working Group were probably no cause for concern.

“The public should not be alarmed by the very small concentrations being reported for most cities,” Dr. Smith wrote in an e-mail message.

Other experts disagreed. Max Costa, chairman of the department of environmental medicine at New York University’s School of Medicine, told The Washington Post that the levels of the chemical were “disturbing” and said that states should strive to eliminate the presence of the chemical from water entirely.”

The Environmental Protection Agency has yet to weigh in on what level of chromium-6 is acceptable.

David Nogueras reports the Bend public works director Paul Reault notes the EWG report doesn’t detail where the Bend water samples were taken or how they were handled. And the samples still meet state and federal drinking water standards.

Paul Reault: “Out of the thousands of samples that are taken here in this city and all of the different elements that are tested for you have one that came back that exceeded not Oregon standards but if I recall correctly, exceeded a California Standard.”

Oh, and another issue Allen Smith mentioned: What about arsenic in well water? Arsenic is a known carcinogen with a 10 parts per billion federal limit in drinking water, and a lot of private well water far exceeds that standard. Are we focusing too much here on a possible threat at the expense of real public health threats?

gfrphoto/Flickr

An environmental advocacy group tested tap water in Bend and found hexavalent chromium, a natural mineral and manufacturing byproduct that the EPA says "is likely carcinogenic in humans," though utilities are not specifically required to test for it in the water supply.

How much hexavalent chromium is too much when it’s in your drinking water?

That is one of many  questions lingering in the wake of The Environmental Working Group’s report on carcinogenic chromium in tap water across the country. Water samples taken by volunteers showed 31 of 35 cities tested had more hexavalent chromium in their tap water than the proposed legal limit in California.

The Environmental Protection Agency says hexavalent chromium is definitely a carcinogen when inhaled, but it is still reviewing how dangerous it is when ingested, as it is in drinking water.

A draft review this year concluded orally ingested hexavalent chromium is “likely to be carcinogenic to humans” based on science showing ingestion increased the risk of gastrointestinal tumors in laboratory rats and mice, evidence tying oral exposure to stomach cancer in humans, and tests indicating that chromium can damage DNA.

There are two well-known types of chromium that can be found in drinking water; hexavalent chromium, or chromium-6 is the more dangerous of the two (chromium-3 can actually have health benefits). It can find its way into drinking water through erosion of natural sources and through discharges from manufacturers of stainless steel, metal plating, wood products and textiles. A reverse osmosis filtration system will remove the contaminant.

In Bend, the samples showed hexavalent chromium levels at .78 parts per billion – 13 times the proposed limit in California. And that’s the only city in Oregon that was tested; the report doesn’t tell us anything about tap water in Portland, Salem, Eugene, Corvallis or elsewhere. Though The Oregonian reports Bend was chosen because its tap water had elevated chromium levels in the past:

“The nonprofit selected cities in 23 states that had elevated levels of total chromium in past water quality reports. Bend had registered two spikes in total chromium in 2004, although both were nearly 100 times less than the EPA’s legal limit, state water quality officials said.”

Why are we talking about proposed limits in California? Well, the EPA hasn’t set a limit on chromium-6 in drinking water. It only regulates total chromium. California, however, is the notorious home of Hinkley, where Erin Brockovich made history by exposing chromium-6 contamination in the groundwater and winning a tort settlement for the locals who had been affected by it. The state allows just half the national limit for total chromium and has set a tap water goal of .06 parts per billion for chromium-6 – the first step toward establishing a binding limit.

Bend officials say the city’s water has always been within the EPA’s total chromium limit of 100 parts per billion – most of the water samples have detected no chromium at all since 1987 – and that the water is safe to drink. But the Environmental Working Group says the EPA should be paying more attention to chromium-6 in particular.

Here’s what the Environmental Working Group said after completing the tests:

“Given the scope of exposure and the magnitude of the potential risk, EWG believes the EPA should move expeditiously to establish a legal limit for chromium-6 and require public water suppliers to test for it.”