EPA to Tighten Limit on Arsenic in Drinking Water

WASHINGTON (Reuters) - The Bush administration said Wednesday it would reinstate a Clinton-era plan to sharply restrict the amount of arsenic allowed in drinking water to help reduce the risk of cancer, heart disease and diabetes.

The Environmental Protection Agency was widely criticized in March when it suspended a regulation written by the Clinton administration that would slash the amount of arsenic in tap water to 10 parts per billion (ppb).

The incoming administration said it wanted another study of the health risks before adopting a rule that would be costly to many businesses and small communities.

Christine Todd Whitman, administrator of the Environmental Protection Agency, announced late Wednesday that the administration would reinstate the 10 ppb limit on arsenic, replacing the 50 ppb standard in effect for decades.

"I said in April that we would obtain the necessary scientific and cost review to ensure a standard that fully protects the health of all Americans, we did that, and we are reassured by all of the data that significant reductions are necessary," Whitman said in a statement.

"A standard of 10 ppb protects public health based on the best available science and ensures that the cost of the standard is achievable," she added.

Arsenic naturally occurs in groundwater as a result of minerals dissolving over time from rocks and soil, and from industrial run-off. Arsenic concentrations are generally highest in water sources in the West and some parts of the Midwest.

The chemical has been linked to a higher rate of bladder and lung cancer, as well as to heart disease, diabetes and birth defects.

Many business and mining groups opposed stricter limits on arsenic, saying they would be too costly for many small town water systems.

"More than 90 percent of the towns that will have to comply with this new rule are very small, with just a few thousand or hundred people," said Mike Keegan, a spokesman for National Rural Water Association, which represents more than 20,000 small U.S. communities.

"It wouldn't be uncommon to see a tripling of water rates in a town of less than 500 people," Keegan added.

The EPA is likely to be sued by communities or businesses, who contend that the agency does not have the authority to order strict new rules unless it provides funding.

Whitman said the EPA would earmark $20 million over the next two years to develop more cost-effective technologies for small towns to meet the standard.

Earlier this year, both the Democratic-led Senate and the Republican House of Representatives passed legislation to force the Bush administration to tighten arsenic limits to at least 10 ppb.

Last month, the National Academies of Science said new studies showed a higher risk of lung or bladder cancer from arsenic than previously thought.

To be fair it did seem like the Clinton administration just picked 10ppb out of their booties but for Whitman to turn this around and say that they were investigating it to make sure is a little insincere.

There were extensive public hearings and research into the epidemiology of arsenic in drinking water, including cost-benefit analyses of how much lowering the standard would cost vs. how many cancer cases would be prevented.

If you're REALLY interested, two of the rule-making reports are linked to the Web page below. They are very long. But they show that the Clinton administration didn't pick 10 ppb "out of their booties". They also estimate that for the 10 ppb (or micrograms/liter) standard, the costs of implementation are about the same as the savings due to the reduced number of cancer cases and other health improvements. Look at Table III.E-7 in the "Final Rule" report.

Drinking Water Priority Rulemaking: Arsenic

But they show that the Clinton administration didn't pick 10 ppb "out of their booties".

That is absolute BS.

If you want the truth, follow this link. Here is an excerpt which clearly shows that the NRC (which has NO National Academy of Science members) deliberately ignored science and forced adoption of the absurd and arbitrary 10 ppb limit.

Some scientists advocate use of mathematical models to predict cancer risk from these lower levels of arsenic exposure. The assumptions used in these models are critical.

The EPA's model assumes that any exposure to arsenic increases cancer risk and that cancer risk increases in a linear fashion with increasing exposure. Other models assume there is a "safe" level of exposure or are "sublinear" with increases in cancer risk that are negligible at low doses. Virtually all known toxicological processes follow a sublinear model.

Based on a variety of biochemical, toxicological and human study findings, the subcommittee stated in its report that only the sublinear models were plausible. But because subcommittee could not agree on which sublinear model was correct, the consensus forced by the NRC/EPA process — incredibly — was to opt for the EPA's linear model, the very model the arsenic subcommittee decided was wrong.

The linear model forced by the NRC process forces the adoption of the low standard because the effects at lower levels are artificially inflated. The correct model (the sublinear model) gives a realistic standard because the low level noneffect of arsenic is properly represented.

Because Steven Milloy calls almost any conclusion that he doesn't agree with "junk science", I don't necessarily agree with his conclusions.

For example, he writes this:

"For years the EPA has wanted to reduce the arsenic standard but was stymied by controversy over the relevant science. The EPA's own expert panel on arsenic concluded in 1997 that arsenic did not directly cause cancer. Available human data on U.S. populations doesn't indicate typical arsenic levels in drinking water cause cancer or other health effects — no doubt this is why the current arsenic standard is almost 60 years old."

What he doesn't say, and what both the NRC and EPA do say, is that the best study of the health effects of arsenic in drinking water was a study done in Taiwan. Milloy selectively chooses his debate ground in the above paragraph.

Having said that... it may very well be that the model is flawed. The NRC report, Arsenic in Drinking Water, does consider nonlinear dose-response models.

"Finally, we turn to some discussion of how the new EPA guidelines (EPA 1996) might apply in the present setting. If biological considerations suggest the presence of a nonlinear dose response, then the new guidelines would suggest specifying an appropriate model and using it to estimate low-dose risks. For example, the Poisson model could be used, in which case the model-based estimates in Table 10-11 might be adopted as the estimated risks at 10, 25, and 50 ppb. In the absence of a convincing biological argument for the use of a nonlinear model to predict risks at low doses, EPA generally recommends the use of a point-of-departure approach (EPA 1996). Basically, the idea is to estimate the dose corresponding to a low risk that is still high enough for the corresponding dose to be within the observable range of data. Risks at lower doses can be estimated by linear extrapolation from the point of departure."

They also say this in the discussion:

"The analyses presented in this chapter are based primarily on what is sometimes called a statistical approach to risk assessment. An argument can be made that the multistage Weibull model is derived for biological considerations; however, the philosophy behind statistical modeling is simply to describe the data using a flexible class of dose-response models that can accommodate a wide variety of shapes. In recent years, there has been a lot of interest in the development and application of more biologically based models that account for intake, metabolic pathways, and mode of action; in practice, the approach is rarely used because usually not enough is known about the mode of action for the compound in question. Arsenic certainly falls into that category. Use of biomarkers in the construction of dose-response models is a related idea that has generated a lot of interest in recent years. In practice, however, the data are generally not available to use that approach. Furthermore, statistical methods to incorporate biomarkers into dose-response models have not been developed. Research to develop such approaches would be extremely valuable."

So first you have to ignore Milloy's ad-hominem attacks on the qualifications of the report authors. So what does Milloy finally say about the models?

"The EPA's model assumes that any exposure to arsenic increases cancer risk and that cancer risk increases in a linear fashion with increasing exposure. Other models assume there is a "safe" level of exposure or are "sublinear" with increases in cancer risk that are negligible at low doses. Virtually all known toxicological processes follow a sublinear model."

The NRC report addresses this by saying that there is insufficient data to support the use of alternative models, even though they might be better. So when faced with what isn't known vs. what is known, in order to come to a conclusion it's preferable to base the conclusion on what is known.

Typical pseudoscientific, Liberal clap-trap. Your repeated referencing of the EPA and NRC (both well established sources of advocacy 'science') make it clear you have predefined the solution and facts are irrelevant. You have in no way offered independent scientific evidence (from real scientists, not 3rd rate, eco-evangelists (NAS non-members) from the EPA and the NRC) that refutes any of the statements made by Milloy.

I'm sure that's not a problem, since Liberals who support thiss drivel from the NRC aren't interested in facts, only about feeling good about what they do ...

As for your comments about Milloy's 'ad-hominem' remarks, the NRC panelists are desperately trying to pass themselves off as members of the NAS, which they are most certainly not. It's the usual attempt by politically motivated, Liberal 'scientists' to perniciously assume the mantle of a respected body in order to perpetuate their fraudulent ideas on an unsuspecting and somewhat naive public.

Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.