[CPEO-MEF] I predict!

[Lenny Siegel <lsiegel@cpeo.org>]

The National Academy of Sciences' forthcoming perchlorate report
Lenny Siegel, Center for Public Environmental Oversight
January 7, 2005

On Monday, January 10, 2005, the National Academy of Science's National
Research Council will brief federal agencies and Congress on its
long-awaited report, HEALTH IMPLICATIONS OF PERCHLORATE INGESTION. On
Tuesday it will release the report to the public and the press. The Bush
Administration sent the issue to the Academy for review in 2003, after
the Defense and Energy Departments, as well as private responsible
parties, objected to U.S. EPA's recommended reference dose for
perchlorate, a level that would have translated into a drinking water
standard (maximum contaminant level) of one part per billion (1 ppb). 

Perchlorate is found in many products, including highway flares,
fireworks, and some fertilizers, but its principal use in the United
States is as an oxidizer in solid rocket fuel. Perchlorate is a health
concern primarily because it interferes with iodide uptake in the human
thyroid gland. This is of particular concern because it impairs the
mental development of fetuses and young children.

The National Academy of Sciences does not conduct its own toxicological
or epidemiological research. Rather, it pulls together a collection of
experts to review existing scientific evidence. The Perchlorate
Committee met five times in 2003 and 2004, and its report was peer
reviewed by a small panel of scientists before completion. 

The Academy does not promulgate health standards, but its health impact
findings are taken seriously by U.S. EPA and state health and
environmental agencies. That is, environmental regulators are expected
to use the Academy's recommended reference dose as a starting point in
developing drinking water standards. As an example of how a reference
dose might translate, the Massachusetts Department of Environmental
Protection associated its reference dose of 3 x 10^-5 (.00003) mg/kg-d
(milligrams per kilogram per day) with a drinking water exposure limit
of 1 part per billion using standard exposure assumptions and methodologies.

So environmental advocates, regulators, responsible parties - that is,
polluters - and other government officials are watching the Academy
closely. The report may determine, over the next few years, whether
millions of people continue to be exposed to low levels of perchlorate
in their drinking water, and whether hundreds of millions of dollars (or
even billions) more are spent on cleanup and water treatment.

I am not an expert in toxicology. And I have absolutely no access to the
internal workings of this particular Academy committee. Still, as a
close observer of the review process, I am repeatedly asked what I think
the Academy will recommend in the forthcoming report, why, and what it
will mean.

I believe that the Academy's report will be a mixture of policy and
science. The science of perchlorate toxicity is uncertain, so the
application of uncertainty factors is a policy decision. I predict that
the Academy's recommended reference dose (essentially what a person can
safely ingest) will translate into a health standard between 6 and 40
ppb. Six is California's Public Health Goal. Forty, I believe, is the
level the Defense Department expected before the Bush team took over.

I expect that the Academy will recommend a number higher than EPA
recommended largely because the scientific playing field is not level. 
Most of the scientific presenters who appeared before the Academy are
supported by the polluters. In fact, most research on perchlorate has
been funded by the major polluters, both from government and industry. 
In 2003 they even organized their own conference on perchlorate
toxicity. I give them credit for sponsoring research, but I think
sponsorship can influence the results, particularly when the sponsors
can go out and do new research whenever they don't like the results of
existing studies. Therefore, there must be countervailing influences.
There need to be independent sources of research funding, both to ensure
that the research universe is balanced and to support a balanced
scientific community.

In technical terms, EPA in part based its more protective recommendation
upon measurements of the brains of rats that had been exposed to
perchlorate. Though responsible parties funded the original study that
EPA used, they were dissatisfied with EPA's conclusions and funded
reviews that undermined the original studies, presenting the results to
the Academy. In that scientific debate, there was no countervailing
interest to argue that the original studies were valid, or that the
rat-brain evidence implied the need for an even more protective health
standard. Though (based upon behavioral observations) I'm prepared to
believe that rats and people are similar, I don't have the expertise to
interpret, challenge, or confirm the rat-brain data. Still, I think it
is likely that the Academy will say that more study is needed before
such data is used in the development of a health standard.

Scientists also presented epidemiological studies to the Academy, but
it's possible that those will have little impact. It depends, to some
degree, upon when the Academy wrapped up its work. That's because
government data, most recently a U.S. Food and Drug Administration
report released in November, 2004, shows the widespread distribution of
low levels of perchlorate in the nation's food supply. In each of the
epidemiological studies, it has been recognized that there is
uncertainty about who has been exposed to perchlorate, and how much. Now
it turns out that there's no way to know whether "control" populations,
against which the exposed populations were compared, were perchlorate
free. In the lay terms of old toothpaste commercials, how can one
conclude that Crest reduces cavities when it turns out that everyone,
including the comparison population, was using Crest in the first place.

That leaves human studies, such as the 2002 Greer study that California
used as the principal basis for its Public Health Goal. In the Greer
study, a favorite of the polluters, a small number of healthy adults
were exposed to perchlorate for a short period of time. Because the
results of such studies do not adequately describe the impact of
continuing perchlorate exposure on fetuses and young children, health
agencies apply uncertainty factors. That is, they take the effect level
directly implied by the results of human studies, and they divide by
factors or three or ten to calculate a final reference dose. There are
standard methodologies for applying uncertainty factors, but in the
final analysis, they require subjective judgment. Should health
standards err on the side of protection, or should they attempt to avoid
what some people - notably polluters - consider a waste of money?

Thus, the reference dose to be recommended by the Academy will in part
be a function of a subjective policy decision. And it is appropriate for
non-scientists to question that policy decision.

The results of the Academy study, if carried forward to the promulgation
of health standards, will have an enormous impact. Assuming the federal
drinking water standard ends up at or higher than California's 6 ppb,
only Massachusetts residents - assuming the state government doesn't
rethink its own review - will end up with a level comparable to EPA's
original proposal. If it's higher than California's, then it's likely
that the rest of the country will end up with even less protection.

But it's not that simple, because the drinking water standard is applied
in three scenarios:

1) Ironically, at major source areas, such as rocket-fuel production,
testing, and disposal sites, the health standard will have marginal
impact. At these sites, perchlorate has been found at high levels, in
the hundreds of even thousands of parts per billion. Many of these sites
already have expensive treatment systems in place. The standard will
affect how these systems are "tuned," and how long they operate. But the
capital investments will occur, or have occurred, regardless of the
health standard.

2) On the other hand, minor and diffuse sources, where concentrations
are below the recommended standard, will be "risked away." (Diffuse
sources may include military testing and training ranges where
perchlorate might be widespread, but rarely occurs at high
concentrations.) That is, investigations will be halted and cleanup
never considered because the levels detected will be considered safe. In
states with more stringent standards than the federal level, the state
standards will generally still hold force. Of course, in California even
the 6 ppb level, if promulgated as a state maximum contaminant level, is
likely to wipe a large number of known contamination sites off the map..

3) People who are drinking low levels of perchlorate, or eating food
products with similar levels, will continue to be exposed. While water
suppliers (including the suppliers of water for agricultural use) may
voluntarily supply purer water than the law requires, they will have to
do so at their own expense, an expense charged to customers. If the
national standard were stringent - such as the EPA's original implied
level of 1 ppb - then water suppliers could install treatment systems or
find alternative supplies and then seek cost recovery from known
polluters in court. But the recommend level is high, reimbursement will
be impossible and treatment won't happen. This is the greatest impact
that I expect from a weak standard, a standard likely to be recommended
by the Academy.

Part of the problem lies in the way that we, as a nation, regulate toxic
substances in water. We set standards by concentration level, with no
consideration of the volume of contamination. The perchlorate in the
Colorado River is perhaps the single largest toxic water plume in human
history, with as many as 20 million people potentially exposed. Unless
we err on the side of caution, millions of children will continue to be
guinea pigs, drinking water containing consistent levels of perchlorate
deemed low enough to be acceptable. However, because the known health
effects of perchlorate are difficult to discern and even harder to
prove, we'll probably never know how many are affected.

Despite the National Academy of Science's cherished history of
independence, I expect its recommendations to be tainted by the
overwhelming quantity of biased evidence placed before it by the
polluters. To compensate for a degraded scientific environment, I call
upon government agencies to recognize that bias and err on the side of
caution when applying uncertainty factors and promulgating standards.
Furthermore, to correct this problem in the long run and prevent
repetition as other toxic compounds, such as trichloroethylene, are
reviewed by the Academy, I urge the federal government to fund genuinely
independent and balanced research into the toxicity of common
pollutants. With such science, the Academy should be able to do a better
job of helping to protect the public.

-- 


Lenny Siegel
Director, Center for Public Environmental Oversight
c/o PSC, 278-A Hope St., Mountain View, CA 94041
Voice: 650/961-8918 or 650/969-1545
Fax: 650/961-8918
<lsiegel@cpeo.org>
http://www.cpeo.org
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