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Executive Summary
In order to protect expecting
mothers, their developing fetuses and their infant children, the California
Department of Health Services (DHS) should set a final health standard for perchlorate
in drinking water at one part per billion or less.
Perchlorate, the primary ingredient in solid rocket fuel, is emerging as a major
contaminant of California’s food and water supplies. The U.S. Food and Drug
administration recently documented widespread contamination in milk and lettuce
from grocery stores in California and across the country. Many water suppliers
in California have detected perchlorate in their wells at levels suggested by
the U.S. Environmental Protection Agency (EPA) as unsafe.
Perchlorate contaminates the drinking water supply of 16 million Californians.
- State agencies have discovered perchlorate pollution in more than 350 water
sources, including the Colorado River and hundreds of municipal wells.
- The bulk of the contamination was caused by the military, aerospace contractors
and other users and manufacturers of explosive chemicals.
- Communities with contaminated water supplies include Riverside, Loma Linda,
San Bernardino, San Fernando, Pasadena, Rancho Cordova, West Orange County,
and Otay.
Perchlorate exposure threatens expecting mothers, developing fetuses and infant
children.
- Perchlorate affects the thyroid hormone system at very low levels of exposure.
It acts by preventing uptake of iodine into the thyroid gland, reducing the
gland’s ability to produce enough hormone.
- Thyroid hormone and iodine are critical for normal brain development in fetuses
and young infants. Children born to mothers with thyroid problems or iodine
deficiency can have lower IQ, impaired learning, hyperactive behavior, delayed
growth, or can suffer a range of serious neurodevelopmental problems, including
mental retardation.
- Exposure to perchlorate during specific and important windows of time during
the growth and development of a child increases the risk of neurodevelopmental
disability.
Neurodevelopmental disabilities, like attention deficit and hyperactivity disorder
(ADHD), are a serious and growing problem in California.
- Learning-disabled students increased 65 percent faster than the general school
population from 1985 to 1999.
- Perchlorate exposure could be contributing to this trend in combination with
exposure to a variety of other chemicals polluting the environment, such as
toxic flame retardants, lead, mercury, and polychlorinated biphenyls (PCBs).
The evidence of perchlorate’s toxicity warrants a strong drinking water standard
of one part per billion or less.
- Exposure to low levels of perchlorate in utero leads to changes in brain structure
and behavior in infant rats.
- Humans are as sensitive as rats to iodine uptake inhibition by perchlorate.
After evaluating the full spectrum of available science on perchlorate, the
U.S. Environmental Protection Agency and the states of Massachusetts, Maryland
and New Mexico have recommended preliminary drinking water health guidelines
of one part per billion or less to provide a margin of safety for developing
fetuses and infants. Accounting for widespread exposure to perchlorate in the
food supply and for the combined effects of other thyroid toxicants in addition
to perchlorate would justify an even lower standard.
However, the state of California is unofficially moving forward with a final
drinking water standard equivalent to the public health goal of six parts per
billion issued in March 2004. The process used to arrive at the public health
goal did not live up to the criteria established by California law, and a standard
set at this level would be inadequate for several reasons:
• California EPA chose a single scientific study as the main basis for calculating
a safe level. The study examined the effect of perchlorate on healthy adults
exposed for a short period of time, as opposed to including other research involving
fetal and newborn rats with long-term perchlorate exposure.
• California EPA applied an atypically small margin of safety to ensure protection
of especially vulnerable people. Almost all established public health goals
in California use a larger margin of safety.
• California EPA failed to consider how perchlorate may be interacting with
other thyroid toxicants (like toxic flame retardants, nitrates, PCBs and other
common environmental contaminants) to contribute to neurodevelopmental problems
in children.
• A final standard of six parts per billion could leave the contamination of
the Colorado River and nearly one-third of the polluted wells in California
unaddressed.
In setting a final perchlorate standard, the state should use the weight of
scientific evidence, including experiments showing neurobehavioral damage to
infant rats exposed to small amounts of perchlorate in the womb, as well as
considering the possible interaction of perchlorate with other toxicants. In
addition, the state should set larger margins of safety to account for uncertainties
in the vulnerability of fetuses and infants to long-term exposure to low levels
of perchlorate. After taking these steps, the state should arrive at a drinking
water standard for perchlorate of one part per billion or less, ensuring a comprehensive
cleanup and providing a margin of safety for pregnant women, their developing
babies and their infant children.
Policy Recommendations
• The California Department of Health Services should set the drinking water
standard for perchlorate at one part per billion or less.
• In addition, the State of California, local governments, and water
suppliers should hold responsible parties fully liable for cleanup and
for supplying replacement drinking water to affected communities.
Congress should not exempt the Department of Defense.
• Congress should reinstate Superfund fees for polluting industries to ensure
that contamination caused by now-bankrupt companies will be cleaned up.
• Federal and state agencies should require American Pacific, Kerr-McGee Chemical
and other responsible parties to accelerate clean up of perchlorate contamination
currently leaking into the Colorado River and local aquifers.
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