Contaminated lettuce Contains Toxins from Rocket Fuel, a National Problem
Perchlorate pollution is highly politicized because almost all production can be either directly or indirectly traced back to the military. The Pentagon has argued that perchlorate is safe in drinking water at levels much higher than the EPA has set.
The Bush administration has backed a bill before Congress that would exempt the Pentagon and defense contractors from environmental regulations requiring the cleanup of toxic waste, saying that compliance would hinder military readiness. Hearings are to begin next week.For six months of the year, 70% of the nation's lettuce comes from a few Western counties irrigated by the Colorado river. Now, two studies have found that some of this winter lettuce is contaminated with perchlorate, a pollutant that has found its way into the groundwater in as many as 20 states, from the manufacture of rocket fuel, flares and munitions and is known to contaminate the Colorado. Every day, hundreds of pounds of the contaminant, perchlorate, enter the lower Colorado River, said Renee Sharp, an analyst with the Environmental Working Group, which has offices in Washington, D.C., and Oakland. The contaminated water provides irrigation water for 1.4 million acres in a region growing most of the nation's winter vegetable crops.
A study by the Environmental Working Group found perchlorate in four of 22 lettuce samples purchased in January and February in the San Francisco Bay Area. The organization refused to disclose the brand names of the lettuce it bought -- which included head lettuce, bagged salads and organic prepackaged greens -- saying it didn't want to spark a food scare.
The four positive samples had more than 30 parts per billion of the pollutant. The U.S. Environmental Protection Agency has set a preliminary safety level of one part per billion of perchlorate in water. But the Environmental Working Group's Bill Walker says recent research shows that to protect infants in utero, it should be set at 0.1 part per billion.The Environmental Working Group says the test results were serious enough to warrant a call for the Food and Drug Administration to conduct its own investigation into U.S.-grown lettuce.
And recent tests by The Press-Enterprise newspaper of Riverside, Calif., found perchlorate in 18 of 18 lettuce samples, at an average of eight parts per billion.
Perchlorate affects the thyroid gland and can disrupt hormone production. This is of particular concern to pregnant women because proper thyroid function is crucial to the development of a baby's brain and nervous system. Pregnant women are advised to avoid perchlorate because it can result in lowered IQ, mental retardation, loss of hearing, and speech and motor skills deficits in infants.
It's believed that the Colorado's contamination comes from two
now-closed perchlorate plants near Las Vegas. The plants' water is known to
contain perchlorate levels from three to 10 parts per billion. It has been reported
that 80 percent of human exposure to perchlorate comes from water, and 20 percent
from food. The environmental group actually thinks the exposure is 60 percent
from water and 40 percent from food, and that the health hazard office changed
the number due to industry pressure. Hirsch denied that, saying that the agency
changed it after seeing EPA data on the presence of perchlorate in produce.
Lettuce was tested because it is mainly composed of water. Jeff Farrar of the California Department of Health Services noted that the environmental group's study was very small, "so no major scientific conclusions can be drawn from it."
But it does raise important questions. "There's just not a lot of information out there on perchlorate, both in crops and in animals used for foods," he says. (This reporter postulates that our animal food population has been contaminated in every one of those states also.)
This is truly a national issue, says Farrar, and California is looking for federal agencies to take the lead. A Food and Drug Administration official said people shouldn't start avoiding lettuce or changing their diets. Agency scientists are developing ways to test for perchlorate in foods before taking a nationwide look at the problem.
``This shows that perchlorate makes it through the packaging and production process and onto grocery store shelves,'' said Bill Walker, West Coast vice president for the Environmental Working Group.
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PERCHLORATE THREAT
Where did the contamination come from and what can perchlorate do?
• The winter lettuce tested in the study was bought in the Bay Area in January and February. It was grown in the Imperial Valley and irrigated by the Colorado River, which contains perchlorate. Lettuce being sold today comes from Monterey County, where there is no known perchlorate contamination.
• In the recent test, the Environmental Working Group found that four of 22 lettuce samples contained detectable levels of perchlorate. The study also found that the perchlorate levels in the contaminated lettuce were four times higher than the levels that the EPA says are safe.
• Perchlorate can cause thyroid problems and affect the thyroid gland's capacity to produce hormones. Pregnant women are advised to avoid perchlorate because it can result in lowered IQ, mental retardation, loss of hearing, and speech and motor skills deficits in infants.
Perchlorate
EPA has released for public review and comment its revised draft toxicity assessment on perchlorate, which is the primary ingredient of solid rocket propellant. The draft assessment, entitled "Perchlorate Environmental Contamination: Toxicological Review and Risk Characterization," is available at www.epa.gov/ncea under "what's new". The Agency will also hold a peer review workshop open to the public on this draft assessment on March 5th and 6th 2002, in Sacramento, California. This meeting will be open to the public, and more information is available at www.epa.gov/fedrgstr under the heading for Jan. 2. Following this opportunity for public and independent scientific input, EPA expects to finalize the document by late summer, 2002.
When finalized, this draft assessment will be an important update to the Agency's health and ecological assessment for potential risks resulting from exposure to perchlorate through drinking water and other sources. The revised human health and ecological risk estimates found in this draft document continue to undergo scientific review and analysis both within EPA and by the external scientific community. As with any draft EPA assessment containing a quantitative risk value, risk estimates in this review document are preliminary. Therefore, it is premature at this stage to interpret risk estimates in this draft document as final EPA conclusions on which the Agency could take risk management action. The draft risk estimate is not a drinking water standard, but is the first step in a lengthy process to determine if the agency should set a federal drinking water standard for this contaminant.
EPA, other federal agencies, states, water suppliers and industry are already addressing perchlorate contamination through a number of activities. EPA is monitoring for perchlorate in drinking water through the Unregulated Contaminant Monitoring Program and the U.S. Geological Survey is monitoring for perchlorate in surface water. In California, Superfund sites are employing new technologies to remove perchlorate from contaminated water. The Ground Water Remediations Technologies Analysis Center is collecting data on perchlorate treatment studies to provide a stronger scientific understanding of the effectiveness of perchlorate treatment.
The draft toxicity assessment provides additional scientific insight into the potential risks posed by perchlorate and ways to reduce those risks. Sensitive populations such as pregnant women should follow the advice of their health care provider regarding the amount and type of liquids, including water to be consumed. Concerns and questions about perchlorate and the safety of tap water can be addressed by contacting local water utilities. Contact EPA's Safe Drinking Water Hotline at 1-800-426-4791 for general information on drinking water issues.
What is Perchlorate?
Perchlorate is both a naturally occurring and man-made chemical.
Most of the perchlorate manufactured in the United States is used as the primary
ingredient of solid rocket propellant. Wastes from the manufacture and improper
disposal of perchlorate-containing chemicals are increasingly being discovered
in soil and water.
How Can Perchlorate Affect Human Health?
Perchlorate interferes with iodide uptake into the thyroid
gland. Because iodide is an essential component of thyroid hormones, perchlorate
disrupts how the thyroid functions. In adults, the thyroid helps to regulate
metabolism. In children, the thyroid plays a major role in proper development
in addition to metabolism. Impairment of thyroid function in expectant mothers
may impact the fetus and newborn and result in effects including changes in
behavior, delayed development and decreased learning capability. Changes in
thyroid hormone levels may also result in thyroid gland tumors. EPA's draft
analysis of perchlorate toxicity is that perchlorate's disruption of iodide
uptake is the key event leading to changes in development or tumor formation.
What are the Preliminary Conclusions of the Draft Toxicity Assessment?
The EPA draft assessment concludes that the potential human
health risks of perchlorate exposures include effects on the developing nervous
system and thyroid tumors. The draft assessment includes a draft reference dose
(RfD) that is intended to be protective for both types of effects. It is based
on early events that could potentially result in these effects, and factors
to account for sensitive populations, the nature of the effects, and data gaps
were used. The draft RfD is 0.00003 milligrams per kilogram per day (mg/kg/day).
The RfD is defined as an estimate, with uncertainty spanning perhaps an order
of magnitude, of a daily exposure to the human population (including sensitive
subgroups) that is likely to be without appreciable risk of adverse effects
over a lifetime. As with any EPA draft assessment document containing a quantitative
risk value, that risk value is also draft and should not at that stage be construed
to represent EPA policy. Thus, the draft RfD for perchlorate is still undergoing
science review and deliberations both by the external scientific community and
within the Agency.
The assessment provides a hypothetical conversion of the draft RfD to a drinking water equivalent level (DWEL), assuming factors of 70 kilogram (kg) body weight and 2 liter (L) of water consumption per day. The converted draft estimate would be 1 microgram per liter (ug/L) or 1 part per billion (ppb). If the Agency were to make a determination to regulate perchlorate, the RfD along with other considerations would factor into the final value.
Does perchlorate cause cancer?
Perchlorate is associated with disruption of thyroid function which can potentially
lead to thyroid tumor formation. This draft toxicity assessment accounts for
both developmental and tumor formation effects.
Does My Water Contain Perchlorate?
There have been confirmed perchlorate releases in at least
20 states throughout the United States. Additional information and maps detailing
those sites are available in Chapter 1 of the draft of the "Perchlorate
Environmental Contamination: Toxicological Review and Risk Characterization."
EPA, other federal agencies, states, water suppliers and industry are already
actively addressing perchlorate contamination through monitoring for perchlorate
in drinking water and surface water. The full extent of perchlorate contamination
is not known at this time.
What Is Being Done about Perchlorate?
The draft toxicity assessment will undergo peer review, and
once it is finalized, the reference dose will be used in EPA's ongoing efforts
to address perchlorate problems. EPA's draft reference dose represents a
preliminary estimate of a protective health level and is not a drinking water
standard. In the future, EPA may issue a Health Advisory that will provide information
on protective levels for drinking water. This is one step in the process of
developing a broader response to perchlorate including, for example, technical
guidance, possible regulations and additional health information. A federal
drinking water regulation for perchlorate, if ultimately developed, could take
several years.
In 1998, perchlorate was placed on EPA's Contaminant Candidate List for consideration for possible regulation. In 1999, EPA required drinking water monitoring for perchlorate under the Unregulated Contaminant Monitoring Rule (UCMR). Under the UCMR, all large public water systems and a representative sample of small public water systems are required to monitor for perchlorate over the next two years to determine whether the public is exposed to perchlorate in drinking water nationwide.
How is perchlorate removed from water?
Several types of treatment systems designed to reduce perchlorate
concentrations are operating around the United States, reducing perchlorate
to below the 4 ppb quantitation level. Biological treatment and ion (anion)
exchange systems are among the technologies that are being used, with additional
treatment technologies under development.
Many other perchlorate studies have been completed during the last several years. A May 2000 summary of 65 perchlorate treatment studies is available online at www.frtr.gov/perchlorate
Follow up to part of the Perchlorate Problem.
Military agrees to work with Calif. to
fix perchlorate problem
SAN ANTONIO (Aug. 15, 2003) -- The Department of Defense has committed to form
a federal-state working group with California to coordinate a response to the
problem of perchlorate contamination.
Perchlorate, an ingredient in a propellant used in rockets and other military
munitions, has been found migrating into drinking water supplies, particularly
in California.
The working group will gather information about perchlorate contamination for the 12 water districts in California that are concerned about contamination from military bases across the state, a Pentagon official said while attending the Joint Services Pollution Prevention Conference in San Antonio.
The working group will also help set cleanup priorities and marshal resources.
U.S. Sen. Barbara Boxer, D-Calif., who has repeatedly called on the military for faster action on the perchlorate issue, called the agreement is an "important breakthrough."
"Defense Department activities have been a major source of perchlorate contamination in California," Boxer said in a written statement. "This kind of active cooperation will help us find and fix perchlorate problems throughout the state."
Woodley characterized the agreement as a statement of the department´s position, not a change of its position.
Boxer heralded the agreement because it calls for the military to adhere to future perchlorate standards that the state may set, but Woodley said that has always been the Defense Department´s position.
Boxer has introduced two perchlorate-related bills in the Senate. One would establish a federal standard for perchlorate contamination in drinking water supplies by July 2004. The second would guarantee a community´s right to know about the use of perchlorate by companies.
Perchlorate can disrupt thyroid functions in adults and
physical, behavioral and mental development in children.