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Is a Perchlorate Clean-up Necessary?
5
by Tengbo Li, Annie Slivka, and Jennifer Xia
Quantitative Methods in Public Policy Decisions
Professor Richard Wilson
January 2009
Introduction
Perchlorate (ClO4-) is used as an oxidizer in rocket fuel, explosives, flares, and fireworks. The United States
Department of Defense (DoD) has used the chemical since the 1940s, citing its "high ignition temperature,
controllable burn rate, and stable chemical characteristics," which minimize the chance of accidents during
handling and storage.4 In the private sector, firms that specialize in aerospace technology, like Aerojet and
Lockheed Martin, also use perchlorate extensively. The DoD and such firms typically dispose of perchlorate
by dumping large amounts of the chemical into local water supplies. As a result, concentrations of
perchlorate in water supplies across the United States have increased drastically, particularly in the West and
Southwest. Perchlorate concentrations of 100,000 ppb and higher have been found.5 Of the 3,700 public
drinking water systems across the United States, 153 have high enough concentrations of perchlorate to be
considered "contaminated."5
Perchlorate has been shown to pose a significant human health risk, as it interferes with the transport of
iodide into the thyroid. Iodide is essential to the production of T3 and T4, hormones which play an important
role in the development of the central nervous system and skeletal growth in fetuses and infants. In addition,
T3 and T4 regulate metabolic activity and affect nearly every organ system in the human body. Perchlorate
prevents the production of T3 and T4 by binding competitively with the sodium-iodide symporter (NIS
protein), which has a higher affinity toward perchlorate than to iodide. Sufficiently high levels of perchlorate
in the body can cause developmental problems, especially in infants (via lactation) and fetuses (via the
placenta), resulting in mental retardation, and lower IQ and motor ability.2
The Environmental Protection Agency's recommended perchlorate level in water, 24.5 ppb, has been in
effect since 2005. However, numerous water supplies around the United States continue to have levels of
perchlorate exceeding the recommended level. This is mainly due to the high cost of removing perchlorate
from the water; a thorough cleanup of contaminated drinking water throughout the United States would cost
billions of dollars. Recently, the EPA has recommended an even lower safe level of 1 ppb. Cleaning the
highly-contaminated Colorado River system alone to meet this standard would cost $40 billion.12 Until
significantly more cost-effective methods of treating perchlorate are discovered, a mass cleanup of
perchlorate to meet EPA standards would be expensive and ultimately futile.
A new study released by the Office of the Inspector General of the EPA on December 30, 2008 further
supports our conviction that a mass cleanup is not the correct method of addressing the issue. The new study
reveals that lowering perchlorate levels in drinking water only slightly improves human thyroid function.13 It
also reveals that even setting extremely conservative levels of perchlorate intake would not necessarily
"prevent mental damage in children."13 In addition, the study indicates that factors that were not included in
the NAS study, such as the presence of other dangerous chemicals in drinking water, may pose much
stronger risks to humans than perchlorate.13 Addressing these other factors may prove to be far more
beneficial to human health than cleaning up perchlorate alone.
A thorough cleanup of perchlorate in the environment, particularly around sources of drinking water and
farm land, would be ideal for human health. However, due to the high costs and relative lack of benefits of
reducing perchorate levels in drinking water, we strongly recommend against a mass cleanup. We advocate a
more reasonable solution: to implement a new law requiring the safe removal and storage of perchlorate
waste.
Background
Perchlorate is a chemical compound that is both naturally occurring and manufactured for use in many
products, such as: rocket fuels, missiles, matches, dyes, paints explosives, flares, and fireworks, employed in
large part because it is the least reactive oxidizer of the generalized chlorates. As Alex Beehler, the Assistant
Deputy under the Secretary of Defense, explains it, "Since the 1940s, Department of Defense has used
potassium and ammonium perchlorate as an oxidizer in explosives, pyrotechnics, rocket fuel, and missiles. If
it by far the safest, most efficient and stable propellant oxidizer available. Perchlorate has a high ignition
temperature, controllable burn rate, and stable chemical characteristics that reduce handling and storage risks
and the likelihood of unexpected detonations." 4
1
Perchlorate is also highly soluble, or easily dissolved and transported in water, which means that if allowed
to contaminate free water sources, it can very easily spread and infiltrate large quantities of water in all its
capacities: groundwater, surface water, as well as soils and other mediums that contain large amounts of
water. Studies have found perchlorate to have contaminated at least 400 groundwater sites and well as 153 of
the 3,700 public drinking water systems in the United States at levels of anywhere from less than 1 part per
billion to more than 3.7 million parts per billion, however most sites did not have high levels of perchlorate.
70% of the contaminated sites had less that the 24.5 parts per billion reference dose set by the EPA, while
only 14 of the 153 public water systems had concentration levels above this reference level. While it is noted
that due to faults in tracking and testing for perchlorate, there are many possible undetected sites, most are
expected to have low levels of concentration, very few are expected to have significantly risky levels.1
Consumption of Perchlorate
The FDA conducted a study in 2004-2005 to try and determine the amount of perchlorate consumed. It
gathered produce data from areas of reportedly high perchlorate, such as Southern California and Arizona,
and data for beverages from across the country. Figures of interest include spinach and collard greens at 115
and 92.4 ppb, respectively, and milk and bottled water at 5.81 and less than 0.5 (non-detected in all samples)
respectively.6
6
In a 2007 analysis of the risk of perchlorate consumption, taking into account such variables such as methods
and frequency of consumption of certain foods, the FDA proceeded to analyze the data from the 2004-2005
exploratory study and determined estimated perchlorate exposure to be 0.053 microgram/kg-day for all
people 2 and older, primarily due to milk and then tomato consumption. The other two population groups,
chosen as sensitive subgroups, included in the study were children 2-5 years of age and females 15-25, which
had estimated mean perchlorate intakes of 0.17 and 0.037 microgram/kg-day, respectively.7
6
This estimate is similar to the estimated dose of 0.066 micrograms of kilograms of body weight per day for
the U.S. population aged 20 and older in Blount et al. based on a study of adjusted geometric means of
urinary levels in 2,820 participants. The 95th percentile in adults was at .234 microgram/kg-day, and only 11
adults out of the 1618 subjects had over the recommended EPA reference dose. This same study also
estimated the population of pregnant women to also have an estimated median perchlorate dose of 0.066
micrograms/kg-day.8
Health Risk
Perchlorate, like any chemical, has many temporary effects in large amounts, everything from itching,
tearing, and pain to gastroenteritis to eventually ringing of the ears, dizziness, elevated blood pressure,
blurred vision, and tremors; however, the main issue in question is how much perchlorate is required to cause
chronic disorders, namely metabolic disorders of the thyroid. 5 Studies have not yet found any other chronic
effects of increased levels of perchlorate in the adult body, but there have been links to impairment of the
development of skeletal and nervous systems in infants.
Perchlorate and the Thyroid
The thyroid gland produces two hormones: triiodothyronine (T3) and thyroxine (T3). Thyroxine is a
precursor hormone with little or no intrinsic biologic activity, but it is converted both in the thyroid and in
other organs, into triiodothyronine. They are crucial in metabolic activity and affect almost every organ
system in the body. Furthermore, T3 is required for fetuses and infants to insure normal development of
central nervous systems as well as skeletal systems.2
2
Iodide plays an essential role in the synthesis of T3 and T4, because its element, iodine, is a component of
both molecules. It can only be gained through consumption: the World Health Organization recommends 150
micrograms/day for adults, 200 for pregnant women, 90-120 for children 2-11, and 50 for infants under 2.2
2
It is transported into the thyroid by a protein molecule called the sodium/iodide symporter, or the NIS
protein. However, the NIS protein will also bind with other ions, like perchlorate. The problem is that the
NIS protein actually has a higher affinity to binding with perchlorate than iodide, which means that at high
levels, perchlorate can dramatically reduce the movement of iodide into the thyroid gland. 2
9
On the other hand, thyroid hormone production and secretion are closely regulated by the hormone
thyrotropin (thyroid-stimulating hormone, TSH) by the pituitary gland which stimulates virtually every step
of the process. The pituitary gland increases secretion of TSH when serum levels of the two hormones are
low (hypothyroidism), and decreases secretion when serum levels are high (hyperthyroidism). There are also
few if any symptoms of temporarily low T3 and T4 levels, besides the possibility of an enlarged thyroid
gland. In addition, 80% of conversion from T4 to T3 occurs outside of the thyroid, especially in the brain, so
with increased levels of TSH, conversion rates outside the thyroid can increase significantly regardless of the
effects of perchlorate on the thyroid. Thus, only daily iodide intake of below about 10 to 20 micrograms will
cause hypothyroidism. However, it is still debated how low hormone levels must drop and for how long to
cause adverse health effects. There is potential that sensitive populations, such as people with thyroid
disorders, pregnant women, fetuses and infants, there is an increased risk of adverse health effects.2
Hypothyroidism in fetuses and infants
In fetuses and infants, T3 is necessary for the development of many crucial structures in the nervous and
skeletal systems. It stimulates the development and growth of neurons, glial cells, synapses between neurons,
myelin sheaths that surround neuronal processes, and neurotransmitters as well as the transcription of
“several genes whose products are important for neural development”. Additionally, it is necessary for the
normal growth of long bones and the production of the pituitary growth hormone and an insulin-like growth
factor.2
Fetuses receive all their iodide from their mothers; thus “the consequences of severe combined maternal and
fetal hypothyroidism during fetal life and in newborn infants include microcephaly (small brain), mental
retardation, deaf-mutism, paraplegia or quadriplegia, and movement disorders. Those abnormalities are not
reversible by treatment with T4.” Additionally, "newborn infants who have hypothyroidism may have other
abnormalities, including lethargy, poor muscle tone, poor feeding, constipation, and persistent jaundice, if not
at birth then thereafter. The changes are similar to those which occur in older children and adults who have
hypothyroidism, and, in contrast with the neurologic abnormalities, they are reversible with adequate T4
treatment." 2
Key Studies:
Because of the health risks associated with perchlorate intake, various studies have been conducted to
determine a level of perchlorate intake by humans which would have no adverse health effects.
The Greer et al. study of 2001 examined the effects of perchlorate exposure in healthy adult humans over a
14-day period. Male and female volunteers were given perchlorate in drinking water in the following doses:
0.007, 0.02, 0.1, and 0.5 mg/kg-day.14 Greer et al. measured the iodide uptake before exposure to
perchlorate, on the second day of exposure, the fourteenth day of exposure, and the fifteenth day (the day
after the final exposure). Greer et al. determined that perchlorate ingestion had little effect on thyroid
function, except in the case of 0.5 mg/kg-day.14 On the fifteenth day, however, thyroid function returned to
normal even in individuals exposed to a level of 0.5 mg/kg-day. Greer et al. concluded that the "true noeffect level" was either approximately 0.0052 or 0.0064 mg/kg-day, based on two methods of calculation.14
In 2005, the National Academy of Sciences (NAS) conducted another study to determine a no-effect level.
The NAS study determined that this level was 0.0007 mg/kg-day, a factor of ten less than the original Greer
study. This new no-effect level was based on the Greer et. al. study. Using Greer et al.'s recommended level
of 0.007 mg/kg-day, the NAS included an uncertainty factor of 10 to account for pregnant women, fetuses,
and infants, the portion of the population most susceptible to the health hazards associated with perchlorate.2
The NAS considered other uncertainty factors, including the effects of long-term exposure, but concluded
that such factors were negligible. Based on the recommendations of the NAS, the Environmental Protection
Agency (EPA) set 24.5 ppb (the equivalent of 0.0007 mg/kg-day) as the suggested maximum concentration
level of perchlorate in drinking water.
Most recently, on December 30, 2008, the Office of the Inspector General (OIG) of the EPA released a new
study that questioned the NAS findings and subsequent EPA regulation. The new study rejects the NAS
findings on the basis that the NAS did not consider chemicals like thiocyanate and nitrate in their evaluation
of the risk of perchlorate contamination. The new study argues that thiocyanate and nitrate, despite being
present in lower concentrations than perchlorate in drinking water, are up to twelve times more potent than
perchlorate in inhibiting thyroid function. Additionally, the new study shows that reducing perchlorate from a
level of 24.5 ppb to even 6 ppb, a 4-fold reduction, would only improve maternal thyroid intake 1%.13
Perhaps most importantly, the new study examines the impact of lack of iodide in the diet on thyroid
function, revealing that low levels of iodide in the diet can have an inhibiting effect on the thyroid 50 times
stronger than that of perchlorate contamination alone.13
While the OIG study does not show that setting the perchlorate concentration level at 24.5 ppb level is
necessarily misguided, the OIG study does point to other issues of concern, foremost being the lack of iodide
intake, which affects nearly 7% of, or 276,000, American infants born each year. Lack of iodide intake in the
diet leads directly to T4 deprivation, and consequently to problems such as lower IQ, ADHD, and lower
motor performance.13 We can address lack of iodide intake effectively by providing low-cost iodide
screening for pregnant women. We recommend that doctors inform pregnant women about the risks of low
iodide intake and encourage them to consider preventative measures such as iodide supplements and highiodide content foods.
The OIG study further reinforces the thesis that a mass cleanup would be ineffectual. A 1% increase in iodide
intake via the reduction of perchlorate levels in drinking waters, which presents no measurable decrease in
terms of the risk of perchlorate-associated problems, is hardly worth the billions of dollars it would cost to
perform a mass cleanup.
Methods of removal:
If a clean-up of perchlorate were deemed necessary, there are three different ways possible, but none efficient
for vast usage. Mainly, the chemical itself is not very reactive to chemical treatments such as removal by a
“reducing agent.” The chemical characteristics of perchlorate do not encourage new methods of removal to
develop and make it virtually impossible to remove low levels of perchlorate from water. Secondly, the
characteristics of the soil and water that the perchlorate contaminates varies from site to site also make it
impossible to use the same technology at all sites, especially if other chemicals are also contaminating the
same soil or water. 10
At the moment, there are three ways to remove perchlorate: “biological and biochemical reactor treatment
systems, conventional chemical reactor treatment systems, and separation and concentration technology.”
Until better technology is found, most removal is currently being done by “Biological treatment and ion
(anion) exchange systems.” Under this treatment, microbes convert perchlorate into chloride and oxygen. To
do this, "anoxic conditions" are needed along with alcohol or another "electron donor to sustain the
microbes." The removal would most likely happen by flowing the contaminated groundwater through a tank
that contains the microbes. The system is potentially viable in the long term as it does not have any "waste
resin" and is "less expensive than ion exchange." However, biological treatments are not an accepted practice
on drinking water in the United States (though they are used in California where perchlorate levels have gone
down from 2500 ug/l to 4 ug/L). 10
The other most prevalent method of removal currently is the "ion exchange system" which removes
perchlorate ions by replacing them with chloride ions. This system may be the answer for potential clean-ups
as unlike the biological treatment system it is potentially viable over more conditions, is produced by more
than one manufacturer, and is accepted for use on drinking water. However, this system does not "destroy"
the perchlorate, but just removes it: this system leaves behind a waste product which then must be disposed
of. This makes this system more expensive; though more testing and technology is currently being done that
may lower costs. Overall, there are many potential ways to remove perchlorate, but no clear effective method
that funding is available for.10
Who would be held responsible?
A number of private corporations could be found liable for their unrestricted use of perchlorate and forced by
the courts to pay for the perchlorate clean up. One example is at the Kerr-McGee Chemical Corporate in
Nevada: this chemical plant is located near the Colorado River whose drinking water is used by twenty
million. Perchlorate has been found in “higher than expected” amounts in 38 milk samples and 67 out of 78
lettuce samples taken far downstream from the plant. Experts estimate that river sentiments contain about
twenty million pounds of perchlorate at this point and will remain contaminated for the next fifty years. In a
river that serves so many for drinking water, this is not good news. Another pertinent example is also in
Nevada at the American Pacific Plant, the sole current producer of the chemical in the US. This plant
produces about 20 millions pounds each year of perchlorate and as a result in the ground near the factory
perchlorate is found in levels up to 750,000 ppb. This high concentration descends three hundred feet below
the plant and “through five groundwater layers.” Former workers describe the “careless handling” of the
chemical and "disposal ... in a trench on the factory site, and washing down the plant-creating a pond of
contaminated water called 'lake louise." Very few companies have paid damages or truly privately changed
their ways. The defense corporation Lockheed Martin did spend $80 million to clean up one site in 1998 and
has pledged another $180 million over the next twenty years over fears of liability. No major court case has
taken place yet.11
Considering that roughly ninety percent of perchlorate in the U.S. is manufactured for or used by the military
and NASA,5 the defense department would be responsible for the almost all clean-up costs rather than the
private companies listed above. After all, perchlorate is used for rocket fuel and, therefore, the defense
department is responsible for discarding, and just leaving, missiles to close to ground water. This would most
likely result in the Department of Defense spending between 16 and 165 billion dollars.5 This cost estimate
varies so greatly as the Defense Department does not have an efficient way of monitoring which areas are
contaminated as each sub-agency (the navy, army, etc) has a different way of counting areas and has different
assumptions in their classifications of contaminated land. Depending on which agency, different levels of
concentration of perchlorate and different testing methods are used to determine how many contaminated
sites there are. Further, one acre of clean up varies from 800 to 7,600 dollars depending on which agency
owns that acre. Considering that the Defense Department has about 24 million acres of possible clean up and
there might be more unreported acres, a better record and testing system is needed to fully understand the
cost burden that clean up would place on the Department of Defense.5
This huge amount of capital required to start clean up is not exactly realistic for a department that spends 12
billion a month in Iraq. Thus, the Defense Department has not made any solid effort to clean up yet. They
have made some recent strides to test new sites and have promised that they will act if they find any site
above the appropriate level. For example, the Defense Department proudly boasts that one site’s groundwater
that they cleaned up is completely fine now. The Department has also pledged 114 million dollars to find
new ways to recycle perchlorate, detect it, and create substitutes. One substitute for military operations was
scheduled for manufacture in 2008, though unclear if this has happened.4 114 million dollars is a good start
for the Department, but is not very much compared to lowest estimated cost of a potential clean up: 14
billion. Until better technology is created to treat contaminated sites most cost effectively, the EPA will
likely have little chance to make the Department of Defense fund the clean up.
Cost-Benefit Analysis:
If the Department of Defense were willing to pay for the clean-up, the clean-up may not even be a socially
efficient cost. 276,000 infants are born each year in the U.S. at risk as their mother’s have low T4 levels. Cost
of screening all adults for hypothyroidism is only the cost of a simple blood test, Radioimmunoassay (RIA),
which depending on availability costs around just $5. Additionally, the CDC estimates that 44 million
women are at risk with low iodine levels. For those 44 million to develop complications from perchlorate,
current studies offer significant support that they must be in an environment of consistently high exposure to
perchlorate. In the case that all these conditions are met and they do develop hypothyroidism, there are drugs
like Levothyroxine, a pure synthetic T4 drug, that have already been developed for other wide-ranging causes
of hypothyroidism. Cost estimates for Levothyoxine are about $120 a year for the rest of their life, and even
this might be unecessary.15 As hypothyroidism is not a chronic illness, in the case of perchlorate obstruction,
studies point toward the simple solution of increasing iodide intake to cure the illness at very low general
costs.16 It is unclear exactly how much medical costs would be with no cleanup, but based on these rough
numbers, we can postulate a total significantly lower than the billions needed for the clean-up.
2
We came to a primitive conclusion on clean-up costs based on a couple basic calculations. From the range of
$16-165 billion Defense of Department (see Who should be held responsible?), we based our approximation
on about a $100 billion expenditure for full perchlorate clean-up.5 We also calculate approximately 84% of
all perchlorate contamination linked to the Department of Defense, (see table in Background) from the
estimates of about 90% of all perchlorate manufactured (21% of all perchlorate activity) for the Department
of Defense in addition to the 65% of all perchlorate activity attributed to the Department of Defense, NASA,
and other defense industries. Thus, using simple cross-multiplication (.84/$100=1.00/x) we estimate that total
clean-up costs would lie somewhere around $120 billion.
Conclusion:
Therefore, we recommend that four actions be taken. One, areas of high concentration should be cleaned.
There are very few in the nation with hundreds of thousands particles per billion of perchlorate. These
Defense Department and private sites along with the other 14 drinking water systems that have thus far been
identified should be cleaned immediately. Sites with low contamination, on the other hand, do not necessitate
a federal mandate to be cleaned. Thus, secondly, instead of cleaning up all sites, a better cross-agency
monitoring system for the remaining sites should be developed. The EPA and DoD should be required to
work together to keep our water safe.1 Thirdly, safe storage and disposal should be required of both private
manufacturers and the Defense Department. Leaving used munitions next to rivers should not be acceptable,
and legislation should be used to enforce this. Lastly and perhaps most importantly, all women, and not just
those who are identified as at-risk women, should be screened for low-iodine levels as a measure to stop the
easily preventable and highly deleterious effects of low-iodine levels in fetuses, namely developmental
restrictions in skeletal and nervous systems. Overall, perchlorate is dangerous in high concentrations, has
significantly contaminated some of our sources of drinking water, but with proper monitoring and
responsible actions can be dealt with efficiently and economically.
Works Cited
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Accounting Office: Report to the Chairman on Environment and Hazardous Materials, Committee on Energy
and Commerce, House of Representatives. May 2005. GAO-05-462. www.gao.gov/cgi-bin/getrpt?GAO05-462.
2. Johnston, Richard B. Jr and et al. Health Implications of Perchlorate Ingestion. Washington, National
Academy of Sciences, 2005. http://www.nap.edu/catalog/11202.html.
3: Blount, Pirkle, Osterloh, Valentin-Blasini, and Caldwell. "Urinary Perchlorate and Thyroid Hormone
Levels in Adolescent and Adult Men and Women Living in the United States". Environmental Health
Perspectives. Volume 114, Number 12. December 2006.
http://www.ehponline.org/members/2006/9466/9466.pdf.
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Safety, & Occupational Health) Before the Subcommitte on Environment and Hazardous Materials of the
House Energy and Commerce Committee April 25, 2007. http://energycommerce.house.gov/cmte_mtgs/110ehm-hrg.042507.Beehler-testimony.pdf.
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Contamination are Needed.” United States General Accounting Office: Report to Congressional Requesters.
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Food Safety and Applied Nutrition: Office of Plant & Dairy Foods. Updated May 2007.
http://www.cfsan.fda.gov/~dms/clo4data.html.
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Foods. May 2007. http://www.cfsan.fda.gov/~dms/clo4ee.html.
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Now Ignites Health Controversy.” Wall Street Journal. 16 Dec. 2002.
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Enviromental Contamination: Toxicological Review and Risk Characterization External Review Draft
(January 16, 2002)’. United States Environmental Protection Agency.
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nse%20to%20NAS%2010-27-2003.pdf.
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Group and its Industry Backers. California, Environment California Research & Policy Center, 2006.
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Dose Response for Inhibition of Thyroidal Radioiodine Uptake in Humans." Environmental Health
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15. Shomon, Mary. "Thyroid Organizations Take On Generic Levothyroxine: Should You Be Concerned
About Taking Generic Thyroid Drugs?" About.com. 4 Oct. 2006.
http://thyroid.about.com/od/thyroiddrugstreatments/a/oct2006.htm.
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Hypothyroidism." endocrineweb.com. http://www.endocrineweb.com/hypo2.html.