|June 24, 2003:
"Perchlorate" has been on the lips of the media but,
unfortunately, not the EPA scientists familiar with two recently
released studies revealing the rocket-fuel component may be
contaminating the winter lettuce feeding 88% of the USA's population.
A gag order imposed by the EPA prevents the scientists from
speaking about perchlorate and, therefore, the studies, which
show lettuce not only absorbs but also concentrates perchlorate
in substantial amounts.
||"...researchers at Texas Tech
University... concluded that 1.6 million U.S. women of
childbearing age are exposed daily to more perchlorate
from winter lettuce alone than the EPA's recommended 'safe
Concerns about rocket fuel, specifically perchlorate, contamination
surfaced last year when the EPA announced research findings
that concentrations of the chemical in drinking water above
one part per billion pose a health risk to humans, particularly
in developing infants. To put this number in perspective,
you should know that the Colorado River, which supplies over
15 million people with drinking water, is polluted at seven
parts per billion. The research recommended contamination
limit be set at five parts per billion.
The Pentagon and several defense contractors, in the face
of a multi-billion dollar cleanup, have funded more than $30
million in research opposing the EPA's assessment and argue
70 to 200 times the EPA's estimate of perchlorate is safe
in drinking water. And, in the name of "military readiness,"
the Bush administration has proposed a bill in Congress pardoning
the Pentagon and defense industry from an array of environmental
laws; forgiving their environmental damages including perchlorate
contamination. US Senator James Inhofe (R., Okla.), chairman
of the Senate's Environmental and Public Works Committee,
even publicly criticized the EPA's report in January.
So what exactly is all this lettuce hubbub about? In one
study performed by researchers at Texas Tech University, Lubbock,
TX, 22 lettuce samples purchased in San Francisco Bay Area
grocery stores between January and February were tested. The
group discovered four of the 22 samples were found to contain
perchlorate in amounts exceeding 30 parts per billion, with
the highest -- "mixed organic baby greens" -- registering
121 parts per billion. They concluded that 1.6 million U.S.
women of childbearing age are exposed daily to more perchlorate
from winter lettuce alone than the EPA's recommended "safe
In case this recent press on perchlorate contamination of
lettuce has you worried, here’s a whirlwind tour of
what perchlorate is, what it’s doing in our food systems,
what that might mean to you, and what you can do about it.
What is perchlorate?
Perchlorate is the substance that has served since the 1940s
as an oxidizer in solid rocket fuel for more effective propulsion
for space shuttles and missiles. Perchlorate compounds are
also used in explosives, matches, fertilizer, fireworks, road-flares,
air-bag inflation systems, lubricating oils, nuclear reactors,
electronic tubes, and finishing processes for rubber, leather,
aluminum paints, enamels and electroplating. It is highly
mobile in water, meaning it can be easily transported in fluid,
either on a large scale (for example a river) and also on
a smaller scale (e.g. vascular transport in plants).
For the scientifically-minded: A perchlorate molecule is
an organochlorine and has the chemical formula ClO4-, four
oxygen atoms surrounding a chlorine atom. Perchlorate can
become an acid or a salt when bound with a positive ion (a.k.a.
cation), such as hydrogen, sodium, potassium or ammonium.
Ammonium perchlorate is the form most commonly produced.
What is perchlorate doing in our food system?
The process of washing perchlorate out of rockets has been
a source of drinking and irrigation water contamination demonstrated
in and around the Colorado River and the Sacramento area.
|"As noted by the Water Eduation
Foundation, 'According to NASA, each solid rocket booster
on the space shuttle contains 700,000 pounds of perchlorate,
for a total of nearly 1.5 million pounds. In years past,
it was disposed of by flushing with high-pressure water
jets – a process that resulted in wastewater with
perchlorate levels at 1 percent of total volume. Often
the water was simply drained directly into the ground.'"
As perchlorate loses efficacy with time, it is washed out,
creating a toxic waste product. As noted by the Water Eduation
Foundation, "According to NASA, each solid rocket booster
on the space shuttle contains 700,000 pounds of perchlorate,
for a total of nearly 1.5 million pounds. In years past, it
was disposed of by flushing with high-pressure water jets
– a process that resulted in wastewater with perchlorate
levels at 1 percent of total volume. Often the water was simply
drained directly into the ground."
Once in the groundwater, removing perchlorate can prove
to be a challenge. Prior to the introduction of an ion chromatography
technique in 1997, perchlorate was very difficult to detect.
The highly mobile contaminant is now much easier to trace.
But, although the procedure for removing perchlorate is not
considered difficult, the amount of contaminated water needing
treatment is enormous and poses logistical challenges.
For many years, efforts to establish a drinking water standard
for perchlorate contamination have been under way, receiving
federal and state attention. While efforts are being made
to speed and ease the lengthy regulatory process, the progression
is painstakingly slow. A slide
show presentation by McGuire Environmental Consultants, Inc.
includes a timeline of some of the regulatory actions prior
to January 2002. Just last month, the possibility of regulatory
action was stalled even further when the debate was referred
to the National Academy of Sciences for review inspiring the
gag on EPA scientists.
But the drinking water standard is not the end of the regulatory
process and, as the two recent lettuce studies suggest, may
be a beginning of the recognition of widespread problems related
to perchlorate’s presence in the water system. The irrigation
of some of our major agricultural land hinges on the very
water sources being contaminated, exposing consumers to perchlorate
nationwide through the very food on their plates.
What impact might perchlorate contamination
of water and food have on me?
||"Contamination of the Colorado
River means that 1.4 million acres of cropland in California
and Arizona is dosed with perchlorate at varying intensities
depending on the area from which the irrigation water
Many sites are contamination confirmed or at high risk of
being contaminated with this rocket fuel component. The Environmental
Working group has posted a list of perchlorate-contaminated
areas at www.ewg.org/reports/rocketwater/table4.php.
Fortunately, if you are drinking uncontaminated water and
eating food that is not irrigated with perchlorate-contaminated
water, then you may not be affected at all. Unfortunately,
even if you do not live by a contaminated site, in this age
of long-distance food shipment, much of what we eat comes
from farther away than the local water supply and could be
from contaminated areas.
Contamination of the Colorado River means that 1.4 million
acres of cropland in California and Arizona is dosed with
perchlorate at varying intensities depending on the area from
which the irrigation water is drawn. The Yuma and Imperial
Valleys (in AZ and CA, respectively), grow 88% of the winter
lettuce that is consumed by Americans. And lettuce is not
the only crop that takes up perchlorate. Any fruit or vegetable
that is highly aqueous or leafy can be a major accumulator
What does perchlorate do in the human body?
Perchlorate disrupts the human metabolism. We all have a
thyroid gland in our necks that secretes hormones that work
in concert with other organs and glands to regulate our metabolism.
Humans can be hyperthyroid, and secrete too many thyroid hormones
or hypothyroid, secreting too few. Both conditions are detrimental.
Our thyroids take in iodide and, when healthy humans have
sufficient iodide, we produce optimum amounts of thyroid hormones
T3 (triiodothyronine) and T4 (thyroxine).
Perchlorate competes with iodide, tying up the transport
mechanism and raising production of thyroid stimulating hormone
TSH (thyrotropin). To gauge the level of someone’s exposure
to perchlorate, tests of TSH, T3 and/or T4 levels could be
an indicator of problems in this respect.
Possible physical ramifications of an overexposure to perchlorate:
altered metabolic rate, thyroid lesions,
thyroid tumors, decreased T3/T4 production, hypothyroidism.
In the 1960s, perchlorate was used to treat hyperthyroidism,
but its long-term use was discontinued after severe side effects
were noted (including deaths) due to aplastic anemia (http://www.thyrolink.com/literature/report1995_2/seite03.html).
There are a few high-risk groups out there, and these people
should be especially wary of perchlorate intake. Those already
battling hypothyroidism should avoid anything that would make
iodide utilization any more difficult than it already is for
Pregnant women have thyroid stress under normal circumstances
and are, therefore, more at risk of developing a severe problem,
such as preclampsia, miscarriage, placental abruption and
low birth weight, or chronic condition when overexposed to
Perchlorate can also pose significant threats to the health
of the developing fetus. Children, infants, and neonates don't
have enough thyroid hormone to cushion them from the dips
in hormone production caused by the contaminant. Chronic health
conditions can result.
What can I do to lower my exposure to perchlorate?
First and foremost, know where
your food and water is coming from, and know
the odds of it being contaminated. Perchlorate is considered
highly mobile in water, but remains quite localized to its
watershed, unless it is shipped elsewhere.
If you live in Yuma Valley, are pregnant, work in a military
installation and suffer from hypothyroidism, avoid tap water
and don't eat salad from a contaminated area. Perchlorate
intake is primarily via food and drink. It is poorly absorbed
through skin, so don’t be afraid to shower or do laundry
in contaminated water.
Some reduction in perchlorate contamination can be achieved
simply by washing vegetables
in uncontaminated water. But, because plants
tend to accumulate perchlorate in their leaves, washing with
uncontaminated water is not enough to rid vegetables of all
contamination. You can limit perchlorate intake simply by
limiting the amount of leafy or extremely watery vegetables
Eat more iodine-rich foods
to combat the thyroid competition posed by perchlorate presence.
Sadly, the most easily-attainable sources for iodine are iodized
salt and sea products, both of which can be taboo for pregnant
women. Cardiac patients are also recommended to restrict sodium
intake, but are often advised to eat fish.
You can also encourage more
of a systems approach to reduction, i.e. making/changing
policy, research, or ecosystem remediation (cleanup) on a
local and national level.
Bioremediation, or using natural
processes to clean up our messes, shows promise.
A 95% reduction in perchlorate contamination was achieved
by non-crop plants taking up the organochlorine and is a step
in the right direction. Unfortunately, disposal of these contaminated
non-crop plants then becomes a challenge.
Prevention is key.
A material called MnO4- may be an effective and less harmful
substitution for perchlorate. This potential substitution
has not be researched fully yet but may offer an alternative
that doesn't currently exist.
And, as always, public outcry
is essential. Contact your House or Congressional
representative and let them know you support safe, clean water
according to guidelines based on science and the precautionary
- air-bag inflation
- lubricating oils
- nuclear reactors
- electronic tubes
Also used in finishing
- aluminum paints
- altered metabolic
- thyroid lesions
- thyroid tumors
- decreased T3/T4
- aplastic anemia
And for pregnant
- placental abruption
- low birth weight
- drink uncontaminated
- eat uncontaminated
- wash contaminated
- increase iodine
- eat fewer leafy/watery
- limit occupational