Silent Spring II
from the Summer 1997 Food First newsletter
Recent Discoveries Reveal New Threats of Pesticides
to Our Health
We have known since Rachel Carson wrote Silent Spring' in
1962 that pesticides accumulate in the food chain and cause cancer,
and that we need to keep residue levels in our food low. But new
findings brought to public attention suggest that pesticides have
much more dramatic effects at much lower doses than previously
suspected. In fact, these findings may be so grave as to question
the entire notion of using pesticides to produce food.
As it becomes clear that many developmental and reproductive
disorders are caused by the complex interactions of multiple pesticides
with our hormone systems, a whole new area of pesticide research
and policy discussion is emerging. New studies are showing that
pesticides have many dangerous health impacts other than causing
cancer. Additionally alarming is the significant synergistic effect
when several pesticides interact.
Silent Spring warned us of health and environmental impacts,
and brought pesticide use under public scrutiny for the first
time in the early 1960s. Since then most research on the health
consequences of pesticides has focused on cancer, trying to estimate
the risk of specific cancers caused by individual pesticides as
the basis for setting tolerance levels that government agencies
feel are safe for human consumption.
This narrow focus on cancer silenced the voices of other scientists
who were quietly studying many other pervasive and detrimental
effects of pesticides on humans, animals, and the environment.
These scientists are now amassing evidence revealing how complex
the interactions between our body chemistry and pesticides really
are, and how the multiple pesticide residues in our diet can magnify
each other's effects.
PESTICIDES IN AGRICULTURE CONTAMINATE AIR, WATER, SOIL AND
Unfortunately pesticide policy is still focused on establishing
tolerance levels for single pesticides and does not address combinations
of pesticides, or even the cumulative impact of pesticides that
function in similar ways. The Environmental Protection Agency
sets a limit for how much of each pesticide is okay to have in
our air, water, and food. But considering that over 700 pesticides
are licensed for use in California alone, we are in fact all continually
exposed to a diverse mixture of hazardous pesticides.
PREVIOUS CONCERNS ABOUT PESTICIDES
Concerns raised over the last 35 years have focused on acute
toxicity and cancer. For years we have known that pesticides can
kill or permanently harm people who work in direct contact with
them. The acute reaction to many pesticides are well documented;
affecting the liver, kidneys, lungs, skin, eyes, and brain. Long-term
chronic effects on humans include a whole series of cancers, liver
and kidney disfunction, sterility, neurological disorders and
BIO-MAGNIFICATION: HUMANS AS PREDATORS
Since Silent Spring we have also known that pesticides that
take a long time to break down in the environment accumulate in
organisms as they move up the food chain. For example, the concentration
of persistent organochlorine chemicals in lake water may be extremely
low and well below the standards established by the U.S. Environmental
Protection Agency (EPA). But in algae that concentration is increased
up to 250 times. As the filter-feeding zooplankton eat the algae
this concentration doubles; tiny shrimp eat so much zooplankton
that the concentration jumps as high as 45,000 times that of the
surrounding water. Fish eat the shrimp, and birds and other top
predators eat the fish. These top predators have concentrations
25 million times that found in the surrounding water. Humans are
top predators and thus can accumulate relatively high concentrations
of pesticides through the food supply.'
NEW CONCERNS ABOUT PESTICIDES:
New evidence indicates that proper functioning of the human
body's endocrine / hormone system, can be severely altered by
low-level cumulative pesticide exposure. This system is directly
linked to our neurological and immunological systems, further
increasing the risks and potential impacts of pesticide exposure.
This evidence indicates that while low level exposure may not
cause acute toxicity in adults, it can cause chronic reproductive,
immunological, and neurological disorders. More alarming, low-level
exposure to unborn children can affect a wide range of developmental
processes from reproductive system formation to brain function.
The endocrine system is the central, internal regulator of
body chemistry, coordinating the 50 trillion cells in our body
into a controlled and integrated organism. Without it our body
cannot function. This system functions by releasing specific hormones,
each from one of over a dozen glands, into the bloodstream. Key
glands include the pituitary, thyroid, pancreas, adrenal, and
testis in men, and ovaries in women. Hormones produced in these
glands are released into the blood stream where many of them bind
with specific proteins which help them arrive at their final destination.
Once they reach specific receptor cells of their target organs
they cause very specific reactions. In turn, these reactions either
increase or decrease the amount of hormone released, creating
a self-regulating feedback loop. In this manner, the endocrine
system controls an incredible number of biochemical functions
ranging from the reabsorption of water in the kidneys to the regulation
of blood sugar levels, from heart rate to responses of the immune
system, and the timing of the menstrual cycle. Additionally, many
important develop mental processes are controlled by hormones
making this system of extreme importance for unborn babies and
It is now clear that a wide variety of pesticides and other
industrial toxins (e.g. PCBs and dioxins) can distort the effects
of hormones, sending the wrong messages to organs and disrupting
the delicate balance of our internal biochemistry. There are many
stages in this process which are vulnerable to this disruption,
and different periods in our life when we are more vulnerable
to specific types of disruption. Additionally, each stage of the
process may be disrupted by different mechanisms.
The most commonly discussed type of hormone disruption is
called hormone mimicking. A synthetic chemical binds to a receptor
site and produces the normal response to a specific (absent) hormone.
This can create unsolicited responses from receptor cells and
may accelerate or prolong responses which were begun by hormonal
glands. Another mechanism is hormone blocking. Here a synthetic
compound binds to the receptor site and does not produce the effect
of the hormone, but occupies the receptor site making active hormones
ineffective. Other mechanisms include disturbing the production
process of the hormones, interfering with the helper or transport
proteins, suppressing hormones, and altering the breakdown of
hormones once they have served their function.
PESTICIDES AND REPRODUCTION
In the last fifty years, human sperm count and quality has
decreased, prostate cancer has skyrocketed, testicular cancer
has nearly doubled, and the incidence of breast cancer has
increased by one percent per year for the last twenty years.
Today it is estimated that one in every eight or nine women in
the U.S. will develop breast cancer in their lifetime. While there
is substantial evidence that endocrine disrupting chemicals including
pesticides can cause these disorders, we still haveinsufficient
evidence to directly connect these over-all trends.
The known impacts of endocrine disruptors for women include
the disruption of normal sexual differentiation of the fetus,
reduced ovarian function, reduced rates of fertilization, implantation,
Exposure to organochloride insecticides is suspected to play
an important role in breast cancer. One known mechanism involving
organochlorines provokes a change in the natural breakdown of
estradiol, the most predominant form of estrogen in women. Normally,
estradiol is changed into one of two products: one is benign,
the other is not. The deleterious compound binds to certain breast
cells and causes continuous cell divisions. Uncontrolled growth
of these cells leads to breast cancer. Excessive exposure to organochlorines
can significantly increase the ratio deleterious to benign estradiol
by-product. This ratio has become a biological marker of risk
for breast cancer. It is estimated that forty percent of all cancers
in women are hormonally mediated.
Endometriosis, an extremely painful reproductive and immunological
disease, is on the rise and currently affects 5 million women
in the U.S.. It too is on the probable suspect list of diseases
caused by endocrine disruption. Additionally, women in Ventura
County, California reported a synchronization of their menstrual
cycles with the spraying of malathion in attempts to eradicate
the Mediterranean Fruit Fly. While the mechanisms of this are
not fully understood it is quite likely related to estrogen mimicking.
Another study found that young women are reaching puberty at much
earlier ages, raising additional troubling questions about the
impacts of environmental estrogens.
For men, the suspected impacts of endocrine disrupting chemicals
are reduced sperm production, reproductive system abnormalities
and testicular cancer. Additionally, a recent study found a correlation
between number of nearby acres sprayed with herbicide and prostate
In males, one gene on the Y chromosome triggers the development
of the testis. All of the other distinguishing features of male
physiology are developed by the testosterone and androgen which
are produced there. Some of the developmental disorders associated
with hormone disruption in male newborns are undescended testicles
(cryptorchidism) and abnormal urethral openings (hypospadias),
which have also doubled in the last half century.
Documented effects of endocrine disrupting chemicals on wild
animals include the low male hatching rates and survival in western
gulls apparently resulting in same sex nesting among females.
Alligators in Lake Apopka, Florida contaminated in 1980 with dicofol
spilled by the Tower Chemical Company, have continued to exhibit
reproductive problems, including underdeveloped penises long after
water sampling has shown the lake to have recovered. We have seen
the feminization of rainbow trout, masculinization of marine snails,
mosquito fish, grizzly and black bears; and decreased hatching
of bald eagle, Foster's tern, cardinal, mocking bird, and snapping
turtle eggs; and reduced thyroid function of salmon and herring
PESTICIDE SYNERGY: THE WHOLE IS GREATER THAN THE SUM OF THE
PARTS (OR WHEN 1+1=10)
A recent study published in Science showed that pesticides
may be thousands of times more potent than previously thought.
It demonstrated that, when tested alone, each of two particular
organochlorine pesticides had to be at concentrations on the order
of 100,000 times greater than natural estrogen to cause responses
in yeast cells reactive to estrogen. Yet the same two organochlorines
mixed together only required concentrations between 10 and 100
times more than natural estrogen to induce the same response.
Thus, exposure to multiple pesticides may be thousands of times
more potent in mimicking estrogen than was previously thought.
A recent study found thirty percent of apples contain at least
three different pesticide residues. Considering the diversity
of pesticides found in our environment the increased potency of
combined pesticides raises many questions. Does this mean that
current tolerance levels set for individual pesticide residues
allowed in our food are actually far above dangerous limits when
combined? What are the implications for the unborn, children,
and adolescents? In light of these findings, how should pesticide
use be assessed? How should new chemicals be evaluated? And, what
are the implications for future pesticide policy formulation?
HOW MANY PESTICIDES ARE REALLY USED?
The significance of the synergistic nature of pesticides is
evident in light of the extensive use and accumulation of pesticides
in both the environment and living organisms. Since WW II, world
pesticide use has increased dramatically. In 1993, approximately
4.5 billion pounds of "conventional pesticide active ingredients"
used for agricultural purposes were applied throughout the world;
24% of those pesticides or over 1 billion pounds used in the US
alone-equivalent to 4.1 pounds per person. In 1995, California
applied over 210 million pounds of active ingredient, (almost
five percent of global use.) or an alarming 6.6 pounds per person.
Actual pesticide exposure is nearly impossible to estimate on
an individual basis because there are so many distinct exposure
pathways. Pesticides are in our food, water, and air. They are
now a nearly universal feature of our environment found in every
ecosystem in the world. They're used not only in food production
and commercial forestry, but also in our homes, schools, public
parks, and work places. Pesticides are a pervasive part of our
environment virtually impossible to avoid.
FREE MARKET GOVERNMENT REGULATION ROLL BACK
Even as we are now discovering that pesticides pose a much
greater threat to society than ever suspected, the U.S. government
is undermining already limited regulations. August 3, 1996 marked
a new era for pesticide regulation roll back, as President Bill
Clinton signed into law the Food Quality Protection Act, dramatically
weakening the way we regulate the dangers of pesticides in our
food. This new law, which President Clinton preferred to call
the "Peace of Mind Act," cleverly eliminated the Delaney
clause of the Federal Food, Drug, and Cosmetic Act which prohibited
the existence of carcinogenic residues in all processed foods.
As industry cheers "Ding-dong Delaney's dead," known
carcinogens and other toxic chemicals are being allowed into our
food supply, but only in quantities which are determined "safe"
by the EPA. Policy makers, moved by major pesticide industry lobby
groups such as the American Crop Protection Association (ACPA),
have lowered our food safety standard from one of banning known
carcinogens, to just "managing" the risk of having them
in our food.
In light of endocrine disruption, this new reliance on tolerance
levels and risk management poses many problems for consumers.
First and fore most, a high proportion of pesticides registered
for use have never had full toxicological studies and risk assessments
performed on them. This is due to a lack of funding and political
will on the part of state and federal agencies. Secondly, the
only pesticides tested for endocrine disruption are those that
are related to very specific events linking them to a rare health
or environmental impact, thus bringing them under suspicion.
There is no routine screening protocol or series of tests
for endocrine disruption that all pesticides must pass to get
registered. Third, there are specific windows of vulnerability
to specific endocrine disrupters such that we have different susceptibility
at different ages. Thus each test must be done on the different
stages of human development starting in the first trimester of
pregnancy and continuing through adolescence and adulthood creating
different tolerances for different stages of development. Fourth,
pesticides react with the endocrine system in unpredictable ways',
some are estrogen mimickers at low doses and estrogen blockers
at high doses. Finally, tolerance levels based on single chemicals
do not take into account the synergistic or additive effects of
two or more endocrine disrupters or the cumulative effects of
pesticides which have the same bio-chemical impacts on our bodies.
The Environmental Protection Agency has created the Endocrine
Disruptor Screening and Testing Advisory Committee (EDSTAC) to
try to address some of these issues. The work groups which have
been established include members of the chemical industry, governmental
agencies, university researchers, and public interest groups.
The quantity of research that would be required to begin to set
new tolerance levels combined with the poor regulatory and enforcement
track records of our federal and state agencies bring this whole
approach into question.
One of the most prominent examples of the lack of control
by the Food and Drug Administration (FDA) occurred when illegal
residues of chlorpyrifos, an organochlorine insecticide, were
detected in Cheerios breakfast cereal. By the time it was discovered,
over one year's worth of Cheerios had already been sold and consumed,
and the FDA could not recall boxes already in commerce without
declaring a public health emergency. Furthermore, General Mills
sold the remaining 18 million bushels of contaminated oats as
animal feed which, if used for either meat or dairy production,
could still reach consumers through accumulation in the food chain.
This contamination of our food supply is a direct reflection of
the broader failure of the FDA's regulatory power.
WHAT ARE THE ALTERNATIVES?
If so many illegal residues already slip through the system,
perhaps the FDA and EPA are not the answer. We must ask the more
fundamental question: Is lowering tolerance levels and increasing
pesticide monitoring an appropriate strategy to guarantee a safe
and secure food supply?
The fact that we have residues of hundreds of industrial and
agricultural chemicals in our bodies is a direct invasion of our
most private property. Chemicals that present serious health risks,
should simply be banned from use. Under such a policy, research
would only focus on detecting those chemicals which cause such
problems. This would eliminate the whole research task of developing
tolerance levels and eliminate the risk rather than attempting
but failing to manage it. Effective alternatives currently exist
for most pesticides. The social costs of continuing their use
outweigh the short-term economic gains they provide to the chemical
and food companies.
Although organic food is more expensive than that grown with
pesticides, the external costs of pesticides are not included
in the price of commercially grown food. It has been very roughly
estimated that a direct investment of $4 billion in pesticides
saves about $16 billion in crop losses, but causes an estimated
$8 billion in environmental and health costs to society. Five
billion of that is paid for by society and not by chemical companies
or direct users. Buying organic food from local farms not only
enhances our own health and that of future generations, but also
benefits us as it decreases pollution, supports local, small-scale
farmers and makes farming itself more sustainable in the long