PESTICIDES AND AGGRESSION

=======================Electronic Edition========================
.                                                               .
.           RACHEL'S ENVIRONMENT & HEALTH WEEKLY #648           .
.                     ---April 29, 1999---                      .
.                          HEADLINES:                           .
.                   PESTICIDES AND AGGRESSION                   .
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PESTICIDES AND AGGRESSION

For the past 25 years, tens of millions of Americans in hundreds
of cities and towns have been drinking tap water that is
contaminated with low levels of insecticides, weed killers, and
artificial fertilizer. They not only drink it, they also bathe
and shower in it, thus inhaling small quantities of farm
chemicals and absorbing them through the skin. Naturally, the
problem is at its worst in agricultural areas of the country.

The most common contaminants are carbamate insecticides
(aldicarb and others), the triazine herbicides (atrazine and
others) and nitrate nitrogen.[1] For years government scientists
have tested each of these chemicals individually at low levels
in laboratory animals -- searching mainly for signs of cancer --
and have declared each of them an "acceptable risk" at the
levels typically found in groundwater.

Now a group of biologists and medical researchers at the
University of Wisconsin in Madison, led by Warren P. Porter, has
completed a 5-year experiment putting mixtures of low levels of
these chemicals into the drinking water of male mice and
carefully measuring the results. They reported recently that
combinations of these chemicals -- at levels similar to those
found in the groundwater of agricultural areas of the U.S. --
have measurable detrimental effects on the nervous, immune and
endocrine (hormone) systems.[2] Furthermore, they say their
research has direct implications for humans.

Dr. Porter and his colleagues point out that the nervous system,
the immune system, and the endocrine (hormone) system are all
closely related and in constant communication with each other.
If any one of the three systems is damaged or degraded the other
two may be adversely affected. The Wisconsin researchers
therefore designed their experiments to examine the effects of
agricultural chemicals on each of the three systems
simultaneously. To assess immune system function, they measured
the ability of mice to make antibodies in response to foreign
proteins. To assess endocrine system function, they measured
thyroid hormone levels in the blood. And to assess nervous
system function they measured aggressive behavior in the
presence of intruder mice introduced into the cages. They also
looked for effects on growth by measuring total body weight and
the weight of each animal's spleen.

The experiments were replicated many times, to make sure the
results were reproducible. They found effects on the endocrine
system (thyroid hormone levels) and the immune system, and
reduced body weight, from mixtures of low levels of aldicarb &nitrate, atrazine & nitrate, and atrazine, aldicarb & nitrate
together. They observed increased aggression from exposure to
atrazine & nitrate, and from atrazine, aldicarb & nitrate
together.

The Wisconsin research team wrote, "Of particular signficance in
the collective work of Boyd and others,[3] Porter and others,[4]
and our current study[2] is that THYROID HORMONE CONCENTRATION
CHANGE was consistently a response due to mixtures, but NOT
usually to individual chemicals." [Emphasis in the original].

In the five-year experiment, thyroid hormone levels rose or fell
depending upon the mixture of farm chemicals put into the
drinking water. Dr. Porter and his colleagues present evidence
from other studies showing that numerous farm chemicals can
affect the thyroid hormone levels of wildlife and humans. PCBs
and dioxins can have similar effects, they note. Proper levels of
thyroid hormone are essential for brain development of humans
prior to birth. Some, though not all, studies have shown that
attention deficit and/or hyperactivity disorders in children are
linked to changes in the levels of thyroid hormone in the blood.
Children with multiple chemical sensitivity (MCS) have abnormal
thyroid levels. Furthermore, irritability and aggressive behavior
are linked to thyroid hormone levels.


Interviewed recently by Keith Hamm of the SANTA BARBARA [CAL.]
INDEPENDENT,[5] Dr. Porter explained, "Earlier work had shown
that thyroid hormone typically changed when exposure to these
pesticides occurred. Thyroid hormone not only affects and
controls your metabolic rate, that is, how fast you burn food,
it also controls your irritability level. For example, Type A
personalities are more assertive, more aggressive, more hyper.
These people tend to have higher levels of thyroid hormone. Type
B personalities--people that are really laid back, really take
things very easily--have lower levels of thyroid hormone. We
expected that changes in thyroid [would] change irritability
levels. This was a concern because there was information that
kids are getting more hyper and [that their] learning abilities
are going down," Dr. Porter said.

A recent study of 4 and 5 year-old children in Mexico
specifically noted a decrease in mental ability and an increase
in aggressive behavior among children exposed to pesticides.[6]
Elizabeth A. Guillette and colleagues studied two groups of Yaqui
Indian children living in the Yaqui Valley in northern Sonora,
Mexico. One group of children lives in the lowlands dominated by
pesticide-intensive agriculture (45 or more sprayings each year)
and the other group lives in the nearby upland foothills where
their parents make a living by ranching without the use of
pesticides. The pesticide-exposed children had far less physical
endurance in a test to see how long they could keep jumping up
and down; they had inferior hand-eye coordination; and they
could not draw a simple stick figure of a human being, which the
upland children could readily do.

Notably, in the Guillette study we find this description of the
behavior of pesticide-exposed children: "Some valley children
were observed hitting their siblings when they passed by, and
they became easily upset or angry with a minor corrective
comment by a parent. These aggressive behaviors were not noted
in the [pesticide-free] foothills [children]."

The human body can defend itself against poisons to some degree,
but Dr. Porter and his colleagues describe ways in which
low-level mixtures of pesticides and fertilizer might get past
the body's defenses:

The body is prepared to protect itself against poisons taken by
mouth. The liver begins to produce enzymes that try to break
down fat-soluble chemicals. However, if a poison enters through
the lungs or the skin, the body does not offer the same kind of
defenses. Furthermore, the body's ability to put up defenses may
be compromised by taking certain medications (e.g.,
antibiotics), or by receiving "pulses" of toxins rather than a
steady dose.

Receiving "pulses" of poisons would be normal in the case of
agricultural poisons which are sprayed onto crops only at
certain times of the year. During those periods, people living
near sprayed fields might get a sudden dose of poison via their
lungs, their skin and their drinking water. Dr. Porter describes
such a situation this way:

"Imagine [that] you're standing in a boxing ring and a boxer
jumps in with you, and he walks toward you smiling with his hand
outstretched. And you reach out to shake his hand and he smacks
you in the stomach as hard as he can. And when you bring your
arms up to defend yourself, he backs away. Finally you get tired
of holding your defenses up and you drop them and he rushes in
and smacks you again. That's the physical equivalent to a 'pulse
dose,' which is normally what we tend to get exposed to.

"The defenses we have take a while to induce, just like it takes
a while to bring your arms up. It takes anywhere from a half a
day to five days to induce those [defenses] to appropriate
levels. If you're in a particular stage of your hormone cycle or
you're taking some antibiotics, it can compromise your ability
to defend yourself even if you did have enough time to induce
your defenses. If you've got pulse doses coming in under your
defenses or coming in faster than you can bring your defenses up
then you've got a situation where you're totally vulnerable.

"If you've got a pregnant mom, for example, in day 20 when the
fetus's neural tube is closing and she gets an exposure, she
hasn't had enough time to induce her defenses. Her thyroid level
goes up or goes down, the hormone crosses the placenta and can
permanently alter the developmental pattern of the fetus's
brain. And then the pulse dose is gone, you have no detection,
mom doesn't even know she's pregnant, and you may have an
offspring that is neurologically compromised and wonder, 'How
did this happen?'"

In the interview with Keith Hamm, Dr. Porter expressed concern
for the overall effect of pesticides on the nation's children:

Hamm: "Are pesticides, herbicides, and fertilizer used more or
less these days than fifty years ago and have the toxicities
changed?"

Porter: "The usage has continued to climb. There's an enormous
amount of these [chemicals being used] right now. There was a
recent study that examined the urine of people across the
country, [asking] if people are being exposed. On average,
anywhere from five to seven compounds were being excreted.
There's a great deal of expo- sure to the general populace.

"And yes, the toxicities have definitely changed. [Some
toxicities are now measured] in the parts-per-trillion range. I
would point out that fetuses are sensitive to chemicals in the
parts per quadrillion range."

Hamm: "I would assume that most people in this country are
eating conventionally grown food. If that's the case, wouldn't
the problems be more apparent? Why are there not more
hyperaggressive dim-witted people with poor immune systems?"

Porter: "If we really looked carefully at what's been happening
in this county, you might find exactly that happening."

*               *               *

Because of recent violence in small cities and towns (such as
Littleton, Colorado, Laramie, Wyoming, and Jasper, Texas), this
is a time when Americans are searching for the causes of violence
in their society. Some are blaming a decline in religious
upbringing. Others are blaming households with the parents
working and no one minding the kids. Some say the cause is
violent movies, violent TV and extremist internet sites, combined
with the ready availability of cheap guns. Still others point to
a government that has often sanctioned the violence of "gunboat
diplomacy" to open foreign markets for U.S. corporations.

No one seems to be asking whether pesticides, fertilizers and
toxic metals [see REHW #529, #551] are affecting our young
people's mental capacity, emotional balance, and social
adjustment. From the work of Warren Porter, Elizabeth Guillette
and others, it is apparent that these are valid questions.

                                                --Peter Montague
                (National Writers Union, UAW Local 1981/AFL-CIO)

References:

==========
[1] Jack E. Barbash and Elizabeth A. Resek, PESTICIDES IN GROUND
WATER (Chelsea, Michigan: Ann Arbor Press, 1996); Richard Wiles
and others, TAP WATER BLUES (Washington, D.C.: Environmental
Working Group, 1994); Brian A. Cohen and Richard Wiles, TOUGH TO
SWALLOW (Washington, D.C.: Environmental Working Group, 1997);
Environmental Working Group, POURING IT ON; NITRATE
CONTAMINATION OF DRINKING WATER (Washington, D.C.: Environmental
Working Group, 1996). See www.ewg.org. And: Gina M. Solomon and
Lawrie Mott, TROUBLE ON THE FARM; GROWING UP WITH PESTICIDES IN
AGRICULTURAL COMMUNITIES (New York: Natural Resources Defense
Council, October, 1998).

[2] Warren P. Porter, James W. Jaeger and Ian H. Carlson,
"Endocrine, immune and behavioral effects of aldicarb
(carbamate), atrazine (triazine) and nitrate (fertilizer)
mixtures at groundwater concentrations," TOXICOLOGY AND
INDUSTRIAL HEALTH Vol. 15, Nos. 1 and 2 (1999), pgs. 133-150.

[3] C.A. Boyd, M.H. Weiler and W.P. Porter, "Behavioral and
neurochemical changes associated with chronic exposure to
low-level concentration of pesticide mixtures," JOURNAL OF
TOXICOLOGY AND ENVIRONMENTAL HEALTH Vol. 30, No. 3 (July 1990),
pgs. 209-221.

[4] W.P. Porter and others, "Groundwater pesticides: interactive
effects of low concentrations of carbamates aldicarb and
methamyl and the triazine metribuzin on thyroxine and
somatotropin levels in white rats," JOURNAL OF TOXICOLOGY AND
ENVIRONMENTAL HEALTH Vol. 40, No. 1 (September 1993), pgs.
15-34. And see: W.P. Porter and others,
"Toxicant-disease-environment interactions associated with
suppression of immune system, growth, and reproduction," SCIENCE
Vol. 224, No. 4652 (June 1, 1984), pgs. 1014-1017.

[5] Keith Hamm, "What's In the Mix?" SANTA BARBARA [CALIFORNIA]
INDEPENDENT April 15, 1999, pg. 21 and following pages. See
www.independent.com/007/001/002.html. Thanks to George Rauh for
alerting us to this interview.

[6] Elizabeth A. Guillette and others, "An Anthropological
Approach to the Evaluation of Preschool Children Exposed to
Pesticides in Mexico," ENVIRONMENTAL HEALTH PERSPECTIVES Vol.
106, No. 6 (June 1998), pgs. 347-353.

Descriptor terms: violence; hormones; thyroid hormone;
development; aggression; chemicals and behavior; behavior and
chemicals; delinquency; studies; mexico; warren p. porter;
elizabeth guillette; adhd; attention disorders; hyperactivity;
learning disabilities; brain development; emotional stability;


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