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  • From: "Tradingpost" <tradingpost@lobo.net>
  • To: livingontheland@lists.ibiblio.org
  • Subject: [Livingontheland] No such thing as "safe" levels of contamination
  • Date: Fri, 27 Jun 2008 19:05:43 -0600


No such thing as "safe" levels of contamination

Cross-disciplinary research reveals low-level pesticide exposure linked to
myriad of learning, behavioral and medical problems.
http://www.rodaleinstitute.org/20080627/n1
By Amanda Kimble-Evans

"In 1998, Elizabeth Guillette published her finding on the affects of
agrichemicals on preschool children in the Yaqui Valley of Sonora, Mexico,
the source of much of the U.S. supply of winter fruits and vegetables.
Children regularly exposed to pesticides on the farms in the valley displayed
classic signs of severe neurological devastation. They also expressed poor
coordination, low stamina, poor memory and heightened aggression when
compared to the children who lived just a few miles away in the mountains and
were not exposed."

--------------------
editor's NOTE
Rodale Institute’s researchers continue to work with a range of soil and
crop scientists to evaluate the dynamics and benefits of regenerative organic
farming. To extend our understanding of the benefits of organics for human
health, we’re looking at the work of Dr. Warren P. Porter.

Officially, Dr. Porter is professor of zoology and environmental
toxicology at the University of Wisconsin, Madison. But the scope of his
expertise includes environmental and molecular toxicology, conservation
biology and engineering physics. Through a series of life events, a gift of
intense curiosity and a willingness to follow the scientific evidence where
it leads, he’s discovered disturbing scientific evidence of unacknowledged
risks from non-organic farming products and techniques.

His research interests include: impacts on organisms subjected to
simultaneous changes in climate, topography and vegetation (as is happening
due to global warming phenomena); impact of low-level contaminant/pesticide
mixtures on organisms and biological communities in terms of reproduction,
food-web interaction, developmental processes, neurological function
(learning abilities and aggression levels), immune function and endocrine
function.

He addressed Rodale Institute staff and local health care professionals
this week, laying out key research findings pointing to the need for a
radical reconsideration of the impact of pesticides on human and wildlife
populations. Here’s a bit of background and some of his major talking points.
-----------

In 1995, Warren P. Porter, Ph.D., read an article in the Wisconsin State
Journal that reported skyrocketing remedial education costs due to an
increase in children with disabilities in the Madison school district. The
numbers were surprising: an 87-percent jump in children with emotional
disturbances, a 70-percent increase in children with learning disabilities
and 83 percent more children with physical disabilities between 1990 and 1995.

What Dr. Porter noticed as he began to look at other communities, was that
there was an epidemic change in these levels worldwide. "My children are
everything to me," said Dr. Porter. And so he began to ask "Why?"

Because he is a professor of zoology and environmental toxicology at the
University of Wisconsin, Madison, Dr. Porter attacked this nagging question
scientifically. Because he is Dr. Warren Porter, he began to look into the
advanced academic research from several disciplines to find the answer.

In 1998, Elizabeth Guillette published her finding on the affects of
agrichemicals on preschool children in the Yaqui Valley of Sonora, Mexico,
the source of much of the U.S. supply of winter fruits and vegetables.
Children regularly exposed to pesticides on the farms in the valley displayed
classic signs of severe neurological devastation. They also expressed poor
coordination, low stamina, poor memory and heightened aggression when
compared to the children who lived just a few miles away in the mountains and
were not exposed.

In the 10 years since Dr. Guillette published her shocking findings, Dr.
Porter and a number of other researchers have begun to take a
cross-disciplinary look at the effects common pesticides have on the health
and well-being of our communities at levels considered "safe" by the current
regulatory bodies in the U.S. According to Dr. Porter, "normal" exposures in
food, water and air may be creating many of the serious long-term health
problems emerging in humans and wildlife.

National and international research projects show that pesticides contribute
to an increase in aggressive behavior, birth defects, developmental
roadblocks, failing immune function and sexual disorders. And evidence is
just surfacing that our fundamental genetic constitution could be in jeopardy.

There are no straight lines in nature

Dr. Porter cites a number of problems with how the wider scientific community
and the Environmental Protection Agency have underestimated the risks
associated with pesticides, including herbicides and fungicides.

"They assume a linear dose response. In toxicology the size of the dose is
what is considered important in determining how poisonous something will be."
Meaning, the more to which you are exposed, the worse the effect.

But, says Dr. Porter, a bell-shaped dose response is much more common in real
life. "Physiologically, the timing of the dose is often more important than
size." Meaning, it is possible that a very low-level exposure during a
particular period of development can have a dramatic affect, whereas the same
exposure before or after that period may have no affect at all.

A study by Levin, et al. in 2002 found the learning ability of female rats
was affected the most when exposed to the lowest dose of a pesticide called
chlorpyrifos during in-utero development. Higher-dose exposure showed much
less of a negative response. Another study by Agoos, et al. in 2007 found the
very same "inverse dose response" in female mice. As mice are very different
than rats physiologically, it was surprising to see a consistent response.

"[The systemic affects of herbicides] is like ripping up telephone cables.
The signals get mixed and broken. You end up with serious long-term
consequences that are very difficult to diagnose."

The same inverse dose response pattern was seen in a 2002 study by Cavieres,
et al. where researchers dosed the drinking water of pregnant mice with a
common herbicide at high, intermediate, low and very low levels. The highest
degree of fetal losses was at the very low level.

And, again, in a 2005 study on another common pesticide's ability to affect
brain function, the inverse dose response appeared. Rodriguez, et al. found 5
mg of atrazine had more of an effect on neurotransmitters in the brain than
10 mg of the very same chemical.

"It should be noted that the EPA only tests the effects of intermediate
concentrations," says Dr. Porter, "since the assumption is that there will be
less of an effect the smaller the concentration."

Porter also points to studies by Richard, et al. (2005) and Fan, et al.
(2007) that show how two common herbicides effect the levels of testosterone
and estrogen in the system at "environmentally relevant levels," or levels
currently found in the environment. They found that atrazine increases the
levels of estrogen in the system and glyphosate increases the levels of
testosterone. Changes in the levels of these sex hormones feed back to the
brain and immune systems leading to other systemic problems, says Porter.
"It's like ripping up telephone cables. The signals get mixed and broken. You
end up with serious long-term consequences that are very difficult to
diagnose."

Creating a successful poison

When confronted with these studies, Porter asked himself, "Why do pesticides
and herbicides at low-levels have such devastating systemic affects on
animals, including humans?" This lead him to the second assumption in our
regulatory process that has created a toxic loophole.

"It all goes back to the principles of creating a poison that effectively
kills," says Porter. "You want something that is quickly and easily absorbed
through the 'skin' or outer defense system and something that is water- and
fat-soluble which gives it a 'master entry key' to every cell in the body,
brain and/or fetus."

The "inactive" ingredients in Round-up make it twice as biologically active
and, therefore, twice as potentially toxic as the potential of it's "active"
chemical parts.


Solvents (organic soaps) and surfactants (that diminish the surface tension
of water) are added to pesticide and herbicide formulations to create a
product that encourages effective uptake and allows access to all cells of
the targeted organism. The problem is that they are also absorbed through our
skin and lungs more effectively and they have a master entry key to our
cells, says Porter.

Dr. Porter cites two independent studies that determined the "inactive"
ingredients in Round-up make it twice as biologically active and, therefore,
twice as potentially toxic as the potential of it's "active" chemical parts.
Unfortunately, solvents and surfactants are not tested as part of the EPA
registration process. "For example," says Porter, "the EPA registers
glyphosate, the chemical considered an active ingredient in Round-up, not
Round-up itself."
Passing the damage on

Researchers at Washington State University studied DNA of male rats and
discovered DNA sequences were altered through methylation (changes in the
epigenic pattern) by exposure to the fungicide vinclozolin. "Methylation
patterns reflect our environmental history," says Dr. Porter. "It's our
genetic response to environmental insults." Porter points out that
early-immune insults have also been linked to asthma, allergies, autoimmune
diseases, cancer, cerebral palsy and male sterility.

The expression of the NCAM1 gene, specifically, was blocked by exposure to
the fungicide. Diseases related to this gene include Alzheimer's,
schizophrenia, neural tube defects and various tumors, says Porter.

The revealing piece of the Washington State University study was the fact
that the DNA alterations caused by exposure to the fungicide were actually
passed down four generations.
"The evidence is strong," says Dr. Porter. "We are compromising our children
and our children's children."

The extent of our exposure

Recent studies have begun to capture the true extent of our low-level
exposure to pesticides that could be quietly causing serious health problems
in our population. The toxins are nearly inescapable in the water we drink,
the food we eat and the air we breathe.

Lu, et al. (2006) measured organophosphates in the urine of Seattle children
and discovered levels of chemical indicators up to 14 parts per billion
"Organophosphates are neurotoxins by design and we're capable of responding
to neurotoxins in the parts per trillion level," says Porter, "especially
during [fetal] development."

"The public has been slow awakening to the danger of low-level pesticide
exposure. And the EPA regulatory process doesn't capture the full and
devastating risk of these chemical cocktails."


And new work by Paul Winchester, et al. is taking a look at the correlation
between the amount of atrazine in the water at the time of conception to the
math and reading skills of Indiana children.

"The public has been slow awakening to the danger of low-level pesticide
exposure," said Porter. "And the EPA regulatory process doesn't capture the
full and devastating risk of these chemical cocktails."

Dr. Porter suggests we rework the way chemical products are registered to
reflect discoveries related to non-linear dose responses, the effects of
solvents and surfactants, the compound and synergistic affects of chemical
mixtures, and the differences in hormonal and developmental responses between
males and females.

In the meantime, the study by Lu, et al. offers a path to reducing our
exposure. When the Seattle children were put on an organic food diet,
concentrations of the chemical indicators in their urine were undetectable
within five days.

Porter agrees: "Buy organic or grow your own, and get a really good water
filter for your drinking and washing water. It won't eliminate all your
exposure, but it will dramatically reduce your risk."

Amanda Kimble-Evans is assistant editor at Rodale Institute. She specializes
in nutrition issues, recently became a mom and enjoys her organic garden.






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