Healthy soil and sustainable growing

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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.