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  • From: "Tradingpost" <tradingpost@lobo.net>
  • To: livingontheland@lists.ibiblio.org
  • Subject: [Livingontheland] Weed-Whacking Herbicide Proves Deadly to Human Cells
  • Date: Thu, 25 Jun 2009 11:32:03 -0600


Weed-Whacking Herbicide Proves Deadly to Human Cells
Used in gardens, farms, and parks around the world, the weed killer Roundup
contains an ingredient that can suffocate human cells in a laboratory,
researchers say
June 23, 2009
http://www.scientificamerican.com/article.cfm?id=weed-whacking-herbicide-p


Used in yards, farms and parks throughout the world, Roundup has long been
a top-selling weed killer. But now researchers have found that one of
Roundup’s inert ingredients can kill human cells, particularly embryonic,
placental and umbilical cord cells.

The new findings intensify a debate about so-called “inerts” — the
solvents, preservatives, surfactants and other substances that
manufacturers add to pesticides. Nearly 4,000 inert ingredients are
approved for use by the U.S. Environmental Protection Agency.

Glyphosate, Roundup’s active ingredient, is the most widely used
herbicide in the United States. About 100 million pounds are applied to
U.S. farms and lawns every year, according to the EPA.

Until now, most health studies have focused on the safety of glyphosate,
rather than the mixture of ingredients found in Roundup. But in the new
study, scientists found that Roundup’s inert ingredients amplified the
toxic effect on human cells—even at concentrations much more diluted than
those used on farms and lawns.

One specific inert ingredient, polyethoxylated tallowamine, or POEA, was
more deadly to human embryonic, placental and umbilical cord cells than the
herbicide itself – a finding the researchers call “astonishing.”

“This clearly confirms that the [inert ingredients] in Roundup
formulations are not inert,” wrote the study authors from France’s
University of Caen. “Moreover, the proprietary mixtures available on the
market could cause cell damage and even death [at the] residual levels”
found on Roundup-treated crops, such as soybeans, alfalfa and corn, or
lawns and gardens.

The research team suspects that Roundup might cause pregnancy problems by
interfering with hormone production, possibly leading to abnormal fetal
development, low birth weights or miscarriages.

Monsanto, Roundup’s manufacturer, contends that the methods used in the
study don’t reflect realistic conditions and that their product, which
has been sold since the 1970s, is safe when used as directed. Hundreds of
studies over the past 35 years have addressed the safety of glyphosate.

“Roundup has one of the most extensive human health safety and
environmental data packages of any pesticide that's out there,” said
Monsanto spokesman John Combest. “It's used in public parks, it's used to
protect schools. There's been a great deal of study on Roundup, and we're
very proud of its performance.”

The EPA considers glyphosate to have low toxicity when used at the
recommended doses.

“Risk estimates for glyphosate were well below the level of concern,”
said EPA spokesman Dale Kemery. The EPA classifies glyphosate as a Group E
chemical, which means there is strong evidence that it does not cause
cancer in humans.

In addition, the EPA and the U.S. Department of Agriculture both recognize
POEA as an inert ingredient. Derived from animal fat, POEA is allowed in
products certified organic by the USDA. The EPA has concluded that it is
not dangerous to public health or the environment.

The French team, led by Gilles-Eric Seralini, a University of Caen
molecular biologist, said its results highlight the need for health
agencies to reconsider the safety of Roundup.

“The authorizations for using these Roundup herbicides must now clearly
be revised since their toxic effects depend on, and are multiplied by,
other compounds used in the mixtures,” Seralini’s team wrote.

Controversy about the safety of the weed killer recently erupted in
Argentina, one of the world’s largest exporters of soy.

Last month, an environmental group petitioned Argentina’s Supreme Court,
seeking a temporary ban on glyphosate use after an Argentine scientist and
local activists reported a high incidence of birth defects and cancers in
people living near crop-spraying areas. Scientists there also linked
genetic malformations in amphibians to glysophate. In addition, last year
in Sweden, a scientific team found that exposure is a risk factor for
people developing non-Hodgkin lymphoma.

Inert ingredients are often less scrutinized than active pest-killing
ingredients. Since specific herbicide formulations are protected as trade
secrets, manufacturers aren’t required to publicly disclose them.
Although Monsanto is the largest manufacturer of glyphosate-based
herbicides, several other manufacturers sell similar herbicides with
different inert ingredients.

The term “inert ingredient” is often misleading, according to Caroline
Cox, research director of the Center for Environmental Health, an
Oakland-based environmental organization. Federal law classifies all
pesticide ingredients that don’t harm pests as “inert,” she said.
Inert compounds, therefore, aren’t necessarily biologically or
toxicologically harmless – they simply don’t kill insects or weeds.

Kemery said the EPA takes into account the inert ingredients and how the
product is used, whenever a pesticide is approved for use. The aim, he
said, is to ensure that “if the product is used according to labeled
directions, both people’s health and the environment will not be
harmed.” One label requirement for Roundup is that it should not be used
in or near freshwater to protect amphibians and other wildlife.

But some inert ingredients have been found to potentially affect human
health. Many amplify the effects of active ingredients by helping them
penetrate clothing, protective equipment and cell membranes, or by
increasing their toxicity. For example, a Croatian team recently found that
an herbicide formulation containing atrazine caused DNA damage, which can
lead to cancer, while atrazine alone did not.

POEA was recognized as a common inert ingredient in herbicides in the
1980s, when researchers linked it to a group of poisonings in Japan.
Doctors there examined patients who drank Roundup, either intentionally or
accidentally, and determined that their sicknesses and deaths were due to
POEA, not glyphosate.

POEA is a surfactant, or detergent, derived from animal fat. It is added to
Roundup and other herbicides to help them penetrate plants' surfaces,
making the weed killer more effective.

"POEA helps glyphosate interact with the surfaces of plant cells,"
explained Negin Martin, a scientist at the National Institute of
Environmental Health Sciences in North Carolina, who was not involved in
the study. POEA lowers water's surface tension--the property that makes
water form droplets on most surfaces--which helps glyphosate disperse and
penetrate the waxy surface of a plant.

In the French study, researchers tested four different Roundup
formulations, all containing POEA and glyphosate at concentrations below
the recommended lawn and agricultural dose. They also tested POEA and
glyphosate separately to determine which caused more damage to embryonic,
placental and umbilical cord cells.

Glyphosate, POEA and all four Roundup formulations damaged all three cell
types. Umbilical cord cells were especially sensitive to POEA. Glyphosate
became more harmful when combined with POEA, and POEA alone was more deadly
to cells than glyphosate. The research appears in the January issue of the
journal Chemical Research in Toxicology.

By using embryonic and placental cell lines, which multiply and respond to
chemicals rapidly, and fresh umbilical cord cells, Seralini’s team was
able to determine how the chemicals combine to damage cells.

The two ingredients work together to “limit breathing of the cells,
stress them and drive them towards a suicide,” Seralini said.

The research was funded in part by France’s Committee for Research and
Independent Information on Genetic Engineering, a scientific committee that
investigates risks associated with genetically modified organisms. One of
Roundup’s primary uses is on crops that are genetically engineered to be
resistant to glyphosate.

Monsanto scientists argue that cells in Seralini’s study were exposed to
unnaturally high levels of the chemicals. “It's very unlike anything
you'd see in real-world exposure. People's cells are not bathed in these
things,” said Donna Farmer, another toxicologist at Monsanto.

Seralini’s team, however, did study multiple concentrations of Roundup.
These ranged from the typical agricultural or lawn dose down to
concentrations 100,000 times more dilute than the products sold on shelves.
The researchers saw cell damage at all concentrations.

Monsanto scientists also question the French team’s use of laboratory
cell lines.
“These are just not very good models of a whole organism, like a human
being,” said Dan Goldstein, a toxicologist with Monsanto.

Goldstein said humans have protective mechanisms that resist substances in
the environment, such as skin and the lining of the gastrointestinal tract,
which constantly renew themselves. “Those phenomena just don't happen
with isolated cells in a Petri dish.”

But Cox, who studies pesticides and their inert ingredients at the Oakland
environmental group, says lab experiments like these are important in
determining whether a chemical is safe.

“We would never consider it ethical to test these products on people, so
we're obliged to look at their effects on other species and in other
systems,” she said. “There's really no way around that.”

Seralini said the cells used in the study are widely accepted in toxicology
as good models for studying the toxicity of chemicals.

“The fact is that 90 percent of labs studying mechanisms of toxicity or
physiology use cell lines,” he said.

Most research has examined glyphosate alone, rather than combined with
Roundup’s inert ingredients. Researchers who have studied Roundup
formulations have drawn conclusions similar to the Seralini group’s. For
example, in 2005, University of Pittsburg ecologists added Roundup at the
manufacturer’s recommended dose to ponds filled with frog and toad
tadpoles. When they returned two weeks later, they found that 50 to 100
percent of the populations of several species of tadpoles had been killed.

A group of over 250 environmental, health and labor organizations has
petitioned the EPA to change requirements for identifying pesticides’
inert ingredients. The agency’s decision is due this fall.

“It would be a big step for the agency to take,” said Cox. “But
it’s one they definitely should.”

The groups claim that the laws allowing manufacturers to keep inert
ingredients secret from competitors are essentially unnecessary. Companies
can determine a competitor’s inert ingredients through routine lab
analyses, said Cox.

“The proprietary protection laws really only keep information from the
public,” she said.

This article originally ran at Environmental Health News, a news source
published by Environmental Health Sciences, a nonprofit media company.






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