The evidence continues to mount regarding the adverse health effects caused by the triazines, and those of us unwittingly exposed to this toxic chemical have to sit and wait … and wait … and wait … for our regulators to debate on whether they can act on this information.
The email petition to ban the triazines remains open until March 2010
Parliament House Web Address for Petition: HERE
Study Finds Weed Killer Affects Frogs Sexually
Date: 04-Dec-09
Country: CANADA
Author: Randall Palmer
A frog floats in a pond in Farmingdale, New York in this June 20, 2009 file photo.
Photo: Mike Segar
OTTAWA – The widely used weed killer atrazine affects the sexual development of frogs, raising questions about the effects of its use in the environment, the University of Ottawa said on Thursday.
A study by researchers at the university found that at low levels comparable to those measured in the Canadian environment, fewer tadpoles reached the froglet stage and the ratio of females to males increased.
“Atrazine is one of the top-selling herbicides used worldwide and was designed to inhibit weed growth in cornfields,” the university said in a statement.
“It is so widely used that it can be detected in many rivers, streams and in some water supplies. This has raised the alarm on the possibility of other serious detrimental environmental effects.”
Syngenta AG, a major Swiss manufacturer of atrazine, has long defended its safety. The company has said it is one of the best-studied herbicides available and pointed to previous safety reviews from the U.S. Environmental Protection Agency (EPA) and World Health Organization, among others.
The EPA said in October that it was reviewing the health impacts of the herbicide. Some studies have tied it to birth defects, low birth weight and premature babies.
(Editing by Peter Galloway)
© Thomson Reuters 2009 All rights reserved
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And,
Cancer From the Kitchen?
Published: December 5, 2009
Nicholas D. Kristof
On the Ground
But what about broader public health challenges? What if breast cancer in the United States has less to do with insurance or mammograms and more to do with contaminants in our water or air — or in certain plastic containers in our kitchens? What if the surge in asthma and childhood leukemia reflect, in part, the poisons we impose upon ourselves?
This last week I attended a fascinating symposium at Mount Sinai School of Medicine in New York, exploring whether certain common chemicals are linked to breast cancer and other ailments.
Dr. Philip Landrigan, the chairman of the department of preventive medicine at Mount Sinai, said that the risk that a 50-year-old white woman will develop breast cancer has soared to 12 percent today, from 1 percent in 1975. (Some of that is probably a result of better detection.) Younger people also seem to be developing breast cancer: This year a 10-year-old in California, Hannah, is fighting breast cancer and recording her struggle on a blog.
Likewise, asthma rates have tripled over the last 25 years, Dr. Landrigan said. Childhood leukemia is increasing by 1 percent per year. Obesity has surged. One factor may be lifestyle changes — like less physical exercise and more stress and fast food — but some chemicals may also play a role.
Take breast cancer. One puzzle has been that most women living in Asia have low rates of breast cancer, but ethnic Asian women born and raised in the United States don’t enjoy that benefit. At the symposium, Dr. Alisan Goldfarb, a surgeon specializing in breast cancer, pointed to a chart showing breast cancer rates by ethnicity.
“If an Asian woman moves to New York, her daughters will be in this column,” she said, pointing to “whites.” “It is something to do with the environment.”
What’s happening? One theory starts with the well-known fact that women with more lifetime menstrual cycles are at greater risk for breast cancer, because they’re exposed to more estrogen. For example, a woman who began menstruating before 12 has a 30 percent greater risk of breast cancer than one who began at 15 or later.
It’s also well established that Western women are beginning puberty earlier, and going through menopause later. Dr. Maida Galvez, a pediatrician who runs Mount Sinai’s pediatric environmental health specialty unit, told the symposium that American girls in the year 1800 had their first period, on average, at about age 17. By 1900 that had dropped to 14. Now it is 12.
A number of studies, mostly in animals, have linked early puberty to exposure to pesticides, P.C.B.’s and other chemicals. One class of chemicals that creates concern — although the evidence is not definitive — is endocrine disruptors, which are often similar to estrogen and may fool the body into setting off hormonal changes. This used to be a fringe theory, but it is now being treated with great seriousness by the Endocrine Society, the professional association of hormone specialists in the United States.
These endocrine disruptors are found in everything from certain plastics to various cosmetics. “There’s a ton of stuff around that has estrogenic material in it,” Dr. Goldfarb said. “There’s makeup that you rub into your skin for a youthful appearance that is really estrogen.”
More than 80,000 new chemicals have been developed since World War II, according to the Children’s Environmental Health Center at Mount Sinai. Even of the major chemicals, fewer than 20 percent have been tested for toxicity to children, the center says.
Representative Louise Slaughter, the only microbiologist in the House of Representatives, introduced legislation this month that would establish a comprehensive program to monitor endocrine disruptors. That’s an excellent idea, because as long as we’re examining our medical system, there’s a remarkable precedent for a public health effort against a toxic substance. The removal of lead from gasoline resulted in an 80 percent decline in lead levels in our blood since 1976 — along with a six-point gain in children’s I.Q.’s, Dr. Landrigan said.
I asked these doctors what they do in their own homes to reduce risks. They said that they avoid microwaving food in plastic or putting plastics in the dishwasher, because heat may cause chemicals to leach out. And the symposium handed out a reminder card listing “safer plastics” as those marked (usually at the bottom of a container) 1, 2, 4 or 5.
It suggests that the “plastics to avoid” are those numbered 3, 6 and 7 (unless they are also marked “BPA-free”). Yes, the evidence is uncertain, but my weekend project is to go through containers in our house and toss out 3’s, 6’s and 7’s.
I invite you to comment on this column on my blog, On the Ground. Please also join me on Facebook, watch my YouTube videos and follow me on Twitter. —
“It may be that universal history is the history of a handful of metaphors.”
Jorge Luis Borges, “Labyrinths”
And
US lawsuit targets pesticide impact on polar bears. The US government violated the Endangered Species Act by failing to curb use of pesticides (including atrazine and endosulfan) that have been accumulating in the Arctic food chain and in the fat of polar bears, a species listed as threatened, environmentalists charged in a lawsuit. Reuters HERE
AND
Exposure to the common herbicide atrazine rapidly induces the release of stress hormones in rats, which may explain how the weed killer produces some its harmful reproductive effects. Elevated stress hormones can disrupt the hormone signals that spur ovulation. Atrazine is one of the most frequently used herbicides in the US. More…
HERE
Atrazine sparks stress hormones in female rats.
Dec 04, 2009
Powers Fraites, MJ, RL Cooper, A Buckalew, S Jayaraman, L Mills and SC Laws. 2009. Characterization of the hypothalamic-pituitary-adrenal axis response to atrazine and metabolites in the female rat. Toxicological Sciences 112(1):88-99.
Synopsis by Heather Patisaul, Ph.D.
Exposure to the common herbicide atrazine rapidly induces the release of stress hormones in rats, which may explain how the weed killer produces some its harmful reproductive effects.
A new study reveals that female rats fed atrazine at the time of ovulation released a flow of hormones that are associated with stress and that are known to interfere with hormones essential for reproduction. The stress reaction is similar to that seen when the animals are restrained against their will, say the authors in an article published in the journal Toxicological Sciences.
The findings reveal one way atrazine may impact female reproduction.
Elevated stress hormones can disrupt the hormone signals that spur ovulation.
Such a stress response to atrazine could partially explain why previous studies find that the herbicide inhibits reproduction.
Atrazine is one of the most frequently used herbicides in the US. It is primarily used during the spring to control weeds in agricultural fields. The chemical frequently washes off the fields and into aquatic systems, contaminating surface and ground water. In field and laboratory studies, the herbicide can alter the levels of hormones important to reproduction, delay or advance development and induce other reproductive abnormalities in vertebrates, including amphibians and rodents.
For this study, the researchers fed groups of adult female rats either atrazine or one of its two common metabolites – DIA or DACT – either once at a dose of 75 miligrams/kilogram or every day for four days at doses of 12.5 or 75 miligrams/kilogram. The doses were somewhat higher than would be considered relevant for humans but were in the range of what has previously been tested in similar studies. A variety of hormones were measured in the rats’ blood. Determining how atrazine affects stress and reproduction in animals is important for making predictions about how atrazine exposure might affect people.
The researchers found that exposure to a single, oral dose of atrazine or to one of its common metabolites provoked the release of the stress hormones – including corticosterone and progesterone – within 15 minutes of exposure. Animals exposed in the same way for four days showed similar effects.
Although the stress hormones elevated by atrazine and one of its metabolites are known to suppress the hormone signalling cascade needed for ovulation, future studies will need to establish if a true cause-and-effect relationship exists. The data presented in this study suggest that such a relationship – where atrazine activates stress hormones which then suppress hormones important for reproduction – is plausible.
