Scientists Warn of Low-Dose Risks of Chemical Exposure By Elizabeth Grossman, Yale Environment 360
26 March 12
Since before the publication of Rachel Carson’s Silent Spring 50 years ago, scientists have known that certain synthetic chemicals can interfere with the hormones that regulate the body’s most vital systems. Evidence of the health impacts of so-called endocrine-disrupting chemicals grew from the 1960s to the 1990s. With the 1996 publication of Our Stolen Future by Theo Colborn, Dianne Dumanoski, and J. Peterson Myers, many people heard for the first time how such exposures – from industrial pollution, pesticides, and contact with finished consumer products, such as plastics – were affecting people and wildlife. Since then public concern about these impacts has grown.
In 2009, the American Medical Association called for reduced exposure to endocrine- disrupting chemicals. Last year, eight scientific societies, representing some 40,000 researchers, urged federal regulators to incorporate the latest research on endocrine-disrupters into chemical safety testing.
Last week, 12 scientists – including such experts as Colborn and the University of Missouri’s Frederick vom Saal – published a paper that they say significantly advances the debate. Their research, based on a review of 800 scientific studies, concludes that it is “remarkably common” for very small amounts of hormone-disrupting chemicals to have profound, adverse effects on human health. Hormone- disrupting chemicals, the paper explains, challenge a fundamental tenet of toxicology – “the dose makes the poison” – which contends that the greater the dose, the greater the effect. Hormone-disrupting chemicals don’t necessarily behave like this. Significant health effects, the researchers say, sometimes occur at low rather than high doses. (more…)
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Environment Becomes Heredity By Valerie Brown
Chemicals in the environment acting as Endocrine Disruptors and affecting gene expression. Advances in the field of epigenetics show that environmental contaminants can turn genes “on” and “off” triggering serious diseases that are handed down through generations. But there’s also a more heartening prospect: The same diseases may be treated by relatively simple changes in nourishment and lifestyle.
The studies by Gore, Crews, Skinner and their colleagues sit at the intersection of several major developments in biology. The vinclozolin acted as an endocrine disrupter, affecting male reproductive fitness. The diseases lying in wait for the adult male rats were a manifestation of the Barker hypothesis, which posits that events in very early development can result in strong susceptibility to adult disease. And the inherited disease susceptibilities are governed by the rules of epigenetics.A selection from the research reports reviewed for this article:
Crews, David, Andrea C. Gore, Timothy S. Hsu, Nygerma L. Dangleben, Michael Spinetta, Timothy Schallert, Matthew D. Anway, and Michael K. Skinner. 2007. “Transgenerational Epigenetic Imprints on Mate Preference.” Proceedings of the National Academy of Sciences, Vol. 104, No. 14, pp. 5942-5946. Retrieved fromhttp://www.pnas.org/cgi/reprint/104/14/5942.
Dolinoy, Dana C., Dale Huang, and Randy L. Jirtle. 2007. “Maternal Nutrient Supplementation Counteracts Bisphenol A-Inducted DNA Hypomethylation in Early Development.” Proceedings of the National Academy of Sciences, Vol. 104, No. 32, pp. 13056-13061. Retrieved from http://www.pnas.org/cgi/reprint/0703739104v1.
Gross, Liza. 2007. “The Toxic Origins of Disease.” PLoS Biology 5(7): e193. Retrieved from http://biology.plosjournals.org/perlserv/?request=get-document&doi=10.1371/journal.pbio.0050193&ct=1.
Tabb, Michelle M., and Bruce Blumberg. 2006. “New Modes of Action for Endocrine-Disrupting Chemicals.” Molecular Endocrinology, Vol. 20, No. 3, pp. 475-482.
Weinhold, Bob. 2006. “Epigenetics: The Science of Change.” Environmental Health Perspectives, Vol. 114. Retrieved fromhttp://www.ehponline.org/members/2006/114-3/ehp0114-a00160.pdf
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The endocrine system is the exquisitely balanced system of glands and hormones that regulates such vital functions as body growth, response to stress, sexual development and behavior, production and utilization of insulin, rate of metabolism, intelligence and behavior, and the ability to reproduce. Hormones are chemicals such as insulin, thyroxin, estrogen, and testosterone that interact with specific target cells. The interactions occur through a number of mechanisms, the easiest of which to conceptualize is the lock and key. For example, target cells such as those in the uterus contain receptors (locks) into which specific estrogenic hormones (keys) can attach and thereby cause specific biological actions, such as regulating ovulation or terminating pregnancy. Other endocrine disrupting mechanisms include binding hormone transport proteins or other proteins involved in signaling pathways, inhibiting or inducing enzymes, interfering with uptake and export from cells, and modifying gene expression. (more…)
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In the early 1990’s, it was revealed that the traditional toxicological testing protocols used to determine chemical safety had completely missed vast numbers of chemicals that penetrate the womb and interfere with the construction and programming of developing animals, including humans. Since that time, overwhelming evidence has accumulated indicating that the presence of infinitesimally small quantities of certain chemicals during the continuously changing stages of development before birth can alter one’s inherited phenotype, e.g., the ability to learn, to love, to bond, to process information, to reproduce, and even to maintain normal body weight. Because these chemicals interfere with development by disturbing the function of the endocrine system, they are called endocrine disruptors. The endocrine system is so fine tuned that it depends upon changes in hormones in concentrations as little as a tenth of a trillion of a gram to control the womb environment. That’s as inconspicuous as one second in 3,169 centuries. (more…)
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Source: http://www.endocrinedisruption.com/endocrine.resources.php#pesticides Click here to see our resources and links related to pesticides.
Most people are not aware of the thousands of pesticides and their formulations that are in use today, some of them in huge volumes and on huge acreages worldwide. They comprise acaricides, algicides, antifoulants, avicides, bactericides, herbicides, insecticides, fungicides, molluscicides, nematicides, piscicides, rodenticides, virucides, and the related plant and insect growth regulators; chemosterilants; bird, mammal and insect repellents, insect pheromones and other attractants. Product formulations may contain more than one active ingredient, as well as synergists, “safeners”, and other ingredients formerly known as “inerts”.
Our particular concern about pesticides is that they have been designed to disrupt biological systems, causing death to target organisms, such as insects or plants. Some actually work by acting on the endocrine systems of insects. The problem is that the biochemistry of most living things is similar enough that humans, wildlife and plants can also be adversely affected by pesticides. (more…)
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|Ground-breaking scientific review calls for better methods for determining safety standards.
A paradigm shift in how chemicals are assessed for safety is underway, led by the need to address chemicals that affect the endocrine system at very low exposure levels. Source : http://edrv.endojournals.org/content/early/2012/03/14/er.2011-1050.full.pdf+htmlFor decades, studies of endocrine-disrupting chemicals (EDCs) have challenged traditional concepts in toxicology, in particular the dogma of “the dose makes the poison,” because EDCs can have effects at low doses that are not predicted by effects at higher doses. Here, we review two major concepts in EDC studies: low dose and nonmono- tonicity. Low-dose effects were defined by the National Toxicology Program as those that occur in the range of human exposures or effects observed at doses below those used for traditional toxicological studies. We review the mechanistic data for low-dose effects and use a weight-of-evidence approach to analyze five examples from the EDC literature.
Additionally, we explore nonmonotonic dose-response curves, defined as a nonlinear relationship be- tween dose and effect where the slope of the curve changes sign somewhere within the range of doses examined. We provide a detailed discussion of the mechanisms responsible for generating these phenomena, plus hundreds of examples from the cell culture, animal, and epidemiology literature.
We illustrate that nonmonotonic responses and low-dose effects are remarkably common in studies of natural hormones and EDCs. Whether low doses of EDCs influence certain human disorders is no longer conjecture, because epidemiological studies show that environmental exposures to EDCs are associated with human diseases and disabilities. We conclude that when nonmonotonic dose-response curves occur, the effects of low doses cannot be predicted by the effects observed at high doses. Thus, fundamental changes in chemical testing and safety determination are needed to protect human health. (Endocrine Reviews 33: 0000–0000, 2012)
Download the article free from Endocrine Reviews:http://edrv.endojournals.org/content/early/2012/03/14/er.2011-1050.full.pdf+html
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Posted in GMO's on March 23, 2012|
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The Patenting of Life Through Genetic Modification By Samm Simpson
Since the foundation of the Republic, farmers have planted, propagated and protected their seeds. Nestled into soil amidst a bevy of beneficial microorganisms, the seeds purpose is unleashed, nurtured by the elements and cultivated by the hands that had sown them. Crops were created. Families were fed. Markets were made. Seeds were saved, shared and preserved for future generations. It was an implicit tenet that seeds – also called germ plasm – were a gift endowed by the Creator, belonging to all mankind. The patenting of this gift was an anathema. Corporate ownership of any life force seemed unthinkable: at least until June 16, 1980.
That’s the day the Supreme Court ruled that a live human-made micro-organism is patentable, thus opening the floodgates to corporate ownership of genetic material. Once patented, thus owned. (more…)
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