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Veel gebruikte onkruidverdelger is zeer schadelijk*
Uit een studie van de universiteit van het Franse Caen blijkt dat blootstelling aan de herbicide Roundup tot schade aan cellen kan leiden. De Franse onderzoekers hebben met reageerbuisproeven onderzocht wat de werking is van de chemische stof polyethoxide tallowamine, in samenhang met glyfosaat, de werkzame stof van Roundup op celculturen. Met name cellen in de navelstreng, placenta en embryo’s bleken zeer kwetsbaar voor minimale doses van de herbicide. Polyethoxide tallowamine is een oppervlakte-actieve stof die de oppervlaktespanning van een vloeistof kan verlagen. Polyethoxide tallowamine is een inerte stof die geen goedkeuring en vermelding behoeft doch blijkbaar samen met glyfosaat blijkt deze zgn. inerte stof helemaal niet zo inert te zijn. Afhankelijk van de vermenging van beide producten kan het toxisch effect ook nog worden versterkt. Eerder brachten Amerikaanse wetenschappers glyfosaat al in verband met verhoogde risico’s op lymfklierkanker (non-Hodgkin), miskramen en ADHD. Uit ander onderzoek blijkt dat glyfosaat ook kan leiden tot een vermindering van de productie van geslachtshormonen. Directe blootstelling aan een bestrijdingsmiddel met glyfosaat kan lijden tot hoesten, oogirritatie, diaree, korte ademhaling, overgeven en vermoeidheid. Eerder onderzoek heeft ook laten zien dat het bestrijdingsmiddel Roundup leidt tot sterfte van kikkers en andere amfibieën. Bij kikkers is ook abnormale ontwikkeling en genetische schade aangetoond. Dit werd recent nog eens bevestigd door Argentijnse wetenschappers waarbij blootgestelde embryo’s minder grote hoofden hadden, ondergingen ze genetische veranderingen in het centrale zenuwstelsel en was er meer sterfte onder cellen die de schedel vormen.
Wereldwijd wordt Roundup al bijna dertig jaar gebruikt, met name in de teelt van genetisch gemanipuleerde (GM) gewassen. Maar liefst driekwart van alle GM-gewassen betreft variëteiten die resistent zijn gemaakt tegen RoundUp of andere middelen met glyfosaat. De nieuwste generatie GM-gewassen is ook in staat om het middel af te breken. Een gewas als maïs of tabak verdraagt daardoor zes maal de hoeveelheid glyfosaat in vergelijking tot de eerste reeks GM-varianten, aldus Amerikaanse wetenschappers in het vakblad Science.
Secret Ingredient in the Herbicide Roundup Kills Human Cells
(Beyond Pesticides, ) Researchers have found that one of the so-called “inert” ingredients in the popular herbicide product Roundup can kill human cells, particularly embryonic, placental and umbilical cord cells. Over 4,000 inert ingredients are approved for use in the U.S. and can be mixed with pesticide “active” ingredients; however these chemicals are not disclosed to consumers or users on pesticide product labels due to EPA’s intepretation (many would say incorrect interpretation) of federal pesticide law. Many inerts are classified as highly toxic, while others have not been adequately studied.
About 100 million pounds of Roundup are applied to U.S. farms and lawns every year and until now, most health studies have focused on the safety of glyphosate the active ingredient in Roundup, rather than the mixture of “inert” ingredients found in the herbicidal product. In this new study, “Glyphosate Formulations Induce Apoptosis and Necrosis in Human Umbilical, Embryonic, and Placental Cells,” researchers 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, and which correspond to low levels of residues in food or feed. 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.” 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. The researchers compared the formulations (glyphosate with POEA) with glyphosate and POEA alone. All formulations cause total cell death within 24 hours, through an inhibition of the mitochondrial succinate dehydrogenase activity, and necrosis, by release of cytosolic adenylate kinase measuring membrane damage. While glyphosate also damaged cells, the researchers found that POEA changes human cell permeability and amplifies toxicity induced already by glyphosate, through apoptosis and necrosis. POEA alone was more deadly to cells than glyphosate. The study concluded that the work clearly confirms that the adjuvants in Roundup formulations are not biologically or chemically inert. Moreover, the proprietary mixtures available on the market, according to the research, could cause cell damage and even death around residual levels to be expected, especially in food and feed derived from Roundup-treated crops, such as soybeans, alfalfa and corn, or lawns and gardens. The research team also suspects that Roundup might cause pregnancy problems by interfering with hormone production, possibly leading to abnormal fetal development, low birth weights or miscarriages.
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.
Monsanto, Roundup’s manufacturer, contends that the methods used in the study do not reflect realistic conditions and that their product, which has been sold since the 1970s, is safe when used as directed. EPA and the U.S. Department of Agriculture both recognize POEA as an inert ingredient. POEA is allowed in products certified organic by the USDA. EPA has concluded that it is not dangerous to public health or the environment. The researchers however, believe that their 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,” said Gilles-Eric Seralini, Ph.D., a University of Caen molecular biologist and lead researcher, wrote.
World controversy over the safety of the weed killer continues. In May, 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 glyphosate. 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 are not required to publicly disclose them. Caroline Cox, research director of the Center for Environmental Health, an Oakland-based environmental organization, says that the term “inert ingredient” is often misleading. EPA classifies all pesticide ingredients that do not harm pests as “inert,” Ms. Cox said. Inert compounds, therefore, are not necessarily biologically or toxicologically harmless.
Other 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. A study recently found that an herbicide formulation containing atrazine caused DNA damage, which can lead to cancer, while atrazine alone did not.
For years, scientists and activists have been calling for inert disclosures. In 2006, the Northwest Coalition for Alternatives to Pesticides, along with Beyond Pesticides and other allies, filed a legal petition challenging the EPA’s policy of secrecy on these inert ingredients. The court found that manufacturers are not able to protect inerts as proprietary from competitors, but only keep the ingredients secret from consumers and users. An agency decision on the issue is due this fall. A December 2006 commentary in the National Institute of Environmental Health Sciences’ journal Environmental Health Perspectives calls for improvements in pesticide regulation and “inert” ingredient disclosure, citing an extensive body of literature illustrating the concern over related human and environmental health effects. In May 2009, the California State Senate’s Health Committee passed legislation that requires the disclosure of inert ingredients in pesticides before they are approved for use by state regulators, and that provides public health agencies and emergency responders timely access to complete ingredient lists of aerial pesticides. For more about pesticide ingredients, visit “What’s in a Pesticide” by Beyond Pesticides.
Source: Environmental Health News (Augustus 2009)