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It is often claimed by industry and regulators that the toxic effects caused by glyphosate and Roundup in animal studies don't matter because we are only exposed to "safe" levels that do not cause such effects.
Regulators set safety limits for glyphosate exposure based on data from industry-specific toxicity studies on laboratory animals. These toxicity studies are supposed to provide evidence of possible adverse effects on mammals, most commonly rats, whose physiology is similar to that of humans, are sufficient. Long-term experiments are based on blood and organ tests from the past two years, about two-thirds of the average lifespan of a rat. Companies carry out different tests according to the standards established in consultation with the industry by the Organization for Economic Cooperation and Development (OECD), a body not dedicated to public health, but to facilitate international trade.
The results of these industry tests, which are classified as trade secrets and kept hidden from public opinion and the scientific community, are presented to expert groups in government or food safety agencies based in various countries or regions, like the European Union.
To assess whether exposure is a health risk, it is calculated based on a safety threshold called “Acceptable Daily Intake” (ADI).
The ADI is an estimate of the amount of a substance in food or drinking water, expressed on a body mass basis, that can be ingested daily during life by human beings, without appreciable risks to health.
In the case of glyphosate, the ADI value differs from country to country. It has been set at 0.3 mg per kg of body weight per day (written as 0.3 mg / kg bw / d) in Europe, and 1.75 mg / kg of body weight / day in the USA. The calculation to establish the ADI is based on the lowest dose considered non-toxic in animal feeding trials (30 mg / kg of body weight, sponsored by the industry.
Are these levels of security? There are several reasons to doubt the validity of the current ADI values for glyphosate, including:
The so-called safe levels of exposure to glyphosate have never been directly tested to determine whether they are very safe for long-term consumption. Instead, "safe" levels are extrapolated from the highest doses tested in industry studies.
Industry toxicity study protocols are out of date. All toxicity testing done by industry for regulatory purposes is based on the old adage, "The dose makes the poison" - that is, the higher the dose, the higher the degree of toxicity. However, in some cases, low doses corresponding to human exposures can be more toxic than the highest doses tested on laboratory animals in industry studies. This is especially true for chemicals that disrupt the hormonal system (endocrine disruptors).
Safe levels of these chemicals cannot be extrapolated from effects at higher doses. Evidence shows that glyphosate can be an endocrine disruptor at permitted levels in tap water in the EU.
Findings that glyphosate and its commercial formulations may be endocrine disruptors imply that long-term industry standard animal studies are insufficient. These studies are carried out in adult animals, and cannot prove the effects of exposure during important stages of development, such as fetal development. However, hormones are vital regulators of development. A subtle hormonal effect during early life can modify organ morphology and function for the rest of life, as well as leading to chronic diseases such as cancer and reproductive dysfunction in adults.
Glyphosate-based herbicide formulations are not tested for long-term toxic effects. These formulations contain adjuvants and additives that are themselves toxic and / or increase the toxicity of glyphosate's safe limits. But tests for long-term toxic effects are only set for the single ingredient glyphosate, regardless of formulations, which are generally more toxic.
This limitation of the regulatory process applies to all pesticides in all countries of the world. Studies in rats confirm that glyphosate-based herbicide formulations are toxic at levels considered safe by regulators for the isolated ingredient glyphosate. Other feeding studies in rats to directly compare the toxicity of the formulations with glyphosate only found that the formulations were much more toxic.
Even glyphosate alone may not be as safe as claimed. Industry testing on glyphosate only revealed toxic effects, particularly birth defects, below levels that regulators claimed showed no toxic effects - but these results were ignored or dismissed by regulators in establishing the supposedly safe ADI.
Independent studies have found toxic effects of glyphosate and its commercial formulations at realistic levels with the environment, which have never been tested by regulators. Effects include oxidative stress on the liver and endocrine disruptors.
Glyphosate that is claimed to be so safe was reclassified as a probable carcinogen by the World Health Organization in 2015.
Glyphosate has never been tested during sensitive periods of life (such as fetal development) at ambient levels of exposure. Furthermore, the fact that its commercial formulations have never been tested for more than a month in rats, without any type of blood test, raises further questions about the validity of the current ADI values.
These results, taken together, suggest that the Roundup levels that are exposed are not safe in the long term.
(Abstract. Full version in English: http://feedtheworld.info/)