Glyphosate herbicide toxicity is an interesting topic for many people since it is a main ingredient found in herbicides that are used worldwide like Roundup. The purpose of this article is to share information regarding glyphosate and glyphosate products and their impacts on human and animal health.
Table of Contents
The Glyphosate Issue
Glyphosate is a ubiquitous pesticide and is “one of the most widely used herbicides with applications in agriculture, forestry, industrial weed control, lawn, garden, and aquatic environments” (National Pesticide Information Center). Locally, Canada allows glyphosate usage in concentrations ranging from 0.08 (eggs) to 40 (un-delinted cotton seeds) parts per million across 56 different agricultural products (Maximum Residue Limits Search). This means that finding glyphosate in food is not an uncommon situation in Canada.
From a consumer standpoint, we don’t like extra questionable chemicals in our food and as consumers we have several points at which we can control how much toxicity we put into our bodies. One option is to simply eat organic food. One study has shown that “an organic diet was associated with significantly reduced urinary levels of glyphosate.“ Another option, for people who cannot afford or don’t have access to organic produce is to clean produce. Dr. Peter Solomon from Long Beach Chiropractic and Wellness writes that glyphosate residues on food can be reduced (but never altogether eliminated) by washing and drying produce, by peeling off outer layers of certain foods and by removing fat and skin on meat.
In general, the measures above are a good idea to apply, regardless of whether you’re trying to control for glyphosate content (better safe than sorry). However, this article’s focus is more academic. It’s not practical information that people can use when it comes to dietary choices. It’s more of a political question. And the two important questions are these - 1) is glyphosate dangerous and 2) if it is, is it possible to get governments to remove it from local produce?
Is Glyphosate Dangerous?
There are numerous animal and human studies showing different effects of glyphosate. These studies can be challenged on their methodologies, interpretations, conclusions, etc. This section is just going to be a brief look at three studies involving people.
A research study by Hoppinet et al. 2008 found that "pesticides may contribute to atopic asthma” among farm women." They specifically name glyphosate as one of ten pesticides analyzed that had significant associations with atopic asthma. Potrebic et al. 2009 looked at a single case in which “a 56-year old woman ingested about 500 mL of herbicide containing glyphosate isopropylamine salt. The most prominent manifestation of poisoning included hypotension, coma, hyperkaliemia, respiratory and renal failure.” Chang and Chang 2009 looked at a single case in which a “57-year-old woman who was admitted to the emergency department unconsciousness after ingestion of glyphosate surfactant in a suicide attempt. Metabolic acidosis, refractory respiratory failure, and shock developed during hospitalization. Despite aggressive supportive care, the patient died in the hospital.”
While the Hoppinet study doesn't give me a sense of worry (perhaps those women were exposed to multiple pesticides and those ones were toxic but not the glyphosate) the Potrebic and Chang and Chang studies, on their surface seem to point to a conclusion that glyphosate products, when ingested by the wrong person in large amounts can be severely toxic. Now, whether this is a question of personal sensitivity (for example some people with nut allergies can't even smell them without having side effects) or indicative of a more serious effect on human beings in general, is not something that I can tell based on this information.
Is Glyphosate Safe?
The European Commission (the body that “promotes the general interest of the EU by proposing and enforcing legislation as well as by implementing policies and the EU budget”) decided in November 2023 to “renew the approval of glyphosate for 10 years.” Their renewal process was based on a consideration of 780 relevant publications and reviewed “an unprecedented body of published scientific literature.”
I will consider some of the evidence they provide on their background documents page. Specifically, I’m going to quote some findings from their Peer Review Report on Glyphosate Part 1 of 6 (download is 61.5 mb and readily available for anyone who's interested in reading it). Even more specifically, I’m only going to refer to actual studies that commentators respond to with regard to human health impacts. Even more specifically, I’m going to look at Germany’s comments on pages 42-56 with regard to the impact on Human and Animal Health as well as pages 65-77 on ecotoxicology.
European Commission Report - Findings
Their findings are presented as a series of notes about different studies. Many studies the reviewers excluded and considered non-acceptable for review, while others were noted as acceptable. Some recommendations for further research were made.
One research finding found “unexplained severe necropsy.” The reviewers noted that no explanation was provided for this finding, which affected the reliability of the research.
Another research finding found a “significant reduction in egg weight” for birds. However, they concluded that this factor does not “represent a population relevant adverse effect.”
One troubling finding was that a volume of findings relating to farm animals found that “in all acute test performed including the higher test rate of 5000 mg/kg/bw strong clinical signs were observed including ataxia, convulsions, muscle tremors, red nasal discharge, clear oral discharge, urinary staining of the abdomen, diarrhea, piloerection, lethargy, and fecal staining of the abdomen, decreased spontaneous motor activity, and sedation and crouching position.”
Another troubling finding came from a study (or a review of studies; I’m unclear about this) regarding rabbit foetal deaths and found “a significant increase in foetal deaths” related to glyphosate exposure. Many of the researchers' names in that note were redacted, which is also odd.
The most serious finding seems to be that “bees exhibited 94% mortality with Roundup Ready to Use and 30% mortality with RoundUp Proactive over 24hr.” However, “Weedol did not cause significant mortality, demonstrating that the active ingredient glyphosate is not the cause of the mortality.” They note further that the “surfactants, or other co-formulants in the Roundup products, may cause death by incapacitating the gas exchange system.”
In general, the reviewers expressed that “DE agrees with no classification of glyphosate for acute dermal toxicity” and “no classification of glyphosate for acute oral toxicity.”
I interpret the findings above to mean a two things. First, glyphosate, by itself, appears to be fairly safe. That is to say that glyphosate poisoning through acute or long-term exposure doesn't appear to be likely. It isn't entirely without negative consequences (large consumption of it for example appears to be linked with some cases of serious toxic effects, including death), but we cannot say that acute or long term exposure to it is typically linked to serious health consequences for human beings. Second, glyphosate is never the only chemical in glyphosate products. RoundUp contains an assortment of other products, and ones identified as surfactants and co-formulants can pose a danger. Bees are one victim of these chemicals, and this has been established. We should not assume that what's bad for bees is bad for people, but it should be understood that glyphosate-products aren't as well researched as a glyphosate itself.
The European Commission report is lengthy, and for anyone interested in the topic, I recommend reading it. Germany's notes are only 50 pages or so out of the 1,100 page document. There are other review documents available as well.
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