Evidence continues to mount that the pesticide glyphosate is harmful to humans, animals, insects, microbes, etc.
Despite well financed campaigns by the manufacturer of Roundup, of which glyphosate is the key ingredient, to obfuscate the science, an avalanche of scientific papers continues to flow.
For a number of years now, in my capacity as a science journalist with decades of experience, I have been following the research into the pesticide glyphosate, which has become ubiquitous in the environment. My last major update on the subject was published in March 2023, in the online magazine Truthdig, and can be found at this link.
As I pointed out in that article:
“The weed-killer glyphosate is the most widely used herbicide in the world. It is manufactured by a number of companies, but is best known by its original trade name, “Roundup.” (Rolled onto the market by Monsanto in 1974, the product is now sold worldwide by Bayer, which purchased Monsanto in 2018.) In the United States alone, the Environmental Protection Agency has estimated that about 280 million pounds are applied to croplands each year. To get a perspective on that number, the combined weight of all the kale, brussels sprouts and eggplants consumed annually in the U.S. is just a bit over 300 million pounds.”
I also summarized the scientific research up to that time:
“The official U.S. position is that genetically modified organisms and commonly used herbicides, such as glyphosate, have been scientifically demonstrated to be safe for human consumption. But the science is anything but conclusive. Indeed, with regard to glyphosate, there is mounting evidence pointing in the opposite direction. Dozens of new studies over the past few years strongly suggest that the herbicide, even in the relatively low concentrations that farmers are supposed to use, has demonstrably harmful effects on humans, animals, insects (especially bees; more about that below), microbes and the environment in general. While the evidence that glyphosate can cause cancer in humans is controversial and less definitive, the support for so-called non-cancer effects in humans and other organisms is steadily piling up. This research is validating decades of efforts by governments, local communities and activists who have fought hard to limit or ban its use.”
Since I published that piece, the evidence against glyphosate has only continued to mount. I carefully file away each scientific paper, ready for the next time I have the chance to write about the multi-faceted harm that this chemical compound appears to be doing.
Earlier this month, two scientists, including the well known environmental researcher Edward Rubin at the University of Oregon in Eugene, published a new paper in the Proceedings of the National Academy of Sciences entitled “Glyphosate exposure and GM seed rollout unequally reduced perinatal health.”
The paper is unfortunately behind a paywall, but I will hit its highlights in a moment. The paper is significant for two reasons: First, PNAS is one of our leading journals, and this paper was peer reviewed (a so-called “Direct Submission”), unlike some papers in the journal which are contributed by NAS members and do not receive serious scientific scrutiny. (To its credit, in recent years PNAS has begun to limit what might be called vanity papers.)
Second, it adds importantly to a mountain of findings that glyphosate is potentially harmful to human health. In my Truthdig piece, I pointed out that while the question of whether glyphosate is a carcinogen continues to be debated—both in the scientific literature and in the courts—there is a lot of evidence that it has other potentially harmful effects on humans, animals, insects, microbes, the environment, and so forth.
Here are the basic findings of the new paper, taken first from the more technical abstract, and then in a summary accessible to non-scientific readers:
Abstract:
“The advent of herbicide-tolerant genetically modified (GM) crops spurred rapid and widespread use of the herbicide glyphosate throughout US agriculture. In the two decades following GM-seeds’ introduction, the volume of glyphosate applied in the United States increased by more than 750%. Despite this breadth and scale, science and policy remain unresolved regarding the effects of glyphosate on human health. We identify the causal effect of glyphosate exposure on perinatal health by combining 1) county-level variation in glyphosate use driven by 2) the timing of the GM technology and 3) differential geographic suitability for GM crops. Our results suggest the introduction of GM seeds and glyphosate significantly reduced average birthweight and gestational length. While we find effects throughout the birthweight distribution, low expected-weight births experienced the largest reductions: Glyphosate’s birthweight effect for births in the lowest decile is 12 times larger than that in the highest decile. Together, these estimates suggest that glyphosate exposure caused previously undocumented and unequal health costs for rural US communities over the last 20 years.”
Significance:
“While the herbicide glyphosate is the most commonly used herbicide globally, the effects of glyphosate exposure on human health and the environment remain unclear—particularly in more developed countries, where glyphosate exposure is often considered low. Using spatiotemporal variation in the adoption of glyphosate-resistant crops, we document significant adverse perinatal health effects due to increased glyphosate exposure in the rural United States. Further, historically disadvantaged groups disproportionately bear these health effects. These results conflict with current regulatory guidance, suggest current regulations may be inadequate, and highlight the need to improve pesticide use and exposure monitoring.”
My former colleague Erik Stokstad at Science, where I was a correspondent for 25 years, also published a very good summary of the findings in that journal, which I recommend reading for those who do not have access to PNAS. Erik ran the paper past several environmental scientists who were not involved with the study, and all of them clearly took it seriously.
As I discuss in the Truthdig piece, and as other journalists have documented over many years now, the scientific data calling into question glyphosate’s safety have continued to mount despite strenuous efforts by manufacturers like Monsanto (now owned by Bayer) and proven industry front organizations (eg Genetic Literacy Project and the American Council on Science and Health, among others) to obfuscate what the science says.
There seems little doubt that will continue, even though the Environmental Protection Agency and other regulatory agencies in the U.S., Europe, and elsewhere continue to do little to protect the public. I will update this story from time to time, as new evidence emerges that is worth making note of.
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