15
Sep
Group Urges Regulation of Weed Killer Glyphosate, Found in Food Supply, for Its Synergistic Effects
(Beyond Pesticides, September 15, 2025) With residues of the widely used weed killer glyphosate (Roundupᵀᴹ) in the food supply long documented, scientific attention has turned to the synergistic effects of the weedkiller— a magnified effect greater than the individual chemical effects added together. The authors of an article in World’s Poultry Science Journal write, “The synergistic toxic effects of commercial glyphosate formulations and their bioaccumulation in animal tissues are often overlooked in current safety assessments.” Following up on a previous action, Beyond Pesticides is telling Congress and the U.S. Environmental Protection Agency (EPA) that the agency must consider the effects of pesticides in the context in which they are used and promote the organic alternative.
Glyphosate residues in animal feed, as well as in water and through other exposure routes from food generally and residential areas, pose risks to both animal and human health, as these residues can bioaccumulate. As previously examined by Beyond Pesticides, the effects of pesticides are not limited to the crops to which they are applied. Synergistic effects of multiple chemical exposures are the rule, rather than the exception.
With poultry, the herbicide enters the production system through residues in genetically engineered feed. An earlier article in Scientific Reports concludes that glyphosate’s (GLP) “widespread application on feed crops leaves residues in the feed,” while residues are “found to be common in conventional eggs acquired from grocery stores.” In analyzing the biochemical, toxicological, and ecological impacts of glyphosate on poultry, particularly chickens, the authors find a wide body of evidence linking glyphosate and its metabolite (breakdown product) aminomethylphosphonic acid (AMPA) to debilitating hazards that extend beyond mortality. These sublethal effects include disruption of the gut microbiome and gastrointestinal disease; decreased productivity and diminished reproductive health; hepatic and kidney toxicity; growth and developmental impacts, including teratogenicity and embryotoxicity; endocrine disruption and oxidative stress; and impaired immune functions.
Glyphosate residues in animal feed, as well as in water and through other exposure routes from food generally and residential areas, pose risks to both animal and human health, as these residues can bioaccumulate. With a high reliance on corn and soybeans in the diets of poultry, genetically modified (GM) crops are a significant source of exposure for these animals. The ubiquitous nature of glyphosate residues throughout the environment and within organisms is a result of the widespread application of this toxic chemical in forestry, agriculture, landscaping, and gardening. Over 750 herbicides contain glyphosate as the active ingredient, and it also plays a large role in the production of GM crops, “with approximately 80% of GM crops bred specifically for GLP tolerance.”
Although the effects of glyphosate alone, as have long been documented in the scientific literature, range from negative impacts on biodiversity and the environment to food safety risks and human health implications, the true impacts can only be seen when looking at the whole agroecosystem. EPA’s regulatory processes ignore factors that enhance the toxicity of these already harmful chemicals, such as synergy, mixtures, and “inert” ingredients. “Current safety evaluations mostly concentrate on glyphosate in isolation, overlooking the synergistic toxic effects of commercial formulations and their capacity for bioaccumulation in adipose tissues,” the review’s authors point out.
Fortunately, adopting a systems approach to analyzing risks also reveals the systemic solution—regenerative organic production and land management—that is both successful and a suitable standard of comparison. The only way to truly protect humans, as well as pollinators, insects, birds, and other species, and the biosphere as a whole, is to stop the use of pesticides completely. Converting the world’s agricultural systems to organic would have a tremendous positive impact on threatened populations.
Letter to U.S. Congress
Recent research on glyphosate demonstrates how people are multiply exposed as the pesticide moves through the food chain. A scientific review in World’s Poultry Science Journal highlights the adverse health effects on avian species from exposure to the widely used weed killer glyphosate throughout poultry production. The herbicide enters poultry production through residues in genetically engineered feed. An earlier article in Scientific Reports concludes that glyphosate’s “widespread application on feed crops leaves residues in the feed,” while residues are “found to be common in conventional eggs acquired from grocery stores.” In analyzing the biochemical, toxicological, and ecological impacts of glyphosate on poultry, particularly chickens, the authors find a wide body of evidence linking glyphosate and its metabolite aminomethylphosphonic acid (AMPA) to debilitating hazards that extend beyond mortality. These sublethal effects include disruption of the gut microbiome and gastrointestinal disease; decreased productivity and diminished reproductive health; hepatic and kidney toxicity; growth and developmental impacts, including teratogenicity and embryotoxicity; endocrine disruption and oxidative stress; and impaired immune functions.
Glyphosate residues in animal feed, as well as in water and through other exposures from food generally and residential areas, pose risks to both animal and human health, as these residues can bioaccumulate. The GM corn and soybeans in the diets of poultry are a significant source of exposure for these animals. The ubiquitous nature of glyphosate residues throughout the environment and within organisms is a result of the widespread application of this toxic chemical in forestry, agriculture, landscaping, and gardening. Over 750 herbicides contain glyphosate as the active ingredient.
Although the effects of glyphosate alone, as have long been documented in the scientific literature, range from negative impacts on biodiversity and the environment to food safety risks and human health implications, the true impacts can only be seen when looking at the whole environment. EPA’s regulatory processes ignore factors that enhance the toxicity of these already harmful chemicals, such as synergy, mixtures, and “inert” ingredients. “Current safety evaluations mostly concentrate on glyphosate in isolation, overlooking the synergistic toxic effects of commercial formulations and their capacity for bioaccumulation in adipose tissues,” the review’s authors point out.
Other studies highlight the need for a broader overhaul of EPA’s current risk assessment process. A November 2023 European study published in Nature challenges “the current assumption of pesticide regulation—that chemicals that individually pass laboratory tests and semifield trials are considered environmentally benign.”
Since interactions and synergism are the rule, pesticides cannot be evaluated based on single-chemical, single-species tests. They must be evaluated in context—that is, the system of chemical-dependent management must itself be questioned. Fortunately, adopting a systems approach to analyzing risks also reveals the systemic solution—regenerative organic production and land management—that is both successful and a suitable standard of comparison. The only way to truly protect humans, as well as pollinators, insects, birds, and other species, and the biosphere as a whole, is to stop the use of pesticides completely. Converting the world’s agricultural systems to organic would have a tremendous positive impact on threatened populations.
EPA must consider effects of pesticides in the context in which they are used and with reference to the organic alternative.
Thank you.
Letter to U.S. Environmental Protection Agency
Recent research on glyphosate demonstrates how people are multiply exposed as the pesticide moves through the food chain. A scientific review in World’s Poultry Science Journal highlights the adverse health effects on avian species from exposure to the widely used weed killer glyphosate throughout poultry production. The herbicide enters poultry production through residues in genetically engineered feed. An earlier article in Scientific Reports concludes that glyphosate’s “widespread application on feed crops leaves residues in the feed,” while residues are “found to be common in conventional eggs acquired from grocery stores.” In analyzing the biochemical, toxicological, and ecological impacts of glyphosate on poultry, particularly chickens, the authors find a wide body of evidence linking glyphosate and its metabolite aminomethylphosphonic acid (AMPA) to debilitating hazards that extend beyond mortality. These sublethal effects include disruption of the gut microbiome and gastrointestinal disease; decreased productivity and diminished reproductive health; hepatic and kidney toxicity; growth and developmental impacts, including teratogenicity and embryotoxicity; endocrine disruption and oxidative stress; and impaired immune functions.
Glyphosate residues in animal feed, as well as in water and through other exposures from food generally and residential areas, pose risks to both animal and human health, as these residues can bioaccumulate. The GM corn and soybeans in the diets of poultry are a significant source of exposure for these animals. The ubiquitous nature of glyphosate residues throughout the environment and within organisms is a result of the widespread application of this toxic chemical in forestry, agriculture, landscaping, and gardening. Over 750 herbicides contain glyphosate as the active ingredient.
Although the effects of glyphosate alone, as have long been documented in the scientific literature, range from negative impacts on biodiversity and the environment to food safety risks and human health implications, the true impacts can only be seen when looking at the whole environment. EPA’s regulatory processes ignore factors that enhance the toxicity of these already harmful chemicals, such as synergy, mixtures, and “inert” ingredients. “Current safety evaluations mostly concentrate on glyphosate in isolation, overlooking the synergistic toxic effects of commercial formulations and their capacity for bioaccumulation in adipose tissues,” the review’s authors point out.
Other studies highlight the need for a broader overhaul of EPA’s current risk assessment process. A November 2023 European study published in Nature challenges “the current assumption of pesticide regulation—that chemicals that individually pass laboratory tests and semifield trials are considered environmentally benign.”
Since interactions and synergism are the rule, pesticides cannot be evaluated based on single-chemical, single-species tests. They must be evaluated in context—that is, the system of chemical-dependent management must itself be questioned. Fortunately, adopting a systems approach to analyzing risks also reveals the systemic solution—regenerative organic production and land management—that is both successful and a suitable standard of comparison. The only way to truly protect humans, as well as pollinators, insects, birds, and other species, and the biosphere as a whole, is to stop the use of pesticides completely. Converting the world’s agricultural systems to organic would have a tremendous positive impact on threatened populations.
EPA must consider effects of pesticides in the context in which they are used and with reference to the organic alternative.
Thank you.
