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Is Roundup toxic?

Is Roundup toxic?


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Roundup, as we all know, is a herbicide that kills weeds. It does this by preventing the production of amino acids in plants. One of these amino acids is tyrosine. Tyrosine is a nonessential amino acid so it is produced in the human body. So is Roundup toxic because it could also affect the human tyrosine synthesis pathways? Or are the pathways for tyrosine synthesis different for humans and plants?


Glyphosate works by inhibiting 5-enolpyruvylshikimate-3-phosphate (EPSP) synthase. Plants and microbes have this gene, and humans do not.

So, Roundup is toxic to plants because because it inhibits the production of critical amino acids as you surmised (EPSPS makes 5-enolpyruvyl-shikimate-3-phosphate (ESP) which is used as precursor to not only amino acids but also other plant hormones and aromatic chemicals). It does not do this in humans.

It is a very controversial compound though, and weight of evidence for human toxicity has not clearly overwhelmingly swung one way or the other yet. There are some very impassioned believers on both sides of the fence, and I suggest reading pubmed epidemiology studies to make up your own mind.


The pathways are different. Humans synthesize tyrosine by hydroxylating phenylalanine. Plants use the shikimate pathway to produce all of the aromatic amino acids. Roundup inhibits an enzyme in the shikimate pathway but does not affect the human enzyme involved in producing phenylalanine. None of this is to say, however, that it is or isn't toxic.


Glyphosate Toxicity: What You Don’t Know Might Kill You!

Glyphosate is the active ingredient in the popular herbicide, Roundup. Glyphosate toxicity is a big deal and what you don’t know just might kill you! Many people routinely spray their lawns with this chemical totally unaware of the toxicity. In the United States, farmers are applying ever increasing amounts to their crops before harvest. According the the World Health Organization, glyphosate is now declared a “probable carcinogen” which means it may cause cancer. The industry still asserts that it is totally safe for humans, however, one only needs to look at the data to know that is not true.

Ignorance may be bliss but I believe we may be on the verge of one of the most toxic man made environmental disasters in history… and unfortunately this chemical is persistent in both the environment and the human body and it is not easy to clean up. France’s highest court found Monsanto guilty of lying as far back as 2008 about the toxicity of it’s popular weedkiller, Roundup. “The court confirmed an earlier judgment that Monsanto had falsely advertised its herbicide as “biodegradable” and claimed it “left the soil clean” (Read more here)

According to an Article in Nature published March 24, 2015:

Glyphosate is the world’s most widely produced herbicide, by volume. It is used extensively in agriculture and is also found in garden products in many countries. The chemical is an ingredient in Monsanto’s weedkiller product Roundup, and glyphosate has become more popular with the increasing market share of crops that are genetically engineered to be tolerant to the herbicide.

California recently became the first state to issue plans to list glyphosate as a chemical known to cause cancer according to EcoWatch. This is big news and we need to pay attention. The use of glyphosate has nearly doubled from 95 million pounds in 2001 to nearly 185million pounds in 2007, according to the latest released report form the EPA and who knows how much it’s increased sine 2007! This is likely in part due to the increase usage of Round-up Ready genetically modified crops during that same time period.

Dr. Anthony Samsel and Dr. Stephanie Seneff state in their recent article published August 2015:

Glyphosate has a large number of tumorigenic [ cancer-causing ] effects on biological systems, including direct damage to DNA in sensitive cells, disruption of glycine homeostasis, succinate dehydrogenase inhibition, chelation of [minerals such as] manganese, modification to more carcinogenic molecules, such as N-nitrosoglyphosate and glyoxylate, disruption of fructose metabolism, etc…

Sadly epidemiological evidence supports a strong correlation between the dramatic rise in use of glyphosate on crops and the multitude of cancers reaching epidemic proportions, such as breast, pancreatic, kidney, thyroid, bladder, and liver cancers.

In perhaps the most ironic twist of all, glyphosate has proven highly toxic to the basic phase one detoxification of the liver, the cytochrome pathways. I find it incredibly alarming that one of the most toxic chemicals known to mankind also exerts it’s influence by impairing human detoxification. Did you get that!? A toxic chemical that makes is harder to detox… what nonsense!

Here is an excerpt from Entropy 2013, Glyphosate’s Suppression of Cytochrome P450 enzymes and amino acid biosynthesis by the gut microbe:

Glyphosate’s inhibition of cytochrome P450 (CYP) enzymes is an overlooked component of its toxicity to mammals. CYP enzymes play crucial roles in biology, one of which is to detoxify xenobiotics. Thus, glyphosate enhances the damaging effects of other food borne chemical residues and environmental toxins. Negative impact on the body is insidious and manifests slowly over time as inflammation damages cellular systems throughout the body.

Harvesting wheat after glyphosate application

Glyphosate may trigger autoimmunity, such as celiac disease by the following mechanisms:

  • Spraying of wheat before harvest with glyphosate, a common practice in North America allows for a large exposure to glyphosate in wheat.
  • Wheat may be the most common ingredient in processed foods.
  • Glyphosate also damages the microvilli in gut reducing ability to absorb vitamins and minerals
  • Wheat contains gliadin, which is difficult for genetically susceptible individuals to break down.
  • Glyphosate may attach to the gliadin as a consequence of a chemical interaction between the chemical make it even harder to break down this large protein molecule.
  • It may not be recognized by the body or able to be broken down, making even more likely to induce an immunological response in susceptible individuals, contributing to development of celiac disease

In addition to celiac disease, researchers now believe that glyphosate may be linked to the following diseases:

  1. Autism
  2. Autoimmune diseases
  3. Cancer
  4. Parkinson’s
  5. Alzheimer’s disease
  6. Inflammatory bowel diseases (Crohn’s and Ulcerative Colitis)
  7. Cardiovascular disease
  8. Depression
  9. Infertility

Glyphosate is also toxic to our gut microbiome

Glyphosate is toxic to many of our benetifical gut microbes. It may preferentially kill off species, like lactobacillus while leaving potential pathogens, like clostridia to run wild. Glyphosate also chelates essential minerals, such as manganese, iron, cobalt, molybdenum, and copper so that the gut microbes do not have access to them. This leads to chronic inflammatory states in the gut as well as increased intestinal permeability, a mechanism at the core of many chronic illnesses, including inflammatory bowel disease, depression, and autoimmunity.

If you are eating processed food, you are eating glyphosate…

Residues of glyphosate are commonly found in the most common foods in the American Diet, including

  1. Corn
  2. Soy
  3. Sugar Beets (sugar)
  4. Canola
  5. Cotton (not food but in clothing, sanitary napkins and many products we use daily)

Nearly one billion pounds of glyphosate are doused on both conventional and genetically modified crops world-wide each year but GMO crops receive the largest amounts. Processed foods undoubtable expose you to this toxic contamination, courtesy of wheat, corn, soy and the vegetable oil used. And the meats from conventionally raised animals in confined feed lots are given fed that most likely contains glyphosate-laden corn and soy.

And finally… it gets personal

You may know that I grew up on a farm in Central Illinois. My Dad and brothers still farm corn and soybeans there and I couldn’t be more proud that they have recently switched over to non-GMO versions of these crops. My brothers have started a few fields of organic crops as well. Due to my own history of breast cancer and Crohn’s disease, I have followed at 100% organic diet for at least the past 10-15 years.

Recently I realized just how pervasive this glyphosate exposure is in our environment when I sent out my urine to test my own glyphosate level. I was shocked to get the results back (below) showing that my level was higher than the “Farmer” study, which tested farm workers on application day! This made me realize how pervasive this dangerous chemical is in our environment and how important it is to remain vigilant to decrease exposure and work to get it banned. I am currently working hard on detoxing this chemical from my body and will keep you posted when I do repeat testing.

Dr. Jill glyphosate levels

Ok, so what can I do about it?!

The most important thing to realize is that you cannot wash glyphosate off food since it is incorporated into each cell of plant.

Here are some tips to keep your diet free of glyphosate:

  • Only way to 100% eliminate fromyour diet is to avoid conventionally grown and processedfoods
  • Glyphosate accumulates in animal tissues, so make sure your meat was not fed GMO grains and your butter and dairy is organic
  • Switch over to a 100% organic diet
  • Take activated charcoal or rice bran powder in aiding elimination of organophosphates and glyphosate after exposure
  • Maintain adequate mineral status by taking a multi-mineral supplement that includes trace minerals
  • Support glutathione production with N-acetylcysteine, glycine and glutamine or oral liposomal glutathione
  • Support phase 1 and phase 2 liver detoxification by avoiding alcohol and taking liver support, like silymarin, lipoid acid
  • It is much harder to reverse damage once it’s done, so best to avoid glyphosate from the start—especially in children!
  • A glyphosate test kit. HRI Labs will give 10% off when you use code ‘DrJill’ at checkout. This makes the price $89.

So go to it… It’s worth every penny to grown your own food or buy organic and begin to detox your body of this dangerous chemical!

* These statements have not been evaluated by the Food and Drug Administration. The product mentioned in this article are not intended to diagnose, treat, cure, or prevent any disease. The information in this article is not intended to replace any recommendations or relationship with your physician. Please review references sited at end of article for scientific support of any claims made.


Glyphosate + Toxins

Over the last 25 years we have seen the most profound explosion of chronic disease in human history.

By 2011, our Centers of Disease Control (CDC) was reporting 54% of US children with some form of chronic disorder or disease by the age of seventeen. 1 (View the study here) These conditions occur in nearly every facet of biology – the hormone and immune systems, the respiratory and neurologic systems, and beyond.

By 2016 the CDC reported 1 in every 14 kids in the US with developmental disabilities, and 1 in 28 boys (1:28) with an Autism Spectrum Disorder (View the study here). 2 Attention Deficit disorder found in one in ten (1:10) children.

All on near identical trajectories of increase since 1996.

Research from around the globe now suggests that environmental factors are now contributing a combination of genetic, neurologic, autoimmune, and metabolic injuries that underpin the collapse of health in our children and adults.

As we continue to uncover the intricacies of this eloquent balance between soil, the microbiome, and ourselves, the timeline of our chronic disease epidemic becomes very interesting, and in fact provides a pathway to the recovery toward human health.

It is now estimated that we spray more than 4.5 billion pounds of glyphosate (the active ingredient in Roundup) into the soils, plants, and water systems of our planet. And there are now dozens of genetically modified plant species around the world which have allowed chemical companies to develop a seemingly infinite market for their weedkillers. And after “Roundup Ready” crops were introduced in the mid-late 1990’s, this water soluble toxin would subsequently work its way into the water within the grains, fruits, and vegetables, as well as infiltrating the groundwater, slowly making its way into rivers, oceans, our air, and ultimately our rainfall. Not surprisingly, the diseases in our domesticated animals – from pets to livestock – have followed a similar trajectory.

What I’m saying is, we need to stop trying to micromanage the gut. It is important for you to start backing off, to let the carbon redox system (the communication system between the bacteria in the gut) reestablish a healthy balance in the gut.


Glyphosate

As of 2011, NPIC stopped creating technical pesticide fact sheets. The old collection of technical fact sheets will remain available in this archive, but they may contain out-of-date material. NPIC no longer has the capacity to consistently update them. To visit our general fact sheets, click here. For up-to-date technical fact sheets, please visit the Environmental Protection Agency's webpage.

Laboratory Testing: Before pesticides are registered by the U.S. EPA, they must undergo laboratory testing for short-term (acute) and long-term (chronic) health effects. Laboratory animals are purposely given high enough doses to cause toxic effects. These tests help scientists judge how these chemicals might affect humans, domestic animals, and wildlife in cases of overexposure.

Molecular Structure -
Glyphosate

Chemical Class and Type:

  • Glyphosate is a non-selective systemic herbicide that is applied directly to plant foliage. 1 When used in smaller quantities, glyphosate can act as a plant growth regulator. 2 Glyphosate is a glycine derivative. 1 The International Union of Pure and Applied Chemistry (IUPAC) name for glyphosate is N-(phosphonomethyl) glycine 3 and the Chemical Abstracts Service (CAS) registry number is 1071-83-6. 1
  • Glyphosate's potential as an herbicide was reported in 1971. 1,4 Glyphosate was first registered for use by the United States Environmental Protection Agency (U.S. EPA) in 1974 5 , and reregistration was completed in 1993. 6 See the text box on Laboratory Testing.
  • Formulations of glyphosate include an acid, monoammonium salt, diammonium salt, isopropylamine salt, potassium salt, sodium salt, and trimethylsulfonium or trimesium salt. 1,2,4 Unless otherwise stated, all data in this fact sheet refer to the acid form.
  • Technical grade glyphosate is used in formulated products, as are the isopropylamine, sodium, and monoammonium salts. Of these, the isopropylamine salt is most commonly used in formulated products. 2,7

Physical / Chemical Properties:

Glyphosate and associated forms
Active Ingredient Form 1,4 Vapor pressure 1,4,8 Henry's constant 8 Molecular weight 1,4,8 Solubility in water (mg/L) 1,4 Log Kow 1,4,8 Koc 3
Glyphosate acid odorless, white solids 1.31 x 10 -2 mPa (25 °C)
1.84 x 10 -7 mmHg (45 °C)
4.08 x 10 -19 atm·m 3 /mol 169.07 g/mol pH 1.9: 10,500 mg/L
pH 7.0: 157,000 mg/L
Less than -3.2 300 - 20,100
Glyphosate isopropylamine salt odorless, white solids 2.1 x 10 -3 mPa (25 °C)
1.58 x 10 -8 mmHg (25 °C)
6.27 x 10 -27 atm·m 3 /mol 228.19 g/mol pH 4.06: 786,000 mg/L -3.87 or -5.4 300 - 20,100
Glyphosate ammonium salt odorless, white solids 9 x 10 -3 mPa (25 °C)
6.75 x 10 -8 mmHg (25 °C)
1.5 x 10 -13 atm·m 3 /mol 186.11 g/mol pH 3.2: 144,000 mg/L -3.7 or 5.32 300 - 20,100
  • Glyphosate is one of the most widely used herbicides with applications in agriculture, forestry, industrial weed control, lawn, garden, and aquatic environments. 1,6 Sites with the largest glyphosate use include soybeans, field corn, pasture and hay. 2,6
  • Some plants have been genetically engineered to be resistant to glyphosate. Glyphosate-tolerant soybeans, corn, cotton, and canola are examples of such plants. 4,9 This fact sheet does not address glyphosate-tolerant crops.
  • Uses for individual products containing glyphosate vary widely. Always read and follow the label when applying pesticide products.
  • Signal words for products containing glyphosate may range from Caution to Danger. The signal word reflects the combined toxicity of the active ingredient and other ingredients in the product. See the pesticide label on the product and refer to the NPIC fact sheets on Signal Words and Inert or "Other" Ingredients.
  • To find a list of products containing glyphosate which are registered in your state, visit the website http://npic.orst.edu/reg/state_agencies.html select your state then click on the link for "State Products."

Mode of Action:

Target Organisms

  • In plants, glyphosate disrupts the shikimic acid pathway through inhibition of the enzyme 5-enolpyruvylshikimate-3-phosphate (EPSP) synthase. The resulting deficiency in EPSP production leads to reductions in aromatic amino acids that are vital for protein synthesis and plant growth. 1,4
  • Glyphosate is absorbed across the leaves and stems of plants and is translocated throughout the plant. 1,3 It concentrates in the meristem tissue. 10
  • Plants exposed to glyphosate display stunted growth, loss of green coloration, leaf wrinkling or malformation, and tissue death. Death of the plant may take from 4 to 20 days to occur. 4,10
  • The sodium salt of glyphosate can act as a plant growth regulator and accelerate ripening of specific crops. 2

Non-target Organisms

  • The shikimic acid pathway is specific to plants and some microorganisms. The absence of this pathway in mammals may explain the low toxicity of glyphosate to non-target organisms. 11,12
  • Studies indicate that the surfactant polyoxyethyleneamine or polyethoxylated tallow amine (both abbreviated POEA), used in some commercial glyphosate-based formulations, may be more toxic by the oral route to animals than glyphosate itself. 13,14
  • The mechanism of toxicity of glyphosate in mammals is unknown, but it may cause uncoupling of oxidative phosphorylation. 15 However, this hypothesis has been disputed. 16

Acute Toxicity:

  • Glyphosate is low in toxicity to rats when ingested. The acute oral LD50 in rats is greater than 4320 mg/kg. 17 See the text boxes on Toxicity Classification and LD50/LC50.

LD50/LC50: A common measure of acute toxicity is the lethal dose (LD50) or lethal concentration (LC50) that causes death (resulting from a single or limited exposure) in 50 percent of the treated animals. LD50 is generally expressed as the dose in milligrams (mg) of chemical per kilogram (kg) of body weight. LC50 is often expressed as mg of chemical per volume (e.g., liter (L)) of medium (i.e., air or water) the organism is exposed to. Chemicals are considered highly toxic when the LD50/LC50 is small and practically non-toxic when the value is large. However, the LD50/LC50 does not reflect any effects from long-term exposure (i.e., cancer, birth defects or reproductive toxicity) that may occur at levels below those that cause death.

Dermal

  • Glyphosate is low in toxicity to rabbits when applied to the skin. The acute dermal LD50 in rabbits is greater than 2 g/kg. 17
  • Glyphosate is low in toxicity for eye irritation and very low in toxicity for dermal irritation. In studies with glyphosate manufacturing use products, researchers observed mild eye irritation in rabbits that cleared in seven days. 18,19
  • Glyphosate was not found to be a skin sensitizer. 6
  • The isopropylamine and ammonium salts are also low in toxicity via the dermal route. The LD50 in rabbits was greater than 5000 mg/kg for both salts, and these salts are considered slight eye irritants but not skin irritants. 1
  • Of three formulated products tested, skin irritation varied from none to moderate, and eye irritation was rated as none, moderate, and severe. Dermal LD50 values in rabbits exposed to these products were greater than 5000 mg/kg. 4
  • The formulated product Roundup®, containing 41% glyphosate, was applied to the skin of 204 male and female volunteers in a modified Draize test. No sensitization was observed. The researchers concluded that exposure would not lead to photoirritation or photosensitization. 20

Inhalation

  • Glyphosate is very low in toxicity to rats when inhaled. The acute inhalation LC50 in rats is greater than 4.43 mg/L based on a 4-hour, nose-only inhalation study. 21
  • The 4-hour LC50 for rats exposed to the isopropylamine form of glyphosate was greater than 1.3 mg/L air. 1
  • The LC50 for rats exposed to the ammonium salt form of glyphosate was greater than 1.9 mg/L in a whole body exposure. 1
  • Inhalation LC50 values for two formulated products were greater than 1.3 mg/L and 3.2 mg/L in rats. 4

Signs of Toxicity - Animals

  • Animals exposed to formulated glyphosate herbicides have displayed anorexia, lethargy, hypersalivation, vomiting, and diarrhea. Symptoms persisted for 2 to 24 hours following exposure. The surfactants in formulated products are thought to be responsible for the clinical signs. 22
  • Clinical signs typically appear within 30 minutes to 2 hours following ingestion. Animals may exhibit excitability and tachycardia at first, followed by ataxia, depression, and bradycardia. Severe cases may progress to collapse and convulsions. 15
  • The Veterinary Poisons Information Service in London, England recorded 150 cases over an 8-year period of dogs exposed to glyphosate primarily from eating grass recently treated with formulated products. Of these, roughly 40% of the dogs exhibited no clinical signs, 45% exhibited mild to moderate clinical signs, and roughly 15% were classified as serious. 15
  • The Centre National d'Informations Toxicologiques Veterinaires of France reported 31 certain cases of intoxication of domestic animals by glyposate-containing products in a 3-year period. Most exposures resulted from animals ingesting the product prior to application. Of these cases, 25 were dogs and 4 were cats. Vomiting occurred within 1-2 hours of ingestion in 61% of the cases. Hypersalivation occurred in 26% of cases, and mild diarrhea was reported in 16% of cases. Centre records did not report long-lasting effects or any fatalities. 23

Signs of Toxicity - Humans

  • In a review of 80 intentional ingestion cases, 79 of which were suicide attempts, researchers identified typical symptoms of erosion of the gastrointestinal tract, dysphagia or difficulty swallowing, and gastrointestinal hemorrhage. Seven cases resulted in death. 24 Accidental ingestions are associated with mild gastrointestinal effects. 14
  • Eye and skin irritation have occasionally been reported from dermal exposure to glyphosate formulations. 13,14 However, adverse health effects are typically associated with exposure that occurs while mixing a concentrated product, not the use of dilute spray solutions. 13 Permanent ocular or dermal damage is very rare. 13,14,25
  • Inhalation of spray mist may cause oral or nasal discomfort, as well as tingling and throat irritation. 14
  • Always follow label instructions and take steps to minimize exposure. If any exposure occurs, be sure to follow the First Aid instructions on the product label carefully. For additional treatment advice, contact the Poison Control Center at 1-800- 222-1222. If you wish to discuss an incident with the National Pesticide Information Center, please call 1-800-858-7378.

Chronic Toxicity:

Animals

  • Researchers gave beagle dogs capsules containing 0, 20,100, or 500 mg/kg/day of glyphosate for one year. No effects were observed the NOEL for systemic toxicity is greater than or equal to 500 mg/kg/day. 26 See the text box on NOAEL, NOEL, LOAEL, and LOEL.

NOAEL: No Observable Adverse Effect Level

NOEL: No Observed Effect Level

LOAEL: Lowest Observable Adverse Effect Level

LOEL: Lowest Observed Effect Level

Humans

  • Researchers collected urine samples over 8 months from workers at two forestry nurseries where glyphosate was used for weed control. No glyphosate was detected in any of the 355 urine samples. The researchers attributed the lack of detected glyphosate in worker urine samples to the poor absorption of glyphosate through the skin. 34 See the text box on Exposure.

Exposure: Effects of glyphosate on human health and the environment depend on how much glyphosate is present and the length and frequency of exposure. Effects also depend on the health of a person and/or certain environmental factors.

Endocrine Disruption:

  • Rats and mice were fed a diet containing 0, 3125, 6250, 12,500, 25,000, or 50,000 ppm of 99% pure glyphosate for 13 weeks. The two highest dose groups of male rats had a significant reduction in sperm concentrations, although concentrations were still within the historical range for that rat strain. The highest dose group of female rats had a slightly longer estrus cycle than the control group. 37
  • Researchers reviewed the scientific literature on glyphosate, its major metabolite AMPA, formulated Roundup® products manufactured by Monsanto, and the surfactant POEA. They found no evidence of endocrine effects in humans or other mammals. 13
  • Using results from the EPA's Endocrine Disruptor Screening Program (EDSP), glyphosate was not considered to be an endocrine disruptor based on a lack of potential interaction with the estrogen, androgen or thyroid pathways. 38

Carcinogenicity:

Animals

  • Researchers fed rats a diet containing glyphosate at 0, 89, 362, or 940 mg/kg/day (males) and 0, 113, 457, or 1183 mg/kg/day (females) for two years. The high dose in this study approaches or exceeds the limit dose recommended for carcinogenicity studies. Slight increases in pancreatic islet cell adenomas, hepatocellular adenomas, and thyroid C-cell adenomas were observed in some cases. None of these findings were statistically significant. The incidence of tumors was within the range of historical controls (historical control data from seven years of laboratory research) for the evaluated tumor types in this study. The U.S. EPA concluded the tumors were not treatment-related. 27,39
  • In a carcinogenicity study, mice were fed a diet containing glyphosate (0, 161/195, 835/968, 4945/6069 mg/kg/day for males and females, respectively) for 24 months. The moderate and high doses in this study exceed or approach the limit dose recommended for carcinogenicity studies. In the high-dose groups researchers observed decreased body weight gain in both male and female mice. In high-dose males, slightly increased incidence of renal tubular adenomas was noted. A later re-evaluation of tissues determined that renal tumors were not related to glyphosate exposure. An independent group of pathologists and biometricians also concluded that the occurrence of adenomas was not caused by glyphosate. Kidney tissue examinations found chronic interstitial nephritis and tubular epithelial basophilia and hypertrophy in male rats. Overall, there was not an increase in tubular lesions observed in male mice. 39,40,41
  • In a carcinogenicity study, technical grade glyphosate was given to male and female rats in their diet (0, 95, 316.9, and 1229.7 mg/kg/day). In female rats, a slight increase in mammary gland tumors was noted. Tumor incidence was not statistically significant in pairwise comparisons. 39
  • Goldfish (Carassius auratus) were exposed to 5, 10, or 15 ppm of the formulated product Roundup® containing the IPA salt of glyphosate and the surfactant POEA for 6 days. Researchers noted increased DNA and micronuclei damage in the peripheral erythrocytes. This may have resulted from decreased DNA repair. Genotoxicity test results are generally mixed, although formulated products appear to be more likely to cause effects than glyphosate alone. 42
  • Glyphosate has been the subject of numerous genotoxicity tests and the results are overwhelmingly negative. 31 Doses that showed positive results in vivo were too high to be considered relevant for human health risk assessment. 39

Humans

  • The U.S. EPA classified glyphosate as "not likely to be carcinogenic to humans." Human carcinogenic potential was evaluated by reviewing available epidemiological, animal carcinogenicity, and genotoxicity data. 30,39 See the text box on Cancer.

Cancer: Government agencies in the United States and abroad have developed programs to evaluate the potential for a chemical to cause cancer. Testing guidelines and classification systems vary. To learn more about the meaning of various cancer classification descriptors listed in this fact sheet, please visit the appropriate reference, or call NPIC.

Reproductive or Teratogenic Effects:

Animals

  • In a developmental study, pregnant rabbits were given glyphosate by gavage (stomach tube) on gestation days 7-19 at doses of 0, 100, 175, 300 mg/kg/day. Rabbits in the middle and higher doses had diarrhea or few and/or no feces. Rabbits were the most sensitive animal species tested, with a developmental NOAEL of 300 mg/kg/day. Based on this rabbit study, the chronic dietary and incidental exposure NOAEL and LOAEL are 100 and 175 mg/kg/day, respectively. 30
  • Researchers dosed pregnant rats with glyphosate by gavage (stomach tube) on gestation days 6-19 at doses of 0, 300, 1000, or 3500 mg/kg/day. At the highest dose, they detected decreased body weight gains in both the dams and fetuses, increased maternal mortality, and an increased number of fetal skeletal abnormalities. The NOEL for maternal and developmental toxicity was 1000 mg/kg/day and the LOEL was 3500 mg/kg/day. 30,53
  • In a developmental study, scientists exposed pregnant rabbits to glyphosate by gavage on gestation days 6-27 at doses of 0, 75, 175, or 350 mg/kg/day. They detected no developmental effects. At the highest dose tested, the animals exhibited diarrhea, nasal discharge, and increased mortality too many animals died in this group to assess developmental effects at this dose. The NOEL for maternal effects was 175 mg/kg/day. 30,54
  • After reviewing the toxicological database, EPA found no evidence of increased susceptibility of young rats and rabbits to in utero exposures of glyphosate. 30
  • Dietary concentrations of up to 10,000 ppm or 293 mg/kg/day of glyphosate given to rats over two generations had no effect on male or female sexuality and fertility. The NOAEL for parental and offspring toxicity is 3000 ppm, based upon a reduction of body weight at 10,000 ppm. 31,55
  • Researchers reviewed the scientific literature on glyphosate, its major metabolite AMPA, formulated Roundup® products manufactured by Monsanto, and the surfactant POEA. They concluded that neither glyphosate, AMPA, nor POEA caused reproductive effects in various animal studies. 13

Humans

  • Questionnaires filled out by farm operators and eligible couples collected during the Ontario Farm Family Health Study suggested that there was an association between preconception exposure to pesticide products containing glyphosate and elevated risks of late spontaneous abortion. 56

Fate in the Body:

Absorption

  • Animal studies have indicated that 30-36% of glyphosate is absorbed after ingestion. 11,13,57
  • Dermal absorption of glyphosate is poor. 6 An in vitro experiment with human skin resulted in a maximum of 2.2% of 2.6 &mug/cm 2 glyphosate was absorbed across the skin. Absorption peaked 8 hours after administration. 58
  • Researchers applied glyphosate to abdominal skin of monkeys at doses of 5400 &mug or 500 &mug over 20 cm 2 of skin. Over a 7 day period, 73.5% and 77.1% of the applied dose remained on the skin. 58
  • Glyphosate is non-volatile. 6 Absorption from inhalation exposure is not expected to be significant. 14

Distribution

  • Rats dosed orally with 10 mg/kg glyphosate attained peak concentrations in their tissues 6 hours following dosing. The gastrointestinal tract contents accounted for 50% of the dose, with the tissue of the small intestine accounting for an additional 18%. Approximately 5% of the dose was found in bone and 6% in the carcass, with 1% or less of the dose distributed to abdominal fat, blood, colon, kidney, liver, and stomach. 57
  • Researchers gave rats a single oral dose of 10 mg/kg or 1000 mg/kg of glyphosate. Seven days after administration, the absorbed dose had distributed throughout the body, although it was primarily concentrated in the bone. 59
  • Researchers fed hens and goats glyphosate and found glyphosate and its major metabolite AMPA in eggs, milk, and the animals' body tissues. 13,60,61

Metabolism

  • Glyphosate undergoes little metabolism and is excreted mostly unchanged in the feces and secondarily in the urine. 3,13,62
  • Samples taken from goats and hens fed glyphosate contained the parent compound and AMPA, but there was no evidence of other glyphosate metabolites in body tissues, eggs, or milk. 6
  • High ratios of glyphosate to AMPA were detected in a human patient's blood serum 8 hrs (22.6 &mug/mL glyphosate to 0.18 &mug/mL AMPA) and 16 hrs (4.4 &mug/mL glyphosate to 0.03 &mug/mL AMPA) post-ingestion, as well as in the patient's total amount of urine. This indicates that glyphosate metabolism was minimal. 63

Excretion

  • Animal studies indicate that glyphosate is primarily excreted through the urine and feces. 3,13,62
  • A rat given a single oral dose of glyphosate eliminated 0.27% of the administered dose as carbon dioxide, and excreted 97.5% as glyphosate in urine and feces. Researchers detected AMPA in urine (0.2-0.3% of administered dose) and feces (0.2-0.4% of administered dose). 64,65
  • Glyphosate is cleared from the body of rats 168 hours after administration. 11
  • Two human patients who were poisoned with glyphosate had peak plasma glyphosate concentrations within 4 hours of ingestion. After 12 hours, glyphosate was almost undetectable. 66

Medical Tests and Monitoring:

  • Glyphosate exposure can be monitored through measurement of glyphosate and AMPA concentrations in blood or urine. 11,67,68 Detection methods include gas chromatography and high-performance liquid chromatography. 63,68,69 However, the clinical significance of residues in human tissues is unknown.
  • Researchers developed a sensitivity enhanced multiplexed fluorescence covalent microbead immunosorbent assay (FCMIA) for the measurement of glyphosate in urine. 70 This method was used to detect glyphosate in a study among farm and non-farm households in Iowa. 71

Environmental Fate:

  • The median half-life of glyphosate in soil has been widely studied values between 2 and 197 days have been reported in the literature. 7,62 A typical field half-life of 47 days has been suggested. 4 Soil and climate conditions affect glyphosate's persistence in soil. 1 See the text box on Half-life.

The "half-life" is the time required for half of the compound to break down in the environment.

1 half-life = 50% remaining
2 half-lives = 25% remaining
3 half-lives = 12% remaining
4 half-lives = 6% remaining
5 half-lives = 3% remaining

Half-lives can vary widely based on environmental factors. The amount of chemical remaining after a half-life will always depend on the amount of the chemical originally applied. It should be noted that some chemicals may degrade into compounds of toxicological significance.

Water

  • The median half-life of glyphosate in water varies from a few days to 91 days. 1
  • Glyphosate did not undergo hydrolysis in buffered solution with a pH of 3, 6, or 9 at 35 °C. Photodegradation of glyphosate in water was insignificant under natural light in a pH 5, 7, and 9 buffered solution. 72,73
  • Glyphosate in the form of the product Roundup® was applied to aquatic plants in fresh and brackish water. Glyphosate concentrations in both ponds declined rapidly, although the binding of glyphosate to bottom sediments depended heavily on the metals in the sediments. If chelating cations are present, the sediment half-life of glyphosate may be greatly increased. 74
  • Glyphosate has a low potential to contaminate groundwater due to its strong adsorptive properties. However, there is potential for surface water contamination from aquatic uses of glyphosate and soil erosion. 6
  • Volatilization of glyphosate is not expected to be significant due to its low vapor pressure. 6
  • Glyphosate and all its salts are very low in volatility with vapor pressures ranging from 1.84 x 10 -7 mmHg to 6.75 x 10 -8 mmHg at 25 °C. 1,4,8
  • Glyphosate is stable in air. 1

Plants

  • Glyphosate is absorbed by plant foliage and transported throughout the plant through the phloem. 3 Glyphosate absorption across the cuticle is moderate, and transport across the cell membrane is slower than for most herbicides. 4 Because glyphosate binds to the soil, plant uptake of glyphosate from soil is negligible. 3
  • Glyphosate accumulates in meristems, immature leaves, and underground tissues. 4
  • Very little glyphosate is metabolized in plants, with AMPA as the only significant degradation product. 3
  • Lettuce, carrots, and barley contained glyphosate residues up to one year after the soil was treated with 3.71 pounds of glyphosate per acre. 75,76
  • Glyphosate had a median half-life of 8 to 9 days in leaf litter of red alder and salmonberry sprayed with Roundup®. 62

Indoor

  • All surface wipe and dust samples collected from five farm households in Iowa contained detectable levels of glyphosate ranging from 0.0081-2.7 ng/cm 2 . In six non-farm households, 28 out of 33 samples collected contained detectable levels of glyphosate ranging from 0.0012-13 ng/cm 2 . 77

Food Residue

  • Glyphosate was not included in compounds tested for by the Food and Drug Adminstration's (FDA) Pesticide Residue Monitoring Program (PRMP), nor in the United States Department of Agriculture's Pesticide Data Program (PDP).

Ecotoxicity Studies:

Birds

  • An acute oral toxicity study found that a single dose of technical grade glyphosate is practically non-toxic to bobwhite quail, with an LD50 of greater than 2000 mg/kg. 78
  • Studies with technical grade glyphosate found an 8-day dietary LC50 greater than 4000 ppm for mallard ducks and bobwhite quail, indicating slight toxicity. 78,79
  • Glyphosate is not expected to cause reproductive impairment in birds at dietary levels of up to 1000 ppm. 6
  • An ecological risk assessment concluded that the greatest risk posed by glyphosate and its formulated products to birds and other wildlife results from alteration of habitat. 7

Fish and Aquatic Life

  • Technical grade glyphosate ranges from slightly toxic to practically non-toxic to freshwater fish, with a 48-hour LC50 of greater than 24 mg/L to 140 mg/L. 6
  • Formulated glyphosate products range from moderately toxic to practically non-toxic to freshwater fish, with 96-hour LC50 values ranging from 1.3 mg/L to greater than 1000 mg/L. 6
  • The preparation of the surfactant POEA known as MON 0818 is used in some glyphosate formulations. 7 POEA is moderately toxic to very highly toxic to freshwater fish. The 96-hour LC50 values ranged from 0.65 mg/L to 13 mg/L. Products containing MON 0818 state on the label "This pesticide is toxic to fish". 6
  • The LC50 of glyphosate for rainbow trout (Onchorynchus mykiss) was 140 mg/L, for fathead minnows (Pimephales promelas) was 97 mg/L, for channel catfish (Icalurus punctatus) was 130 mg/L and for bluegill sunfish (Lepomis macrochirus) was 150 mg/L. When they were exposed to Roundup®, the LC50s for these same fish were 8.3, 2.4, 13.0, and 6.4 mg/L, respectively. 80
  • Technical grade glyphosate is slightly toxic to practically non-toxic to freshwater invertebrates, with a 48-hour LC50 ranging from 55 ppm to 780 ppm. 6 The 48-hour LC50 for Daphnids was 3.0 mg/L and the LC50 for midge larvae was 16 mg/L when exposed to the formulated product Roundup®. 80
  • Researchers calculated LC50 values for four species of amphibians (the northern leopard frog (Rana pipiens), the wood frog (R. sylvatica), the green frog (R. clamitans), and the American toad (Bufo americanus)) exposed to the original Roundup® formulation of glyphosate. The 24-hour LC50 values for the different species ranged from 6.6 to 18.1 mg/L. 81
  • Green frogs (R. clamitans) were exposed to technical glyphosate in the form of the isopropylamine salt, the surfactant POEA, and six formulated products containing glyphosate. The surfactant was most toxic to R. clamitans with a 24 and 96- hour LC50 of 1.1 mg/L (95% CI 1.1-1.2) and 1.1 mg/L (95% CI 1.0-1.1), respectively. Technical glyphosate was least toxic, with 24 and 96-hour LC50 of >38.9 g/L. The toxicity of the formulated products fell between these values. 81
  • A chronic toxicity study with technical grade glyphosate reported reduced reproductive capacity in Daphnia magna with a maximum acceptable toxicant concentration of 50 to 96 ppm. 82
  • Technical grade glyphosate is practically non-toxic to slightly toxic to estuarine and marine organisms. The 96-hour LC50 is 281 ppm for grass shrimp (Palaemonetas vulgaris) and 934 ppm for fiddler crab (Uca pagilator). 83 The 48-hour median lethal time (TL50) is greater than 10 mg/L for Atlantic oyster (Crassostrea virginica). 84

Terrestrial Invertebrates

  • Studies indicate that both technical and formulated glyphosate are practically non-toxic to honeybees, with acute oral and acute contact LD50 values greater than 100 &mug/bee. 85
  • An ecological risk assessment of Roundup® concluded that the greatest risks to arthropods were from altered habitat structure and food availability. 7
  • The earthworm LC50 in soil is greater than 5000 ppm for Monsanto's formulated product Roundup®. 4

Regulatory Guidelines:

Reference Dose (RfD): The RfD is an estimate of the quantity of chemical that a person could be exposed to every day for the rest of their life with no appreciable risk of adverse health effects. The reference dose is typically measured in milligrams (mg) of chemical per kilogram (kg) of body weight per day.

U.S. Environmental Protection Agency, Health Effects Notebook Glossary, 2019. https://www.epa.gov/haps/health-effects-notebook-glossary

  • The U.S. EPA classified glyphosate as "not likely to be carcinogenic to humans." 30,39
  • The reference dose (RfD) for glyphosate is 1.75 mg/kg/day. 33 See the text box on Reference Dose (RfD).
  • The Acceptable Daily Intake (ADI) of a combination of glyphosate and certain metabolites (AMPA, N-acetyl glyphosate, and N-acetyl AMPA) for humans is 1.0 mg/kg. 31,32

Maximum Contaminant Level (MCL): The MCL is the highest level of contaminant that is legally allowed in drinking water. The MCL is enforceable. The MCL is typically measured in milligrams (mg) of contaminant per liter (L) of water.


Why You Should Avoid Chemical Weed Killers and What to Use Instead

Weeds are part of life if you are a gardener or have a lawn.

Healthy soil will always draw hungry weeds.

However- how you treat and manage weeds is important, as many quick acting chemical herbicides contain some very potent and harmful chemicals chemicals that are especially harmful to young children and pets who enjoy playing and rolling in the grass.

WHAT ARE HERBICiDES?

Any substance used to control, repel or destroy plant (weed) or animal life is a pesticide. Herbicides are a type of pesticide that focus on weeds.

THE WORSE OFFENDERS:

Roundup: The most popular weed killer in the U.S. The WHO calls its main ingredient, glyphosate, a “probably carcinogen”. University of Washington looked at available data and concluded that glyphosate could increase the risk of developing non-Hodgkin’s lymphoma by 41 percent. Researchers in Europe have claimed that the weed killer has serious toxic effects due to inert ingredients that amplify the toxicity of Roundup’s active ingredient, glyphosate.

Roundup is banned in nearly every European country. The US EPA and Monsanto, the maker of Roundup, claim it is safe when used as directed. However, even recent US government testing has found that some formulations using glyphosate can be genotoxic, meaning it can cause damage to human DNA (but are still studying to see if it is the glyphosate, the other ingredients or the interaction of these that have the harmful effect… and in the mean time while they figure that out allowing people to continue being exposed to it)

Additionally, glyphosate isn’t good for beneficial insects, birds and other animals, or for the rich soil biology that is the underpinning of any healthy garden.

2. 2,4-dichlorophenoxyacetic acid: If your chemical weedkiller doesn’t contain glyphosate it most likely contains 2,4 D. This weed killer works by attacking both the roots and leaves of weeds. It's used widely in agriculture in soybean, corn, sugarcane, and wheat fields and is found in home use herbicides sold in Walmart, Home Depot and other large stores.

There are links to non-Hodgkin's lymphoma and sarcoma (a soft-tissue cancer). The International Agency for Research on Cancer declared 2,4-D a possible human carcinogen, based on evidence that it damages human cells and, in a number of studies, caused cancer in laboratory animals. Additionally it is a known endocrine disrupting chemical that could decrease fertility and raise the risk of birth defects

NATURAL HERBICIDE/ WEED CONTROL

The good news is that there is no reason to use chemical weedkillers at home. Here are some alternatives that work on managing and even eliminating weeds and are safe for everyone

Hand-weeding: Regularly pulling up any weeds that appear is the easiest and safest way to control weeds in a home garden. The key to success with hand weeding is to do it regularly to avoid it getting out of hand and overwhelming, The best time to kill weeds is when you can barely see them so daily monitoring pays off. In a large lawn you might just want to live with small weeds like dandelions

Boiling water: Spot pouring boiling water right onto the root of a weed will also kill it. This method is ideal for weeds growing on flooring like sidewalks and driveways.

Vinegar, dish soap and salt: MIX: 1 gallon vinegar, 1 cup table salt and 1 TBSP dish soap. This is ideal for weeds growing through cracks on flooring or in areas where you DO NOT WANT any plants to regrow: the salt mixture will make it impossible to grow any healthy plants in the sprayed area afterwards - so be careful where you use this. This mixture is most effective when exposed to the sun. TIP: use a spray bottle where you can switch between spray and stream. If it’s a small area, shoot a stream if it’s an all-over weed situation, spray.

Lemon Juice: Fill a spray bottle with lemon juice and spray weeds (careful not to get any on your skin as lemon juice can burn and stain your skin if exposed to sun). This will require a couple of days of repeating. To make it stronger add vinegar

MULCH: To mulch is to add, like a blanket, a specific material over the surface of the soil. Mulch is one of the most effective ways of preventing weeds. Not all mulch is safe- avoid treated wood mulch and be careful with some store bought mulches which could have gone bad and ( smell vinegary and pungent). The right organic mulches can not only help control weeds but improve the soil’s structure, drainage, and nutrient-holding capacity as they decompose. Some examples are newspaper, fallen leaves and grass clippings. Pea Straw works well with new growth vegetable gardens- you will put about 2 cm of mulch around the new growth and then wet to keep in place. Straw, pine needles, seaweed can work for larger plants.

For home gardens: plants are most vulnerable to weeds when they are just starting to grow and are weakest. One option is to germinating seeds in containers and transplanting them into the ground once they have reached two inches or more- this will at least give the plant a head start. Full grown crops are stronger and more resistant to weeds


SULFATE TRANSPORT AND CARBON RINGS

Extensive prior research has led me to a hypothesis that sulfate transport in the blood poses a special challenge to the body, and that this may be the main reason why there is a plethora of biologically interesting molecules that are typically sulfated when they are transported in the blood, as well as a huge number of sulfotransferases that can attach these sulfates 15 and transfer them from one molecule to another. I suspect that one of the important but heretofore overlooked consequences is that they transport sulfate from a source site in the body such as the gut to a delivery site such as the liver, the pancreas, or the brain, and that this is a crucial part of their function in biology.

Two major classes of these biologically active sulfate-transporting molecules are the sterols (cholesterol, vitamin D3, DHEA, estrone) and the monoamine neurotransmitters (dopamine, serotonin, norepinephrine). All of these molecules have the interesting property that their biological effects are inactivated when they are sulfated. This is of course beneficial so that they are inert during transport, an attractive feature. But I believe that, more important than this, is the fact that the sulfate that is attached to these molecules is also inactive while being transported. And it might even be the case that one of the most important functions these molecules perform is to transport sulfate! All of these molecules share the property that the sulfate anion is attached to a carbon ring, and the ring distributes the negative charge on the sulfate, changing its biophysical properties in important ways.

What are these biophysical properties? Sulfate is a member of a class of anions called anionic kosmotropes. Other biologically important members of this class are phosphates and carbonates, both of which are also pervasive in biological systems. These three anions are essential for maintaining the water in the immediate vicinity of the cells’ plasma membranes in the tissues and of particles suspended in the blood in a structured almost crystal-like “liquid ice” configuration, creating a protective “exclusion zone” (the glycocalyx). 45 Gelatin desserts are a familiar version of this structured water—it’s mainly carbonate that structures the water in this case. Water is by far the most common molecule in our bodies, yet this is hard to imagine given how firm our bodies are. With 99 percent of our molecules being water, it’s surprising that we don’t just collapse into a puddle! Pollack believes that the main reason our tissues are not liquid is that nearly all the water is maintained in a gelled state by these kosmotropes. 45

However, the one big exception to this model is the blood. The blood that courses through our veins is definitely a liquid, and if it were to become gelled it would lead to a no-flow situation and a major catastrophe. This, to me, is the key reason why all these biologically active molecules travel through the blood stream in a sulfated form.


Figure 2: The molecular structure of glyphosate.

Now let’s consider what happens when glyphosate enters the picture. Glyphosate is almost certainly an anionic kosmotrope as well. As shown in Figure 2, it contains a carbonyl group and a phosphonyl group, and it doesn’t have any carbon rings. When a person takes an overdose of glyphosate in an attempt to commit suicide, a blood pathology called “disseminated intravascular coagulation” (DIC) ensues 59 and this can easily be fatal. So glyphosate causes an increase in blood viscosity and competes with free sulfate, which also has this effect, for a limited load capacity. This problem would be especially acute in the hepatic portal vein carrying nutrients from the gut to the liver. The liver desperately depends on sulfate to make cholesterol sulfate, which is essential in the synthesis of bile acids, and bile acids in turn are essential for digesting fats. Cholesterol sulfate also plays an important role in the outer shell of LDL and HDL particles, to protect them from reactive agents in the blood (e.g., oxidizing and glycating agents). The “small dense LDL particles” that are most damaging in heart disease arise because of oxidation and glycation damage that disrupts the lock-and-key mechanism during reuptake in the liver after they have delivered their goods, and therefore prevents them from being recycled. So, insufficient sulfate leads to LDL and HDL particles that are more susceptible to such damage, a key factor in heart disease.

In addition to “jamming the waterways” in blood vessels, glyphosate also interferes with the supply of sulfate carrier molecules that depend on the shikimate pathway. Dopamine, serotonin and norepinephrine are all derived from the aromatic amino acids whose synthesis is blocked by glyphosate. Worse than this, glyphosate also interferes with a class of enzymes called cytochrome P450 enzymes (CYP enzymes for short), 31 which play many different roles in the body, especially in the liver and the reproductive system.42 Certain members of this class are essential for bile acid synthesis. These enzymes are also involved in cholesterol homeostasis and vitamin D activation in the liver, whose disruption will further interfere with sulfate transport, among other problems.

In our recent paper on glyphosate 47 we argued that the toxic phenolic compounds like p-Cresol that are produced by pathogenic bacteria like C. diff actually perform an important service by transporting sulfate from the gut to the liver and pancreas. According to this hypothesis, toxic phenolic compounds are produced because the sterols and monoamine neurotransmitters are impaired in their ability to perform this much-needed service. However, once the phenol drops off its sulfate, it becomes a highly reactive molecule, capable of doing damage to the lipids and DNA in the liver and pancreas, as well as in the gut, as a single phenol is likely cycled around again and again to deliver multiple sulfates to the liver and pancreas, and, whenever it’s not sulfated, it’s toxic.


Glyphosate: Weed Killer or Carcinogen?

The molecule at the center of the Roundup debate is a pretty small one. Despite its size, glyphosate has caused big problems for consumers who used it, and for its manufacturers, Monsanto and Bayer.

Glyphosate may be a small molecule, but it's causing big problems for Monsanto and Bayer.

A Monsanto chemist discovered the plant-killing properties of glyphosate nearly half a century ago. As that scientist would learn, this small molecule inhibits an enzyme necessary for growing plants to stay alive.

For people concerned with weed control, glyphosate presented a number of attractive properties. Plants could absorb it easily through their leaves, though they would not absorb glyphosate through their roots.

This meant that farmers or gardeners could apply glyphosate to plants they wanted to kill without worrying that it would seep into the ground and kill important, neighboring plants that were wanted. Additionally, most plants were highly susceptible to glyphosate poisoning as long as they were actively growing.

Monsanto brought glyphosate to market as a broad-spectrum herbicide in 1974, but its popularity didn't truly skyrocket until the introduction of Roundup Ready crops. Roundup Ready crops were engineered with immunity to glyphosate. So farmers could effectively blanket their crops with glyphosate and kill only unwanted weeds.

Glyphosate in Food

The practice of spraying crops with glyphosate created controversy when laboratory tests revealed glyphosate contamination in a number of food products. If people consume glyphosate in their food on a daily basis, they technically experience long-term, low-level exposure to the herbicide.

According to Dr. Jorge Chavarro, associate professor at the Harvard T.H. Chan School of Public Health, the risks for long-term, low-level exposure are unknown. Government regulations address acute exposure to toxic levels of glyphosate, not long-term exposure to food-borne glyphosate.

On the topic of glyphosate safety, experts caution that legal does not mean safe. Linda Birnbaum, former Director of the National Institute of Environmental Health Sciences (NIEHS), highlighted this issue in an editorial for scientific journal PLOS Biology:

"[Low-level] exposures pose unique risks to children at critical windows of development--risks that existing regulations fail to consider."

Individuals who choose to exercise caution regarding glyphosate in their food can try to avoid the contaminated foods listed below.

List of Glyphosate-Contaminated Foods

Sources: The Detox Project, The Environmental Working Group, Moms Across America, Friends of the Earth Europe
Several independent organizations have recently found glyphosate contamination in a variety of products available in most grocery stores.
Breakfast Cereals
  • Original Cheerios
  • Honey Nut Cheerios
  • Wheaties
  • Trix
  • Kellog's Corn Flakes
  • Kellog's Raisin Bran
  • Kashi Organic Promise
  • Kellog's Special K
  • Kellog's Frosted Flakes
  • Nature's Path Organic Honey Almond Granola
  • Back to Nature Classic Granola
  • Quaker Simply Granola Oats, Honey, Raisins & Almonds
  • Back to Nature Banana Walnut Granola Clusters
  • Nature Valley Granola Protein Oats 'n Honey
  • KIND Vanilla, Blueberry Clusters with Flax Seeds
  • Giant Instant Oatmeal, Original Flavor
  • Simple Truth Organic Instant Oatmeal, Original
  • Quaker Dinosaur Eggs, Brown Sugar, Instant Oatmeal
  • Great Value Original Instant Oatmeal
  • Umpqua Oats, Maple Pecan
  • Market Pantry Instant Oatmeal, Strawberries & Cream
  • Kashi Heart to Heart Organic Honey Toasted Cereal
  • Cheerios Toasted Whole Grain Oat Cereal
  • Lucky Charms
  • Barbara's Multigrain Spoonfuls, Original Cereal
  • Kellogg's Cracklin' Oat Bran Oat Cereal
  • 365 Organic Old-Fashioned Rolled Oats
  • Quaker Steel Cut Oats
  • Quaker Old Fashioned Oats
  • Bob's Red Mill Steel Cut Oats
  • Nature's Path Organic Old Fashioned Organic Oats
  • Whole Foods Bulk Bin Conventional Rolled Oats
  • Bob's Red Mill Organic Old Fashioned Rolled Oats
  • Annie's Gluten Free Bunny Cookies Cocoa & Vanilla
  • Cheez-It Original
  • Cheez-It Whole Grain
  • Kashi Soft Bake Cookies, Oatmeal, Dark Chocolate
  • Ritz Crackers
  • Triscuit Crackers
  • Oreo Original
  • Oreo Double Stuf Chocolate Sandwich Cookies
  • Oreo Double Stuf Golden Sandwich Cookies
  • Stacy's Simply Naked Pita Chips (Frito-Lay)
  • Lay's: Kettle Cooked Original
  • Doritos: Cool Ranch
  • Fritos (Original) (100% Whole Grain)
  • Goldfish Crackers Original (Pepperidge Farm)
  • Goldfish Crackers Colors
  • Goldfish Crackers Whole Grain
  • Little Debbie Oatmeal Cream Pies
  • Oatmeal Cookies Gluten Free
  • 365 Organic Golden Round Crackers
  • Back to Nature Crispy Cheddar Crackers
  • Cascadian Farm Organic Harvest Berry, Granola Bar
  • KIND Oats & Honey with Toasted Coconut
  • Nature Valley Crunchy Granola Bars, Oats 'n Honey
  • Quaker Chewy Chocolate Chip Granola Bar
  • Kellogg's Nutri-Grain Soft Baked Breakfast Bars, Strawberry
  • Tropicana Orange Juice
  • Minute Maid Orange Juice
  • Stater Brothers Orange Juice
  • Signature Farms Orange Juice
  • Kirkland Orange Juice
  • Soybeans
  • Soybean Fodder
  • Cotton Seed
  • Maize Grain
  • Sorghum
  • Cotton Seed
  • Maize Grain
  • Barley Straw and Fodder Grass Hay
  • Lentils
  • Sweetcorn
  • Sugar Beet
  • Wheat

Does Roundup (or Glyphosate) Cause Cancer?

Despite thousands of lawsuits claiming glyphosate-containing Roundup caused a variety of cancers, the evidence on the topic is mixed. Regulatory agencies worldwide have come to different conclusions regarding glyphosate's potential for causing cancer, and juries have been forced to weigh the evidence on both sides

Regulatory Body Glyphosate Determination
The United States Environmental Protection Agency (EPA) Glyphosate is not likely to cause cancer in humans.
The International Agency for Research on Cancer (IARC) Glyphosate is probably carcinogenic to humans.
European Food Safety Authority Glyphosate-containing formulations are genotoxic (DNA-damaging) and pose a carcinogenic threat to humans, but glyphosate alone does not.
Source: Chemical Entities of Biological Interest

Glyphosate proponents are quick to point out the IARC classifies a number of things as possibly carcinogenic to humans, including sunlight, oral birth control and alcohol. Glyphosate critics observe that Monsanto had clear ties to the EPA when the agency made its determination.

Scientific Studies on Glyphosate and Cancer

Much like the regulators, scientists have not come to an agreement about the carcinogenicity of glyphosate. Studies investigating the relationship between any kind of glyphosate exposure and cancer typically find no link between the two.

Conversely, researchers who study heavy glyphosate exposure and cancer have found that heavy glyphosate exposure leads to between a 40% and 200% increased risk of developing non-Hodgkin's lymphoma.

Individuals Who May Be At Risk of Developing Roundup-Related Cancer(s)

  • Landscapers
  • Groundskeepers
  • Plant Nursery Employees
  • Farmers
  • Garden Center Employees
  • Anyone Experiencing Workplace Exposure to Glyphosate
  • Home Gardeners Who Regularly Use Roundup

Monsanto's legal team attempts to focus all proceedings on scientific studies that have found no link between Roundup/glyphosate and non-Hodgkin's lymphoma (NHL). Plaintiff's legal teams have thus far attempted to focus on studies showing an increased risk of NHL after heavy glyphosate exposure.

Plaintiffs' lawyers have also presented evidence of Monsanto's efforts (some successful) to plant pro-glyphosate studies, ghostwritten by Monsanto officials, in an effort to sway public and legal perception in favor of Roundup.

At this point, neither scientists nor regulators have a conclusive answer regarding glyphosate's carcinogenicity. According to consumer advocacy group U.S. Right to Know, Monsanto has never publicly acknowledged performing a long-term test of Roundup carcinogenicity.

In a deposition, plaintiff's lawyers questioned Sam Murphey, a Monsanto executive, on the topic of Roundup's long-term cancer-causing potential. Speaking for the company, Murphey claimed he did not know the cost of such a test.

Only time will tell if Bayer will use some portion of Roundup's $1.9 billion in gross profits (in 2015) to provide its own evidence of glyphosate's safety, or lack thereof.

The Difference Between Glyphosate and Roundup

Despite glyphosate's attractive, herbicidal qualities--such as its status as a non-selective chemical herbicide with almost non-existent root absorption--it was not an optimal weed killer on its own. According to Monsanto, some plants have natural resistance or tolerance to glyphosate.

Consumers can buy Roundup in multiple different glyphosate concentrations.

For some of them, this resistance came in the form of enhanced external barriers. For example, if glyphosate couldn't get through the leaf to the inside of the plant, it could not kill it. Monsanto solved this issue by adding a number of chemicals to the Roundup cocktail, all intended to maximize its weed-killing efficiency.

Many of the non-glyphosate chemicals increase Roundup's ability to go through external barriers like the skin of plant foliage. This type of chemical is called a surfactant. According to scientists, some surfactants increase the lethality of glyphosate-containing substances by up to 100x.

Some studies have even speculated the additives in Roundup pose more danger to humans than glyphosate itself. Some of the successful lawsuits have argued the specific Roundup formulation may have acted similarly on human skin as it did on plants, increasing the rate and amount of glyphosate entering the bloodstream. If true, this assertion could directly implicate Roundup as the culprit in making it possible for glyphosate to cause NHL.

Similar to the controversy surrounding glyphosate lawsuits, scientists and regulatory bodies disagree on the safety of these additives. Regardless of the ultimate determination on Roundup additive safety, one thing remains clear: glyphosate is a component of Roundup, but Roundup is much more than glyphosate alone.


Contents

Glyphosate was first synthesized in 1950 by Swiss chemist Henry Martin, who worked for the Swiss company Cilag. The work was never published. [18] : 1 Stauffer Chemical patented the agent as a chemical chelator in 1964 as it binds and removes minerals such as calcium, magnesium, manganese, copper, and zinc. [19]

Somewhat later, glyphosate was independently discovered in the United States at Monsanto in 1970. Monsanto chemists had synthesized about 100 derivatives of aminomethylphosphonic acid as potential water-softening agents. Two were found to have weak herbicidal activity, and John E. Franz, a chemist at Monsanto, was asked to try to make analogs with stronger herbicidal activity. Glyphosate was the third analog he made. [18] : 1–2 [20] [21] [22] Franz received the National Medal of Technology of the United States in 1987 and the Perkin Medal for Applied Chemistry in 1990 for his discoveries. [23] [24] [25]

Monsanto developed and patented the use of glyphosate to kill weeds in the early 1970s and first brought it to market in 1974, under the Roundup brandname. [26] [27] While its initial patent [28] expired in 1991, Monsanto retained exclusive rights in the United States until its patent [29] on the isopropylamine salt expired in September 2000. [30]

In 2008, United States Department of Agriculture (USDA) Agricultural Research Service (ARS) scientist Stephen O. Duke and Stephen B. Powles – an Australian weed expert – described glyphosate as a "virtually ideal" herbicide. [26] In 2010 Powles stated: "glyphosate is a one in a 100-year discovery that is as important for reliable global food production as penicillin is for battling disease." [31]

As of April 2017, the Canadian government stated that glyphosate was "the most widely used herbicide in Canada", [32] at which date the product labels were revised to ensure a limit of 20% POEA by weight. [32] [ failed verification ] Health Canada's Pest Management Regulatory Agency found no risk to humans or the environment at that 20% limit, and that all products registered in Canada at that time were at or below that limit.

Glyphosate is an aminophosphonic analogue of the natural amino acid glycine and, like all amino acids, exists in different ionic states depending on pH. Both the phosphonic acid and carboxylic acid moieties can be ionised and the amine group can be protonated and the substance exists as a series of zwitterions. Glyphosate is soluble in water to 12 g/L at room temperature. The original synthetic approach to glyphosate involved the reaction of phosphorus trichloride with formaldehyde followed by hydrolysis to yield a phosphonate. Glycine is then reacted with this phosphonate to yield glyphosate, and its name is taken as a contraction of the compounds used in this synthesis step, namely glycine and a phosphonate. [33]

The main deactivation path for glyphosate is hydrolysis to aminomethylphosphonic acid. [34]

Synthesis

Two main approaches are used to synthesize glyphosate industrially, both of which proceed via the Kabachnik–Fields reaction. The first is to react iminodiacetic acid and formaldehyde with phosphorous acid (sometimes formed in situ from phosphorus trichloride using the water generated by the Mannich reaction of the first two reagents). Decarboxylation of the hydrophosphonylation product gives the desired glyphosate product. Iminodiacetic acid is usually prepared on-site by various methods depending on reagent availability. [18]

The second uses glycine in place of iminodiacetic acid. This avoids the need for decarboxylation but requires more careful control of stoichiometry, as the primary amine can react with any excess formaldehyde to form bishydroxymethylglycine, which must be hydrolysed during the work-up to give the desired product. [18]

This synthetic approach is responsible for a substantial portion of the production of glyphosate in China, with considerable work having gone into recycling the triethylamine and methanol solvents. [18] Progress has also been made in attempting to eliminate the need for triethylamine altogether. [35]

Chelation

Impurities

Technical grade glyphosate is a white powder which, according to FAO specification, should contain not less than 95% glyphosate. Formaldehyde, classified as a known human carcinogen, [37] [38] and N-nitrosoglyphosate, have been identified as toxicologically relevant impurities. [39] The FAO specification limits the formaldehyde concentration to a maximum of 1.3 g/kg glyphosate. N-Nitrosoglyphosate, "belonging to a group of impurities of particular concern as they can be activated to genotoxic carcinogens", [40] should not exceed 1 ppm. [39]

Glyphosate is marketed in the United States and worldwide by many agrochemical companies, in different solution strengths and with various adjuvants, under dozens of tradenames. [41] [42] [43] [44] As of 2010, more than 750 glyphosate products were on the market. [45] In 2012, about half of the total global consumption of glyphosate by volume was for agricultural crops, [46] with forestry comprising another important market. [47] Asia and the Pacific was the largest and fastest growing regional market. [46] As of 2014, Chinese manufacturers collectively are the world's largest producers of glyphosate and its precursors [48] and account for about 30% of global exports. [46] Key manufacturers include Anhui Huaxing Chemical Industry Company, BASF, Bayer CropScience (which also acquired the maker of glyphosate, Monsanto), Dow AgroSciences, DuPont, Jiangsu Good Harvest-Weien Agrochemical Company, Nantong Jiangshan Agrochemical & Chemicals Co., Nufarm, SinoHarvest, Syngenta, and Zhejiang Xinan Chemical Industrial Group Company. [46]

Glyphosate is an acid molecule, so it is formulated as a salt for packaging and handling. Various salt formulations include isopropylamine, diammonium, monoammonium, or potassium as the counterion. The active ingredient of the Monsanto herbicides is the isopropylamine salt of glyphosate. Another important ingredient in some formulations is the surfactant polyethoxylated tallow amine (POEA). Some brands include more than one salt. Some companies report their product as acid equivalent (ae) of glyphosate acid, or some report it as active ingredient (ai) of glyphosate plus the salt, and others report both. To compare performance of different formulations, knowledge of how the products were formulated is needed. Given that different salts have different weights, the acid equivalent is a more accurate method of expressing and comparing concentrations.

Adjuvant loading refers to the amount of adjuvant [49] [50] already added to the glyphosate product. Fully loaded products contain all the necessary adjuvants, including surfactant some contain no adjuvant system, while other products contain only a limited amount of adjuvant (minimal or partial loading) and additional surfactants must be added to the spray tank before application. [51]

Products are supplied most commonly in formulations of 120, 240, 360, 480, and 680 g/L of active ingredient. The most common formulation in agriculture is 360 g/L, either alone or with added cationic surfactants. [42]

For 360 g/L formulations, European regulations allow applications of up to 12 L/ha for control of perennial weeds such as couch grass. More commonly, rates of 3 L/ha are practiced for control of annual weeds between crops. [52]

Glyphosate interferes with the shikimate pathway, which produces the aromatic amino acids phenylalanine, tyrosine and tryptophan in plants and microorganisms [53] – but does not exist in the genome of animals, including humans. [54] [55] It blocks this pathway by inhibiting the enzyme 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS), which catalyzes the reaction of shikimate-3-phosphate (S3P) and phosphoenolpyruvate to form 5-enolpyruvyl-shikimate-3-phosphate (EPSP). [56] Glyphosate is absorbed through foliage and minimally through roots, meaning that it is only effective on actively growing plants and cannot prevent seeds from germinating. [57] [58] After application, glyphosate is readily transported around the plant to growing roots and leaves and this systemic activity is important for its effectiveness. [26] [18] Inhibiting the enzyme causes shikimate to accumulate in plant tissues and diverts energy and resources away from other processes, eventually killing the plant. While growth stops within hours of application, it takes several days for the leaves to begin turning yellow. [59]

Under normal circumstances, EPSP is dephosphorylated to chorismate, an essential precursor for the amino acids mentioned above. [60] These amino acids are used in protein synthesis and to produce secondary metabolites such as folates, ubiquinones, and naphthoquinone.

X-ray crystallographic studies of glyphosate and EPSPS show that glyphosate functions by occupying the binding site of the phosphoenolpyruvate, mimicking an intermediate state of the ternary enzyme–substrate complex. [61] [62] Glyphosate inhibits the EPSPS enzymes of different species of plants and microbes at different rates. [63] [64]

Glyphosate is effective in killing a wide variety of plants, including grasses and broadleaf and woody plants. By volume, it is one of the most widely used herbicides. [57] In 2007, glyphosate was the most used herbicide in the United States agricultural sector, with 180 to 185 million pounds (82,000 to 84,000 tonnes) applied, the second-most used in home and garden with 5 to 8 million pounds (2,300 to 3,600 tonnes) and government applied [ clarification needed ] 13 to 15 million pounds (5,900 to 6,800 tonnes) in industry and commerce. [6] It is commonly used for agriculture, horticulture, viticulture, and silviculture purposes, as well as garden maintenance (including home use). It has a relatively small effect on some clover species and morning glory. [65]

Glyphosate and related herbicides are often used in invasive species eradication and habitat restoration, especially to enhance native plant establishment in prairie ecosystems. The controlled application is usually combined with a selective herbicide and traditional methods of weed eradication such as mulching to achieve an optimal effect. [66]

In many cities, glyphosate is sprayed along the sidewalks and streets, as well as crevices in between pavement where weeds often grow. However, up to 24% of glyphosate applied to hard surfaces can be run off by water. [67] Glyphosate contamination of surface water is attributed to urban and agricultural use. [68] Glyphosate is used to clear railroad tracks and get rid of unwanted aquatic vegetation. [58] Since 1994, glyphosate has been used in aerial spraying in Colombia in coca eradication programs Colombia announced in May 2015 that by October, it would cease using glyphosate in these programs due to concerns about human toxicity of the chemical. [69]

Glyphosate is also used for crop desiccation (siccation) to increase harvest yield and uniformity. [58] Glyphosate itself is not a chemical desiccant rather glyphosate application just before harvest kills the crop plants so that the food crop dries from environmental conditions ("dry-down") more quickly and evenly. [70] [72] Because glyphosate is systemic, excess residue levels can persist in plants due to incorrect application and this may render the crop unfit for sale. [73] When applied appropriately, it can promote useful effects. In sugarcane, for example, glyphosate application increases sucrose concentration before harvest. [74] In grain crops (wheat, barley, oats), uniformly dried crops do not have to be windrowed (swathed and dried) prior to harvest, but can easily be straight-cut and harvested. This saves the farmer time and money, which is important in northern regions where the growing season is short, and it enhances grain storage when the grain has a lower and more uniform moisture content. [58] [75] [76]

Genetically modified crops

Some micro-organisms have a version of 5-enolpyruvoyl-shikimate-3-phosphate synthetase (EPSPS) resistant to glyphosate inhibition. A version of the enzyme that was both resistant to glyphosate and that was still efficient enough to drive adequate plant growth was identified by Monsanto scientists after much trial and error in an Agrobacterium strain called CP4, which was found surviving in a waste-fed column at a glyphosate production facility. [64] [77] [78] : 56 This CP4 EPSPS gene was cloned and transfected into soybeans. In 1996, genetically modified soybeans were made commercially available. [79] Current glyphosate-resistant crops include soy, maize (corn), canola, alfalfa, sugar beets, and cotton, with wheat still under development.

In 2015, 89% of corn, 94% of soybeans, and 89% of cotton produced in the United States were from strains that were genetically modified to be herbicide-tolerant - including but not limited to glyphosate. [80]

Glyphosate strongly sorbs onto soil minerals, and, exception made of colloid-facilitated transport, its soluble residues are expected to be poorly mobile in the free porewater of soils. The spatial extent of ground and surface water pollution is therefore considered to be relatively limited. [81] Glyphosate is readily degraded by soil microbes to aminomethylphosphonic acid (AMPA, which like glyphosate strongly adsorbs to soil solids and is thus unlikely to leach to groundwater). Though both glyphosate and AMPA are commonly detected in water bodies, a portion of the AMPA detected may actually be the result of degradation of detergents rather than from glyphosate. [82] Glyphosate does have the potential to contaminate surface waters due to its aquatic use patterns and through erosion, as it adsorbs to colloidal soil particles suspended in runoff. Detection in surface waters (particularly downstream from agricultural uses) has been reported as both broad and frequent by USGS researchers, [83] although other similar research found equal frequencies of detection in urban-dominated small streams. [84] Rain events can trigger dissolved glyphosate loss in transport-prone soils. [85] The mechanism of glyphosate sorption to soil is similar to that of phosphate fertilizers, the presence of which can reduce glyphosate sorption. [86] Phosphate fertilizers are subject to release from sediments into water bodies under anaerobic conditions, and similar release can also occur with glyphosate, though significant impact of glyphosate release from sediments has not been established. [87] Limited leaching can occur after high rainfall after application. If glyphosate reaches surface water, it is not broken down readily by water or sunlight. [88] [81]

The half-life of glyphosate in soil ranges between 2 and 197 days a typical field half-life of 47 days has been suggested. Soil and climate conditions affect glyphosate's persistence in soil. The median half-life of glyphosate in water varies from a few to 91 days. [57] At a site in Texas, half-life was as little as three days. A site in Iowa had a half-life of 141.9 days. [89] The glyphosate metabolite AMPA has been found in Swedish forest soils up to two years after a glyphosate application. In this case, the persistence of AMPA was attributed to the soil being frozen for most of the year. [90] Glyphosate adsorption to soil, and later release from soil, varies depending on the kind of soil. [91] [92] Glyphosate is generally less persistent in water than in soil, with 12- to 60-day persistence observed in Canadian ponds, although persistence of over a year has been recorded in the sediments of American ponds. [88] The half-life of glyphosate in water is between 12 days and 10 weeks. [93]

Residues in food products

According to the National Pesticide Information Center fact sheet, glyphosate is not included in compounds tested for by the Food and Drug Administration's Pesticide Residue Monitoring Program, nor in the United States Department of Agriculture's Pesticide Data Program. [57] The U.S. has determined the acceptable daily intake of glyphosate at 1.75 milligrams per kilogram of bodyweight per day (mg/kg/bw/day) while the European Union has set it at 0.5. [94]

Pesticide residue controls carried out by EU Member States in 2016 analysed 6,761 samples of food products for glyphosate residues. 3.6% of the samples contained quantifiable glyphosate residue levels with 19 samples (0.28%) exceeding the European maximum residue levels (MRLs), which included six samples of honey and other apicultural products (MRL = 0.05 mg/kg) and eleven samples of buckwheat and other pseudo‐cereals (MRL = 0.1 mg/kg). Glyphosate residues below the European MRLs were most frequently found in dry lentils, linseeds, soya beans, dry peas, tea, buckwheat, barley, wheat and rye. [95] In Canada, a survey of 7,955 samples of food found that 42.3 % contained detectable quantities of glyphosate and only 0.6 % contained a level higher than the Canadian MRL of 0.1 mg/kg for most foods and 4 mg/kg for beans and chickpeas. Of the products that exceeded MRLs, one third were organic products. Health Canada concluded based on the analysis "that there was no long-term health risk to Canadian consumers from exposure to the levels of glyphosate". [96]

Glyphosate is the active ingredient in herbicide formulations containing it. However, in addition to glyphosate salts, commercial formulations of glyphosate contain additives (known as adjuvants) such as surfactants, which vary in nature and concentration. Surfactants such as polyethoxylated tallow amine (POEA) are added to glyphosate to enable it to wet the leaves and penetrate the cuticle of the plants.

Glyphosate alone

Humans

The acute oral toxicity for mammals is low, [97] but death has been reported after deliberate overdose of concentrated formulations. [98] The surfactants in glyphosate formulations can increase the relative acute toxicity of the formulation. [99] [100] In a 2017 risk assessment, the European Chemicals Agency (ECHA) wrote: "There is very limited information on skin irritation in humans. Where skin irritation has been reported, it is unclear whether it is related to glyphosate or co-formulants in glyphosate-containing herbicide formulations." The ECHA concluded that available human data was insufficient to support classification for skin corrosion or irritation. [101] Inhalation is a minor route of exposure, but spray mist may cause oral or nasal discomfort, an unpleasant taste in the mouth, or tingling and irritation in the throat. Eye exposure may lead to mild conjunctivitis. Superficial corneal injury is possible if irrigation is delayed or inadequate. [99]

Cancer

As of 2020 [update] , the evidence for long-term exposure to glyphosate increasing the risk of human cancer remains inconclusive. [102] There is weak evidence human cancer risk might increase as a result of occupational exposure to large amounts of glyphosate, such as in agricultural work, but no good evidence of such a risk from home use, such as in domestic gardening. [103] [104] A meta-analysis published in 2019 looked at whether there was an association between an increased risk of non-Hodgkin lymphoma in humans and high cumulative exposures to glyphosate-based herbicides. The research found a "compelling link" between exposures to glyphosate-based herbicides and increased risk for non-Hodgkin lymphoma. [105] A 2021 meta-analysis of glyphosate exposure and non-Hodgkin lymphoma cautioned that such results can be biased by "assumptions made about both exposure level and latency period." [106]

The consensus among national pesticide regulatory agencies and scientific organizations is that labeled uses of glyphosate have demonstrated no evidence of human carcinogenicity. [107] The Joint FAO/WHO Meeting on Pesticide Residues (JMPR), [108] the European Commission, the Canadian Pest Management Regulatory Agency, the Australian Pesticides and Veterinary Medicines Authority [109] and the German Federal Institute for Risk Assessment [110] have concluded that there is no evidence that glyphosate poses a carcinogenic or genotoxic risk to humans. The EPA has classified glyphosate as "not likely to be carcinogenic to humans." [111] [112] One international scientific organization, the International Agency for Research on Cancer, classified glyphosate in Group 2A, "probably carcinogenic to humans" in 2015. [13] [11]

Other mammals

Amongst mammals, glyphosate is considered to have "low to very low toxicity". The LD50 of glyphosate is 5,000 mg/kg for rats, 10,000 mg/kg in mice and 3,530 mg/kg in goats. The acute dermal LD50 in rabbits is greater than 2,000 mg/kg. Indications of glyphosate toxicity in animals typically appear within 30 to 120 minutes following ingestion of a large enough dose, and include initial excitability and tachycardia, ataxia, depression, and bradycardia, although severe toxicity can develop into collapse and convulsions. [57]

A review of unpublished short-term rabbit-feeding studies reported severe toxicity effects at 150 mg/kg/day and "no observed adverse effect level" doses ranging from 50 to 200 mg/kg/day. [113] Glyphosate can have carcinogenic effects in nonhuman mammals. These include the induction of positive trends in the incidence of renal tubule carcinoma and haemangiosarcoma in male mice, and increased pancreatic islet-cell adenoma in male rats. [11] In reproductive toxicity studies performed in rats and rabbits, no adverse maternal or offspring effects were seen at doses below 175–293 mg/kg/day. [57]

Glyphosate-based herbicides may cause life-threatening arrhythmias in mammals. Evidence also shows that such herbicides cause direct electrophysiological changes in the cardiovascular systems of rats and rabbits. [114]

Aquatic fauna

In many freshwater invertebrates, glyphosate has a 48-hour LC50 ranging from 55 to 780 ppm. The 96-hour LC50 is 281 ppm for grass shrimp (Palaemonetas vulgaris) and 934 ppm for fiddler crabs (Uca pagilator). These values make glyphosate "slightly toxic to practically non-toxic". [57]

Antimicrobial activity

The antimicrobial activity of glyphosate has been described in the microbiology literature since its discovery in 1970 and the description of glyphosate's mechanism of action in 1972. Efficacy was described for numerous bacteria and fungi. [115] Glyphosate can control the growth of apicomplexan parasites, such as Toxoplasma gondii, Plasmodium falciparum (malaria), and Cryptosporidium parvum, and has been considered an antimicrobial agent in mammals. [116] Inhibition can occur with some Rhizobium species important for soybean nitrogen fixation, especially under moisture stress. [117]

Soil biota

When glyphosate comes into contact with the soil, it can be bound to soil particles, thereby slowing its degradation. [88] [118] Glyphosate and its degradation product, aminomethylphosphonic acid are considered to be much more benign toxicologically and environmentally than most of the herbicides replaced by glyphosate. [119] A 2016 meta-analysis concluded that at typical application rates glyphosate had no effect on soil microbial biomass or respiration. [120] A 2016 review noted that contrasting effects of glyphosate on earthworms have been found in different experiments with some species unaffected, but others losing weight or avoiding treated soil. Further research is required to determine the impact of glyphosate on earthworms in complex ecosystems. [121]

Endocrine disruption

In 2007, the EPA selected glyphosate for further screening through its Endocrine Disruptor Screening Program (EDSP). Selection for this program is based on a compound's prevalence of use and does not imply particular suspicion of endocrine activity. [122] On June 29, 2015, the EPA released the Weight of Evidence Conclusions of the EDSP Tier 1 screening for glyphosate, recommending that glyphosate not be considered for Tier 2 testing. The Weight of Evidence conclusion stated ". there was no convincing evidence of potential interaction with the estrogen, androgen or thyroid pathways." [123] A review of the evidence by the European Food Safety Authority published in September 2017 showed conclusions similar to those of the EPA report. [124]

Effect on plant health

Some studies have found causal relationships between glyphosate and increased or decreased disease resistance. [125] Exposure to glyphosate has been shown to change the species composition of endophytic bacteria in plant hosts, which is highly variable. [126]

Glyphosate-based formulations

Glyphosate-based formulations may contain a number of adjuvants, the identities of which may be proprietary. [127] Surfactants are used in herbicide formulations as wetting agents, to maximize coverage and aid penetration of the herbicide(s) through plant leaves. As agricultural spray adjuvants, surfactants may be pre-mixed into commercial formulations or they may be purchased separately and mixed on-site. [128]

Polyethoxylated tallow amine (POEA) is a surfactant used in the original Roundup formulation and was commonly used in 2015. [129] Different versions of Roundup have included different percentages of POEA. A 1997 US government report said that Roundup is 15% POEA while Roundup Pro is 14.5%. [130] Since POEA is more toxic to fish and amphibians than glyphosate alone, POEA is not allowed in aquatic formulations. [131] [130] [132] A 2000 review of the ecotoxicological data on Roundup shows at least 58 studies exist on the effects of Roundup on a range of organisms. [89] This review concluded that ". for terrestrial uses of Roundup minimal acute and chronic risk was predicted for potentially exposed non-target organisms". [133]

Human

Acute toxicity and chronic toxicity are dose-related. Skin exposure to ready-to-use concentrated glyphosate formulations can cause irritation, and photocontact dermatitis has been occasionally reported. These effects are probably due to the preservative benzisothiazolin-3-one. Severe skin burns are very rare. [99] Inhalation is a minor route of exposure, but spray mist may cause oral or nasal discomfort, an unpleasant taste in the mouth, or tingling and irritation in the throat. Eye exposure may lead to mild conjunctivitis. Superficial corneal injury is possible if irrigation is delayed or inadequate. [99] Death has been reported after deliberate overdose. [99] [98] Ingestion of Roundup ranging from 85 to 200 ml (of 41% solution) has resulted in death within hours of ingestion, although it has also been ingested in quantities as large as 500 ml with only mild or moderate symptoms. [134] Adult consumption of more than 85 ml of concentrated product can lead to corrosive esophageal burns and kidney or liver damage. More severe cases cause "respiratory distress, impaired consciousness, pulmonary edema, infiltration on chest X-ray, shock, arrhythmias, renal failure requiring haemodialysis, metabolic acidosis, and hyperkalaemia" and death is often preceded by bradycardia and ventricular arrhythmias. [99] While the surfactants in formulations generally do not increase the toxicity of glyphosate itself, it is likely that they contribute to its acute toxicity. [99]

A 2000 review concluded that "under present and expected conditions of new use, there is no potential for Roundup herbicide to pose a health risk to humans". [135] A 2012 meta-analysis of epidemiological studies (seven cohort studies and fourteen case-control studies) of exposure to glyphosate formulations found no correlation with any kind of cancer. [136] The 2013 systematic review by the German Institute for Risk Assessment of epidemiological studies of workers who use pesticides, and were exposed to glyphosate formulations found no significant risk, stating that "the available data are contradictory and far from being convincing". [9] : vol. 1, 64–66 However, a 2014 meta-analysis of the same studies found a correlation between occupational exposure to glyphosate formulations and increased risk of B cell lymphoma, the most common kind of non-Hodgkin lymphoma. Workers exposed to glyphosate were about twice as likely to get B cell lymphoma. [10]

A 2016 systematic review and meta-analysis found no causal relationship between glyphosate exposure and risk of any type of lymphohematopoietic cancer including non-Hodgkin lymphoma and multiple myeloma. [137] The same review noted that the positive associations found may be due to bias and confounding. [137] The Natural Resources Defense Council has criticized that review, noting that it was funded by Monsanto. [138]

A 2015 systematic review of 10 observational studies found that except for an excess of attention deficit hyperactivity disorder among children born to glyphosate appliers, there was no evidence that glyphosate exposure among pregnant mothers caused adverse developmental outcomes in their children. Noting the limited size and scope of the review articles available, the authors noted that "these negative findings cannot be taken as definitive evidence that GLY, at current levels of occupational and environmental exposures, brings no risk for human development and reproduction." [139]

Aquatic fauna

Glyphosate products for aquatic use generally do not use surfactants, and aquatic formulations do not use POEA due to aquatic organism toxicity. [131] Due to the presence of POEA, such glyphosate formulations only allowed for terrestrial use are more toxic for amphibians and fish than glyphosate alone. [131] [130] [132] The half-life of POEA (21–42 days) is longer than that for glyphosate (7–14 days) in aquatic environments. [140] Aquatic organism exposure risk to terrestrial formulations with POEA is limited to drift or temporary water pockets where concentrations would be much lower than label rates. [131]

Some researchers have suggested the toxicity effects of pesticides on amphibians may be different from those of other aquatic fauna because of their lifestyle amphibians may be more susceptible to the toxic effects of pesticides because they often prefer to breed in shallow, lentic, or ephemeral pools. These habitats do not necessarily constitute formal water-bodies and can contain higher concentrations of pesticide compared to larger water-bodies. [132] [141] Studies in a variety of amphibians have shown the toxicity of GBFs containing POEA to amphibian larvae. These effects include interference with gill morphology and mortality from either the loss of osmotic stability or asphyxiation. At sub-lethal concentrations, exposure to POEA or glyphosate/POEA formulations have been associated with delayed development, accelerated development, reduced size at metamorphosis, developmental malformations of the tail, mouth, eye and head, histological indications of intersex and symptoms of oxidative stress. [132] Glyphosate-based formulations can cause oxidative stress in bullfrog tadpoles. [13]

A 2003 study of various formulations of glyphosate found, "[the] risk assessments based on estimated and measured concentrations of glyphosate that would result from its use for the control of undesirable plants in wetlands and over-water situations showed that the risk to aquatic organisms is negligible or small at application rates less than 4 kg/ha and only slightly greater at application rates of 8 kg/ha." [142]

A 2013 meta-analysis reviewed the available data related to potential impacts of glyphosate-based herbicides on amphibians. According to the authors, the use of glyphosate-based pesticides cannot be considered the major cause of amphibian decline, the bulk of which occurred prior to the widespread use of glyphosate or in pristine tropical areas with minimal glyphosate exposure. The authors recommended further study of per-species and per-development-stage chronic toxicity, of environmental glyphosate levels, and ongoing analysis of data relevant to determining what if any role glyphosate might be playing in worldwide amphibian decline, and suggest including amphibians in standardized test batteries. [143]

Genetic damage

Several studies have not found mutagenic effects, [144] so glyphosate has not been listed in the United States Environmental Protection Agency or the International Agency for Research on Cancer databases. [ citation needed ] Various other studies suggest glyphosate may be mutagenic. [ citation needed ] The IARC monograph noted that glyphosate-based formulations can cause DNA strand breaks in various taxa of animals in vitro. [13]

Government and organization positions

European Food Safety Authority

A 2013 systematic review by the German Institute for Risk Assessment (BfR) examined more than 1000 [145] epidemiological studies, animal studies, and in vitro studies. It found that "no classification and labelling for carcinogenicity is warranted" and did not recommend a carcinogen classification of either 1A or 1B. [9] : 34–37, 139 It provided the review to EFSA in January 2014 which published it in December 2014. [9] [146] [147] In November 2015, EFSA published its conclusion in the Renewal Assessment Report (RAR), stating it was "unlikely to pose a carcinogenic hazard to humans". [148] The EU was largely informed by this report when it made its decision on the use of glyphosate in November 2017. [149]

EFSA's decision and the BfR report were criticized in an open letter published by 96 scientists in November 2015 saying that the BfR report failed to adhere to accepted scientific principles of open and transparent procedures. [150] [151] The BfR report included unpublished data, lacked authorship, omitted references, and did not disclose conflict-of-interest information. [151]

In April 2016, Dr. Vytenis Andriukaitis, European Commissioner for Health and Food Safety, wrote an open letter to the Chair of the Board of the Glyphosate Task Force at Monsanto Europe asking them to publish the full studies provided to the EFSA. [152]

In September 2017, The Guardian reported that sections of the Renewal Assessment Report prepared by the BfR and used by EFSA were copy-pasted from a study done by Monsanto. Some sections of copy contained small changes such as using British spelling rather than American forms but others were copied word for word, including most of the peer-reviewed papers that were used in the report. The Guardian reported that a "Monsanto spokesperson said that Efsa allowed renewal reports to be written this way because of the large volume of toxicological studies submitted." [149]

US Environmental Protection Agency

In a 1993 review, the EPA, considered glyphosate to be noncarcinogenic and relatively low in dermal and oral acute toxicity. [88] The EPA considered a "worst case" dietary risk model of an individual eating a lifetime of food derived entirely from glyphosate-sprayed fields with residues at their maximum levels. This model indicated that no adverse health effects would be expected under such conditions. [88] In 2015, the EPA initiated a review of glyphosate's toxicity and in 2016 reported that glyphosate is likely not carcinogenic. [8] [153]

In May 2019, CNN reported that the agency had reaffirmed its position that, when used according to instructions, glyphosate is not carcinogenic. Noting company emails between Monsanto and EPA executives released in 2015 which appear to suggest that an EPA official offered to kill an agency glyphosate review, [154] CNN cited "concerns about whether Monsanto has had undue influence over regulators." [155]

International Agency for Research on Cancer

In March 2015, the International Agency for Research on Cancer (IARC), an intergovernmental agency forming part of the World Health Organization of the United Nations, published a summary of their forthcoming monograph on glyphosate, and classified glyphosate as "probably carcinogenic in humans" (category 2A) based on epidemiological studies, animal studies, and in vitro studies. It noted that there was "limited evidence" of carcinogenicity in humans for non-Hodgkin lymphoma. [8] [11] [12] [13] [156] The IARC classifies substances for their carcinogenic potential, and "a few positive findings can be enough to declare a hazard, even if there are negative studies, as well." Unlike the BfR, it does not conduct a risk assessment, weighing benefits against risk. [157]

The BfR responded that IARC reviewed only a selection of what they [ who? ] had reviewed earlier, and argued that other studies, including a cohort study called Agricultural Health Study, do not support the classification. [158] The IARC report did not include unpublished studies, including one completed by the IARC panel leader. [159] The agency's international protocol dictates that only published studies be used in classifications of carcinogenicity, [160] since national regulatory agencies including the EPA have allowed agrochemical corporations to conduct their own unpublished research, which may be biased in support of their profit motives. [161]

Monsanto response and campaign

Monsanto called the IARC report biased and said it wanted the report to be retracted. [162] In 2017, internal documents from Monsanto were made public by lawyers pursuing litigation against the company, [163] who used the term "Monsanto papers" to describe the documents. [164] This term was later used also by Leemon McHenry [165] and others. [166] The documents indicated Monsanto had planned a public relations effort to discredit the IARC report, and had engaged Henry Miller to write a 2015 opinion piece in Forbes Magazine challenging the report. Miller did not reveal the connection to Forbes, and according to the New York Times, when Monsanto asked him if he was interested in writing such an article, he replied "I would be if I could start from a high-quality draft" provided by the company. [167] Once this became public, Forbes removed his blog from their site.

Two journalists from Le Monde won the 2018 European Press Prize for a series of articles on the documents, also titled Monsanto Papers. Their reporting described, among other things, Monsanto's lawyers' letters demanding that IARC scientists turn over documents relating to Monograph 112, which contained the IARC finding that glyphosate was a "probable carcinogen" several of the scientists condemned these letters as intimidating. [168]

Reviews of the EFSA and IARC reports

A 2017 review done by personnel from EFSA and BfR argued that the differences between the IARC's and EFSA's conclusions regarding glyphosate and cancer were due to differences in their evaluation of the available evidence. The review concluded that "Two complementary exposure assessments . suggests that actual exposure levels are below" the reference values identified by the EFSA "and do not represent a public concern." [169]

In contrast, a 2016 analysis concluded that in the EFSA's Renewal Assessment Report, "almost no weight is given to studies from the published literature and there is an over-reliance on non-publicly available industry-provided studies using a limited set of assays that define the minimum data necessary for the marketing of a pesticide", arguing that the IARC's evaluation of probably carcinogenic to humans "accurately reflects the results of published scientific literature on glyphosate". [170]

In October 2017, an article in The Times revealed that Christopher Portier, a scientist advising the IARC in the assessment of glyphosate and advocate for its classification as possibly carcinogenic, had received consulting contracts with two law firm associations representing alleged glyphosate cancer victims that included a payment of US$160,000 to Portier. [171] [172] The IARC final report was also found to have changed compared to an interim report, through the removal of text saying certain studies had found glyphosate was not carcinogenic in that study's context, and through strengthening a conclusion of "limited evidence of animal carcinogenicity," to "sufficient evidence of animal carcinogenicity". [173]

California Office of Environmental Health Hazard Assessment

In March 2015, the California Office of Environmental Health Hazard Assessment (OEHHA) announced plans to have glyphosate listed as a known carcinogen based on the IARC assessment. In 2016, Monsanto started a case against OEHHA and its acting director, Lauren Zeise, [174] but lost the suit in March 2017. [175]

Glyphosate was listed as "known to the State of California to cause cancer" in 2017. [176] In February 2018, as part of an ongoing case, an injunction was issued prohibiting California from enforcing carcinogenicity labeling requirements for glyphosate until the case was resolved. The injunction stated that arguments by a US District Court Judge for the Eastern District of California "[do] not change the fact that the overwhelming majority of agencies that that have examined glyphosate have determined it is not a cancer risk.". [177] In August 2019, the EPA also said it no longer allowed labels claiming glyphosate is a carcinogen, as those claims would "not meet the labeling requirements of the Federal Insecticide, Fungicide, and Rodenticide Act" and misinform the public. [178]

European Chemicals Agency

On March 15, 2017 the European Chemicals Agency (ECHA) announced recommendations proceeding from a risk assessment of glyphosate performed by ECHA's Committee for Risk Assessment (RAC). Their recommendations maintained the current classification of glyphosate as a substance causing serious eye damage and as a substance toxic to aquatic life. However, the RAC did not find evidence implicating glyphosate to be a carcinogen, a mutagen, toxic to reproduction, nor toxic to specific organs. [179]

Emergence of resistant weeds

In the 1990s, no glyphosate-resistant weeds were known to exist. [180] By 2014, glyphosate-resistant weeds dominated herbicide-resistance research. At that time, 23 glyphosate-resistant species were found in 18 countries. [181] "Resistance evolves after a weed population has been subjected to intense selection pressure in the form of repeated use of a single herbicide." [180] [182]

According to Ian Heap, a weed specialist, who completed his PhD on resistance to multiple herbicides in annual ryegrass (Lolium rigidum) in 1988 [183] – the first case of an herbicide-resistant weed in Australia [184] – by 2014 Lolium rigidum was the "world’s worst herbicide-resistant weed" with instances in "12 countries, 11 sites of action, 9 cropping regimens" and affecting "over 2 million hectares." [181] Annual ryegrass has been known to be resistant to herbicides since 1982. The first documented case of glyphosate-resistant L. rigidum was reported in Australia in 1996 near Orange, New South Wales. [185] [186] [187] In 2006, farmers associations were reporting 107 biotypes of weeds within 63 weed species with herbicide resistance. [188] In 2009, Canada identified its first resistant weed, giant ragweed, and at that time 15 weed species had been confirmed as resistant to glyphosate. [182] [189] As of 2010, in the United States 7 to 10 million acres (2.8 to 4.0 million hectares) of soil were afflicted by herbicide-resistant weeds, or about 5% of the 170 million acres planted with corn, soybeans, and cotton, the crops most affected, in 22 states. [190] In 2012, Charles Benbrook reported that the Weed Science Society of America listed 22 herbicide-resistant species in the U.S., with over 5.7 × 10 ^ 6 ha (14 × 10 ^ 6 acres) infested by GR weeds and that Dow AgroSciences had carried out a survey and reported a figure of around 40 × 10 ^ 6 ha (100 × 10 ^ 6 acres). [191] The International Survey of Herbicide Resistant Weeds database lists species that are resistant to glyphosate. [189]

In response to resistant weeds, farmers are hand-weeding, using tractors to turn over soil between crops, and using other herbicides in addition to glyphosate.

Monsanto scientists have found that some resistant weeds have as many as 160 extra copies of a gene called EPSPS, the enzyme glyphosate disrupts. [192]

Palmer amaranth

In 2004, a glyphosate-resistant variation of Palmer amaranth was found in the U.S. state of Georgia and confirmed by a 2005 study. [193] In 2005, resistance was also found in North Carolina. [194] The species can quickly become resistant to multiple herbicides and has developed multiple mechanisms for glyphosate resistance due to selection pressure. [195] [194] The glyphosate-resistant weed variant is now widespread in the southeastern United States. [193] [196] Cases have also been reported in Texas [196] and Virginia. [197]

Conyza species

Conyza bonariensis (also known as hairy fleabane and buva) and Conyza canadensis (known as horseweed or marestail) are other weed species that have lately developed glyphosate resistance. [198] [199] [200] A 2008 study on the current situation of glyphosate resistance in South America concluded "resistance evolution followed intense glyphosate use" and the use of glyphosate-resistant soybean crops is a factor encouraging increases in glyphosate use. [201] In the 2015 growing season, glyphosate-resistant marestail proved to be especially problematic to control in Nebraska production fields. [202]

Ryegrass

Glyphosate-resistant ryegrass (Lolium) has occurred in most of the Australian agricultural areas and other areas of the world. All cases of evolution of resistance to glyphosate in Australia were characterized by intensive use of the herbicide while no other effective weed control practices were used. Studies indicate resistant ryegrass does not compete well against nonresistant plants and their numbers decrease when not grown under conditions of glyphosate application. [203]

Johnson grass

Glyphosate-resistant Johnson grass (Sorghum halepense) has been found in Argentina as well as Arkansas, Louisiana, and Mississippi. [204]

Monarch butterfly populations

Use of 2-4 D and other herbicides like glyphosate to clear milkweed along roads and fields may have contributed to a decline in monarch butterfly populations in the Midwestern United States. [205] Along with deforestation and adverse weather conditions, [206] the decrease in milkweed contributed to an 81% decline in monarchs. [207] [208] The Natural Resources Defense Council (NRDC) filed a suit against the EPA in 2015, in which it argued that the agency ignored warnings about the potentially dangerous impacts of glyphosate usage on monarchs. [209]

Glyphosate was first approved for use in the 1970s, and as of 2010 was labelled for use in 130 countries. [18] : 2

In 2017 Vandenberg et al. cited a 100-fold increase in the use of glyphosate-based herbicides from 1974 to 2014, the possibility that herbicide mixtures likely have effects that are not predicted by studying glyphosate alone, and reliance of current safety assessments on studies done over 30 years ago. They recommended that current safety standards be updated, writing that the current standards "may fail to protect public health or the environment." [210]

European Union

In April 2014, the legislature of the Netherlands passed legislation prohibiting sale of glyphosate to individuals for use at home commercial sales were not affected. [211]

In June 2015, the French Ecology Minister asked nurseries and garden centers to halt over-the-counter sales of glyphosate in the form of Monsanto's Roundup. This was a nonbinding request and all sales of glyphosate remain legal in France until 2022, when it was planned to ban the substance for home gardening. [212] However, more recently the French parliament decided to not to impose a definitive date for such a ban. [213] In January 2019, "the sale, distribution, and use of Roundup 360 [wa]s banned" in France. Exemptions for many farmers were later implemented, and a curb of its use by 80% for 2021 is projected. [214] [215]

A vote on the relicensing of glyphosate in the EU stalled in March 2016. Member states France, Sweden, and the Netherlands objected to the renewal. [216] A vote to reauthorize on a temporary basis failed in June 2016 [217] but at the last minute the license was extended for 18 months until the end of 2017. [218]

On 27 November 2017, a majority of eighteen EU member states voted in favor of permitting the use of glyphosate for five more years. A qualified majority of sixteen states representing 65% of EU citizens was required. [219] The German Minister of Agriculture, Christian Schmidt, unexpectedly voted in favor while the German coalition government was internally divided on the issue which usually results in Germany abstaining. [220]

In December 2018, attempts were made to reopen the decision to license the weed-killer. These were condemned by Conservative MEPs, who said the proposal was politically motivated and flew in the face of scientific evidence. [221]

In March 2019, the European Court of Justice (ECJ) ordered the European Food Safety Authority (EFSA) to release all carcinogenicity and toxicity pesticide industry studies on glyphosate to the general public. [222]

In March 2019, the Austrian state of Carinthia outlawed the private use of glyphosate in residential areas while the commercial application of the herbicide is still permitted for farmers. The use of glyphosate by public authorities and road maintenance crews was already halted a number of years prior to the current ban by local authorities. [223]

In June 2019, Deutsche Bahn and Swiss Federal Railways announced that glyphosate and other commonly used herbicides for weed eradication along railway tracks will be phased out by 2025, while more environmentally sound methods for vegetation control are implemented. [224] [225]

In July 2019, the Austrian parliament voted to ban glyphosate in Austria. [226]

In September 2019, the German Environment Ministry announced that the use of glyphosate will be banned from the end of 2023. The use of glyphosate-based herbicides will be reduced starting from 2020. [227]

The assessment process for an approval of glyphosate in the European Union will begin in December 2019. France, Hungary, the Netherlands and Sweden will jointly assess the application dossiers of the producers. The draft report of the assessment group will then be peer-reviewed by the EFSA before the current approval expires in December 2022. [228]

Other countries

In September 2013, the Legislative Assembly of El Salvador approved legislation to ban 53 agrochemicals, including glyphosate the ban on glyphosate was set to begin in 2015. [229] [230] [231]

In May 2015, the President of Sri Lanka banned the use and import of glyphosate, effective immediately. [232] [233] However, in May 2018 the Sri Lankan government decided to re-authorize its use in the plantation sector. [234]

In May 2015, Bermuda blocked importation on all new orders of glyphosate-based herbicides for a temporary suspension awaiting outcomes of research. [235]

In May 2015, Colombia announced that it would stop using glyphosate by October 2015 in the destruction of illegal plantations of coca, the raw ingredient for cocaine. Farmers have complained that the aerial fumigation has destroyed entire fields of coffee and other legal produce. [69]

In April 2019, Vietnam's Ministry of Agriculture and Rural Development banned the use of glyphosate throughout the country. [236]

In August 2020, Mexican President Andrés Manuel López Obrador announced that glyphosate will be gradually phased out of use in Mexico by late 2024. [237]

Thailand's National Hazardous Substances Committee decided to ban the use of glyphosate in October 2019 [238] but reversed the decision in November 2019. [239]

Lawsuits claiming liability for cancer

In June 2018, Dewayne Johnson, a 46-year-old former California school groundskeeper who is dying of non-Hodgkin lymphoma, took Monsanto (which had been acquired by Bayer earlier that month) to trial in San Francisco County superior court, alleging that it has spent decades hiding the cancer-causing dangers of its Roundup herbicides. The judge ordered that jurors be allowed to consider both scientific evidence related to the cause of Johnson's cancer and allegations that Monsanto suppressed evidence of the risks, with possible punitive damages. [240] [241] In August 2018, the jury awarded Johnson US$289 million in damages. Monsanto said they would appeal, [242] saying they were confident that glyphosate does not cause cancer when used appropriately. [243] On appeal, the award was reduced to $78.5 million in November 2018, [244] and subsequently further reduced to $21.5 million in July 2020. [245]

In August 2018, the potential for additional cases was estimated at up to 4,000. [246] Bayer announced in April 2019 that over 13,000 lawsuits related to Roundup had been launched in the US.

In March 2019, a man was awarded $80 million in a lawsuit claiming Roundup was a substantial factor in his cancer, [247] [248] resulting in Costco stores discontinuing sales. [249] In July 2019, U.S. District Judge Vince Chhabria reduced the settlement to $26 million. [250] Chhabria stated that a punitive award was appropriate because the evidence "easily supported a conclusion that Monsanto was more concerned with tamping down safety inquiries and manipulating public opinion than it was with ensuring its product is safe." Chhabria stated that there is evidence on both sides concerning whether glyphosate causes cancer and that the behavior of Monsanto showed "a lack of concern about the risk that its product might be carcinogenic." [250]

On 13 May 2019 a jury in California ordered Bayer to pay a couple $2 billion in damages after finding that the company had failed to adequately inform consumers of the possible carcinogenicity of Roundup. [251] On July 26, 2019, an Alameda County judge cut the settlement to $86.7 million, stating that the judgement by the jury exceeded legal precedent. [252]

Using litigation discovery emails it was later revealed that in 2015 when Monsanto was discussing papers they wanted to see published to counter the expected IARC glyphosate results they wrote in an email, "An option would be to add Greim and Kier or Kirkland to have their names on the publication, but we would be keeping the cost down by us doing the writing and they would just edit & sign their names so to speak. Recall that is how we handled Williams Kroes & Munro, 2000." [253]

In June 2020 Bayer, which acquired Monsanto in 2018, agreed to a $10 billion settlement as a result of a number of class-action lawsuits alleging that Roundup had caused cancer. [254]

Advertising controversies

The New York Times reported that in 1996:

Dennis C. Vacco, the Attorney General of New York, ordered the company Monsanto to pull ads that said Roundup was "safer than table salt" and "practically nontoxic" to mammals, birds and fish. The company withdrew the spots, but also said that the phrase in question was permissible under E.P.A. guidelines. [255]

In 2001, French environmental and consumer rights campaigners brought a case against Monsanto for misleading the public about the environmental impact of its herbicide Roundup, on the basis that glyphosate, Roundup's main component, is classed as "dangerous for the environment" and "toxic for aquatic organisms" by the European Union. Monsanto's advertising for Roundup had presented it as biodegradable and as leaving the soil clean after use. In 2007, Monsanto was convicted of false advertising and was fined 15,000 euros. Monsanto's French distributor Scotts France was also fined 15,000 euros. Both defendants were ordered to pay damages of 5,000 euros to the Brittany Water and Rivers Association and 3,000 euros to the Consommation Logement Cadre de vie, one of the two main general consumer associations in France. [256] Monsanto appealed and the court upheld the verdict Monsanto appealed again to the French Supreme Court, and in 2009 it also upheld the verdict. [257]

In 2016, a lawsuit was filed against Quaker Oats in the Federal district courts of both New York and California after trace amounts of glyphosate were found in oatmeal. The lawsuit alleged that the claim of "100% natural" was false advertising. [258] That same year General Mills dropped the label "Made with 100% Natural Whole Grain Oats" from their Nature Valley granola bars after a lawsuit was filed that claimed the oats contained trace amounts of glyphosate. [259]

Trade dumping allegations

United States companies have cited trade issues with glyphosate being dumped into the western world market areas by Chinese companies and a formal dispute was filed in 2010. [260] [261]


How to Avoid Glyphosate

If you&rsquore concerned about glyphosate toxicity, you can follow some basic guidelines when sourcing your food. Steer clear of processed foods and buy ingredients that are either clearly labeled &ldquoUSDA Certified Organic&rdquo or come from a trusted local grower who doesn&rsquot use herbicides. Certified Organic crops can&rsquot be sprayed with glyphosate at any stage of the growing, harvesting, or drying processes, and none of the ingredients in USDA Certified Organic foods are allowed to be genetically engineered. The USDA Certified Organic standards for meat, eggs, and dairy require that livestock are fed 100-percent-organic feed and forage.

For more information, browse our collection on The Dangers of Glyphosate Herbicide.

Thierry Vrain is an organic gardener and retired genetic engineer. For more information about glyphosate&rsquos toxicity and its use on genetically modified crops, we recommend watching Vrain&rsquos presentation to the American College of Nutrition on the nutritional implications of GMOs .


Roundup (a weed-killer whose active ingredient is glyphosate) was shown to be toxic to as well as to promote developmental abnormalities in frog embryos. This finding one of the first to confirm that Roundup/glyphosate could be an "ecological health disruptor".

Embryos of Xenopus laevis were exposed to Roundup, Kilo Max and Enviro Glyphosate at concentration of 0.3‐1.3, 130‐280 and 320‐560 mg acid equivalent (a.e.)/L respectively. The results showed Roundup to be more toxic than the other formulations with a 96‐hour LC50 of 1.05 mg a.e/L. compared with 207 mg a.e./L, and 466 mg a.e./L for Kilo Max and Enviro Glyphosate respectively.

From the above cited 1979 link referring to previous aquatic LC50 values:

Application of Roundup, at recommended rates, along ditchbank areas of irrigation canals should not adversely affect resident populations of fish or invertebrates. However, spring applications in lentic situations, where dissolved oxygen levels are low or temperatures are elevated, could be hazardous to young-of-the-year-fishes.

The 48-h LC50 values for Roundup(R) Herbicide (MON 2139) tested against tadpoles of Crinia insignifera, Heleioporus eyrei, Limnodynastes dorsalis, and Litoria moorei ranged between 8.1 and 32.2 mg/L (2.9 and 11.6 mg/L glyphosate acid equivalent [AE]), while the 48-h LC50 values for Roundup(R) Herbicide tested against adult and newly metamorphosed C. insignifera ranged from 137-144 mg/L (49.4-51.8 mg/L AE). Touchdown(R) Herbicide (4 LC-E) tested against tadpoles of C. insignifera, H. eyrei, L. dorsalis, and L. moorei was slightly less toxic than Roundup(R) with 48-h LC50 values ranging between 27.3 and 48.7 mg/L (9.0 and 16.1 mg/L AE). Roundup(R) Biactive (MON 77920) was practically nontoxic to tadpoles of the same four species producing 48-h LC50 values of 911 mg/L (328 mg/L AE) for L. moorei and >1,000 mg/L (>360mg/L AE) for C. insignifera, H. eyrei, and L. dorsalis. Glyphosate isopropylamine was practically nontoxic, producing no mortality among tadpoles of any of the four species over 48 h, at concentrations between 503 and 684 mg/L (343 and 466 mg/L AE). The toxicity of technical-grade glyphosate acid (48-h LC50, 81.2-121 mg/L) is likely to be due to acid intolerance. Slight differences in species sensitivity were evident, with L. moorei tadpoles showing greater sensitivity than tadpoles of the other four species. Adult and newly emergent metamorphs were less sensitive than tadpoles.

This is the only time I will insert my own thoughts here, but OP’s statement about this being one of the first datasets indicating any adverse effects of direct glyphosate exposure to aquatic species seems incorrect to me given the previously cited literature.