A recent study, on the other hand, has shown that Roundup formulations and metabolic products cause the death of human embryonic, placental, and umbilical cells in vitro even at low concentrations. The effects are not proportional to Glyphosate concentrations but dependent on the nature of the adjuvants used in the formulation.[35] [edit]
Humans Glyphosate has a United States Environmental Protection Agency? Toxicity Class of III in 1993,[34] . It has been rated as class I (Severe) for eye irritation. Glyphosate is being evaluated for effects to unborn fetuses and their development. It is currently on the USEPA Endocrine Disrupter Screening list, published in 2007.[36][37]
Outside its intended use, glyphosate can be lethal. For example, with intentional poisonings there is approximately a 10% mortality for those ingesting glyphosate, compared to 70% for those ingesting paraquat.[38] Laboratory toxicology studies suggest that other ingredients combined with glyphosate may have greater toxicity than glyphosate alone. For example, a study comparing glyphosate and Roundup found that Roundup had a greater effect on aromatase than glyphosate alone.[9]
Statistics from the California Environmental Protection Agency's Pesticide Illness Surveillance Program indicate that glyphosate-related incidents are one of the highest reported of all pesticides.[39][40] However, incident count does not take into account the number of people exposed and the severity of symptoms associated with each incident.[40] For example, if hospitalization were used as a measure of the severity of pesticide related incidents, then glyphosate would be considered relatively safe, since, over a 13 year period in California, none of the
515 pesticide-related hospitalizations recorded were attributed to glyphosate.[40]Greenpeace states that the acute human toxicity of glyphosate is very low, but note that, as mentioned above, other added chemicals (particularly surfactants, e.g. polyoxy-ethyleneamine, POEA), can be more toxic than glyphosate itself.[17] Over-application, or application directly to the soil may impact earthworms.
A review of the toxicological data on Roundup shows that there are at least 58 studies of the effects of Roundup itself on a range of organisms.[41] This review concluded that "for terrestrial uses of Roundup minimal acute and chronic risk was predicted for potentially exposed non-target organisms". It also concluded that there were some risks to aquatic organisms exposed to Roundup in shallow water. More recent research suggests glyphosate induces a variety of functional abnormalities in fetuses and pregnant rats.[42] Also in recent mammalian research, glyphosate has been found to interfere with an enzyme involved testosterone production in mouse cell culture[43] and to interfere with an estrogen biosynthesis enzyme in cultures of human placental cells.[44] There is a reasonable correlation between the amount of Roundup ingested and the likelihood of serious systemic sequelae or death. Ingestion of
toxicity in adults. Gastrointestinal corrosive effects, with mouth, throat and epigastric pain and dysphagia are common. Renal and hepatic impairment are also frequent, and usually reflect reduced organ perfusion. Respiratory distress, impaired consciousness, pulmonary oedema, infiltration on chest x-ray, shock, arrythmias, renal failure requiring haemodialysis, metabolic acidosis and hyperkalaemia may supervene in severe cases. Bradycardia and ventricular arrhythmias are often present pre-terminally. Dermal exposure to ready-to-use glyphosate formulations can cause irritation, and photo-contact dermatitis has been reported occasionally; these effects are probably due to the preservative Proxel (benzisothiazolin-3-one). Severe skin burns are very rare. Inhalation is a minor route of exposure, but spray mist may cause oral or nasal discomfort, an unpleasant taste in the mouth, tingling and throat irritation. Eye exposure may lead to mild conjunctivitis, and superficial corneal injury is possible if irrigation is delayed or inadequate.[45] [edit]
Other species The direct toxicity of pure glyphosate to mammals and birds is low.[46][unreliable source?] The acute oral toxicity of Roundup is >
5,000 mg/kg in the rat.[47] It showed no toxic effects when fed to animals for 2 years, and only produced rare cases of reproductive effects when fed in extremely large doses to rodents and dogs. It has not demonstrated any increase in cancer rates in animal studies and is poorly absorbed in the digestive tract. Glyphosate has no significant potential to accumulate in animal tissue.[48][49]An in vitro study indicates that glyphosate formulations could harm earthworms[50] and beneficial insects.[51] However, the reported effect of glyphosate on earthworms has been criticized.[41] The results conflict with results from field studies where no effects were noted for the number of nematodes, mites, or springtails after treatment with Roundup at 2 kilograms active ingredient per hectare.[52] Glyphosate can negatively affect nitrogen-fixing bacteria,[53] and increase the susceptibility of plants to disease.[54] A 2005 study concluded that certain amphibians may be at risk from glyphosate use.[55]
Certain surfactants used in some glyphosate formulations have higher toxicity to fish and invertebrates, resulting in some formulations of glyphosate not being registered for use in aquatic applications.[56] Monsanto produces glyphosate products with alternative surfactants that are specifically formulated for aquatic use, for example "Biactive" and "AquaMaster".[57] According to Monsanto, "Conservation groups have chosen glyphosate formulations because of their effectiveness against most weeds as glyphosate has very low toxicity to wildlife".[58] Glyphosate is used with five different salts, but commercial formulations of it contain surfactants, which vary in nature and concentration. As a result, human poisoning with this herbicide is not with the active ingredient alone, but with complex and variable mixtures.[45]
Glyphosate's effect on soil life may be limited, because when glyphosate comes into contact with the soil, it rapidly binds to soil particles and is inactivated.[59][60] Unbound glyphosate is degraded by bacteria. Low activity because of binding to soil particles suggests that glyphosate's effects on soil flora are limited. Low glyphosate concentrations can be found in many creeks and rivers in U.S. and Europe.[citation needed] The United States Environmental Protection Agency,[59] the EC Health and Consumer Protection Directorate, and the UN World Health Organization have all concluded that pure glyphosate is not carcinogenic. Opponents of glyphosate claim that Roundup has been found to cause genetic damage, citing Peluso et al.[61] The authors concluded that the damage was "not related to the active ingredient, but to another component of the herbicide mixture".
Mammal research indicates oral intake of 1% glyphosate induces changes in liver enzyme activities in pregnant rats and their fetuses.[62] [edit]
Aquatic effects Fish and aquatic invertebrates are more sensitive to Roundup than terrestrial organisms.[41] Glyphosate is generally less persistent in water than in soil, with 12 to 60 day persistence observed in Canadian pond water, yet persistence of over a year have been observed in the sediments of ponds in Michigan and Oregon.[34]
The EU classifies Roundup as R51/53 Toxic to aquatic organisms, may cause long-term adverse effects in the aquatic environment.[63] Roundup is not registered for aquatic uses[64] and studies of its effects on amphibians indicate it is toxic to them.[65] Other glyphosate formulations that are registered for aquatic use have been found to have negligible adverse effects on sensitive amphibians.[66] [edit]
Endocrine disruptor debate In vitro studies have shown glyphosate affects progesterone production in mammalian cells[67] and can increase the mortality of placental cells.[9] Whether these studies classify glyphosate as an endocrine disruptor is debated.
Some[who?] feel that in vitro studies are insufficient, and are waiting to see if animal studies show a change in endocrine activity, since a change in a single cell line may or may not impact an entire organism. Additionally, current in vitro studies expose cell lines to concentrations orders of magnitude greater than would be found in expected exposures, and through pathways that would not be typically experienced in real organisms.
Others[who?] feel that in vitro studies, particularly ones identifying not only an effect, but a chemical pathway, are sufficient evidence to classify glyphosate as an endocrine disruptor, on the basis that even small changes in endocrine activity can have lasting effects on an entire organism that may be difficult to detect through whole organism studies alone. Further research on the endocrine effects of glyphosate is ongoing, including through the EPA endocrine screening program on 73 chemicals, published in 2007. [edit]
Environmental degradation When glyphosate comes into contact with the soil, it can be rapidly bound to soil particles and be inactivated.[34] Unbound glyphosate can be degraded by bacteria.[68] However, glyphosate has been shown to increase the infection rate of wheat by fusarium head blight in fields that have been treated with glyphosate.[69]
In soils, half-lives vary from as little as 3 days at a site in Texas to
141 days at a site in Iowa.[70] In addition, the glyphosate metabolite aminomethylphosphonic acid has been shown to persist up to 2 years in Swedish forest soils.[71] Glyphosate adsorption varies depending on the kind of soil.[72] [edit]Resistance in weeds and microorganisms The first documented cases of weed resistance to glyphosate were found in Australia, involving rigid ryegrass near Orange, New South Wales.[73] Some farmers in the United States have expressed concern that weeds are now developing with glyphosate resistance, with 13 states now reporting resistance, and this poses a problem to many farmers, including cotton farmers, that are now heavily dependent on glyphosate to control weeds.[74][75] Farmers associations are now reporting 103 biotypes of weeds within 63 weed species with herbicide resistance[74][75]. This problem is likely to be exacerbated by the use of roundup-ready crops [76]. [edit]
Legal cases [edit]
False advertising In 1996 Monsanto was accused of false and misleading advertising of glyphosate products, prompting a law suit by the New York State attorney general.[77]
On Fri Jan 20, 2007, Monsanto was convicted of false advertising of Roundup for presenting Roundup as biodegradable and claiming that it left the soil clean after use. Environmental and consumer rights campaigners brought the case in 2001 on the basis that glyphosate, Roundup's main ingredient, is classed as "dangerous for the environment" and "toxic for aquatic organisms" by the European Union. Monsanto France planned to appeal the verdict at the time.[78] [edit]
Scientific fraud On two occasions the United States Environmental Protection Agency has caught scientists deliberately falsifying test results at research laboratories hired by Monsanto to study glyphosate.[79][80][81] In the first incident involving Industrial Biotest Laboratories, an EPA reviewer stated after finding "routine falsification of data" that it was "hard to believe the scientific integrity of the studies when they said they took specimens of the uterus from male rabbits".[82][83][84] In the second incident of falsifying test results in 1991, the owner of the lab (Craven Labs), and three employees were indicted on 20 felony counts, the owner was sentenced to 5 years in prison and fined 50,000 dollars, the lab was fined 15.5 million dollars and ordered to pay 3.7 million in restitution.[85][86] Craven laboratories performed studies for 262 pesticide companies, including Monsanto.
Monsanto has stated that the studies have been repeated, and Roundup's EPA certification does not now use any studies from Craven Labs or IBT. Monsanto also claims that the Craven Labs investigation was started by the EPA after a pesticide industry task force discovered irregularities.[87]