Executive Summary

The use of glyphosate-based herbicides, especially Monsanto’s Roundup formulation, has increased dramatically since the introduction of genetically modified (GM) glyphosate-tolerant crops, resulting in the contamination of our food, environment and water supplies.

Glyphosate-based herbicides are now the most commonly used herbicides in the world. It is still promoted as ‘safe’, despite damning evidence of serious harm to health and the environment.

Evidence of harm to health

– Monsanto and the European Commission (EC) have known about birth defects since the 1980s. Industry studies found statistically significant skeletal and/or visceral abnormalities as well as reduced viability and increase in spontaneous abortions in rats and rabbits exposed to high doses of glyphosate. Lower doses were later shown to cause dilated hearts.  The EC dismissed all the findings. 

– Independent studies have since found caudal vertebrae loss in rats treated with sub-lethal doses of the herbicide; as well as craniofacial abnormalities, increased embryonic mortality and endocrine disruption, abnormal onset of puberty, and abnormal sexual behaviour and sperm count in male offspring of mothers exposed during gestation. 

– GM soybean-fed female rats gave birth to excessive numbers of severely stunted pups, with over half of the litter dead by three weeks, and the surviving pups were sterile. 

– Non-mammalian animals exposed to glyphosate resulted in increased gonad size, increased mortality, craniofacial abnormalities correlating with abnormal retinoic acid signalling, and reduced egg viability. 

– In vitro exposure to glyphosate resulted in endocrine disruption and death of cells of the testis, placenta, and umbilical cord. 

– A long term in vivo study on rats found females exposed to Roundup and/or Roundup Ready GM maize were two to three times as likely to die as controls and much more likely to develop large mammary tumours, while males presented large tumours four times controls and up to 600 days earlier.
 
– Clinical data from Argentina are consistent with lab findings of increases in birth defects and cancers in regions with large areas cultivating glyphosate-tolerant soybean. 

– Endocrine disruption has been observed in both in vivo and in vitro studies in the laboratory, including abnormal levels of testosterone, aromatase enzyme, testosterone and oestrogen receptors, leutinising hormone, follicle-stimulating hormone. Endocrine disruption can lead to cancers and reproductive problems. 

– Epidemiological studies have found links to cancer including non-Hodgkin lymphoma and increased plasma cell proliferation. Cancer rates have risen in in glyphosate-use zones in Argentina. Lab studies found significant increases in interstitial cell tumour incidence in rats as well as skin tumour-promoting activity. Numerous lab studies including those performed by industry showed glyphosate damages DNA of cells in culture as well as in humans living in glyphosate-sprayed regions of Argentina. Non-mammalian studies found defects in cell cycle checkpoints and DNA damage repair machinery. DNA damage is a major prelude to cancers. AMPA, the glyphosate metabolite, also has genotoxic effects. 

– Neurotoxicity effects include Parkinsonism have emerged following acute exposure. Exposure to glyphosate resulted in oxidative stress in lab animals and death of neuronal cells, correlating with Parkinsonian pathology. Acute exposure in fish resulted in acetylcholine esterase (AChE) inhibition. An epidemiological study linked glyphosate -exposure to Attention-Deficit-Hyperactive disorder in children, a disorder associated with AChE inhibition. The original neurotoxicity studies carried out by industry were ruled invalid by the US Environment Protection Agency and urgently need re-examining by independent scientists. 

– Internal organ toxicity has been documented in animal feeding studies with glyphosate-tolerant soybean. Rats suffered kidney abnormalities including renal leakage and ionic disturbances, and liver pathology including irregular hepatocyte nuclei, and increased metabolic rates. 

– Acute toxicity of glyphosate is officially declared low by government agencies; however agricultural workers have reported many symptoms including skin irritation, skin lesions, eye irritation, allergies, respiratory problems and vomiting. Ingestion of large volumes causes systemic toxicity and death.