Acute poisoning

Acute poisoning effects of glyphosate herbicides include:

Gastrointestinal corrosive effects, with mouth, throat and epigastric (upper central abdomen) pain and dysphagia (difficulty in swallowing) are common. Kidney and liver impairment are also frequent. Respiratory distress, impaired consciousness, pulmonary oedema, shock, arrythmia, renal failure requiring haemodialysis, metabolic acidosis and hyperkalaemia (high blood potassium levels) are observed in severe cases. Bradycardia (low heart rate) and ventricular arrhythmias are often present prior to death. 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 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.¹

The complete herbicide formulations are more acutely toxic than glyphosate alone. A Brazilian formulation of Roundup was studied by Dallegrave et al (2002) and was found to be more acutely toxic than the level reported in the World Health Organisation assessment of 1994 for glyphosate alone.²

References

1. Bradberry SM, Proudfoot AT, Vale JA. Glyphosate poisoning. Toxicol Rev. 2004;23:159–167.
2. Dallegrave E, Mantese FDG, Dalsenter PR, Langeloh A. Acute oral toxicity of glyphosate in Wistar rats. Online J Vet Res. 2002;1:29–36.