| toxicity summary | IDENTIFICATION AND USE: Glyphosate is an odorless white solid. Glyphosate is a non-selective herbicide registered for use on many food and non-food field crops as well as non-crop areas where total vegetation control is desired. When applied at lower rates, glyphosate is also a plant growth regulator. HUMAN EXPOSURE AND TOXICITY: Glyphosate is an active ingredient of the most widely used herbicide and it is believed to be less toxic than other pesticides. However, several studies showed its potential adverse health effects to humans as it may be an endocrine disruptor. Concentrated solutions of glyphosate can also cause dermal irritation. Most intoxicated cases are from ingestion, inhalation, and skin exposure. Pulmonary edema, shock, and arrhythmia were the reported causes of mortality. Ingestion of glyphosate-surfactant herbicides can result in acute kidney injury, electrolyte abnormalities, acidosis, cardiovascular collapse, and death. In severe toxicity, the use of hemodialysis is reported, but largely unsupported by kinetic analysis. Commercial formulations were more cytotoxic than the active component alone, supporting the concept that additives in commercial formulations play a role in the toxicity attributed to glyphosate-based herbicides. Glyphosate was found nongenotoxic in human lymphocytes with or without metabolic activation. However it induced micronuclei formation and DNA damage in a buccal epithelial cell line . In addition, glyphosate was toxic to human placental JEG3 cells. ANIMAL STUDIES: Glyphosate did not produce dermal sensitization in guinea pigs. It produced moderate to severe eye irritation in rabbits. In a 13-week study with glyphosate administration, lesions of the salivary glands were found in rats and mice. A study in a 2-stage mouse skin carcinogenesis model and proteomic analysis suggested that glyphosate has tumor promoting potential in skin carcinogenesis. Studies in rats and rabbits indicated that technical glyphosate is not teratogenic. In the first /multigenerational/ study, the only effect noted was an increased incidence of unilateral renal tubular dilation in F3b male pups at 30 mg/kg body weight. Maternal exposure to glyphosate disturbed the masculinization process in the offsping and promoted behavioral changes and histological and endocrine problems in reproductive parameters. These changes associated with the hypersecretion of androgens increased gonadal activity and sperm production. The entire body of the developmental toxicity data reviewed fails to support a potential risk for increased cardiovascular defects as a result of glyphosate exposure during pregnancy. A broad array of in vitro and in vivo assays has consistently demonstrated that glyphosate and glyphosate-containing herbicide formulations are not genotoxic. Occasionally, however, related and contradictory data are reported, including findings of mouse liver and kidney DNA adducts and damage following intraperitoneal injection. ECOTOXICITY STUDIES: Gene expression data suggests that glyphosate-based herbicides have the potential to alter hormonal pathways during tadpole development. Roundup exposure had negative impact on the immune system of European sea bass. Roundup at environmentally relevant concentrations has lethal and genotoxic impact on the Indian skittering frog. Roundup also altered normal histology of the studied organs and caused a significant decrease in the number of copulations and mating success in male fish exposed to the herbicide in the neotropical native fish, Jenynsia multidentata. |