The Science of DioxinJune 21, 2016 | |
FAO and WHO Determine That Glyphosate Is Unlikely to Pose Carcinogenic Risk to Humans from Exposure through Diet
The Food and Agriculture Organization of the United Nations (“FAO”) Panel of Experts on Pesticide Residues in Food and the Environment and the World Health Organization (“WHO”) Core Assessment Group on Pesticide Residues have determined that glyphosate “is unlikely to pose a carcinogenic risk to humans from exposure through the diet.”
A joint meeting of the FAO panel and the WHO’s Core Assessment Group on Pesticide Residues was held at WHO headquarters in Geneva, Switzerland, from May 9 to May 13, 2016. Glyphosate, among other things, was placed on the agenda by the joint meeting’s Secretariat, based on the recommendation of the last session of the joint meeting to re-evaluate it given the number of new studies that had become available since the last full assessment.
The Joint FAO/WHO Meeting on Pesticide Residues (“JMPR”) has just reported its results.
With respect to glyphosate, the JMPR noted that several epidemiological studies on cancer outcomes following occupational exposure to glyphosate were available. The evaluation of these studies focused on the occurrence of non-Hodgkin lymphoma (“NHL”). Overall, the JMPR said, there was “some evidence of a positive association between glyphosate exposure and risk of NHL from the case-control studies and the overall meta-analysis.” It stated, however, that it was “notable that the only large cohort study of high quality found no evidence of an association at any exposure level.”
The JMPR pointed out that glyphosate “has been extensively tested for genotoxic effects using a variety of tests in a wide range of organisms.” It declared that the “overall weight of evidence” indicated that administration of glyphosate and its formulation products “at doses as high as 2000 mg/kg body weight by the oral route, the route most relevant to human dietary exposure, was not associated with genotoxic effects in an overwhelming majority of studies conducted in mammals, a model considered to be appropriate for assessing genotoxic risks to humans.”
The meeting concluded, therefore, “that glyphosate is unlikely to be genotoxic at anticipated dietary exposures.”
The JMPR observed that several carcinogenicity studies in mice and rats are available and it concluded that “glyphosate is not carcinogenic in rats,” but said that it could not exclude the possibility that it “is carcinogenic in mice at very high doses.”
The JMPR concluded that, in view of the absence of carcinogenic potential in rodents at human-relevant doses and the absence of genotoxicity by the oral route in mammals, and considering the epidemiological evidence from occupational exposures, “glyphosate is unlikely to pose a carcinogenic risk to humans from exposure through the diet.”
The JMPR reaffirmed the group acceptable daily intake (“ADI”) for the sum of glyphosate and its metabolites of 0-1 mg/kg body weight on the basis of effects on the salivary gland. It declared that it was not necessary to establish an acute reference dose (“ARfD”) for glyphosate or its metabolites “in view of its low acute toxicity.”