An assessment of the acute dietary exposure to glyphosate using deterministic and probabilistic methods

Use of glyphosate in crop production can lead to residues of the active substance and related metabolites in food. Glyphosate has never been considered acutely toxic; however, in 2015 the European Food Safety Authority (EFSA) proposed an acute reference dose (ARfD). This differs from the Joint FAO/WHO Meeting on Pesticide Residues (JMPR) who in 2016, in line with their existing position, concluded that an ARfD was not necessary for glyphosate. This paper makes a comprehensive assessment of short-term dietary exposure to glyphosate from potentially treated crops grown in the EU and imported third-country food sources. European Union and global deterministic models were used to make estimates of short-term dietary exposure (generally defined as up to 24 h). Estimates were refined using food-processing information, residues monitoring data, national dietary exposure models, and basic probabilistic approaches to estimating dietary exposure. Calculated exposures levels were compared to the ARfD, considered to be the amount of a substance that can be consumed in a single meal, or 24-h period, without appreciable health risk. Acute dietary intakes were <100% of the ARfD for all foodstuffs, except wild fungi, when calculated using the EFSA model. The model assumptions differ from those of the source model (German national model), resulting in the use of a higher variability factor. Intakes estimated with the German model represented only 18% of the ARfD. The impact of differing assumptions regarding variability and other input parameters is discussed. Probabilistic exposure estimates showed that the acute intake on no person-days exceeded 10% of the ARfD, even for the pessimistic scenario.