An assessment of dietary exposure to glyphosate using refined deterministic and probabilistic methods. (September 2016) - Stephenson, C.L.
Abstract: Glyphosate is a herbicide used to control broad-leaved weeds. Some uses of glyphosate in crop production can lead to residues of the active substance and related metabolites in food. This paper uses data on residue levels, processing information and consumption patterns, to assess theoretical lifetime dietary exposure to glyphosate. Initial estimates were made assuming exposure to the highest permitted residue levels in foods. These intakes were then refined using median residue levels from trials, processing information, and monitoring data to achieve a more realistic estimate of exposure. Estimates were made using deterministic and probabilistic methods. Exposures were compared to the acceptable daily intake (ADI)—the amount of a substance that can be consumed daily without an appreciable health risk. Refined deterministic intakes for all consumers were at or below 2.1% of the ADI. Variations were due to cultural differences in consumption patterns and the level of aggregation of the dietary information in calculation models, which allows refinements for processing. Probabilistic exposure estimates ranged from 0.03% to 0.90% of the ADI, depending on whether optimistic or pessimistic assumptions were made in the calculations. Additional refinements would be possible if further data on processing and from residues monitoring programmes were available. Highlights: Deterministic and probabilistic estimates of glyphosate dietary exposure were made. Exposure estimates were refined using processing and residue monitoring information. The TMDI was identified as an appropriate screening tool to identify potential risk. Refined and probabilistic assessments provided a more realistic estimate of exposure. Refined deterministic and probabilistic exposure was 1.2% and <0.9% ADI respectively.