EFSA advises on acute dietary exposure to pesticides

To calculate the likely exposure of a person eating a large portion of a certain pesticide-treated food in one day, risk managers use a method known as the International Estimate of Short Term Intake (IESTI). Authorities rely on the IESTI’s ability to flag up any risk of consumers exceeding safe levels through acute dietary exposure. Currently, there are discussions at international level about changing the way the IESTI is calculated. The European Commission asked EFSA how conservative the existing calculation is as a basis for ensuring the European population is protected from exceeding safe levels, and what the consequences of changing some of its parameters would be.

EFSA’s Panel on plant protection products and their residues (PPR Panel) worked with a large team of experts from the Member States, using data on food consumption, body weight and residues to analyse a range of scenarios for different countries, age groups and pesticides. By applying the current IESTI equation and using monitoring data to calculate protection for national populations, the experts estimated that in all scenarios over 99% of each national population is within safe levels and in most cases over 99.9% The Panel also examined the particular case of individual consumers eating large portions of certain foods containing the highest legal residue levels, focusing on the safety of young children. In most scenarios nearly all the individuals were protected (at least 99%), with a slightly lower level of protection (90-99%) for some pesticide/food combinations. These conservative figures are likely to underestimate true levels of protection since the Panel overestimated dietary intakes and underestimated the level of protection to account for uncertainties arising mainly from limitations in the available data. Changing the variability factor used to account for the uneven distribution of residues in crops-- an important parameter of the IESTI equation-- was found to have little impact on overall protection for whole populations but could affect the level of protection of individual consumers.

The Panel’s results suggest that the IESTI equation is a good tool to assess the safety of individual consumers exposed to maximum legal residue levels through foods, as originally intended. However, the equation would need to be modified, on the basis of substantial research, to reliably assess the level of protection for the entire European population. EFSA’s scientific advice has been forwarded to the European Commission, to support the risk management process of deciding on any possible changes to the IESTI calculation as a basis for estimating acute exposure to pesticides residues.