Impact of a proposed revision of the IESTI equation on the acute risk assessment conducted when setting maximum residue levels (MRLs) in the European Union (EU): A case study

Abstract

Proposals to update the methodology for the international estimated short-term intake (IESTI) equations were made during an international workshop held in Geneva in 2015. Changes to several parameters of the current four IESTI equations (cases 1, 2a, 2b, and 3) were proposed. In this study, the overall impact of these proposed changes on estimates of short-term exposure was studied using the large portion data available in the European Food Safety Authority PRIMo model and the residue data submitted in the framework of the European Maximum Residue Levels (MRL) review under Article 12 of Regulation (EC) No 396/2005. Evaluation of consumer exposure using the current and proposed equations resulted in substantial differences in the exposure estimates; however, there were no significant changes regarding the number of accepted MRLs. For the different IESTI cases, the median ratio of the new versus the current equation is 1.1 for case 1, 1.4 for case 2a, 0.75 for case 2b, and 1 for case 3. The impact, expressed as a shift in the IESTI distribution profile, indicated that the 95th percentile IESTI shifted from 50% of the acute reference dose (ARfD) with the current equations to 65% of the ARfD with the proposed equations. This IESTI increase resulted in the loss of 1.2% of the MRLs (37 out of 3110) tested within this study. At the same time, the proposed equations would have allowed 0.4% of the MRLs (14 out of 3110) that were rejected with the current equations to be accepted. The commodity groups that were most impacted by these modifications are solanacea (e.g., potato, eggplant), lettuces, pulses (dry), leafy brassica (e.g., kale, Chinese cabbage), and pome fruits. The active substances that were most affected were fluazifop-p-butyl, deltamethrin, and lambda-cyhalothrin.

Proposed prospective scenarios for cumulative risk assessment of pesticide residues

“…The exposure for case 2a may both increase and decrease and the exposure for case 2b decreases when changing to the proposed equations. The results are in agreement with the findings by Breysse et al (Breysse, 2018).…”

“…The change in case 2b equations may decrease the exposure, while the change in case 3 equations substantially increases the exposure (up to 5.17 times). The results are in agreement with the findings by Breysse et al (Breysse, 2018). The present document has been produced and adopted by the bodies identified above as author(s).…”

Benchmarking the Current Codex Alimentarius International Estimated Short-Term Intake Equations and the Proposed New Equations

“…The importance of the IESTI version is evident in recent publications using different forms of the IESTI equations. The published projected EU MRL loss is 1 to 2% . However, outside the EU, the proposal results in published losses of 4 to 12% of MRLs with applicable ARfD .…”

“…The published projected EU MRL loss is 1 to 2%. 13 However, outside the EU, the proposal results in published losses of 4 to 12% of MRLs with applicable ARfD. 14 Thus, at the Codex level, all intake estimates increase, and the risk-assessment process becomes more stringent and less refined under the Geneva proposal.…”

“…The 2015 FAO/WHO Geneva proposal includes assumptions for harmonization for several versions of the IESTI, with an emphasis on the EU. Because the EU currently uses higher variability factors of 5 and 7 for some commodities, the impact of the proposed changes in the EU is not equivalent to the impact on the JMPR estimate . At the JMPR, the math dictates that the use of MRL will increase all estimated exposures.…”