Guidelines for Uncertainty Analysis: Application of the respective Documents of EFSA and BfR for Exposure Assessments

uncertainty, uncertainty analysis, scientific assessment
First published in EFSA Supporting Publications
31 luglio 2018
Approved
27 luglio 2018
Type
External Scientific Report

The present document has been produced and adopted by the bodies identified above as authors. This task has been carried out exclusively by the authors in the context of a contract between the European Food Safety Authority and the authors, awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the authors.

Abstract

Uncertainty analysis is an integral part of risk assessment, therefore institutions like the European Food Safety Authority (EFSA) or the German Federal Institute for Risk Assessment (BfR) have developed uncertainty guidelines. An in‐depth comparison of both documents yielded that both documents share the same overall philosophy. They differ mainly in their preferences regarding the employed method for the assessment of uncertainties. While BfR's guideline describes and recommends the use of a qualitative method, EFSA's guidance strongly recommends the quantification of the overall uncertainty. After the comparison of the uncertainty guidelines, they were applied to two case studies. As for the first case study, an exposure assessment regarding the marking of eel with alizarin red S (ARS) and strontium chloride (SC) was selected. Aspects of both guidance documents were used: For the BfR guideline, the default qualitative approach was employed, while for EFSA guidance document, a quantitative approach was used. It should be noted that the step of the overall quantification using an expert knowledge elicitation (EKE) recommended by EFSA was not carried out here for organisational reasons. Since the original risk assessment had very little available time (1‐2 weeks), methods were selected which were not time‐consuming. A quantitative description of the uncertainty could be obtained. The second case study is an exposure assessment regarding aluminium in cocoa and chocolate. The BfR guideline was mainly employed to identify sources of uncertainties, while the EFSA guidance document, building on the results of the BfR uncertainty analysis, was applied to handle the quantification of these uncertainties. An expert knowledge elicitation (EKE) was employed not only to derive the distribution of one parameter, but also to characterise the overall uncertainty. As a result, the uncertainty of the selected exposure assessment was obtained. The report concludes with an overall evaluation of the two uncertainty guidelines and recommendations for further development are given.

Contact
thomas.schendel [at] bfr.bund.de
doi
10.2903/sp.efsa.2018.EN-1472
Question Number