Authors: Sarah Priestly,  Amy Brooks
Cambridge Environmental Assessments

In October 2022 EFSA published a proposal document for the use of Critical Appraisal Tools (CATs)1 for ecotoxicology studies that may not follow a prescribed guideline. The document outlines the theory behind the development of the CATs, why they are considered relevant and seven types of studies they have created CATs for.

CATs were developed for ecotoxicity tests for both aquatic and terrestrial risk assessment and in four domains. The selected studies are listed below.

  • Aquatic organisms:
    • Modified exposure studies (tier 2)
    • Mesocosm studies (tier 3)
  • Bees:
    • Honeybee brood test (feeding and tent test version)
  • Non-target arthropods other than bees:
    • Extended laboratory studies
    • Aged residue studies
    • Field studies
  • Residue decline studies and related kinetics (currently relevant for bird, mammal, and bee risk assessment):
    • Field studies

The purpose of the CATs is to provide a structured and transparent approach for evaluating non-standard studies including literature for use in risk assessments for regulators and EFSA staff/experts.  They are based on the Criteria for Reporting and Evaluating Ecotoxicity Data (CRED)2 approach as it evaluates both the reliability and relevance of studies. As a result, each CAT has 2 components: reliability and relevance.

Reliability and relevance are defined by EFSA as follows:

Reliability is defined as the inherent quality of an effect value in a test report or publication relating to (1) a clearly described experimental design to allow for the study to be repeated independently, (2) the way the experimental procedures were performed, and (3) the reporting of the results to provide evidence of the reproducibility and accuracy of the findings.

Relevance is the extent to which data and tests are appropriate to answer a specified question from a regulatory, biological and/or exposure point of view.

Briefly, the tools are comprised of Excel spreadsheets for each study type, these are paired with a word document (handbook) outlining how to evaluate each criteria in the CAT.  The Excel workbook comprises of different criteria and a scoring table. The scores are then added up to give an overall score for each of the two components.

CATs are predominately designed to be used by regulators in evaluating whether non-standard studies are reliable and/or relevant for use in the risk assessment. It is understood that these would be used for evaluating both new and existing studies.

CATs are also useful tools for risk assessors and laboratories when designing studies as they give an overview of what is required for a study to be accepted as part of the risk assessment process, both in terms of study design and study reporting.

They are a useful tool for laboratories in terms of what needs to be included in a study report and it would be good practice for the CATs to be reviewed against study plans and study report templates in order to help stave off any potential regulatory failures. It is also useful to compare existing study reports to the relevant CAT to determine whether report amendments or expert statements would be useful to address any potential issues highlighted by the CAT that may affect the study’s reliability or relevance score.

The use of these CATs is not yet mandatory, however, two CATs are included in the revised EFSA (2023) bird and mammal guidance document3: ecological field studies and effect field studies. This is in addition to the seven published in the EFSA supporting publication document1.

In summary, the harmonisation that is being attempted by EFSA in the use of these CATs is potentially a good tool. However, the introduction of these may mean that more studies will be assigned as not relevant or reliable and therefore will not be included in the risk assessment. Potential implications of this are increased costs to industry for repeat studies and delayed registration of their products. It is unclear whether it could trigger more vertebrate testing. It is therefore advisable for those seeking authorisations of products or active substances to review their existing ecotoxicology studies against the available CATs such that the need for new studies can be identified and ideally discussed with regulators before studies are repeated.

If you would like to discuss how this may affect your ongoing or future ecotoxicology dossier sections, please feel free to contact us.

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References

  1. Lahr J, Arts G, Duquesne S, Mazerolles V, de Jong F, Moermond C, van der Steen J, Alalouni U, Baujard E, van den Berg S, Buddendorf B, Faber M, Mahieu K, Montforts M, Smit E, van Spronsen R, Swarowsky K, Chaton P-F, Foldrin J, Lambin S and Pieper S, 2023. Proposal of critical appraisal tools for the evaluation of ecotoxicology studies. EFSA supporting publication 2023:EN-7787. 70 pp. doi:10.2903/j.efsa.2023.EN-7787
  2. Moermond CTA, Kase R, Korkaric M and Ågerstrand M. 2016. CRED: Criteria for reporting and evaluating ecotoxicity data. Environmental Toxicology and Chemistry, 35 (5), 1297-1309.
  3. EFSA (European Food Safety Authority), Aagaard A, Berny P, Chaton PF, AntiaAL, McVey E, Arena M, Fait G, Ippolito A, Linguadoca A, Sharp R, Theobald A and Brock T, 2023. Guidance on the risk assessment for Birds and Mammals. EFSA Journal 2023;21(2):7790, 300 pp.