CRED - Criteria for Reporting and Evaluating ecotoxicity Data

CRED - Criteria for Reporting and Evaluating ecotoxicity Data

Core planning team: Marlene Ågerstrand (Stockholm University, SE), Anette Küster (UBA, DE), Caroline Moermond (RIVM, NL) , Muris Korkaric (Eawag), Dieter Schudoma (UBA, DE)

The objective of ecotoxicological risk assessments is to determine the risk potential of environmental chemicals for the ecosystem. Reliable and relevant ecotoxicological data are necessary to derive standard values for critical concentrations in the environment, also called Environmental Quality Standards (EQS) or quality criteria. 

The selection of adequate data in both substance authorisation (ECHA 2008, EMEA 2006, EEC 1991) and retrospective assessment under the Water Framework Directive (EC 2011) is usually performed according to the criteria established by Klimisch (1997). However, a number of studies have shown that these criteria are not precise enough to ensure consistency between various experts so that international harmonisation is required.

Therefore, international ring tests were conducted where extended criteria recommendations (Kase et al. 2016, Ågerstrand et al. 2011, Kuester et al. 2009) for data reliability and  relevance are applied to case substances and compared with conventional assessment. The objective was to increase the transparency, robustness and comparability of risk assessments performed by different experts and make environmental decisions more reliable.

Starting from the ring test results and subsequent discussions, a new evaluation and reporting method CRED (Criteria for Reporting and Evaluating ecotoxicity Data) was developed that contains 20 criteria for the evaluation of reliability and 13 criteria for the evaluation of relevance. Appropriate publications for regulation and science are currently submitted by the project team to ET&C. The final CRED Excel tool for the evaluation method is freely available: CRED method - excel file.  

The CRED evaluation method is currently piloted and tested in the revision of the EU Technical Guidance Document for EQS values for key studies and in the revision of EQS proposals for Switzerland. Additionally, the CRED criteria are applied in the Literature Evaluation Tool of the Joint Research Centre, as well as in the reliability evaluation of ecotoxicity studies for data bases, such as the NORMAN EMPODAT. In addition, the CRED evaluation method is being considered for inclusion in the project Intelligence-led Assessment of Pharmaceuticals in the Environment (iPiE), which is financed by the pharmaceutical industry and the EU Commission.


Kase, R., Korkaric, M., Werner, I., Ågerstrand, M. (2016): Criteria for Reporting and Evaluating ecotoxicity Data (CRED): Comparison and perception of the Klimisch and CRED methods for evaluating reliability and relevance of ecotoxicity studies. Environmental Sciences Europe 2016, 28:7; DOI: 10.1186/s12302-016-0073-x 
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Moermond, C.T., Kase, R., Korkaric, M., Ågerstrand, M. (2016) CRED: Criteria for reporting and evaluating ecotoxicity data. Environmental Toxicology and Chemistry, 35, 1297–1309
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Ågerstrand, M., et al. (2011) Reporting and evaluation criteria as means towards a transparent use of ecotoxicity data for environmental risk assessment of pharmaceuticals, Environmental Pollution 159:2487-2492

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European Commission (2011). Common implementation strategy for the Water Framework Directive (2000/60/EC). Technical guidance for deriving environmental quality standards (TGD-EQS). Guidance document No. 27. Technical Report - 2011 – 055. DOI: 10.2779

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