Paul Van Den Brink, Wageningen University; Simón Gutiérrez Alonso, ECHA; Udo Hommen, Fraunhofer Institute; Anna-Maija Nyman, ECHA; Véronique Poulsen, L’Oréal; and Thomas Preuss, Bayer

The SETAC Europe 13th Special Science Symposium, which was held from 23–24 October 2018 in Brussels, Belgium, addressed one of the biggest challenges in the ecological risk assessment of chemicals: How to extrapolate effects of chemicals across different levels of biological organization.

A total of 74 people, scientists from universities (32), industry and consultancy (47), governmental bodies (national and European regulatory agencies and authorities, and research institutes [13]), and other organizations (8), attended this event.

The symposium started with an overview of the different European regulations related to industrial chemicals, biocides, plant protection products and pharmaceuticals, presented by ECHA, EFSA, German UBA and European Commission representatives. Each regulation already includes a certain level of extrapolation using currently available tools (e.g., QSARs, read across, Assessment Factors, Species Sensitivity Distributions), but speakers highlighted knowledge gaps and the lack of tools to go beyond the current methods. Speakers also noted the steps and challenges faced in the different regulations when including new methodologies and models in current practices for hazard and risk assessments.

Experts from different fields presented existing or in-development modeling tools to extrapolate from the sub-organism to the organism level, and from the organism to the population, community, or ecosystem or landscape level. Additionally, the applicability and the potential use in regulatory risk assessment of such models was addressed and discussed. Twenty posters also presented examples of new extrapolation tools or case studies.

The presentations and discussions addressed the following themes:

  • What is the state of the art of the models used at different levels of extrapolation?
  • Is there a possibility to use models to extrapolate between species, or to help in the identification of the most sensitive species, in a framework of reduction, refinement or replacement of vertebrate testing?
  • What is the level of uncertainty of the models? How can regulators assess the validity of the models? What information is needed to validate them?
  • What is the level of trust and the steps needed from regulatory authorities to start using these models for regulatory hazard and risk assessment purpose? Is there a need for additional expertise within regulatory authorities to use those models?
  • What do we need to develop for more accurate community and ecosystem models?
  • How can models be used for compounds and regulatory frameworks were less data is available (such as REACH) or for data-poor compounds?
  • Can European projects fund research in this area?
  • Can monitoring be used to validate population, community or ecosystem models?

An important issue of the presentations and related discussions was to remind everybody that models need input data. These data sources are wide and varied, and they may come from ecotoxicological experiments, ecology or other area of expertise, for example:

  • Organism level toxicity data are needed to calibrate and test TK/TD and population models to the compound of concern
  • Ecological data are needed to develop relevant population and ecosystem models
  • Geographical data are necessary to construct landscape level models

It was stressed that while some of these tools (i.e., models) may already be available, they are often not yet implemented in regulatory risk assessments. However, it was agreed among participants that there are still some areas that need further research or improvement in order to be used in the regulatory arena. In particular, more work and further discussions are needed to identify the direct application for the different extrapolation tools within the different regulatory frameworks acknowledging the differences that exist among these regulations with regards to availability of data or differences in protection. These discussions may reveal some areas where further development is needed but, in the end, will result in tools which are useful for the identified regulatory purpose.

In order to identify further research in particular areas and to ensure that the models that are developed adequately answer the questions raised by regulators and help meet the ultimate goal of protecting human health and the environment, there is a need to have all stakeholders around the table (regulators, academics and industry). Through this interaction between stakeholders, it will be ensured that relevant models are being developed, which cover current data gaps in regulatory practices and, at the same time, increases the trust from all stake holders.

The presenters have kindly provided copies of their presentations, and they are available online.

We would like to take the opportunity to thank all the participants, speakers, chairpersons and SETAC office for all their time, planning and efforts!

Authors’ contact information:,,,, and

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