Chemical safety and biosafety

Webinar Series on Testing and Assessment Methodologies


The OECD webinars on Testing and Assessment Methodologies focus on selected ongoing projects that will result in the short to medium term in new methodologies to test and assess chemicals. These free webinars are open to potential end users among regulators and contract research organisations who want to get familiar with new standards and approaches. Video recordings of our webinars are made available online afterwards.


WATCH THE WEBINAR REPLAY ON particle size and size distribution of nanomaterials: OECD Test Guideline No. 125

The recording is available in Spanish / El video está disponible en español

On 7 February 2023, the OECD organised a webinar to present the methods described in Test Guideline No. 125 to determine the size and size distributions of nanomaterial particles and fibres spanning from 1 nm to 1000 nm. It also presented the use and limitation of this Test Guideline, as well as on the validation exercise that was done to support its development.

The OECD organised this webinar to increase awareness of this newly adopted Test Guideline.


  • Test Guidelines (TGs) at the OECD
  • Introduction and background for developing TG 125
  • Overview and general messages
  • Methods for Particle measurements
  • Methods for Fibre measurements
  • Summary and Q&A

 Access the presentations.



On 14 December 2022, the OECD organised a webinar to present recent improvements and future challenges for the Adverse Outcome Pathway framework and the AOP-Wiki.

The Adverse Outcome Pathway Framework and related AOP-Wiki are constantly adapting in order to meet the requirements of an evolving regulatory environment. Interaction with the stakeholder community to consider the AOP-related needs of their communities is thus essential. This webinar not only reported on recent changes to the AOP-Wiki, but also gathered insights from participants to inform future developments to the Framework and Wiki in order to maximise the impact of AOPs in various regulatory environments.

This webinar was open to the public and highly relevant to all parties involved in regulatory chemical risk assessment, including the increased uptake of mechanistic approaches and New Approach Methodologies (NAMs) supported by AOPs.






  • Introduction
  • AOP-Wiki 2.6: Rationale behind added features, hands-on technical implementation
  • Beyond AOP-Wiki 2.6: Challenges ahead and how to address them 
  • Q&A and discussion: Possibility to weigh in on the future of the AOP-Wiki and the AOP Framework, with emphasis on increased uptake of AOPs in regulatory environments
  • Outlook and next steps

Access the presentations.



Webinar on Physiologically Based Kinetic (PBK) Models


6 April 2022: Gaining acceptance in next generation PBK modelling approaches for regulatory assessments: case studies | Access the presentations here.

10 May 2021: Gaining acceptance in next generation PBK modelling approaches for regulatory assessment | Access the presentation here.


Webinars on Adverse Outcome Pathways (AOPs) 

25 January 2022: AOP co-operative activities between scientific journals and the OECD

  • The AOP framework: Dan Villeneuve | Presentation.
  • The importance of co-operation: Clemens Wittwehr (EC Joint Research Centre) | Presentation.
  • The OECD AOP review and endorsement process: Nathalie Delrue (OECD Secretariat) | Presentation.
  • Case study and Lessons learnt from ET&C and EMM: Dries Knapen (University of Antwerp, Belgium) and Jason O’Brien (National Wildlife Research Centre, Canada) | Presentation.

30 November 2020: Training needs, resources, and opportunities for Adverse Outcome Pathways (AOPs) | Presentations:

  • Introduction by Magdalini Sachana and Mirjam Luijten | Presentation
  • From Data to Knowledge and Beyond AOPs as common interface by Brigitte Landesmann | Presentation
  • OECD Programme on Adverse Outcome Pathways (AOPs) by Bette Meek | Presentation
  • Concluding remarks by Mirjam Luijten | Presentation

30 January 2020: AOP knowledge base and AOP developing tips | Presentations:

  • Nathalie Delrue from the OECD Environment Directorate introduced the presenters and scope of the webinar | Presentation
  • Clemens Wittwehr from the European Commission Joint Research Centre provided an introduction on AOP-KB | Presentation
  • Dan Villeneuve from the US Environmental Protection Agency provided some tips on the development of AOPs | Presentation
  • Holly Mortensen from the US Environmental Protection Agency presented ways of retrieving information from databases and other AOP tools | Presentation

15 January 2020: Assembling and evaluating weight of evidence and quantitative understanding | Presentations

  • Magda Sachana from the OECD Environment Directorate introduced the presenters and scope of the webinar | Presentation
  • Bette Meek from the University of Ottawa provided an introduction to WoE for AOPs | Presentation
  • Kristie Sullivan from the Physicians Committee for Responsible Medicine shared examples of implementing WoE in an AOP | Presentation
  • Dan Villeneuve from the US Environmental Protection Agency spoke about quantitative understanding of relationships and why that’s important | Presentation.

30 April 2019: Adverse Outcome Pathway (AOP) framework | Presentations: 

  • Nathalie Delrue (OECD Secretariat): OECD AOP Programme | Presentation
  • Catherine Willett (Humane Society International): An Introduction to AOP framework | Presentation
  • Jason O’Brien (Environment Canada): AOP collaborative development | Presentation
  • Dan Villeneuve (US Environmental Protection Agency): Examples of AOP application in chemical risk assessment | Presentation 


Webinars on Testing and Assessment Methodologies:

27 September 2022: Webinar on the implementation of the first stand-alone Non-Animal Methods (NAMs) for eye hazard identification into OECD guidelines: OECD Guideline No. 467 and Test Guideline No. 492BPresentations

18 October 2021: Implementation of the Defined Approaches on Skin Sensitisation for Chemical Safety

  • Anne Gourmelon: OECD Environment Directorate | Presentation
  • Nicole Kleinestreuer (NICEATM) and Silvia Casati (EURL ECVAM) | Presentation
  • Anna Lowit (US EPA OPP)
  • Paul Brown (US FDA) 
  • Laura Rossi (ECHA) | Presentation
  • Andre Muller (RIVM) | Presentation

Access the Question and Answers document here

27 September 2019: OECD Alternatives to in vivo eye irritation testing

  • Chantra Eskes (Swiss 3Rs Competence Centre): Available test methods and IATA Guidance Document 263 | Presentation
  • Dave Allen (Integrated Laboratory Systems): Alternatives for eye irritation testing: usefulness and limitations | Presentation
  • Bertrand Desprez (Cosmetics Europe): Two defined approaches for ocular toxicity predictions | Presentation

16 January 2019: Defined Approaches for Skin Sensitisation


Webinars on Nanomaterials:

2 December 2021: How to assess exposure to nanomaterials? The evaluation results of existing tools/models (English - Spanish)

  • Occupational project: Carla Ribalta Carrasco, PhD (Danish National Research Center for Working Environment) | Occupational project
  • Consumer project: Mohammad Zein Aghaji, PhD (Health Canada) | Presentation
  • Environmental project: Marc LaPointe, Mathieu Dextraze (Environment and Climate Change Canada) | Presentation

25 February 2021: Assessing the dispersion stability and dissolution rate of nanomaterials in the environment

The recording is available in Spanish / El video está disponible en español.

26 January 2021: Guidance document No. 317 on aquatic & sediment ecotoxicity testing of nanomaterials

The recording is available in Spanish / El video está disponible en español.




Related Documents