MANY WAYS
Combined exposure to multiple chemicals: assessing risks across regulatory silos
People are continuously exposed to multiple chemicals from a variety of sources, also referred to as unintentional mixtures. The EU’s Chemicals Strategy for Sustainability towards a toxic-free environment set the objective to better account for mixture effects when assessing risks from chemicals. Available methodologies mainly cover the assessment of predefined groups of chemicals (e.g. dioxins) or assessments within specific regulatory domains (e.g. pesticides). However, they often do not account for all the chemicals to which humans may be potentially exposed, and therefore do not address combined exposure across different regulatory domains. We intend to discuss the current challenges associated with the risk assessment of combined exposure to multiple chemicals and explore how to further advance and harmonise mixture risk assessment across regulatory domains. The outcome of the session is expected to facilitate the identification of possible synergies among national, European and global stakeholders, and stimulate the establishment of legal requirements for chemical mixture risk assessment beyond the current regulatory silos.
Vision
As part of the European Green Deal, the Chemical Strategy for Sustainability has set the goal of improving the protection of human health and the environment from risks caused by chemicals. This includes risks arising from simultaneous exposure to multiple chemicals, including those in food and feed. There is a growing scientific consensus that the effect of simultaneous exposure to multiple chemicals (also referred to as unintentional mixtures) must be considered and integrated more generally into chemical risk assessment. Building on the mixture risk assessment approaches that have been developed within specific regulatory domains, the thematic session will explore possibilities for new risk assessment strategies that can pragmatically address exposure to multiple chemicals across regulatory domains. The thematic session will also provide an opportunity for exchange and identification of possible synergies among different research communities, agencies and policymakers, including international stakeholders.
Background – Challenges and opportunities
Human health and environmental risk assessment of chemicals currently relies mainly on the assessment of individual chemical substances. In practice, however, people are continuously exposed to multiple chemicals from a variety of sources (also referred to as ‘chemical mixtures’). To guarantee the highest possible level of public health protection, approaches need to be developed for the risk assessment of combined exposure to multiple chemicals. This need has been identified as a key priority area by the European Commission and most EU agencies involved in chemical risk assessment.
Numerous institutions and organisations, including JRC, ECHA, EFSA, US-EPA, WHO/FAO and OECD have been addressing the risk assessment of mixtures. For example, in recent years, EFSA has made substantial progress in the development of harmonised approaches to assess the risks related to multiple chemicals, primarily for pesticides. At the EU level, a plethora of research activities is running in parallel seeking to address the topic from different perspectives: the environment (SOLUTIONS), human health (EuroMix, HBM4EU), endocrine disruption (EDC-MixRisk) and alternatives to animal testing (EUToxRisk). Moreover, the European Commission is currently working on the establishment of an EU-wide research and innovation partnership (PARC) to support and drive innovation in chemical risk assessment, including the assessment of health risks from combined exposure to multiple chemicals.
Methodologies and research activities developed so far mainly focussed on combined exposure to predefined groups of chemicals within a specific regulatory domain (e.g. pesticides, biocides). However, they often do not cover mixtures of chemicals across different regulatory domains/sectors, nor do they account for all the chemicals humans may be potentially exposed to. Moreover, methodologies developed for domains that have a strong evidence-base in terms of hazard and exposure data (e.g. pesticides), are difficult to combine with other domains where less information is available and more pragmatic approaches are recommended, such as the mixture assessment (or allocation) factor (MAF).
To tackle the complexity of mixture risk assessments, close cooperation between researchers and regulators across different sectors is required. In this context, EFSA recently launched a call to develop a roadmap for action on the risk assessment of combined exposure to multiple chemicals (RACEMiC). The main objective of the RACEMiC roadmap is to provide a full overview of the ongoing activities, knowledge gaps, societal interests and concerns as well as collaboration opportunities and potential partners. Whereas the RACEMiC roadmap is mainly intended to address the needs within EFSA’s domains of activity, this thematic session will build upon that experience and explore possibilities for applying mixtures risk assessment to any combination of chemicals, across regulatory domains.
Scope and objectives
The scope of the thematic session is to discuss ongoing and future developments regarding human health risk assessment of combined exposure to multiple chemicals, and to promote its implementation in the context of regulatory risk assessment.
The main objectives of the thematic session are to:
- Discuss experiences and learnings, and explore how methodologies currently developed in different regulatory domains (e.g. mixture assessment factor and cumulative risk assessment of pesticides) could be integrated, for example in tiered approaches, to address the exposure to unintentional mixtures from different sources, across regulatory domains;
- Identify and prioritise the necessary scientific advancements to address the exposure to unintentional mixtures via different sources, and underpin the development of a holistic approach across all chemical sectors. This includes the possible use of effect-based modelling, biomonitoring and exposome analysis.
| Time | Duration | Talk |
|---|---|---|
| 14:00 | 5 |
Opening and welcome Susanne Hougaard Bennekou, Technical University of Denmark (DTU) |
Part I - New developments in risk assessment of combined exposure to multiple chemicals
| Time | Duration | Talk |
|---|---|---|
| 14:05 | 20 |
Novel strategies to assess risks associated with human relevant mixtures Chris Gennings, Icahn School of Medicine at Mount Sinai |
| 14:25 | 10 |
Q&A Susanne Hougaard Bennekou, Technical University of Denmark (DTU) |
Part II - Implementing risk assessment of combined exposure to multiple chemicals across regulatory frameworks
| Time | Duration | Talk |
|---|---|---|
| 14:35 | 10 |
Introduction to Part 2 Susanne Hougaard Bennekou, Technical University of Denmark (DTU) |
| 14:45 | 10 |
EU Chemical Strategy for Sustainability and the requirements to account for simultaneous exposure to chemicals across regulatory domains Peter Korytar, European Commission |
| 14:55 | 10 |
Regulatory risk assessment of chemical in food and the need for targeted methodologies in specific policy areas Almut Bitterhof, European Commission |
| 15:05 | 10 |
The mixture assessment factor and the underlying principles Christina Rudén, Stockholm University |
| 15:15 | 10 |
Possibilities for assessing multiple chemicals across regulatory domains through tiered approaches Paul Price, University of Iowa |
| 15:25 | 10 |
Risk assessment of combined exposure to multiple chemicals: case studies in food safety Philip Marx-Stoelting , German Federal Institute for Risk Assessment (BfR) |
| 15:35 | 30 |
Coffee break |
| 16:05 | 60 |
Panel discussion moderated by Dick Sijm Almut Bitterhof, European Commission | Philip Marx-Stoelting , German Federal Institute for Risk Assessment (BfR) | Peter Korytar, European Commission | Christina Rudén, Stockholm University | Paul Price, University of Iowa |
| 17:05 | 10 |
Wrap up and concluding remarks Susanne Hougaard Bennekou, Technical University of Denmark (DTU) | Jacob Van Klaveren, Institute for Public Health and the Environment (RIVM) |