Abstract
Unintentional chemical mixtures that are present in the environment are of societal concern as the (environmental) chemicals contained therein, either singly or in combination, may possess properties that are hazardous (toxic) for human health. The current regulatory practice, however, is still largely based on evaluating single chemical substances one-by-one. Over the years various research efforts have delivered tools and approaches for risk assessment of chemical mixtures, but many of these were not considered sufficiently mature for regulatory implementation. This is (partly) due to mixture risk assessment (MRA) being very complex because of the large number of chemicals present in the environment. A key element in risk assessment is information on actual exposures in the population of interest. To date, information on actual personal (internal) mixture exposures is largely absent, severely limiting MRA. The use of human biomonitoring data may improve this situation. Therefore, we investigated within the European Human Biomonitoring Initiative (HBM4EU) various approaches to assess combined exposures and MRA. Based on the insights and lessons learnt in the context of the HBM4EU project, conclusions as well as recommendations for policy development regarding chemical mixtures and for further research were drafted. These conclusions and recommendations relate to both exposure and adverse health effects in humans. The recommendations were discussed with stakeholders in a workshop held in October 2021. There was considerable support and agreement with the spirit, scope and intention of the draft recommendations. Here we describe the lessons learnt on mixture risk assessment through the HBM4EU project and present the final recommendations. Overall, HBM4EU results demonstrated the potential of human biomonitoring as an instrument to obtain insight into the real-life mixtures the human population is exposed to. Also, HBM4EU results demonstrated that chemical mixtures are of public health concern. In the majority of the cases, it was possible to identify risk drivers, i.e. chemicals that contribute more strongly than others to the health risk. The novel approaches to identify co-occurrence patterns demonstrated clusters of co-occurring chemicals; chemicals in these mixture clusters are regulated independently under different legislative frameworks. Moreover, HBM4EU data and expertise can support a science-based derivation of a Mixture Assessment Factor and gauge potential impacts on the population's exposure to chemicals. While further expansion is needed on various aspects of the mixture activities carried out in the context of HBM4EU, application of available methodologies for mixture risk assessment should already be implemented to the degree possible.
| Original language | English |
|---|---|
| Article number | 114135 |
| Number of pages | 7 |
| Journal | International Journal of Hygiene and Environmental Health |
| Volume | 249 |
| Early online date | 7 Feb 2023 |
| DOIs | |
| Publication status | Published - 1 Apr 2023 |
Bibliographical note
Funding Information:The authors gratefully acknowledge the valuable contributions from all WP15 partners throughout the duration of the project, the presenters and rapporteurs at the preceding webinars and at the workshop, the open and frank discussion with the workshop participants and constructive comments received from Susana Pedraza-Diaz, Anne Marie Vinggaard, Hans Mol and the HBM4EU Management Board. This research has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 733032 HBM4EU.
Funding Information:
The discussions at the workshop demonstrated that the majority of the participants was in strong support of, where possible, the implementation of available methodologies and approaches for MRA in processes for regulatory decision-making. Also, the need for MRA approaches across regulatory sectors (e.g. cosmetics, industrial chemicals, chemicals used in food) was stressed, which is in line with the ‘one chemical, one assessment approach’ for chemical safety assessments proposed by the European Commission. Broader implementation may be hampered by insufficient data availability, in particular regarding observations at the level of the individual. This aspect should be addressed in a strategy for an inclusive European HBM/exposome programme, including the required infrastructure. In this context, the term ‘infrastructure’ not only relates to the collection and analysis of human biomonitoring samples (and thus the necessary network of laboratories), but also to data interpretation and making data FAIR (findability, accessibility, interoperability, and reusability), all in a harmonized fashion. EIRENE, the European research infrastructure on human exposome developed under ESFRI (European Strategy Forum on Research Infrastructures) was seen as a step in the right direction (https://www.eirene-ri.eu/). Such a strategy should also cover collection of auxiliary information on exposure routes, e.g. from questionnaires or indoor measurements (like indoor air, house dust, carpeting, etc).
Publisher Copyright:
© 2023 The Authors
Keywords
- Chemical mixtures
- Combined exposure
- Policy making
- Mixture risk assessment
- HBM4EU
- HBM
