Our State of the Art report on the toxicology and ecotoxicology of chemical mixtures has just been published by the European Commission. It is actually open for discussion, i.e. the Commisssion invites feedback until the 30th of April.
Our main conclusions are:
- We need a European guideline for the assement of the toxic effects of chemical mixtures on human health and the environment. Current US guidelines can serve as a template, but efforts should be made to incorporate human health oriented efforts with environmental assessments.
- Only a strong legal mandate (as it recently has been implemented in the new European pesticide regulation) would motivate a wide-spread and regular consideration of ”cocktail effects” of chemical mixtures in environmental and human health oriented regulations.
- Especially media-oriented regulations, such as the IPPC and WFD Directives (the latter was not considered within the report), provide a suitable perspective for the consideration of mixtures in regulatory settings.
- Concentration Addition should be used as a first, default assessment concept for chemical mixtures in general.
- It needs to be ensure that the generation, storage and dissemination of toxicological and ecotoxicological data facilitates their use for a later modeling of mixture effects.
The work was led by Andreas Kortenkamp of the London School of Pharmacy. Michael Faust and myself teamed up with him for the work. The tasks of the report were to analyze
- the scientific literature on mixture toxicity,
- current EU risk assessment regimes relevant to mixture toxicity assessments,
- the practical experiences in assessing mixture toxicity, approaches and methodologies used for this purpose in the EU, and
- approaches to assess mixture toxicity in major competing economies of EU and international bodies
with respect to human toxicology and ecotoxicology. You find the report as a whole PDF for download here.
The reports starts with an executive summary and it is introduced by the discussion of a series of common mixture-related questions:
- Is an assessment of the effects of chemical mixtures necessary from a scientific
viewpoint? - Is there not sufficient protection against mixture effects if we make sure that each
chemical is present individually at exposures unlikely to pose risks? - Is it necessary to test every conceivable combination of chemicals or is it possible to
predict the effects of a mixture? - Which of the two assessment and prediction concepts, dose addition or independent
action, should be utilized in practice? - Which chemicals should be subjected to mixtures risk assessment?
- How should mixture effect assessment concepts be applied in practice?
- What knowledge gaps hamper the consideration of mixture toxicology and
ecotoxicology in chemical risk assessment?
We then also provide an overview of the current European regulatory system with respect to chemical mixtures and feedback that we received from a questionaire on the practical experiences with mixture toxicity assessments in the European member states.
Thomas
