GESS - the Graduate Programme in Environmental Stress Studies - is offering a Ph.D. scholarship to be affiliated with the Department of Environmental, Social and Spatial Change (ENSPAC), Roskilde University. The ph.d. is partly funded by the Velux foundation as it is part of a larger project involving The Danish Ecological Council and the Danish Technical University. The scholarship is for a period of 3 years and shall be filled as soon as possible, within the area.
Risk Assessment and Regulation of Mixture toxicity
The thesis should aim at addressing the implementation of mixture toxicity into European chemicals regulation, with focus on REACH and the Water Framework Directive.
In general, we have a good fundamental understanding of the theoretical knowledge regarding how to access mixture effects, and two well tested models are currently used within mixture toxicity prediction namely Concentration Addition and Independent Action. These models may possibly be used in a tiered manner with Concentration Addition as the default prediction model.
Some of the major persisting knowledge gaps is concerned with i) how this knowledge can be applied to real life mixture scenarios, ii) how it can be implemented in the specific risk assessment scenarios that constitute the foundation of the two above mentioned regulations and iii) what kind of information is needed to reach this point. The focus of the thesis should address these issues. This produced science shall subsequently be used by the Danish Ecological Council both in order to improve the policy process regarding the development of mixture toxicity regulation within EU and for educational purposes.
The following tasks and questions will be addressed:
- Literature search on state-of-the-art of mixture toxicity and risk assessment.
- Can recommendations be made on how to select chemicals for specific mixture toxicity assessment?
- Can a general guideline for mixture toxicity assessment be constructed, in order to facilitate a uniform and more comprehensive implementation of mixture toxicity?
- Is it possible to conduct mixture toxicity testing with experimental design including limited replicates and where full dose response curves might not be obtainable?
- Concentration Addition and Independent Action can in principle by applied as soon as we have data for single chemical toxicity. But how can they be applied in reality to the data that is already present?
- Is it feasible to apply Concentration addition as a default prediction model rather than evaluating both Concentration Addition and Independent Action?
These questions should be addressed from a theoretical perspective, and the study does thus not have an experimental dimension from the start.
Ph.D scholarship in Risk Assessment and Regulation of Mixture Toxicity
