Combined stressors in dynamic ecosystems (NoMiracle)

Dr David Spurgeon

Interactions between pollutants in a mixture occur at three levels:

Greater scientific knowledge of the mechanisms involved in the interactions would allow informed management of pollutant mixtures in contaminated land. For example, use of new chemicals likely to excessively increase overall toxicity could be avoided. Additionally, different remediation options for contaminated land could be assessed to determine their effectiveness in light of the nature of the pollutant mixture present and the potential addition of new ones. Dealing with chemicals and chemical mixtures in real ecosystems means dealing with a new series of complications. This is because changes in both biological and non-biological parameters may affect interactions at all of the three levels set out above. The problem, of assessing the combined risk from multiple stressors and indirect effects in dynamic and heterogeneous environments, is the focus of the latest EU project we are working on, called NoMiracle.

NoMiracle

This is an integrated project that aims to mobilise European expertise in terrestrial ecological risk assessment to address issues key to the future sustainable use of soils. The need for the research is derived from the recognition that chemical contamination has important economic consequences caused by its pronounced and long-lasting effect on soil productivity. Already, within the European Union, there are a large number of designated contaminated sites, the inclusion of the Accession Countries will see a large increase in this number. For these sites and for agricultural and industrial chemicals in general, current ecological risk assessment practices consider only the effect of single compounds under static conditions. This is despite the fact that complex mixtures of contaminants pollute the vast majority of contaminated sites and that agricultural and industrial practices frequently result in release of chemical mixtures into dynamic and changing ecosystems.

The nature of current EU wide risk assessment approaches means that at present the sustainable status of soil can not be assured. Damaging synergistic interactions between compounds and also the interaction of chemical (mixtures) with other environmental stresses such as climatic change and acidification may compromise soils. Such effects thus have the potential to limit the productivity and ecological value of soil and need to be accounted for in advanced ecological risk assessment methods and decision support tools.

To support current and future European strategies, in particular for environment and health, there is an urgent need for development of methods for assessing the cumulative risks from combined exposures to multiple stressors including complex mixtures of chemical, physical, and biological agents.

Deliverables: This project will help support the development and improvement of a coherent series of methodologies that will be underpinned by mechanistic understanding, while integrating the risk analysis approaches of environmental and human health. The project will deliver understanding and tools for sound risk assessment, developing a research framework for the description and interpretation of combined stressor effects that leads to the identification of biomarkers and other indicators of cumulative impacts.

NoMiracle will also help increase knowledge on the transfer of pollutants between different environmental compartments, including how these processes are influenced by natural stressors such as climate, and on the impact of cumulative stressors including chemical mixtures. This will facilitate the link information concerning the condition of air, water, soil and the built environment with human and ecosystem health monitoring data. By developing and using improved assessment tools and novel models, the project will quantify and aim at reducing uncertainty in current risk assessment and screening methodologies, e.g. by improving the scientific basis for setting safety factors. The new methods will take into account geographical, ecological, social and cultural differences across Europe.

The project consortium: We are highly competent in the relevant areas and include in the team : leading scientists within human toxicology and epidemiology, aquatic and terrestrial ecotoxicology, environmental chemistry / biochemistry, toxicogenomics, physics, mathematical modelling, geographic informatics, and socio-economic science.