EFSA's 21st Scientific Colloquium on Harmonisation of human and ecological risk assessment of combined exposure to multiple chemicals

The 21st meeting in the EFSA Scientific Colloquium Series was held in Edinburgh, UK on 11-12 September 2014 and addressed the “Harmonisation of human and ecological risk assessment of combined exposure to multiple chemicals”. Human and ecological risk assessment of combined exposure to multiple chemicals (“chemical mixtures”) poses several challenges to scientists, risk assessors and risk managers, particularly due to the large number of chemicals involved and their associated exposure patterns and toxicological profiles in humans and other species present in the environment. In principle, methodological frameworks for human and ecological risk assessment use tiered approaches for exposure assessment, hazard assessment and risk characterisation. Overall, the tiers range from qualitative/semi-quantitative tiers to fully probabilistic tiers – the choice of the tier often depending on data availability – and the purpose of the risk assessment.