In the environment, substances from various sources are mixed and influence organisms and, consequently, the functioning balance of the ecosystems. Assessments and regulations have exclusively dealt with the effects of individual substances to date. However, this is not enough because the toxicity of a mixture is usually higher than that of an individual substance. Toxic mixture effects may also occur if all mixture components are present in concentrations that are harmless if taken individually. This especially applies to substances with similar mechanisms of action, such as substances with an estrogen-like effect that accumulate from numerous sources like drugs, synthetic materials, or industrial chemicals.
Attempts are under way on an international level to improve the assessment of mixture effects - with active participation by the Ecotox Centre. The Ecotox Centre held a workshop on the assessment of mixture toxicity in November 2010. About 60% of the participants in this workshop spoke out in favour of a toolbox to be developed as quickly as possible for measuring and assessing mixture toxicity. The Ecotox Centre is involved in various projects to achieve this goal and to develop practical solutions.