June 16, 2009 by Peter Simpson

This week I’ve been sent back to school to learn all about the latest techniques to understand, model and predict the toxicity of mixtures. Is the toxicity of a mixture the sum of its parts, or more or less than them? I’m going to find out.

The course is being hosted by CESAM (Centro de Estudos do Ambiente e do Mar) at the University of Averio in Portugal and is an offshoot of the EU’s No Miracle Project. Today’s sessions concentrated on the basics of techniques like Concentration Addition and Independent Action, and how they can be used to detect antagonism, synergism and potentiation of toxicity in simple binary mixtures of two components. The techniques are applicable to metals, organics and pesticides and can be used in terrestrial and aquatic systems. Sessions later this week will introduce response surface analysis and the analysis of three-component and complex mixtures.

I’m still contemplating how these techniques can practically and usefully be incorporated into the types of chemical risk assessment we do, but I’ll post again when it’s had a chance to sink in.