Mixture Toxicity

Dr Claus Svendsen

Modern day pollution and contamination rarely occur as isolated patches of single chemicals. This is a simple consequence modern industry and society, where most processes involve several chemicals. The mixing of pollutants can result in their combined effect being either more or less toxic than would be expected from their individual toxicity (synergy or antagonism). The potential effects on plants, wildlife or human beings of exposure to mixtures can therefore be very hard to predict.

Current risk assessment deals with toxic chemical mixtures through generic safety factors. However, mixture effects are not generic, and ongoing research aims to deliver more appropriate safety measures.

 

There are two main problems to deal with when considering mixture toxicity:

  • How to describe and analyse the effects of mixtures, and
  • Integrating the many different levels at which chemicals can interact in the process of causing effects.

We have been working on the first point since 1997, when we and our European collaborators started work on a three-year European Union project called MIXTOX.

The second point is the focus of our current work on the EU integrated project NoMiracle, which also addresses how non-chemical stressors like climate or acidification might interact with the effects of chemicals.