A new document in the Organisation for Economic Co-operation and Development series on testing and assessment sets out the considerations for assessing the risks of combined exposure to multiple chemicals, so-called “chemical cocktails”.

The document provides an overview of the technical aspects of the various approaches and methodologies available with respect to the assessment of risks from combined exposures to multiple chemicals. It draws on the approaches applied and experience gained in the regulatory context and will therefore be most relevant to the regulatory authorities addressing chemicals, the regulated community and other interested stakeholders. The considerations are not presented as strict guidance but rather elements to recognise in assessing combined exposures to multiple chemicals. The concepts are often presented at a more general level as the aim is to address multiple potential assessment scenarios of different types of combined exposures.

The document will be of significant value to anyone involved in performing a hazard, exposure and risk assessment in this context. It provides further guidance in the following areas.

  • Problem formulation for prioritising and scoping of an assessment of combined exposures.

  • Hazard characterisation to inform assessment of combined exposures.

  • Co-exposure characterisation to inform assessment of combined exposures.

  • Risk assessment of combined exposures using various approaches and capturing and communicating uncertainties in findings.

The hazards and risks of chemicals are generally assessed on the evaluation of single substances. However, there are concerns that analysing individual chemicals alone does not provide sufficient security and that the combination effects of chemicals should be addressed in a more systematic way.

Last reviewed 28 December 2018