Mixtures in the environment are usually composed of multiple components from a range of sources with different chemical structures and modes of action. However, environmental risks of chemicals are still often assessed substance by substance, neglecting mixture effects, that is, the effects arising from the presence of multiple chemicals in mixtures.
This document describes a practical approach to how the Persistent Organic Pollutants Review Committee could consider toxicological interactions. The approach is adapted to the working procedures of the committee and is based on the state-of-the art knowledge on mixture toxicity.
The basic scheme for assessing the combined effects of different contaminants starts when scientific data are available indicating that the presence of other chemicals in the same organism may add to the hazard posed by a given chemical being reviewed for persistent organic pollutant characteristics.
As part of the GEF-funded and UNEP-led “Global Development, Review and Update of NIPs under the Stockholm Convention on POPs” project, the Green Growth Knowledge Partnership (GGKP) is executing Component 4, focused on disseminating information, managing knowledge and coordinating with the Stockholm Convention Secretariat to provide accessible, integrated tools and resources for all Parties.