Abstract
Fate, exposure and effect measures provide a basis for the calculation of characterisation factors in Life Cycle Assessment (LCA).  Such characterisation factors provide insights into the relative concern of chemical emissions within and across life cycle inventories in the context of toxicological stress to humans and ecosystems.  A brief overview of the available options for toxicological characterisation factors and their relevance is presented in this paper.  An introduction is provided to issues such as (1) the relevance of measures calculated at midpoints and at endpoints in the toxicological cause-effect chains (sometimes termed environmental mechanisms); (2) the need to use of multimedia models with spatial resolution; (3) uncertainty; and (4) the different options for the basis of the toxicological endpoints.