USES uniform system for the evaluation of substances inclusion of fate in LCA characterisation of toxic releases applying USES 1.0

Most former methods for the impact assessment of toxic releases in LCA gave a relative yardstick for the potential toxic effect of a substance, with no allowance being made for intermedia transport and degradation. These factors may be of major influence on the degree of (eco)toxic effects to be expected. As part of its work on substance policy, RIVM has developed a computer model called Uniform System for the Evaluation of Substances (USES) to assess, as realistically as possible, the degree to which the no-effect level is transgressed in practice. This model makes allowances for the fate of substances in the environment. An important offspring of the project is not only that substance assessment has been linked to the LCA method, but also that it shows LCA users how they can establish the LCA equivalency factors for the (eco)toxicity of "unknown" substances by themselves, and how they can recalculate the equivalency factors that were reported from the project. This last point is particularly of interest because the new list of equivalency factors suffers from serious uncertainties due to data gaps. Lastly, some future perspectives as to further modelling activities is discussed, in particular with respect to a generic fate model for all emission-related impact types