Risk and regulatory hazard-based toxicological effect indicators in life-cycle assessment (LCA)

In life-cycle assessment (LCA), it is desirable to compare quantities of chemicals released into the environment in terms of the risk and consequences of toxicological effects. Many current methods rely directly on adaptations of regulatory-orientated approaches. The resultant hazard-based indicators reflect differences in maximum likely individual exposure in the region for an emission and differences in regulatory limits. Such regulatory hazard-based indicators, however, may not provide a consistent basis for relative comparison across chemicals in terms of toxicological risk, as they were not designed for this application purpose. It is therefore essential to consider other methods in LCA to provide comparative estimates, taking into account the full extent of toxicological risks and differences in consequences. This article provides a step-by-step description of the methodological similarities and differences between such risk and hazard based indicators for LCA. An example for benzo[a]pyrene demonstrates a risk-based methodology, highlighting relationships with regulatory approaches and problems that remain in current practice.