Use of Bioelution as a Screening Tool for Characterisation of Substances

Bioelution, the measuring of in vitro metal ion release from metals or metal compounds in simulated body fluids, can be used as a tool to measure bioaccessibility of metals and metal compounds, and as such provide an estimate of their bioavailability. Comparable bioelution results can allow grouping of substances within a “metal” family. By referring to toxicity data on a metal substance (reference substance) within the group, predictions on the hazard of the other substances in the group can be established. This paper discusses how bioelution testing of metals and metal compounds can be used as an alternative to animal testing for obtaining basic information on their potential toxicity, while allowing compliance with strict information requirements. Two human health hazard endpoints are used to illustrate how bioelution can become part of a testing programme and in particular, target the requirement for new studies and minimise the need for animal testing. In these cases, it is shown how bioelution can be used to predict the hazard of several indium compounds as a first screening.