Bioaccessibility testing from powder and massive samples of metals and alloys

The bioaccessability test method enables the quantification of metal species released into artificial solutions (artificial body fluids of relevance for exposure routes including inhalation and ingestion, and dermal contact) from metal or alloy particles or massive sheet at a specific loading and time periods. The released metal species are measured by determining total dissolved metal concentrations in particle-free solutions (leaching analysis). These concentrations can be related and compared with available toxic endpoints for the specific route of interest (inhalation, ingestion, dermal contact), exposure time, particle loading or surface area. Further in-depth studies, also considering surface properties of the particles, speciation of released metals, and mechanisms of release, as well as comparison to some in vivo tests could allow prediction of toxicity of other alloy particles and grouping of materials.

The test method is proposed to be used for classification, ranking, and screening of different metal and alloy particles or massive sheet (relative comparison). Such data cannot be estimated based on bulk alloy compositions.

It is claimed that the data generated with the test method can be used to estimate the impact of alloying on the behaviour of various alloying elements and indicate whether or not hazards associated with one or more of the constituents are likely to persist for the alloy. With regard to the regulatory framework REACH is mentioned.