Use of read-Across in the health risk assessment of ferrochromium alloys under reach

In REACH regulation there is a category of substances called special preparations, to which alloys belong. In the assessment of special preparations not only the bulk composition of an alloy, but also the way the constituent metals are bonded in the chemical matrix, shall be taken into account. The surface of the alloy may limit the ability of constituent metals to be released from the matrix and thus affect the toxicological profile of an alloy. Therefore, the surface characteristics and the release rates of metals shall be taken into account. Finnish Institute of Occupational Health has been carrying out REACH-compliant chemical safety assessment of ferrochromium in collaboration with International Chromium Development Association. Ferrochromium is composed mainly of chromium and iron with small amounts of other metals, e.g. nickel. Since almost no studies have been published on the health effects of ferrochromium, the assessment of ferrochromium should be based on its constituent metals. An approach used in this study included the use of data on surface composition and release of metal constituents from ferrochromium. The chromium oxide surface layer limits the release of nickel and other constituents from ferrochromium and affects the toxicological profile. As a result it can be concluded that ferrochromium alloys can be likened to chromium metal and stainless steel when assessing their health hazards. Thus, the risk assessment can be based largely on existing human, animal and in vitro toxicity data on chromium metal, chromium(III)oxide and stainless steel. By referring to this data, it was possible to make conclusions on health hazards of ferrochromium without need to carry out any new toxicity tests.
QC 20120213