John Wiley & Sons, Ltd.

Transformation/dissolution examination of antimony and antimony compounds, with speciation of the T/D solutions

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Speciation is held to be a key factor in controlling the ecotoxicity of metals in solution. Using the UN Transformation/Dissolution Protocol (T/DP) for Metals and Sparingly Soluble Metal Compounds, we have examined the T/D characteristics in terms of the concentrations of total dissolved Sb at pH 6 and 8.5 in 1, 10 and 100 mg/L loadings over seven days as well as the concentrations of Sb(III) and Sb(V) at the 1 mg/L loadings over 28 days, of sodium hexahydroxoantimonate, NaSb(OH)6; antimony metal, Sb; antimony trioxide, Sb2O3; antimony sulphide, Sb2S3; sodium antimonate, NaSbO3; antimony tris(ethylene glycolate), Sb2(C2H4O2)3; antimony trichloride, SbCl3; antimony triacetate, Sb(CH3COO)3; and antimony pentoxide, Sb2O5. We also measured the concentrations of the dissolved Sb(III) and Sb(V) species at the 1 mg/L loadings. Due to complexing, the trivalent organic Sb compounds exhibited little or no oxidation of Sb(III) to Sb(V). However, oxidation of Sb(III) to Sb(V) was evident for the trivalent inorganic Sb compounds. Conversely, with pentavalent Sb compounds, there was no reduction of Sb(V) to Sb(III).Based on the percentage of Sb in the compound dissolved or metal reacted at 28 days and 1 mg/L loadings, the solubility rankings at pH 6 areNaSb(OH)6 > Sb(CH3COO)3 > Sb metal > Sb2(C2H4O2)3 > Sb2S3 > Sb2O3 > NaSbO3 ∼ SbCl3 > Sb2O5and for pH 8.5 the order is:NaSb(OH)6 > Sb(CH3COO)3 > Sb metal > Sb2(C2H4O2)3 > SbCl3 > Sb2O3 > Sb2S3 > NaSbO3 > Sb2O5.We provide worked examples of how the T/D data have been used to derive hazard classification proposals for Sb metal and these selected compounds for submission to the European Chemicals Agency under the REACH (Registration, Evaluation, Authorisation and Restriction of CHemicals) legislation. Integr Environ Assess Manag © 2012 SETAC

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