Experimental bases for ascorbic acid therapy of poisoning by hexavalent chromium compounds

The most frequent outcome of the usually transdermal absorption of hexavalent chromium compounds is uraemia due to tubular necrosis. We have confirmed earlier observations that this can be prevented by the immediate application of ascorbic acid (AA) with the aim of reducing Cr(VI) to Cr(III). The spontaneous reducing capacity of samples of serum and plasma for Cr(VI) compounds was polarographically determined to be about 2 ppm. Addition of AA in doses of 50 to 1000 ppm led to a rapid and dose-dependent reduction of chromium(VI), which was studied on the concentration level of 5 ppm. For example in the presence of 1000 ppm AA, five ppm chromium(VI) fade to 0.7 ppm within 20 min and to undetectable concentrations after 40 min. These experiments demonstrate the effectiveness of AA for the treatment of Cr(VI) poisoning. Reduction is increased and accelerated by AA and the resulting Cr(III)-protein complexes are non-toxic and can be excreted with the urine. Early and repeated high i.v. doses of AA are recommended as the therapy of choice for Cr(VI) poisoning. In cases of delayed medical treatment, AA should be immediately applied orally.