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Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

This article review approximately 700 results reported in the literature with 32 chromium compunds assayed in 130 short-term tests using different targets and/or genetic end-points. Cr (III) compounds are grouped according to their solubility:

  • highly soluble Cr (III) compunds including chromic chloride, chromic acetate, chromic nitrate chromic sulfate and chromic potassium sulfate. Chromic chloride induced a variety of genetic effects in acellular or subcellular targets. In contrast all Cr (III) compounds almost consistently failed to induce various genetic effects in bacteria. Weak results were obtained in yeasts, under particular treatment, and in plants. They were generally inactive in cultured mammalian cell systems investigating DNA synthesis, DNA damage, forward mutations and sister-chromatid exchanges. Induction of chromosomal abberations was more frequent than sister-chromatid exchanges although, compared to Cr (VI), much higher Cr (III) concentrations were generally needed. Conflicting results were reported in cell transformation assays. Following in vivo treatment, no DNA fragmentation or induction of micronuclei was detected in rats and in mice, respectively
  • Soluble Cr(III) compounds. This group of compounds includes basic chromic sulfate, chromic alum and chromic phosphate. The results reported in the limited number of studies available for these compounds are comparable to those reported for highly soluble Cr (III) compounds.
  • Poorly soluble and insoluble Cr (III) compounds. This group of compounds includes chromic hydroxide, chromic oxide, chromite ore and cupric chromite. These compounds were genotoxic in bacteria only when contaminated with Cr (VI). Conflicting results were obtained in cultured mammalian cells, where chromic oxide was found to be taken up by cells and to induce mutation, chromosomal aberrations and sister-chromatid exchanges, although at concentrations 1000-fold higher than for Cr (VI). In addition to the aforementioned compounds, chromium tannins used in the hide and leather industry, most of which are composed of scarecly soluble sulfates, were also tested. None of 17 tannins reverted his- S. typhimurium, whereas 8 out of 13 tannins, 4 of which were contaminated with Cr (VI), increased the frequency of sister-chromatid exhanges in Chinese hamster ovary cells.
  • Cr (III) complexes with organic ligands were assayed in both prokaryotic and eukaryotic cell systems. Complexes of chromic chloride with salicylate or citrate were positive in the rec assay with B. subtilis. Out of 17 hexacoordinated Cr (III) complexes, 8 were positive in a differential killing test with E. coli and 4 also reverted his- S. typhimurium. The most active complexes, containing aromatic amine ligands such as 2,2'-bipyridine and 1,10-phenanthroline were confirmed to be mutagenic. On the other hand, complexes of Cr (III) with amino acids did not revert his- S.typhimurium strains. In mammalian cultured cells, chromic glycine complexes did not induce unscheduled DNA synthesis in human skin fibroblasts nor mutation in Chinese hamster V79 cells. However, a chromic phenanthroline complex induced fragmentation and produced a weak DNA fragmentation in the same cells. Cr (acetylacetonate)3 but not Cr maltolate increased the frequency of sister-chromatid exchanges in Chinese Hamster ovary cells.
Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (negative)

Genetic toxicity in vivo

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

Note that both chromium III and oxalic acid salts are found in food. Chromium III is an essential element and oxalic acid is a product of metabolism that is typically excreted.

In view of high concentrations in the diet and in living tissues, the substance is not considered to be mutagenic.

Justification for classification or non-classification

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