[Chromates: resistance and detoxification in bacteria]

Derivatives of hexavalent chromium (chromates and dichromates) are highly toxic and have been shown to be mutagens and carcinogens. These compounds are often disposed to the environment as a result of diverse industrial procedures. The presence of chromates selects bacterial strains possessing chromate resistance determinants, commonly carried by plasmids. Some bacteria are able to reduce hexavalent chromium to trivalent chromium which is much less toxic. Bacterial strains combining both properties, resistance to and reduction of chromate, are potentially useful for decontamination of sewage or other refuse contaminated by chromates.