Oral absorption of chromium compounds in humans can range between 0.5% and 10%, with the hexavalent (VI) chromium more easily absorbed than the trivalent (III) form. In human cells _in vitro_, Cr (VI) caused chromosomal aberrations, sister chromatid exchanges and oxidative DNA damage.Ĭhromium compounds are both absorbed by the lung and the gastrointestinal tract. There have been associations of increased frequencies of chromosome aberrations in lymphocytes from chromate production workers. Hexavalent chromium compounds were mutagenic in bacteria assays and caused chromosome aberrations in mammalian cells. Soluble chromium VI compounds are human carcinogens. Chronic exposure may cause damage to the following organs: kidneys, lungs, liver, upper respiratory tract. The oral lethal dose in humans has been estimated to be 1-3 g of Cr (VI) oral toxicity most likely involves gastrointestinal bleeding rather than systemic toxicity. Hexavalent chromium is a Class A carcinogen by the inhalation route of exposure and Class D by the oral route. There is no known antidote for chromium toxicity. In case of overdose with minimal toxicity following acute ingestion, treatment should be symptomatic and supportive. Acute overdose of chromium is rare and seriously detrimental effects of hexavalent chromium are primarily the result of chronic low-level exposure. Other LD50 values reported for rats include: 3.5 g/kg (CI 3.19-3.79 g/kg) for chromium sulphate 11.3 g/kg for chromium (III) acetate 3.3 g/kg for chromium nitrate and 1.5 g/kg for chromium nitrate nonahydrate.
LD50 of chromium (III) oxide in rats is reported to be > 5g/kg.
Oral LD50 for Cr (III) in rat is >2000 mg/kg. Oral LD50 for Cr (VI) is 135 - 175 mg/kg in mouse and 46 - 113 mg/kg in rat.
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