Hexavalent chromium
描述
Hexavalent chromium refers to chemical compounds that contain the element chromium in the +6 oxidation state. Chromium(VI) is more toxic than other oxidation states of the chromium atom because of its greater ability to enter cells and higher redox potential. (L16)
类别
"Industrial/Workplace Toxin", "Pollutant", "Airborne Pollutant", "Natural Toxin"
同义词
"Chromium hexavalent ion", "Chromium ion", "Chromium ion (6+)", "Chromium(6+)", "Chromium(6+) ion", "Chromium(VI)", "Chromium(VI) cation", "Chromium(VII) ion", "Cr(6+)", "Cr6+", "Hexavalent chromium", "Metallic chromium"
IUPAC 名称
λ⁶-chromium(6+) ion
InChI 标识符
InChI=1S/Cr/q+6
键
InChIKey=JOPOVCBBYLSVDA-UHFFFAOYSA-N
化合物类型
Inorganic compounds
大分类
Homogeneous metal compounds
类型
Homogeneous transition metal compounds
直接大类
Homogeneous transition metal compounds
取代基
"Homogeneous transition metal"
外部描述符
"a cation", "chromium cation", "monoatomic hexacation"
地位
Detected and Not Quantified
蜂窝位置
"Cytoplasm", "Extracellular"
暴露途径
Oral (L16) ; inhalation (L16) ; dermal (L16)
毒性机制
Hexavalent chromium's carcinogenic effects are caused by its metabolites, pentavalent and trivalent chromium. The DNA damage may be caused by hydroxyl radicals produced during reoxidation of pentavalent chromium by hydrogen peroxide molecules present in the cell. Trivalent chromium may also form complexes with peptides, proteins, and DNA, resulting in DNA-protein crosslinks, DNA strand breaks, DNA-DNA interstrand crosslinks, chromium-DNA adducts, chromosomal aberrations and alterations in cellular signaling pathways. It has been shown to induce carcinogenesis by overstimulating cellular regulatory pathways and increasing peroxide levels by activating certain mitogen-activated protein kinases. It can also cause transcriptional repression by cross-linking histone deacetylase 1-DNA methyltransferase 1 complexes to CYP1A1 promoter chromatin, inhibiting histone modification. Chromium may increase its own toxicity by modifying metal regulatory transcription factor 1, causing the inhibition of zinc-induced metallothionein transcription. (A12, L16, A34, A35, A36)
代谢
Chromium is absorbed from oral, inhalation, or dermal exposure and distributes to nearly all tissues, with the highest concentrations found in kidney and liver. Bone is also a major storage site and may contribute to long-term retention. Hexavalent chromium's similarity to sulfate and chromate allow it to be transported into cells via sulfate transport mechanisms. Inside the cell, hexavalent chromium is reduced first to pentavalent chromium, then to trivalent chromium by many substances including ascorbate, glutathione, and nicotinamide adenine dinucleotide. Chromium is almost entirely excreted with the urine. (A12, L16)
致死剂量
1 to 3 grams for an adult human. (A119)
致癌性
1, carcinogenic to humans. (L135)
用途/来源
Hexavalent chromium is used for chrome plating, dyes and pigments, leather tanning, and wood preserving. (A12)
最低风险等级
Intermediate Oral: 0.005 mg/kg/day (L134)
Chronic Oral: 0.001 mg/kg/day (L134)
健康影响
Hexavalent chromium is a known carcinogen. Chronic inhalation especially has been linked to lung cancer. Hexavalent chromium has also been know to cause reproductive and developmental defects. (A12)
症状
Breathing hexavalent chromium can cause irritation to the lining of the nose, nose ulcers, runny nose, and breathing problems, such as asthma, cough, shortness of breath, or wheezing. Ingestion of hexavalent chromium causes irritation and ulcers in the stomach and small intestine, as well as anemia. Skin contact can cause skin ulcers. (L16)
治疗
There is no known antidote for chromium poisoning. Exposure is usually handled with symptomatic treatment. (L16)
创建于
2009-03-06 18:57:56 UTC
更新于
2014-12-24 20:20:53 UTC