六价铬

六价铬，又称铬(VI)或Cr(VI)，是任何含有氧化态+6的铬的化合物。几乎所有的铬矿都是通过一种六价铬化合物——重铬酸钠加工的。六价铬是所有由铬制成的材料的关键。1985年人们约生产了136,000公噸（150,000英噸）的六价铬。^[1]

三氧化铬是六价铬的例子

六价铬化合物包括三氧化铬以及各种铬酸盐和重铬酸盐。六价铬用于纺织染料、木材防腐（英语：Wood preservation）、防蚀剂（英语：Corrosion inhibitor）、铬酸盐转化涂层（英语：Chromate conversion coating）以及各种小众用途。六价铬化合物的工业用途包括染料、油漆、油墨和塑料中的铬酸盐颜料，作为防腐剂添加到油漆、底漆和其他表面涂层中的铬酸盐以及电镀到金属部件上以提供装饰或保护涂层的铬酸。在进行如在不锈钢上进行焊接或熔化铬金属等“热加工”时，也会形成六价铬。在这些情况下的铬最初不是六价的，但过程中涉及的高温会使铬被氧化，将铬转化为六价。^[2]六价铬也存在于饮用水和公共供水系统中。^[3][4]

由于六价铬的氧化性，它有毒且具会致癌（国际癌症研究机构一类致癌物）。如果吸入六价铬，会导致肺癌。此外，人们还观察到接触六价铬与鼻子和鼻窦的癌症之间存在正相关。^[5]许多职业的工人都会接触到六价铬，其中有问题的暴露发生在处理含有铬酸盐的产品的工人以及研磨和焊接不锈钢的工人中。^[6]接触六价铬的工人患肺癌、哮喘或鼻上皮和皮肤损伤的风险增加。^[2]

参考资料

1. Anger, Gerd; Halstenberg, Jost; Hochgeschwender, Klaus; Scherhag, Christoph; Korallus, Ulrich; Knopf, Herbert; Schmidt, Peter; Ohlinger, Manfred, Ullmann's Encyclopedia of Industrial Chemistry, Weinheim: Wiley-VCH, 2005, doi:10.1002/14356007.a07_067
2. 29 CFR OSHA General Industry 1910
3. Xie, Yun; Holmgren, Stephanie; Andrews, Danica M. K.; Wolfe, Mary S. Evaluating the Impact of the U.S. National Toxicology Program: A Case Study on Hexavalent Chromium. Environmental Health Perspectives. 2017, 125 (2): 181–188. PMC 5289905 . PMID 27483499. doi:10.1289/ehp21.
4. What is chromium-6 and how did it infiltrate America's drinking water?. PBS NewsHour. September 21, 2016 [September 23, 2019]. （原始内容存档于2019-09-23）.
5. IARC. Volume 100C: Arsenic, Metals, Fibres, and Dusts (PDF). Lyon: International Agency for Research on Cancer. 2012 [17–24 March 2009] [2020-01-05]. ISBN 978-92-832-0135-9. （原始内容 (PDF)存档于2020-03-17）. There is sufficient evidence in humans for the carcinogenicity of chromium (VI) compounds. Chromium (VI) compounds cause cancer of the lung. Also positive associations have been observed between exposure to Chromium (VI) compounds and cancer of the nose and nasal sinuses. There is sufficient evidence in experimental animals for the carcinogenicity of chromium (VI) compounds. Chromium (VI) compounds are carcinogenic to humans (Group 1).
6. IARC. Volume 49: Chromium, Nickel, and Welding (PDF). Lyon: International Agency for Research on Cancer. 1999-11-05 [1990] [2006-07-16]. ISBN 978-92-832-1249-2. （原始内容 (PDF)存档于2008-12-24）. There is sufficient evidence in humans for the carcinogenicity of chromium[VI] compounds as encountered in the chromate production, chromate pigment production and chromium plating industries.

外部链接

• ATSDR Case Studies in Environmental Medicine: Chromium Toxicity （页面存档备份，存于互联网档案馆） U.S. Department of Health and Human Services
• Hexavalent Chromium National Emphasis Program （页面存档备份，存于互联网档案馆）
• Economou-Eliopoulos, Maria; Megremi, Ifigenia; Vasilatos, Charalampos. Factors controlling the heterogeneous distribution of Cr(VI) in soil, plants and groundwater: Evidence from the Assopos basin, Greece. Chemie der Erde – Geochemistry. 2011, 71 (1): 39–52. Bibcode:2011ChEG...71...39E. doi:10.1016/j.chemer.2011.01.001.
• 3M US: OSHA Hexavalent Chromium Standard – An overview of the Chromium Six (CrVI) standard
• Michaels, David; Monforton, Celeste; Lurie, Peter. Selected science: An industry campaign to undermine an OSHA hexavalent chromium standard. Environmental Health. 2006, 5: 5. PMC 1402271 . PMID 16504102. doi:10.1186/1476-069X-5-5.
• Australian National Pollutant Inventory Chromium VI fact sheet （页面存档备份，存于互联网档案馆）
• US OSHA Health and Safety Topics: Hexavalent Chromium" （页面存档备份，存于互联网档案馆）
• National Institute for Occupational Safety and Health – Hexavalent Chromium （页面存档备份，存于互联网档案馆）
• M. Economou-Eliopoulos; D. Antivachi; Ch. Vasilatos; Megremi, I. Evaluation of the CR(VI) and other toxic element contamination and their potential sources: The case of the Thiva basin (Greece). Geoscience Frontiers. 2012, 3 (4): 523–539. doi:10.1016/j.gsf.2011.11.010 .