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A Review Of Human Carcinogens--Part C: Metals, Arsenic, Dusts, And Fibres.
Published 2009 · Medicine
In March, 2009, 27 scientists from eight countries met at the International Agency for Research on Cancer (IARC) to reassess the carcinogenicity of metals, arsenic, dusts, and fi bres previously classifi ed as “carcinogenic to humans” (Group 1) and to identify additional tumour sites and mechanisms of carcinogenesis (table). These assessments will be published as part C of Volume 100 of the IARC Monographs. Inhalation is the primary route of exposure to arsenic in the workplace and happens in industries such as nonferrous smelting, arsenic pro duction, wood preservation, glass manu facturing, production and application of arsenic-based pesticides, and electronics. Non-occupational exposure to arsenic is mainly through food, except in areas with high levels of arsenic in the drinking water—eg, Taiwan, Bangladesh, West Bengal (India), northern Chile, and Cordoba Province (Argentina). Epidemiological studies have shown that exposure to arsenic through inhalation or drinking-water causes cancer of the lung, skin, and urinary bladder. Evidence suggests an association between exposure to arsenic in drinking water and the development of tumours at several other sites; however, various factors prevent a conclusion. Analytical studies have provided only limited information to support an association with kidney cancer, causes of liver cancer can be diffi cult to elucidate in groups that are high-risk for hepatitis B, and data on prostate cancer and arsenic exposure are not consistent between countries. Overall, the Working Group classifi ed arsenic and inorganic arsenic compounds as “carcinogenic to humans” (Group 1). The organic arsenicals monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA) are the active ingredients of some herbicides and are metabolites of inorganic arsenic. On the basis of suffi cient evidence of cancer caused by DMA in experimental animals, and because MMA is extensively metabolised to DMA, both compounds are classifi ed as “possibly carcinogenic to humans” (Group 2B). Arsenobetaine and other organic arsenic compounds that are not metabolised in humans are “not classifi able” (Group 3). The Working Group reaffi rmed the classifi cation of beryllium and its compounds, cadmium and its compounds, chromium (VI) compounds, and nickel compounds as “carcinogenic to humans” (Group 1). Studies involved complex occupational exposures to a metal and its compounds, making it impossible to separately assess their carcinogenicity. Globally, an estimated 125 million people are still exposed to asbestos in the workplace. Although asbestos has been banned or restricted in most of the industrialised world, its use is increasing in parts of Asia, South America, and the former Soviet Union. Naturally occurring sources of asbestos, its use in brake linings, and deterioration of asbestos-containing products all contribute to environmental exposure worldwide. Exposure may also come from fi bres carried home on the clothing of asbestos workers. Upcoming meetings June 2–9, 2009 Radiation