What are cadmium and cadmium compounds?

Related cancers:

Lung cancer, possibly prostate and kidney cancer

Exposure routes: Inhalation and ingestion

Where found: Food (particularly grain cereal products, potatoes, and other vegetables), cigarette smoke, zinc and lead ores, electroplating and -coating, alloys, pigments (paint, glass, ceramics, porcelain, textiles, plastics, paper, and fireworks), stabilizers in plastics, nickel-cadmium batteries, smoke detectors, radiation detectors, and various electronics and laboratory equipment

At risk: Workers who refine and smelt zinc and lead ores, workers in industries using thermal processes (iron production or welding cadmium-coated steel), and tobacco smokers

Etiology and symptoms of associated cancers: Cadmium exposure can be acute or chronic. Acute toxicity through ingestion of cadmium may cause only short-term illness, but acute toxicity through inhalation can lead to severe damage to the lungs and even death. Chronic exposure to cadmium can cause damage to the lungs, kidneys, and sometimes bones. Studies have shown that inhalation of cadmium in the workplace is associated with lung cancer. Laboratory studies using cultured cells have shown that cadmium damages the deoxyribonucleic acid (DNA) of the cells and affects the cells’ ability to repair DNA damage. These factors are likely to be the mechanism through which cadmium contributes to the formation of cancer in humans.

Lung cancer can affect one lung or both. Lung cancer detection often occurs when the disease has progressed to late stages because symptoms may take years to appear. When symptoms do appear, they often are mistaken for other less serious conditions. Common signs and symptoms of lung cancer are persistent cough (not related to smoking); persistent pain in the chest, shoulder, or back; coughing up mucus or blood; recurrent respiratory infections; shortness of breath; fatigue; unexplained weight loss; and loss of appetite. Many of these symptoms may be attributed initially to other causes before lung cancer is eventually diagnosed. According to the National Toxicology Program's
Report on Carcinogens
, Twelfth Edition (2011), lung cancer is the only cancer that has been confirmed to be associated with cadmium exposure.

Studies from the 1960s and later have had conflicting results regarding a connection between cadmium and prostate cancer. A number of studies have shown increases in the occurrence of prostate cancer in workers exposed to cadmium in nickel-cadmium battery plants and other industrial sites, but conflicting studies have indicated either no increases or increases that were too small to be statistically significant. Cadmium has also been implicated in kidney cancer, with early studies showing a correlation between exposure and increases in kidney cancer. However, further studies have not confirmed this association.

History: Industrial use of cadmium became widespread in the middle of the twentieth century, and the toxic effects due to occupational exposure began to be recognized by the early 1950s. Studies that examined workers who had been exposed to high levels of cadmium were used to examine the toxic effects, and by the 1960s researchers were investigating cadmium’s potential carcinogenicity. Experimental animal studies also were conducted to research the toxicity and carcinogenicity of cadmium. Regarding the role cadmium played in the development of lung cancer, initial studies were inconclusive or conflicting. Confounding factors, such as workers who were also tobacco smokers or were exposed to additional heavy metals, contributed to the confusing results. Because of its toxic effects, many federal, state, and local agencies, including the Environmental Protection Agency (EPA), began to regulate cadmium in a variety of ways, including stipulation of allowable amounts in air and water. In 1992 the Occupational Safety and Health Administration (OSHA) ruled on permissible exposure limits (PELs) for workers exposed to airborne cadmium in the workplace. By 2000 sufficient studies reported that cadmium contributed to the development of lung cancer for it to be designated as a known human carcinogen by the US Department of Health and Human Services.

Bibliography

Adams, Scott V., Michael N. Passarelli, and Polly A. Newcomb. "Cadmium Exposure and Cancer Mortality in the Third National Health and Nutrition Examination Survey." Occupational and Environmental Medicine 69.2 (2012): 153–156. Digital file.

Amer. Cancer Soc. "Known and Probable Human Carcinogens." Cancer.org. ACS, 17 Oct. 2013. Web. 24 Sept. 2014.

Klaassen, Curtis D., ed. Casarett and Doull’s Toxicology: The Basic Science of Poisons. 8th ed. New York: McGraw, 2013. Print.

Silvera, S. A. N., and T. E. Rohan. “Trace Elements and Cancer Risk: A Review of the Epidemiologic Evidence.” Cancer Causes Control 18 (2007): 7–27. Print.

US Dept. of Health and Human Services, Public Health Service, Natl. Toxicology Program. Report on Carcinogens. 11th ed. Research Triangle Park: USDHHS, PHS, NTP, 2005. Print.

US Dept. of Health and Human Services, Public Health Service, Natl. Toxicology Program. "Cadmium and Cadmium Compounds." Report on Carcinogens. 12th ed. N.p.: USDHHS, PHS, NTP, 2011. 80–83. Digital file.

Waisberg, M., P. Joseph, B. Hale, and D. Beyersmann. “Molecular and Cellular Mechanisms of Cadmium Carcinogenesis.” Toxicology 192 (2003): 95–117. Print.