Hexavalent chromium is recognized as a human carcinogen via inhalation and known to cause lung cancer in humans (Quievryn et al., 2002). Welders are heavily exposed to chromium and therefore are at particular risk. For example, workers exposed to hexavalent chromium in workplace air had significantly increased incidence of lung cancer than workers in control group. However,
lung cancer can only be induced when Cr(VI) doses overwhelm these defense mechanisms. Incidences of cancers of nasal cavity have also significantly increased over the past decade (Sunderman, 2001). In conclusion, Cr(VI) compounds are carcinogenic to humans, Target Selective Inhibitor Library but epidemiological studies provide evidence that its carcinogenicity is strictly site-specific. Various case reports of occupational and nonoccupational Cr(VI) ingestion have been reviewed (Barceloux, 1999a and Barceloux, 1999b). Adverse health effects seen in these cases include gastrointestinal symptoms, hypotension, and hepatic and renal failure. An increase rate in stomach tumours was observed in humans and animals exposed to chromium(VI) in drinking water. Sperm damage and damage to the male reproductive system have also been seen in laboratory animals exposed to chromium(VI). The Occupational Safety and Health Administration (OSHA) announced limits of occupational exposure to Cr(VI) (Occup. Safety, 2006). Safe environment represents less GSK126 in vivo than 5 μg of Cr(VI) per cubic meter of air. Very
recent studies using cells cultures revealed a much greater potential for Cr(VI) to cause chromosomal damage and mutations (Reynolds et al., 2007) than was previously expected. The metal, Cr(0), is less common and does not occur naturally. Cr(0) is not currently believed to cause a serious health
risk. The US National Academy of Science has established a safe daily intake for chromium in adults of 50–200 μg per day (Institute of Medicine, 2001). Chromium(III) is an essential mineral which has a beneficial role in the regulation of insulin, metabolic syndrome and cardiovascular disease. Chromium potentiates insulin and therefore plays a role in the normal glucose metabolism. Decreased levels of chromium in human tissues have been found which correlated with the incidence of diabetes 2. Deficiency of chromium has this website been associated with disturbed glucose tolerance, fasting hyperglycemia, glucosuria, increased body fat, dyslipidemia and impaired fertility (De Flora et al., 1995). There is growing evidence that chromium may facilitate insulin signalling and chromium supplementation therefore may improve systemic insulin sensitivity (Hummel et al., 2007). Chromium metabolism has signs of disturbance in humans with cardiovascular disorders. Picolinate is a byproduct of the amino acid tryptophan and chromium picolinate (200 μg per day) has been shown to reduce insulin resistance and to help reduce the risk of cardiovascular disease and type 2 diabetes (Bagchi et al., 2002).