![]() ![]() A recent study revealed that rats and mice exposed to Cr(VI)-contaminated drinking water developed gastrointestinal abnormalities, including oral and intestinal tumors. A key issue is whether Cr(VI) ingested through the oral route, converts to trivalent Chromium Cr(III) (which does not cross the cell membrane that easily) before entering a living cell. Īt the cellular level, Cr(VI) is a highly active carcinogen. In a recent article using data from the National Toxicology Program (NTP) of the National Institutes of Health, hexavalent chromium was identified as 'likely to be a carcinogen to humans' with an estimate of the cancer potency to humans equal to 0.5 (mg/kg/day) -1. Hexavalent chromium Cr(VI) is recognized by the World Health Organization (WHO) as a human carcinogen through inhalation, but there is significant debate on the carcinogenicity of hexavalent chromium when it is orally ingested. Further studies are needed to determine whether this association is causal, and to establish preventive guidelines and public health recommendations. ConclusionsĮlevated cancer mortality in the Oinofita area of Greece supports the hypothesis of hexavalent chromium carcinogenicity via the oral ingestion pathway of exposure. Elevated SMRs for several other cancers were also noted (lip, oral cavity and pharynx 344, stomach 121, female breast 134, prostate 128, and leukaemias 168), but these did not reach statistical significance. Furthermore, statistically significantly higher SMRs were identified for lung cancer (SMR = 145, 95% CI 100-203, p-value = 0.047) and cancer of the kidney and other genitourinary organs among women (SMR = 368, 95% CI 119-858, p-value = 0.025). The SMR for all cause mortality was 98 (95% CI 89-107) and for all cancer mortality 114 (95% CI 94-136). ResultsĪ total of 474 deaths were observed. ![]() We calculated gender, age, and period standardized mortality ratios (SMRs) for all deaths, cancer deaths, and specific cancer types of Oinofita residents over an 11-year period (1999 - 2009), using the greater prefecture of Voiotia as the standard population. We conducted an ecological mortality study within the Oinofita region of Greece, where water has been contaminated with hexavalent chromium. Water contaminated with hexavalent chromium is a worldwide problem, making this a question of significant public health importance. Dermal exposure to hexavalent chromium may cause contact dermatitis, sensitivity, and ulceration of the skin.Hexavalent chromium is a known carcinogen when inhaled, but its carcinogenic potential when orally ingested remains controversial. Chronic human exposure to high levels of hexavalent chromium by inhalation or oral exposure may produce effects on the liver, kidney, gastrointestinal, and immune systems, and possibly the blood. Chronic inhalation exposure to hexavalent chromium results in effects on the respiratory tract, with perforations and ulcerations of the septum, bronchitis, decreased pulmonary function, pneumonia, and nasal itching and soreness as reported. The respiratory tract is the major target organ for hexavalent chromium following the inhalation exposure in humans. Hexavalent chromium is known to have 100-fold more toxicity than trivalent chromium, for both acute and chronic exposures because of its high water solubility and mobility, as well as easy reduction. ![]() Ore refining, chemical and refractory processing, cement-producing plants, automobile brake lining, catalytic converters for automobiles, leather tanneries, and chrome pigments contribute to the atmospheric burden of chromium. The compounds exhibit a wide range of geometries including square planar, tetrahedral, octahedral, and various distorted geometries. Chromium exists in oxidation states ranging from −IV to +VI, inclusively. ![]()
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