نتایج جستجو برای: chromium compounds
تعداد نتایج: 248683 فیلتر نتایج به سال:
Chromium compounds are potent toxic and carcinogenic substances. With respect to toxicity, hepatic and renal toxicity have been reported both in workers and in animals exposed to chromium (VI). Chromium (VI) compounds induces DNA damage in vivo and in cultured cells as well as the cytotoxicity evaluated by the leakage of lactate dehydrogenase. The present study reports the cytotoxicity of chrom...
The concentration of selenium and thiobarbituric acid reactive substances (TBARS) and activity of glutathione peroxidase (GSH-Px) were determined in blood of 34 workers of a tannery in Gniezno, Poland, who worked in an area containing chromium compounds. Fourteen workers were exposed to chromium compounds at concentrations of 0.11 +/- 0.07 mg Cr/m3 (mean +/- SD) and 20 at concentrations 5-10 ti...
The essentiality and carcinogenicity of chromium depend on its chemical form. Oxidation state and solubility are particularly important in determining the biological effects of chromium compounds. For this reason, total chromium measurements are of little value in assessing its nutritional benefits or its toxicological hazards. Aqueous sodium carbonate-sodium hydroxide solutions have been succe...
Hexavalent chromium compounds exhibit higher toxicity than its trivalent compounds since chromium ions in the +6 oxidation state easily cross biological membranes. It has recently been proposed that substances reducing chromium ions from the +6 to the less toxic +3 oxidation state can be beneficial in management of acute chromium poisoning. In vitro studies also demonstrated quercetin-5 '-sulfo...
Author’s address: J.W.H. Mali, Javastraat 104, Nijmegen (The Netherlands) Last year some doubt arose about the real significance of the positive patch test for bichromate solutions, as positive patch tests and intra-cutaneous reactions for trivalent chromium compounds have been reported (Fregert et al.) and because trivalent chromium compounds, next to bichromate have often been found in the en...
Tannery effluent is a major source of aquatic pollution in India. Hexavalent chromium compounds are being used in a wide variety of commercial processes and unregulated disposal of the chromium containing effluent has led to the contamination of soil, sediment, surface and ground waters. In trace amounts, chromium is considered an essential nutrient for numerous organisms, but at higher level, ...
Chromium, named for its many-colored compounds, exists in the oxidation states of -2 to +6 inclusively. The compounds exhibit a wide range of geometries including square planar, tetrahedral, octahedral, and various distorted geometries. Chromium is found in nature principally as the chromite ore FeCr2O4 in which chromium is in the +3 state. The existence of a particular oxidation state is depen...
Ten years have elapsed since the International Agency for Research on Cancer (IARC) evaluated the carcinogenicity of chromium and chromium compounds. Further studies performed during the last decade have provided further epidemiological, experimental and mechanistic data which support the IARC conclusions. A wealth of results indicate that, at variance with chromium(0) and chromium(III), chromi...
Chromium has been proposed to be an essential trace element useful in the treatment of diabetes, and several chromium(III) compounds have been used as nutritional supplements. However, the fate of the chromium from nutritional supplements has been investigated solely by techniques, such as radio-labeling, which allow only the chromium atom to be traced, not its chemical form. This investigation...
Corrosion is the degradation or deterioration of metal components due to a reaction with the environment. Chromate conversion coating is applied to passivate metallic surface to slow down (and prevent to some extent) corrosion process. Chromate conversion process uses chromium compounds including hexavalent chromium, which is toxic, carcinogenic and hazardous to human health and environment. He...
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