BACKGROUND Chromium is an essential element in human nutrition. Serum concentrations of chromium are not well characterized during pregnancy or in gestational diabetes mellitus. OBJECTIVE The objective of this study was to determine whether low plasma chromium concentrations (< or =3 nmol/L) are associated with altered glucose, insulin, or lipid concentrations during pregnancy. DESIGN The s...

Chromium is one of the 25 most widespread elements in the Earth’s crust and occurs as an indelible non-volatile trace element in raw materials used in cement clinker production (clay, limestone and iron additives in particular). Chromium in raw materials mentioned above is mainly in form of trivalent chromium. Naturally occurring chromium (III) is not initially harmful, since it is chemically s...

Reduction of chromium(VI) to chromium(Ill) by thiourea between pH 3.0 and 5.5 is a key aspect of the chrominm(VI)/thiourea/polyacrylamide gel polymer system used in enhanced oil recovery processes. A method has been developed to determine chromium(Vl) concentration during the reduction of chromium(VI) to chromium(III) in this pH range. The reduction reaction is run in the presence of an acetic ...

The data on the standards for chromium requirements and the safety of various chromium compounds and doses are reviewed. The 350-fold difference between the acceptable daily intake and the calculated reference dose for humans of 70 mg per day seems without precedent with respect to other nutritional minerals. Previous claims of mutagenic effects of chromium are of questionable relevance. While ...

This study was undertaken to develop an assay for biologically active chromium suitable for determining the best form of chromium for human supplementation studies. The assay involved monitoring the decrease in fasting serum glucose for 1-3 hours in normal human subjects following ingestion of 100 μg of chromium. The maximum decline occurred 1-2 hours after taking the chromium. The average maxi...

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...

Two workers exposed to trivalent chromium sulphate in a leather tannery had high concentrations of chromium in the urine. The concentration of chromium showed a workshift-related diurnal fluctuation, but it was remarkably high even after a vacation, indicating accumulation of chromium in the body. The concentrations of chromium in the workplace air, as collected on filters using standard techni...

Chromium exists primarily in two forms: trivalent and hexavalent. Trivalent chromium is present in the cationic form as Cr+3 and is an essential nutrient, but hexavalent chromium is toxic and exists as an anion, either as chromate (CrO4 -2) or dichromate (Cr2O7 -2). Therefore, the analysis of total chromium does not always provide a true indication of the effects of chromium present in a sample...

One factor limiting solid oxide fuel cell (SOFC) performance is the degradation of chromium containing, ferritic stainless steel, interconnects during operation. When chromium-containing steels are used as interconnect materials a chromium oxide layer forms on the surface. Under SOFC operating conditions (Cathode gas 800oC and 2.5-3.1% H2O) chromium ions are vaporized by the cathode gas and red...

Chromium in fumes generated in work environments including sites of welding work appears in various and complex states. Determination of chromium speciation in samples is useful for estimating the toxicity of such fumes. In the present study, determination of chromium speciation in chromium fumes prepared using a plasma metal sprayer, which are regarded as a model of actual fumes, was carried o...