نتایج جستجو برای: chromium cr
تعداد نتایج: 59444 فیلتر نتایج به سال:
176 chromium-exposed and 30 control subjects were selected for this study. Blood samples (3 ml) were collected for the estimation of chromium. The data on chromium concentration indicated a significant higher level of chromium in the blood of the exposed workers as compared to the control. There was no significant correlation between the mean blood and environmental chromium level. This study s...
Chromium exists usually in the (III) or (VI) oxidation states. In contrast to Cr(III), which is essential to mammalian systems, Cr(VI) is dangerous for humans due to its toxicity and carcinogenic properties. Cr(VI) compounds are highly soluble, mobile and bioavailable compared to Cr(III) species. Chromium is usually analyzed using instrumental methods such as AAS or ICP, which are accurate and ...
The evaluations of the potential carcinogenicity of metallic chromium and trivalent chromium by several international and national agencies [International Agency for Research on Cancer (IARC), 1990; Agency for Toxic Substances and Disease Registry (ATSDR), 1993; Canadian Environmental Protection Act (CEPA), 1994; United States Environmental Protection Agency (US EPA), 1998; United States Nation...
Chromium is an important industrial metal, an environmental pollutant, and a human carcinogen. To investigate the mechanisms of chromium-induced carcinogenesis, activation of mitogen-activated protein (MAP) kinases ERK1 and ERK2 was examined in rat hepatoma cells following exposure to hexavalent chromium (Cr(VI)). Cr(VI) was found to activate both forms of MAP kinase in a dose- and time-depende...
Effect of addition of municipal solid waste compost (MSWC) on chromium (Cr) content of submerged rice paddies was studied. Experiments were conducted during the three consecutive wet seasons from 1997 to 1999 on rice grown under submergence, at the Experimental Farm of Calcutta University, India. A sequential extraction method was used to determine the various chromium fractions in MSWC and cow...
Batch adsorption experiments were performed for the removal of chromium (III) and chromium (VI) ions from aqueous solutions using Canadian peat and coconut fiber. The Langmuir model was used to describe the adsorption isotherm. The maximum adsorption for peat reached 18.75 mg/g for Cr(III) and 8.02 mg/g for Cr(VI), whereas the value for fiber was slightly higher and reached 19.21 mg/g for Cr(II...
Chromium reduction by Escherichia coli ATCC 33456 quantitatively transferred hexavalent chromium, Cr(VI), to trivalent chromium, Cr(III). The reduced chromium was predominantly present in the external medium. Supernatant fluids of cell extract, obtained by centrifugation at 12,000 and 150,000 x g, showed almost the same Cr(VI) reduction activity, indicating that Cr(VI) reduction by E. coli ATCC...
the goal of this experiment was to investigating of effects of different levels of nano chromium (n-cr) in diet on egg quality and blood chromium content of japanese quail. two hundred and forty laying japanese quail (45 day old) were randomly distributed to 20 experimental unit with 12 birds in cage pens of 40 × 80 cm. experimental treatments include: 1) control national research council (nrc,...
Chromium (Cr) is a heavy metal that naturally occurs in the Earth’s crust, and can be found in groundwater in either the trivalent, Cr(III), or in the hexavalent, Cr(VI), form. While Cr(III) is considered an essential trace element for the human body, Cr(VI) is potentially dangerous for human health although the type and intensity of the effect are still being investigated. The widespread use o...
Concentration levels of hexavalent chromium in contaminated soil and in Zea mays plant parts were determined and Cr(VI) bioaccumulation and bioconcentration capacity of this plant were discussed. Zea mays seeds were sown in 40 mg Cr(VI)/kg dw polluted soil. After harvesting it was observed that hexavalent chromium concentrations in plant organs decreased in the following order: roots > stems > ...
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