BACKGROUND Contact allergy epidemics to chromate and nickel were addressed in Denmark in 1983 and 1990 by regulatory interventions. OBJECTIVES To evaluate whether regulatory interventions on nickel and chromate exposure have reduced the proportion of strong patch test reactions. METHODS 22 506 patients with dermatitis aged 4-99 years were patch tested with nickel sulfate, potassium dichroma...

Precipitation titrations are based upon reactions that yield ionic compounds of limited solubility. The most important precipitating reagent is silver nitrate. Titrimetric methods based upon silver nitrate are sometimes termed argentometric methods. Potassium chromate can serve as an end point indicator for the argentometric determination of chloride, bromide and cyanide ions by reacting with s...

In the title mol-ecular salt, (C3H12N2)[CrO4], each chromate anion accepts six N-H⋯O and C-H⋯O hydrogen bonds from nearby propane-1,2-di-ammonium cations. Three of the four O atoms of the chromate anion accept these bonds; the remaining Cr-O bond length is notably shorter than the others. In the crystal, the anions and cations stack in layers lying parallel to (100): the hydrogen-bonding patter...

Imaging live molecular events within micro-organisms at single-cell resolution would deliver valuable mechanistic information much needed in understanding key biological processes. We present a surface-enhanced Raman (SERS) chemical imaging strategy as a first step toward exploring the intracellular bioreduction pockets of toxic chromate in Shewanella. In order to achieve this, we take advantag...

Electrochemical reduction of nitrates and nitrites in alkaline media at constant current is rendered inoperable in the presence of hexavalent chromate. Even at chromate concentrations as low as 9mgdm, the chromium hydroxide ®lm, formed by the reduction of chromate, interferes with the reduction of nitrate and nitrite. We show that reversing the polarity of the electrodes at constant time interv...

T HE MOST common radioactive marker for life-span determination of circulating blood elements has been 51chromium. In the two decades since its introduction by Gray and Sterling,’ a considerable number of other isotopic substances both radioactive and nonradioactive have made their appearance, but none achieved the popularity of 51Cr. This substance in its hexavalent form, as chromate ion, lend...

Resistance of the indigenous strains P. jadinii M9 and P. anomala M10, to high Cr(6+) concentrations and their ability to reduce chromium in culture medium was studied. The isolates were able to tolerate chromium concentrations up to 104 μg mL(-1). Growth and reduction of Cr(6+) were dependent on incubation temperature, agitation, Cr(6+) concentration, and pH. Thus, in both studied strains the ...

Zero-valent iron (ZVI) and green rusts can be used as reductants to convert chromium from soluble, highly toxic Cr(VI) to insoluble Cr(III). This study compared the reduction rates of Cr(VI) by ZVI and two carbonate green rust phases in alkaline/hyperalkaline solutions. Batch experiments were carried out with synthetic chromate solutions at pH 7.7-12.3 and a chromite ore processing residue (COP...

The chromium content was measured in the lungs of chromate workers, obtained at necropsy in six patients and at surgery in two. The mean chromium content of peripheral lung tissue was 36.7 micrograms per gm wet weight (range 0.50 to 130.2 micrograms) and that of the large airways was 0.51 micrograms per gm wet weight (range 0.22 to 0.99 micrograms). These means values were high compared with th...

A total of 85 chromate-resistant bacteria were isolated from the rhizosphere of water hyacinth grown in Mariout Lake, Egypt, as well as the sediment and water of this habitat. Only 4 (11%), 2 (8%), and 2 (8%) of isolates from each of the environments, respectively, were able to tolerate 200 mg Cr (VI) L(-1). When these eight isolates were tested for their ability to tolerate other metals or to ...