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The preparation and characterisation of four chromium ore reference materials are described in this paper. The sample material for GCr-1, GCr-3 and GCr-4 was collected from chromite deposits in Tibet, Qinghai province and Inner Mongolia. GCr-2 is a composite sample from GCr-1 and GCr-4. Sample homogeneity was tested by WD-XRF and the relative standard deviations were < 1.0%. An F-test showed that all four materials were homogeneous. Thirteen laboratories involved in the inter-laboratory programme provided 672 determinations (eighteen oxides and elements). Sixteen components were characterised as certified values, of which Cr2O3 ranged from 17.59 to 57.80% m/m. The contents of FeO and CO2 were taken as reference values. [ABSTRACT FROM AUTHOR]

This article discusses how erroneous sample preparation can alter conclusions drawn from qualitative and quantitative X-ray powder diffraction analyses of environmental samples. The authors suggest that mechanical pulverization using non-polar fluids, namely cyclohexane, was the optimal method in determining the reactive potential of chromite ore processing residue (COPR), by reliably quantifying the brownmillerite content, the major unstable mineral phase in COPR. Using water during milling caused extensive hydration reactions and yielded nonrepresentative results for COPR mineralogy. Complementary hand pulverization proved necessary to preserve softer minerals. Similar effects may occur in most reactive environmental media.

The article presents a study which discusses fate and transport of chromium in unsaturated zone-saturated zone. Topics discussed include evaluation of water quality in the long-term under sewage irrigation, role of effluent irrigation in easing the agricultural water shortage and waste-water recycling， and change in state of the adsorption and absorption rate of chromium with pH value of soil.

The article discusses chemical composition of spinel-group minerals from the Paleozoic Asian Ophiolite Mélanges and also expands on its petrogenetic importance, and mentions that many ophiolites have undergone hydrothermal alteration and weathering that have modified chromium (Cr)-spinel composition. It states that analysis of major elements in spinel group minerals was carried out by electron microprobe, and concentrations of minor in primary Cr-spinel cores were determined.