Speciation Analysis Of Chromium In The Xiangjiang River

The existing form of chromium in nature and pre-disposal, separation, enrichment and methods of determination were reviewed in this article. A catalytic polarographic system of diaminoethanenitronatrium and resonance scattering of rhdamine B for determination of Cr(â…¥) were improved respectively, which were successfully applied to determinate chromium speciation in water and soil samples respectively. The distribution and transformation of chromium speciation in Xiang Jiang water system(water,soil and waterweeds) in different position and seasons were systemically researched.The main work of this article includes four parts.1 The application of sensitive catalytic polarographic wave of chromium(â…¥) with diaminoethane-nitronatrium-EDTA in buffer solution of NH₄Cl-NH₃·H₂O for determination trace chromium has been (时态不统一)researched. This method was featured by its high selectivity, stability and sensitivity. The correlative coefficient was r=0.9987, the detection limit was 0.005μg/L, and the linear range of determination was 0.01～20μg/L.2 Characterized by simple, exact and sensitive, a new method was proposed for the determination of chromium(â…¥) by resonance scattering of rhdamine B-I₃^-. It was simple, exact and sensitive. The linear range of determination was 10～500μg/L, and the detection limit was 2.2μg/L, and the correlative coefficient was r=0.9923. Combined with ion exchange, the method had been applied to the determination of chromium speciation in soil and waterweeds samples successfully.3 The distribution and transformation of chromium speciation in water of Xiang Jiang River were systemically researched. The results showed that chromium (â…¥) could be deoxidized to chromium (â…¢) easier in acidic water, and the sullage in river-bottom had stronger adsorption. The content of chromium (â…¥) was lower than national drinking water criterion (GB5749-85) in the fourth sampling spot (toward backward position 1.5Km spot from the limber hole), so the polluted area of chromium in Xiang Jiang River by waste water from the chromic plant was limited. In different seasons, the content of chromium speciation was changed. The content of granular and organic chromium was higher in summer, while other chromium speciation was higher in autumn and winter.4 Distribution and Transformation of chromium speciation in the soil and accumulation in waterweeds were researched systemically. The result indicated that the granular and organic chromium were main existing form of chromium in soil, and the absorbed chromium by soil in water mainly changed into organic chromium, and the content of chromium speciation were varied in different seasons. The organic and ion-exchange chromium species had well correlated with total chromium in waterweeds, and can be absorbed by waterweeds easier while the residue form chromium was difficult.