湘江(长沙段)水中铬的形态分布及其迁移

Distribution,Transferring and Transformation of Chromium Species in Xiangjiang River

研究了湘江水中铬的存在形态、分离方法和分析流程。用极谱催化法测定了江水中的总铬、总溶解铬、颗粒态铬、有机态铬、溶解无机铬、溶解无机态Cr(Ⅵ)、溶解无机态Cr(Ⅲ)。分析了不同季节里铬的存在形态及其迁移转化。结果表明溶解无机态铬是主要的存在形态,其中溶解无机态Cr(Ⅵ)较易转化成毒性较小的Cr(Ⅲ)。不同季节中铬的各形态的含量不同,其中颗粒态铬和有机态铬在夏季的含量较高,而其余各形态的铬在秋、冬两季的含量高于春、夏两季。江水对铬污染的自净能力较强,铬造成的污染的范围较小。

Total chromium, total soluble chromium, granular chromium, organic and soluble inorganic chromium species, and soluble inorganic Cr （ Ⅵ ） and inorganic Cr （ Ⅲ） species in Xiangjiang river were determined with catalytic polarography. The existing species, transferring and transforming of chromium in different seasons were studied. The results indicated that the soluble inorganic chromium was the main species, in which the soluble inorganic Cr（Ⅵ） could be easily transformed to less toxic Cr（ Ⅲ）, and that the concentrations of different chromium species varied with seasons. It was found that the concentrations of granular and organic chromium were higher in summer while those of other chromium species were higher in autumn and winter. The chromium polluted area of Xiangjiang river was relatively small, since the river possessed stronger self-purification capability.