中国城市污泥的重金属含量及其变化趋势

Concentrations and Variation of Heavy Metals in Municipal Sludge of China

于2006年从全国范围内选取107个城市污泥样品,测定了其重金属含量。结果表明,污泥中As、Cd、Cr、Cu、Hg、Ni、Pb和Zn的平均含量分别为20.2、2.01、93.1、219、2.13、48.7、72.3和1058mg/kg。与2001年以前的调查结果相比,污泥中的重金属含量总体呈下降趋势,其中Cd、Cr、Cu、Hg、Ni、Pb和Zn的含量分别降低了32.3%、49.7%、54.9%、25%、37.2%、44.8%和27%。与《城镇污水处理厂污染物排放标准》(GB18918—2002)相比,城市污泥中Cd、Cu、Ni和Zn含量的超标率相对较高,其超标率分别为6.5%、6.5%、6.5%和11.2%。

To identify the concentrations of heavy metals in municipal sludge of China, samples of municipal sludge were collected from 107 sewage treatment plants in China in 2006. The results indicate that the average concentrations of As, Cd, Cr, Cu, Hg, Ni, Pb and Zn in the sludge are 20.2 mg/kg, 2.01 mg/kg, 93.1 mg/kg, 219 mg/kg, 2.13 mg/kg, 48.7 mg/kg, 72.3 mg/kg and 1 058 mg/kg re- spectively. Compared with the results of heavy metals in municipal sludge taken before 2001, there is a significant decrease in heavy metals in the sludge, and the average concentrations of Cd, Cr, Cu, Hg, Ni, Pb and Zn are decreased by 32.3%, 49.7%, 54.9%, 25%, 37.2%, 44.8% and 27% respec- tively. However, the concentrations of Cd, Cu, Ni and Zn in the samples exceed the heavy metal limits of Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant （ GB 18918 - 2002）, being 6.5%, 6.5%, 6.5% and 11.2% respectively.