我国部分城市畜禽粪便中重金属含量及形态分布

通过对部分城市集约化养殖场的畜禽粪便取样调查,分析了其中重金属含量状况及其形态分布。结果表明,畜禽粪便中重金属Cu、Zn、Cd、As、Ni、Cr、Pb和Hg含量分布差异较大,其平均值分别为377.5、1 610.4、0.72、7.79、9.77、22.51、6.31 mg·kg-1和0.06mg·kg-1。不同类型畜禽粪便比较,猪粪中Cu、Zn、Cd、As含量显著高于鸡粪、鸭粪和牛粪,而鸡粪中Cr含量则高于猪粪和牛粪。参照国家农用污泥污染物控制标准,猪粪中Cu、Zn的超标率分别达59.84%和95.08%,As超标率为3.28%,而Cd、Ni、Cr、Pb和Hg的含量则均低于控制标准。根据畜禽粪便安全使用准则中在蔬菜地使用限量标准,猪粪中Zn、Cu、As超标率分别为78.69%、74.59%和9.84%,鸡粪、鸭粪中Zn、Cu、As含量也存在超标现象。对乳猪粪、育肥猪粪和种猪粪的重金属含量和形态分析发现:乳猪粪中Cu和Zn含量高于育肥猪粪,而种猪粪则较低;育肥猪粪中As含量高于乳猪粪和种猪粪;种猪粪的Cd含量高于乳猪粪和育肥猪粪。猪粪中Cu、As水溶态含量分别占总量的30.47%和12.19%,EDTA提取态Cu、Zn含量分别占总量的35.96%和48.93%,猪粪中Cu、Zn、As较高的活性会在一定程度上增加其向环境中流失的风险。

Content and fractionation of heavy metals in livestock manures in some urban areas of China

Samples of livestock manures were taken from intensive farms in some urban areas of China to study content and fractionation of heavy metals. Results indicated that Cu, Zn, Cd, As, Ni, Cr, Pb and Hg content in these livestock manure samples varied greatly, with averages of 377.5, 1610.4, 0.72, 7.79, 9.77, 22.51, 6.31 mg·kg^-1 and 0.06 mg·kg^-1, respectively. The content of Cu, Zn, Cd and As was significantly higher in pig manure than in poultry manure and in cow and sheep dung, while Cr content in poultry manure was the highest among all samples. There were 59.84% and 95.08% of pig manure samples in which Cu and Zn content exceeded the National Control Standards of Contaminants in Agricultural Sludge, respectively. Based on the Standards of Guidelines for the Safe Use of Animal Manure in Vegetable Field, Cd, Ni, Cr, Pb and Hg in the pig manure samples were all safe, while for As there was only 3.28% of samples exceeding the limit. However, for Zn, Cu and As, 78.69%, 74.59%and 9.84% of pig manure samples exceeded the limits, respectively. Copper or Zn content decreased in order of nursery pig manure >growing-finishing pig manure >sow manure. The content of As in growing-finishing pig manure was higher than that in nursery pig manure and sow manure, while Cd content was higher in sow manure than in growing-finishing pig manure and nursery manure. In addition, water soluble Cu and As content accounted for 30.47% and 12.19% of the total, respectively, while EDTA-extractable Zn and Cu were 35.96% and 48.93% of the total, respectively. The high mobility of Cu, Zn and As in pig manure might increase their risk of releasing into the environment.