施用污泥堆肥对土壤和小麦重金属累积的影响

以小麦为供试作物,以施用化学肥料为对照,通过施用不同量的污泥堆肥和化肥配合,研究了污泥堆肥对土壤和小麦重金属累积的影响。结果表明:土壤中Zn、Cu、Cd、As、Hg等5种重金属含量随污泥堆肥用量的增加而增加;植株中Zn、As、Cr含量随污泥堆肥用量的增加而增加。各处理土壤中8种重金属Hg、Cd、Pb、As、Zn、Cu、Cr、Ni含量均未超出"GB15618—1995(《土壤环境质量标准》)"的二级标准。小麦籽粒中Hg、Cd、Pb含量未超出国家食品卫生标准的标准值,污泥用量18000kg/hm2时As含量超出标准值0.02mg/kg;微量元素Zn、Cu在秸秆中的含量小于籽粒中的含量,而其他重金属在秸秆中的含量是籽粒的2~40倍。由此推断,适量污泥堆肥农用短期内不会引起土壤重金属污染,也不会影响可食部分的食用,重复使用多年后应及时监测。

Effect of sewage sludge compost application on heavy metals accumulation in soil and wheat shoots

A field experiment was conducted to study the heavy metals accumulation in soil and winter wheat supplied with different rates of sewage sludge and chemical fertilizer. The results showed that the content of Zn、Cu、Cd、As、Hg in soil were increased responding to sewage sludge proportion. The same tendency with Zn、As、Cr in wheat. The content of Hg, Cd, Pb, As, Zn, Cu, Cr and Ni were not exceed the second class of the standard of soil environmental quality. Hg, Cd, Pb in wheat grain were not exceed the national food and healthy standard value. While As content was exceeded standard value by 0.02 mg/kg at the amount of 1800kg/hm2 level of sludge compost. Zn、 Cu content in straw was lower than grain, and other heavy metals content was 2-40 times of grain. So in a short time, proper amount of sewage sludge fertilizer will not caused pollution in soil, or bring effects in edible part, either. But years of repeated application demand timely monitoring.