城市污泥及蚓粪施用对生菜和土壤中重金属(Cr、Pb和Cd)积累的影响

EFFECTS OF DOMESTIC SEWAGE SLUDGE AND VERMICOMPOST ON Cr,Cd AND Pb CONCENTRATIONS IN LETTUCE AND SOIL

利用盆栽试验研究了不同配比的城市生活污泥和蚓粪(污泥或蚓粪在混配土壤中的质量分数为10%、20%和30%(以干重计))施用于土壤后,对生菜和土壤中Cr、Pb和Cd三种重金属元素积累的影响,以期为污泥蚓粪的农用提供依据及指导。试验结果表明:无论何种比例的污泥和蚓粪,重金属Cr和Cd在生菜体内的含量均低于国家标准限值,而重金属Pb在生菜体内的含量均不同程度地高于国家标准限值,生菜体内的重金属含量从大到小依次为Pb>Cr>Cd。研究发现,无论施用污泥和蚓粪,大多数情况下重金属在生菜体内的含量以10%施用量处理组最高。20%配比的处理种植并收获生菜后,土壤重金属的含量显著低于10%和30%处理组土壤。

In order to provide a scientific basis and guidance for the agricultural use of domestic sewage sludge and vermicompost,pot experiments were conducted to investigate the effect of domestic sewage sludge and vermicompost（ the ratio of domestic sewage sludge or vermicompost in the mixed soil by dry weight was 10%,20% and 30%,respectively） land application on Cr,Cd and Pb concentrations of lettuce and soils. The results showed whatever the ratio of domestic sewage sludge or vermicompost in the mixed soil was,the concentrations of Cr and Cd of lettuce were kept below the maximum levels of contaminants in foods（ GB 2762—2005）,while the concentration of Pb in lettuce exceeded the national standard limit. The concentration of heavy metal in lettuce was in the order of Pb Cr Cd. In the most cases,the heavy metal concentration in lettuce in 10% mixing ratio of domestic sewage sludge or vermicompost was more than the control group and other treatments.After planting and harvesting lettuce,the content of heavy metals in soil in 20% ratio application was significantly lower than that in the 10% and 30% ratio application.