施用城市污泥堆肥对土壤和青椒重金属积累的影响

Effects of Sewage Sludge Compost Application on Heavy Metal Accumulation in Soil and Green Pepper

采用盆栽试验方式,将污泥堆肥与农田土按不同质量比进行混合(0∶100、1∶99、5∶95、10∶90、20∶80、40∶60、80∶20、100∶0),研究施用不同量的城市污泥堆肥对土壤以及青椒器官重金属积累的影响,为城市污泥堆肥农田利用提供参考。试验结果表明:在污泥堆肥施用量为1%~5%的条件下,青椒的总干重随堆肥施用量的增加而增加,5%的污泥堆肥施用量使青椒的总干重达2.67 g·株-1,果实重量达0.84 g·株-1;施用量大于5%时,青椒植株总干重与果实产量均出现下降趋势。施用不同量污泥肥后青椒果实产量(干重)的大小顺序为5%>10%>20%>40%>1%>CK(无果实);随污泥堆肥施用量的增加,基质土中重金属Cu、Zn、Pb、Cr、Cd呈显著增加趋势。在5%的施用量下,土壤及青椒果实中的重金属Cu、Zn、Pb、Cr、Cd、Ni含量均未超过国家相关标准,表明5%的污泥堆肥是青椒的适宜施用量。

Sewage sludge composts applied to soil could supply soil organic matter and plant nutrients, but might also cause heavy metal pollution in soil and plants. In this study, a pot experiment was employed to investigate the effect of applying sewage sludge compost on heavy metal accumulation in soil and green pepper and to determine the maximum application rate of sewage sludge composts. The sewage sludge compost was mixed with soil at different ratios of compost:soil(m∶m), i.e., 0∶100, 1∶99, 5∶95, 10∶90, 20∶80, 40∶60, 80∶20 and 100∶0. The total dry biomass of green pepper increased with sewage sludge compost ratio from 1% to 5%. At 5% compost, the total dry biomass of green pepper was 2.67 g per plant with fruit weight of 0.84 g per plant. However, the total dry biomass and yield of green pepper decreased at the compost ratios higher than 5%. Concentrations of Cu, Zn, Pb, Cr and Cd in soil increased gradually with increasing rates of the compost. At5% compost, the content of Cu, Zn, Pb, Cr, Cd and Ni in both soil and green pepper fruit did not exceed the national standards. These results show that the acceptable application rate of the sewage sludge compost would be 5%.