摘要：The excessive usage of sludge treatment from urban wastewater plants has become a major concern in China because of the potential for heavy metal pollution. Sedum lineare (SL) is a hardy evergreen plant and an important ornamental succulent widely used as a 'greening5 or 'green roof5 plant in China and Japan. In this study, SL was planted in pots of soil with fermented sewage sludge applied in varying concentrations, additionally, to investigate the impact of earthworms on sludge-treated soil, a parallel set of experiments were established with E. fetida. The content and fractionation of heavy metals (Pb, Cr, Cu, Zn, and Ni) in the soil, and the impact of sludge use on the growth of SL were measured over a period of 100 days, plants grown in higher sludge concentration had significantly less growth than those in lower concentrations. The different heavy metals were found to have differing amounts of each fraction, in all cases fraction I, the exchangeable form, was least present. There were considerable differences when comparing test soils with and without earthworms, the earthworms had different effects on different heavy metals suggesting a potential role of the worm in effecting availability of heavy metals. The application of fermented sludge did not appear to impede SL growth at low doses but was found to be harmful at higher doses. Therefore land usage of sludge should be optimized carefully to ensure it is most effective and causes minimal harm.
