Effects Of Biosolids On The Accumulation And Transfer Of Trace Elements In Soil-Wheat/Maize Syetem

Land application of biosolids is one way to recycle both the nutrients and the organic matter contained in biosolids, however, the high content of trace elements in biosolids often restrict the biosolid land application. Most of researches on soil–plant transfer of trace elements in biosolids are carried out under laboratory and glasshouse conditions, which could lead to some experimental artifacts. Now, land application of sewage sludge has become an important way for sewage sludge disposal duo to its lower cost and higher efficiency. But trace elementss are the key factor that affects the land application of sewage sludge. So we have done some researches on the monitoring of nutrient and trace elements concentration .Also the impacts of soil environmental and trace elements contents in wheat by land applications of sewage sludge were evaluated to assess the agronomic benefits and environmental impacts of sewage sludge application to soils. The proposes of this study are (1) to monitor the concentration of trace elements in biosolids; (2) soil–plant transfer of trace elements in biosolids in field experiments .The main results obtained were as the following:1. The content of organic matters, nitrogen, phosphorus and potassium in sewage sludge from Beijing is 35.5%, 2.7%, 3.8% and 0.2%, respectively. Except potassium, those are higher than organic fertilizer as pig manure and chicken manure.2. The mean concentrations of Zn, Cu, Ni,Cr, Pb, Cd,As and Hg in sewage sludge from sludge disposal plant are 1479, 216, 38, 85, 59, 1.0, 19 and 13 mg﹒kg-1, respectively, Compared with the trace elements limits of sewage sludge for land application in china, Zn, Cu, Cr, Pb, Ni and As concentrations in sewage sludge are lower than the limits value, and Hg concentrations in sewage sludge is overran the limits value for pH...