Effects of sewage sludge application on heavy metals status in soil and wheat
Application of sewage sludges on farmland as fertilizers is a common practice in Iran as in many other countries. As a result, large amounts of heavy metals are introduced in this way onto large areas of arable land. Little is known about the uptake of these metals by crop plants and the risks that result to human health via the food chain under the conditions of Iranian agriculture. The objective of this 4-year study was to determine residual and cumulative effects of repetitive sewage sludge applications on the ac-cumulation of lead (Pb), cadmium (Cd), zinc (Zn), and copper (Cu) in soil and wheat (Triticurn aestivum). Sewage sludge was applied in four subsequent years at rates of 25, 50 and 100 Mg·ha<1> on plots of an experimental farm nearby Isfahan. To study not only cumulative, but also residual effects, applications were discontinued in subsequent years on part of the area to which sludge had been applied in the preceding year. Total sludge amounts applied were 25, 50, and 100 Mg·ha<1> in plots with one application, 50, 100, and 200 Mg·ha<1> in plots with two applications, 75, 150, and 300 Mg · ha<1> in plots with three applications and 100, 200, and 400 Mg· ha<1> in plots with four applications. Wheat (Triticum aestivum) was grown each year. After the fourth year, soil samples from 0-20 cm depth were analyzed for total and DTPA-extractable concentrations of Pb, Cd, Zn and Cu. Roots, stalks and grains were separately analyzed. Sludge applications at a rate of 100 Mg· ha<1> (for all the metals) and at a rate of 50 Mg·ha<1> (for Cu) increased DTPA-extractable metal concentrations significantly. DTPA-extractable concentrations of Pb, Zn and Cu were closely correlated with total concentrations. Lead, Cd, Zn and Cu uptakes in stalks and Pb, Zn and Cu concentrations in grains were significantly higher in some of the sludge treatments than on the untreated control plots.
calcareous soil heavy metals sewage sludge wheat
Majid Afyuni Mahin Karami Rainer Schulin
Dept. of Soil Science, College of Agriculture, Isfahan University of Technology, Isfahan 84156, Iran Institute of Terrestrial Ecosystems, ETH Zuerich, Universitaetstr. 16, CH-8092 Zurich, Switzerland
国际会议
第九届痕量元素生物地球化学国际会议(9th International Conference on the Biogeochemistry of Trace Elements)
北京
英文
576-577
2007-07-15（万方平台首次上网日期，不代表论文的发表时间）