Arsenic(As) pollution of soil and drinking water has recently promoted this element into an environmental pollutant of prime concern. Arsenic toxicity is so high and humans may be exposed to As from variety of environmental sources. Sewage sludge application on farmland as fertilizer is very common in many countries. Sewage sludge is rich in organic matter as well as macro and micronutrients. However high concentration of heavy metals in sludge may cause pollution of soil and ground water resources. The objectives of this study were to determine As movement and wheat uptake of As in a sewage sludge amended calcareous soil in central Iran . Sewage sludge was applied at (0, 25, 50 and 100 t/ha) to the soil (fine loamy, mixed, thermic, haplargid). Each plot was divided to five subplots. In 1st year sewage sludge was added to all plots. In the 2nd year sludge was added to 4/5 of plots, in the 3 rd year to the 3/5 of plots and in the 4 th year to the 2/5 of the plots and in the 5 th year to the 1/5 of the plots and finally in 6th year sewage sludge was applied to whole plots again. Soil samples were collected at 0-20, 20-40, 40-60, 60-80, 80-100 cm depths from all the plots. Plant samples (root, shoot and grain) were also collected too. Soil analysis indicated that the sewage sludge increased EC, OM , CEC, As, Ni, Cu, Zn and Fe significantly. The greatest amount of total and DTPA extractable metal concentrations were observed at 0-20 cm depth and decreased significantly with depth. Regarding the As content in wheat, differences between treatments and control were not statistically significant. Sewage sludge caused an increase of concentration of Fe, Cu, Zn in wheat roots and shoots, significantly. Metal concentration in wheat grain were not statistically significant Concentration of. As, Zn, and Cu in soils were higher than critical levels but the concentrations were normal in the plant. Results show that effect and duration was depended in the rate of sludge used.
