Mobility of Cadmium in Distributed Desert Soil Column Amended by Sewage Sludge

Abstract

The main aim of this research is to predict the movement of cadmium (Cd) ions in sewage sludge-amended soil columns. Sewage sludge impact on the mobility of cadmium was studied using disturbed soil columns, to assess the vertical movement of Cd in desert soil treated with different rates of sewage sludge, i.e., (T1= 0, T2= 20, T3=40, and T4= 60 ton/hectare). The obtained results showed that the physiochemical properties of the studied soil had improved significantly due to sewage sludge addition. Soil organic matter and porosity increase the water-holding capacity and structure of studied soil. Sewage sludge had the ability to increase soil fertility. In contrast, the excess of some heavy metals in the amended soil is the negative impact of using sewage sludge. Cadmium concentrations were greater at a higher rate (T4) of sludge treatment (14.2 mg/kg). According to the findings, the sewage sludge addition to the tested columns yielded considerable Cd concentrations in their leachates. Whereby, leachates of the soil column amendment with 60 ton/hectare contained higher Cd concentration (3.03 mg/l). Moreover, after leaching the soil cadmium concentration differ according to the addition rate, leading to this trend: (T1) < (T2) < (T3) < (T4). Distribution of Cd in soil columns after the leaching process distributed on the soil layers. Overall, Cd movement in sludge-amended soil was correlated with organic matter and pH with r= (0.71439 and 0.0.94886) and r= (0.70965 and 0.99047) respectively.