Abstract
The present study included determination of the active portion of Cadmium and predicting its possible solid phases which controlling its activities in sludge amended soils
The results showed that the measured Cd2+activities (using the competitive chelation method) increased with the prolonged use of sewage effluent water in irrigation. As shown from the Table (3) increased Cd2+activity by 9.94 folds than the control soil sample. Furthermore, the results were negatively correlated with pH values (r= 0.81).
Also, the present data clearly show that the tested remedial materials with the three rates of amending (1, 2, and 3% w/w) had great influences on the values of Cd activities. The obtained Cd activities were (4.65006E-09 and 6.89868E-09), (3.7353E-09 and 6.00091E-09), and (4.61439E-09 and 5.93551E-09) in C1, C2, and C3 Zero valent iron- and Rock phosphate amended soil, respectively.
Plotting the determined Cd activities of the tested soil samples on the constructed stability diagrams of the various cadmium minerals indicated that the obtained values of Cd using the competitive chelation method, were lie below the diagrams of the constructed Cd minerals, Suggesting that there are possibility of other minerals could controlling the solubility of Cd in sewage effluent irrigated soil at Egypt.