| Abstract: | Nickel activities were measured in 11 alkaline and slightly acidic soils using the chelate method. The measured activities ranged from 10?6.82 to 10?8.78 M and were inversely related to the pH of the soils. The measured Ni2+ activities in the 11 soils could be predicted using the following expression: (Ni2+) = 106.95 (H+)2. The solubility of Ni was plotted on a log (Ni2+) vs. pH solubility diagram for various Ni solid phase compounds. It is most likely that NiFe2O4 (trevorite) is the solid phase controlling Ni solubility in these soils. Identification of the presence of this mineral needs further investigation. |
