Phosphorus Solubilization of Bacteria and Associated Heavy Metal Releasing from Phosphate Rock Powder

The relationship between the dissolving phosphorus(P) and the releasing heavy metals from phosphate rock powder by phosphate solubilizing bacteria(PSB) was studied in this paper.The results showed that the associated heavy metals in phosphate rock powder could leach out with the P-solubilizing from phosphate rock powder by PSB.Among the 6 associated heavy metals(Zn,Pb,Cu,Ni,Cd and Co),Zn was the easiest to release from phosphate rock powder with the P solubilization by PSB,and the maximum amount of dissolved Zn reached 97.0% of the total Zn associated with P in the phosphate rock powder.On the contrary,Pb and Cd showed high stability,and the concentrations of Pb and Cd released from phosphate rock powder were both lower than 10%.The relationship between the phosphate solubilizing capacity and the amount of associated heavy metal released from phosphate rock powder varied with the characteristics of these phosphate rock powder and the kind of heavy metal.The phosphate solubilizing capacity of PSB in Hunan-shimen phosphate rock powder and Sichuang-mabian phosphate rock powder had an insignificantly positive correlation with the amount of Zn,Ni,Co and Cu releasing,respectively(r= 0.50-0.95,P 0.05).And the phosphate solubilizing capacity of PSB in Guizhou phosphate rock powder had a significantly positive correlation with the amount of Zn,Ni,and Co releasing,respectively(P 0.05).