Study On The Organic Phosphate Solubilizing Bacteria On Amending Acidity And Heavy Metal In Acidic Contaminated

In the study,a soil amendment was prepared by two organic phosphate-solubilizing bacteria isolated form lead polluted soil.The results indicated that the ability of solubilizing phosphate of 3-6-1 was 167.62 mg/L,pH from 7 to 8.95,could grow well in the solution with Pb,Cd and Cu,whereas for 3-6-2,the ability was 152.63 mg/L,pH from 7 to 8.82 and sensitive to death on high concentration of pollution solution.Therefore,this study chose the 3-6-1 as the ultimate test strain.3-6-1 was identified as Serratia marcescens by 16S rRNA technology.Soy lecithin was expensive,compared with the phosphorus content of rapeseed meal,soybean meal and cottonseed meal,the study chose rapeseed meal as organic phosphorus source.Soil immobilization experiment showed that as a soil conditioner,3-6-1 had a multiple impact on heavy metal pollution in acid soil.Soil pH and effective potassium increased significantly,but available phosphate increment was not obvious.It showed this strain reduced the acidity and increased the nutrients in the acidized soil.There were differences between the impact on soil enzyme activity,the phosphatase activity in the pollution treatment were promoted,but the urease and invertase activity changed due to the difference of metal ions and trends were different.In single copper pollution treatment,acidic phosphatase was higher than other pollution treatments.While invertase activity was lower than other treatments.Changes in metal sequential fractions showed that the exchangeable and carbonate bounds of Pb,Cd and Cu in soil transformed into residual bound through this amendment.The preliminary research of mechanism shows that:Precipitate or adsorption of heavy metals has showed that 3-6-1 could quickly remove the heavy metals in the solution.The suitable pH was 7.0 and the adaptable temperature was 20?30 ? for 3-6-1.At last,the adsorption of heavy metals increased quickly,at Pb2+ 400 mg/L,the precipitation and adsorption rate was 61.73%and 96.11%;at Cd2+ 100 mg/L,the precipitation and adsorption rate was 73.68%and 95.22%;at Cu2+ 200 mg/L,the precipitation and adsorption rate of 68.76%and 97.57%,respectively.Stability experiment showed that the precipitation of heavy metal was more stable than adsorption.Above all,organic phosphate solubilizing bacteria had good effect on improvement of pH and immobilization of heavy metals in the acid soil.