Effect Of Bone Char And Phosphate Rock On Remediate Multi-metal Contaminated Soils

The soil pollution is getting worse with the rapid development of industry inrecent years, there are growing worldwide concentrations on the heavy metalpollution in soil as a global environmental problem. Soil heavy metal pollution canaffect plant growth, quality of food. Heavy metals can ultimately affect human healththrough the food chain. So remediation technology research of heavy metalcontaminated soil has a very important scientific and practical significance. Chemicalimmobilization of heavy metal is remediation method to use chemical additives incontaminated soils to reduce the bioavailability and migration of heavy metal, it is aneffective way for the remediation. Therefore, this paper research the effect of differentsizes of bone char and phosphate rock on remediate multi-metal contaminated soils bypot experiment and soil colomn cultivation, the results are as follows:(1)The influence of different sizes of bone char and phosphate rock on CAT,POD, APX, SOD activity and MDA content by plant shoots were conducted byvisible spectrophotometry. According to these physiological changes in plants, seekphysiological mechanisms of plant resist heavy metal in the case of add bone char andphosphate rock. The results show that, compared with the control treatment,application of bone char, phosphate rocks resulted in concentrations of MDA in plantdecreased3.08%-28.48%. Application of200μm of bone char,200μm of phosphaterock and22μm of phosphate rock resulted in SOD activity of plant increasedrespectively78.42%,67.42%,51.23%.22μm of bone char resulted in POD, SOD,APX activity increased101.64%,199.06%,67.74%, respectively. CAT, SOD, APXactivity of plant increased respectively256.34%,140.70%,69.35%after add0.8μmof phosphate rock. Add0.8μm of bone char in the soil could significantly increasedCAT, POD, APX, SOD activity of plant120.66%,120.97%,145.16%,160.45%,respectively.(2)Uptake and accumulation of heavy metals by plants were affected by adddifferent sizes of bone char and phosphate rock. Compared with the control treatment,additives resulted in concentrations of Cd and Pb in corn shoots decreased respectively13.28%-33.78%and1.34%-11.11%, concentrations of Cd and Pb in cornroots decreased respectively20.94%-51.84%and6.08%-26.67%; add0.8μm of bonechar resulted in concentrations of Cu in plant shoots and plant roots decreased12.22%and11.79%, respectively. Compared with other treatments,0.8μm of bone char hasthe most obvious effect on reduce uptake and accumulation of heavy metals byLolium perenne.(3)Both bone char and phosphate rock could change the speciations of heavymetals in soil, from the easily leachable transforms into more difficultly leachingspeciations. Compared with the control treatment, add bone char, phosphate rockresulted in the percentage of soil HOAc-soluble Cd, Pb decreased respectively18.56%-37.32%and26.39%-87.84%, the percentage of Fe-Mn oxide fraction of Cdincreased23.49%-34.04%, the percentage of Fe-Mn oxide fraction of Pb decreased12.43%-48.10%; The proportion of carbonate-Pb decreased49.68%-58.84%, theresidual Cd, Pb fraction increased19.06%-21.31%and165.39%-393.47%,respectively. The effect of0.8μm of bone char was better than other treatments.The experimental result indicates that,0.8μm of bone char is a potential materialto remediate multi-metal contaminated soils.