Geometrical States and Bioavailability of Heavy Metals in Hongqiling Nickel Mining Area,Jilin Province
Surface soil samples with different degrees of impact from tailing ponds were collected from Hongqiling nickel mining area,Jilin province,to evaluate the pollution status of heavy metals in the soil,and the bioavailability of heavy metals was evaluated by risk assessment code method(RAC)and secondary phase to primary phase distribution ratio method(RSP).The results of single-factor pollution index analysis showed that the pollution indexes of soil samples far from the tailing pond in the study area were less than 1,which is at a relatively clean level;the pollution indexes of Ni and Cd in the soil samples close to the tailing pond were both greater than 3.0,indicating a high level of pollution.The comprehensive pollution index analysis results showed the pollution index of soil samples far from the tailing pond in the study area were less than 0.7,which is at a safe level;The soil samples close to the tailing pond had pollution indexes greater than 3.0,indicating a severe pol-lution level.The results of Tessier continuous extraction analysis showed that the residual content of Cr and Pb was higher than that of other states.Cu was mainly in residual and organically bound states;Zn was mainly in the residual state and the combined state of iron and manganese oxides;The exchangeable and carbonate bound states of Ni and Cd were relatively high.Among the three factors of soil pH,organic matter content and total amount of heavy metals in the soil,the total amount of heavy metals in the soil was the main factor affecting the distribution of heavy metals in the soil in the mining areas.The combination of risk assessment coding method(RAC)and secondary phase to primary phase distribution ratio method(RSP)indicates that Ni and Cd were of high bioavailability and environmental risk in nickel mining areas.
nickel mine areaheavy metalpollution assessmentfraction distributionbioavail-abilityJilin province