Bioavailability Assessment of Heavy Metals in the Vicinity of Dabaoshan Mine

In this study,the predictive ability of six extractants(HCl,DTPA,CaCl2,NH4NO3,MgCl2 and deionized water) was investigated with respect to bioavailability of Pb,Zn,Cu and Cd in three types of vegetable planted soils,which were collected from Shangba Village near Dabaoshan mine.The results showed that Pb extracted by HCl and DTPA and the Zn extracted by CaCl2,NH4NO3 and MgCl2 had good correlation with metals concentrations in the three vegatables.Among six extractants,CaCl2 extractable Cd showed the best correlation with bioavailable Cd.Extracted Cu by all six extractants had no significant correlation with Cu concentrations in vegetables.HCl-and DTPA-extractable Fe and Mn concentrations were very high in soils,which indicated that most of Pb,Zn,Cu,and Cd were tightly bound with these fractions and this might be responsible for low extraction rate.Comparing with Pb,Cu and Cd,Zn was least affected by Fe and Mn oxides.Moreover,the heavy metal concentrations in roots could be more reasonable indices to investigate the transfer from soil than those in shoots.