EDTA and industrial waste water improving the bioavailability of different Cu forms in contaminated soil

It is common to find that low bioavailability can prevent the phytoremediation process of heavy metal-contaminated soils. Heavy metals in soil are associated with various forms having different bioavailability. In this study, the bioavailability of various Cu forms in contaminated soils was investigated using ion-exchange resins, a sequential extraction procedure, and combined with methods including partial dissolution procedure, simulated Cu forms, seedling culture, pot experiment when treated with EDTA, or waste water from monosodium glutamate and citric acid production. Results showed that the bioavailability, in decreasing order of different Cu forms to tall fescue (Festuca arundinacea Schreb.) is: exchangeable Cu (EX-Cu) and organic matter bound Cu (OM-Cu) > Cu bound to carbonate (CAB-Cu) > Fe/Mn oxide bound Cu (OX-Cu) > residual Cu (RES-Cu). Effect of EDTA on the activation of Cu contaminated soil or simulated Cu and the uptake and translocation of tall fescue was better than that of monosodium glutamate waste water (MGW) and citric acid waste water (CAW). EDTA, CAW and MGW all improved the plant availability of different Cu forms in contaminated soil, which could be used in chelate-assisted phytoremediation of heavy metal polluted soil.