Risk Assessment of Heavy Metal in Cultivated Soil by Rhizon-SMS and Single Extraction

This study compares Cu and Zn bioavailibity to maize using three extraction procedures for soils. The distribution coefficient Kd based Rhizon-SMS method was used to describe the distribution Cu and Zn in soil solution and rhizosphere soil solid. A good liner regression between log K_d (Zn) and pH was found (R2 = 0.42, P < 0.001), while the application of a stepwise forward multiple for log K_d (Cu) provided a regression equation including total Cu and SOM variables. As for the prediction accuracy of the heavy metals in the maize grain, based on logarithm transformation and simple linear correlation analysis, the Rhizon- SMS method was restricted to soil groups. In contrast, DTPA method is the effective method in predicting plant Cu and Zn concentration in maize grain. CaCh appears to be not a highly effective technique to predict Cu and Zn uptake by plants.