adsorption to both the monodentate sites (Cp1) and the bidentate and tridentate sites (Cp2) were signi fi cant since the total Pb concentrations in soils were much higher The kinetics of metal adsorption and desorption on di fferent soil binding sites were analyzed using model calculations(Figure 4). The total Cu and Zn concentrations in soils (Cp) were relatively low compared with the total Pb concentrations in soils and the bidentate and tridentate sites dominated both Cu and Zn adsorption (Figure 4A and B). However, Pb