Surfactant Linear Alkylbenzene Sulfonate Effect on Soil Cd Fractions and Cd Distribution in Soybean Plants in a Pot Experiment1

A pot experiment was conducted to study the effect of an anionic surfactant linear alkylbenzene sulfonate (LAS) application on cadmium (Cd) fractions in soils and Cd distribution in different tissues of soybean (Glycine max)plants as well as soil pH. Soil samples were treated with three levels of Cd (0, 5, and 10 mg kg−1) and five levels of LAS (0, 5, 15, 50, and 100 mg L−1). Results indicated that compared to the control soils (no Cd and no LAS treatment), soil pH increased and available Cd decreased in the soil treated with external Cd and watered with LAS solutions. Meanwhile, soil exchangeable Cd and Cd bound to carbonates decreased; Cd bound to amorphous iron and manganese oxides and Cd bound to organic matter increased. In addition, LAS application could reduce enrichment of Cd in soybean plants, resulting in decreased Cd in the soybean plants. Thus, suitable LAS application could decrease bioavailability and mobility of soil Cd.