Five soil amendments including acetic acid (AA), citric acid (CA), EDTA, sepiolite and phosphogypsum were serviced. AA, CA and EDTA were pure salts. Sepiolite was obtained from a sepiolite plant in Hunan Province, China. Phosphogypsum, an industrial by-product, was collected from a phosphour fertilizer plant in Guizhou Province, China. Both samples of sepiolite and phosphogypsum were milled and then sieved through a 0.084 mm sieve before use. The concentrations of As, Cd, Pb in sepiolite and phosphogypsum are detailed in Table 2.