Evaluation and Comparison of Phytoavailability of Cadmium in Contaminated Soils by Three Chemical Extraction Procedures

Effects of soil Cd contamination on growth of Brassica chinensis in three different soils were investigated through greenhouse pot trial.Chemical fractions of cadmium (extracted by 0.43 mol·L^-1 HNO₃,0.05 mol·L^-1 EDTA and 0.01 mol·L^-1 CaCl₂) were evaluated by using a single extraction procedure. The results show that the Cd content in the aboveground part of Brassica chinensis had a nonlinear relationship with the metal in soils. It has been found that Cd content in the aboveground part of Brassica chinensis has negative correlation with soil pH values. The Cd mobility was in the order of Fe-accumulic Gleyic Stagnic Anthrosols>Typic Gleyic Stagnic Anthrosols>Lithic Ochri-Aquic Cambosols. 0.43 mol·L^-1 HNO₃,0.05 mol·L^-1 EDTA and 0.01 mol·L^-1 CaCl₂ extractable Cd were significantly correlated with the Cd content in the aboveground part of Brassica chinensis. Considering the simplicity and low cost of 0.43 mol·L^-1 HNO₃,0.05 mol·L^-1 EDTA or 0.01 mol·L^-1 CaCl₂ extraction,the extraction solutions could serve as an alternative method for assessment of phytoavailability of soil Cd to plants.