ABSTRACT
The objectives of the present study were to investigate the mitigation of lead (Pb), cadmium (Cd), and arsenic (As) in a multi-metal contaminated soil and their accumulation in rice plants (Oryza sativa L., cv II You 93) using a combined amendment (CMF, calcium carbonate + metakaolin + fused calcium–magnesium phosphate fertilizer). The results showed that application of CMF was effective in reducing the acid-extractable concentrations of soil Pb and Cd. The exchangeable concentrations of soil As showed an initial decrease followed by a gradual increase. The application of 0.2% CMF notably reduced the concentrations of Pb, Cd, and As in brown rice by 46.5%, 43.6%, and 32.0%, respectively. The concentration of As in brown rice was 0.179 mg kg−1 at 0.2% CMF, which met the maximum levels of contaminants in foods of China (MLs) (the ML of Pb, Cd, and As is 0.2 mg kg−1 according to the China national standard GB 2762-2012). At 1.6% CMF, the concentrations of Pb and Cd in brown rice were 0.002 and 0.185 mg kg−1, respectively, i.e., reductions of 99.6% and 74.1%, and these values also fell within the MLs.
Funding
The project was financially supported by the Hunan Provincial Department of Agriculture (Hunan Agricultural Union 2015-112), the National Natural Science Foundation of China (No. 41501344), and the Science Research Project of the Education Department in Hunan Province (No. 15K148).