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环境科学学报 2012
The effects of sepiolite on immobilization remediation of Cd contaminated red soil
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Abstract:
Pot experiment was conducted to investigate the effects of sepiolite on soil pH,available Cd concentration,and spinach dry biomass,quality and safety.The results showed that under the Cd contamination of 1.25,2.5 and 5 mg · kg-1,the application of sepiolite significantly increased soil pH(p<0.05),while the available Cd contents decreased by 11.0%~44.4%,7.3%~23.0% and 4.1%~17.0%,respectively,with the increase of sepiolite concentration,when compared with unamended soil.The dry biomass of spinach was observed a certain degree increase due to the alleviation of Cd phytotoxicity to spinach by using sepiolite.In contrast,the concentrations of Cd in the shoots of spinach significantly decreased after applying sepiolite to soil,and reduced by 78.6%~300.4%,44.6%~169.0% and 18.1%~89.3%,respectively,with respect to the control group.Under soil Cd concentration of 1.25 mg · kg-1,the concentration of Cd in the edible parts of spinach at ≥ 1% sepiolite was lower than 0.2 mg · kg-1 fresh weight(FW),the maximum permissible concentration(MPC) for Cd in vegetable(GB 2762—2005).Under 2.5 and 5 mg · kg-1 Cd contaminated soil,it met the MPC of pollution-safe cultivars(PSCs) when the treatment of sepiolite was up to 5%.