酸碱度调节剂对稻田土壤中有效态镉的影响研究

Effect of pH Adjustor on Available Cadmium in Paddy Soils

为弄清不同酸碱度调节剂对稻田土壤中有效态Cd的动态影响差异,采用室内培养试验,通过对1、5、10、20 mg/kg外源Cd浓度污染麻砂泥土壤添加4种酸碱度调节剂处理,探讨在第15天和45天其对Cd的有效性影响。结果表明:与不施加酸碱度调节剂的对照对比,添加SH1.5、SH3、GG1.5和GG3调节剂可在一定程度增加土壤pH,从而降低土壤中Cd的有效态含量。4种外源Cd浓度污染土壤中,用TCLP和CaCl_2提取的有效态镉含量与土壤pH均成负相关关系。培养过程中,TCLP提取态和CaCl_2交换态Cd含量分别下降17.41%~48.02%、30.95%~87.89%,同时SH3修复效果表现突出。研究结果可为Cd超标稻田的安全生产及阻控提供科学指导。

To clarify the dynamic effects of different pH adjustors on available Cd in paddy soil, four kinds ofpH adjustor were added to Mashani soils with 1, 5, 10 and 20 mg/kg exogenous Cd, and the adjustors＇ effect onCd effectiveness on the 15^（th）and 45^（th）day was studied by indoor culture experiment. The results showed thatcompared with CK the addition of SH1.5, SH3, GG1.5 and GG3 adjustors could increase soil pH value to acertain extent, thus to reduce the available content of Cd in soil. The contents of available cadmium in Cdcontaminated soil with the four concentrations extracted by TCLP and CaCl_2 were negatively correlated with soilpH value. The Cd contents of TCLP extract state and CaCl_2 exchange state decreased by 17.41%~48.02% and30.95% ~87.89%, and the remediation effect of SH3 was outstanding. The results could provide scientificguidance for safe production and resistance control in Cd over-standard paddy field.