环境材料对作物吸收重金属Pb、Cd及土壤特性研究

A study of environmental materials on lead and cadmium absorption by crops and soil characteristics

重金属固化是原位修复污染土壤和减小作物吸收污染物、提高农产品质量的重要途径.采用盆栽实验方法,研究了单个环境材料(煤基营养材料HA、高分子保水材料SAP、煤基复合材料FM和吸附性矿物材料FS)及复合材料对作物(玉米、大豆)生长及其对土壤重金属Pb、Cd(土壤Pb≤150mg·kg-1、Cd≤10mg·kg-1)吸收的影响,并探讨了相关的土壤理化性能变化机理.结果表明,单个环境材料及复合材料处理较对照能明显减少作物对土壤重金属Pb、Cd的吸收量,并促进作物生长.除个别处理外,大部分处理下玉米地上部分的重金属Pb、Cd吸收量较对照减少51%～71%和66%～84%;所有处理下大豆地上部分的重金属Pb、Cd吸收量较对照减少54%～76%和33%～58%.实验还证明,所用环境材料对重金属Pb、Cd有一定的改良效应,并对土壤pH、EC、土壤有机质、速效氮磷养分及土壤脲酶、磷酸酶活性等有一定的调节作用.相较而言,高分子保水材料SAP及其复合材料F3(FM+SAP+HA)、F2(FS+SAP+HA)能明显降低玉米和大豆对土壤重金属Pb、Cd的吸收量,具有作为重金属污染土壤治理修复剂的可能性.

In situ immobilization or solidification of heavy metals in soil is an important measure to rehabilitate contaminated soil,reduce the heavy metal absorption of crops and improve the crop quality.The pot experiment was carried out to investigate the effect of environmental material,such as based-coal nutrient material（HA,polymer absorbent（SAP）,based-coal compound material（FM） and absorbing mineral materials（FS） and their compound materials on growth of crops and heavy metal lead（Pb≤150 mg · kg^-1） cadmium（Cd≤10 mg · kg^-1） absorption by crops,maize and soybean,and the evolving mechanisms of physical-chemical characteristics of soils were analyzed.The results showed that all investigated environmental materials and the compound materials can significantly reduce Pb and Cd absorption by maize and soybean and improve the growth of crops,with an exception of treatment No.2.The Pb and Cd contents of maize ground body in most treatments were 51%~71% and 66%~84%,respectively,while Pb and Cd content in soybean ground body in all treatments were 54%~76% and 33%~58%,lower than those in parallel treatments,respectively.The study also showed that all environmental materials can improve in-situ immobilization or solidification of heavy metals in soil,and reduce Pb and Cd absorption of crops,to some extent.The treatments with polymer absorbent material and its compound materials,F3（FS＋HA＋SAP） and F2（FS＋SAP＋HA）,can reduce the crops,maize and soybean,to absorb Pb and Cd from the soil markedly,these materials have a great potential use as a kind of renovation agents in dealing with contaminated soil with heavy metal Pb and Cd.