钢渣施用对多金属复合污染土壤的改良效果及水稻吸收重金属的影响

Ameliorative Effects of Steel Slag Application on Multi-metal Contaminated Soil and Heavy Metal Uptake of Rice

通过盆栽实验和大田实验研究了钢渣施用对多金属复合污染土壤pH、有效硅、有效态重金属含量(镉、铅、铜、锌)以及水稻吸收重金属的影响。盆栽实验设置5个处理,分别是CK(无钢渣)、SS3和SS6(分别加入3g·kg-1和6g·kg-1100目钢渣)、FSS3和FSS6(分别加入3g·kg-1和6g·kg-1180目钢渣);大田实验设置两个处理:CK(无钢渣)和SS(加入3g·kg-1100目钢渣)。结果表明,盆栽实验土壤pH值及有效硅含量随钢渣施用量的增加和粒径的减小显著上升,土壤有效态重金属含量则出现显著下降。水稻地上部重金属浓度在施加钢渣后均显著降低,并且远低于地下部浓度;大部分钢渣施加处理对降低地下部重金属浓度也有显著效果。大田实验结果显示,钢渣改良的处理,不仅提高了水稻产量,稻米中的重金属浓度也得到了大幅降低,并达到了国家食品安全标准。综合来看,施用钢渣可有效改良多金属复合污染土壤的性质,抑制水稻对重金属的吸收和转运,降低水稻特别是其地上部的重金属浓度。

Heavy metal pollution of farmland soil is getting more and more serious in China nowadays due to mining activity,discharge of industrial effluents and long-time application of pesticide and chemical fertilizers.Since heavy metals are toxic to crops,the continuous cultivation in contaminated soil would decrease crop production capacity.Heavy metals can be also accumulated in human bodies through food chains.Application of soil amendments is an effective way to solve these kinds of problems,especially in slightly-and moderately-polluted soil.Steel slag is one kind of by-products of steel smelting.In this paper,pot experiment and field experiment were conducted to investigate the effects of steel slag application on pH value,available silicon and available heavy metal content（Cd,Pb,Cu,Zn） in multi-metal contaminated soil and heavy metal uptake by rice plant.Five treatments were designed in the pot experiment consisting of CK（No slag）,SS3 and SS6（3 g·kg-1 and 6 g·kg-1 of 100 mesh slag respectively）,FSS3 and FSS6（3 g·kg-1 and 6 g·kg-1 of 180 mesh slag respectively）.And the field experiment contained 2 treatment：CK（No slag）and SS（3g·kg-1 of 100 mesh slag respectirely）.The results of the pot experiment showed that soil pH and available silicon content increased with the increase of the amount of slag application and along with the decrease of the slag particle size.And soil available heavy metal content decreased significantly in the slag application treatments.Heavy metal concentration in shoot of rice plant decreased significantly with the slag application and was far lower than that in root.Heavy metal concentration in the root with the slag application sharply decreased in compared to CK.And the field experiment showed that steel slag application could dramatically increase rice production and decrease the heavy metal concentration in polished rice.In conclusion,steel slag application could effectively improve the quality of contaminated soil,restrain the heavy metal uptake of rice plant,and decrease the heavy metal concentration especially in the shoot of rice plant.