Please wait a minute...
浙江大学学报（农业与生命科学版）
浙江大学学报(农业与生命科学版)  2012, Vol. 38 Issue (5): 629-638    DOI: 10.3785/j.issn.1008-9209.2012.02.211
资源与环境科学     
矿物改良剂对污染土壤中重金属多目标有效性的影响
麻万诸1， 王浩2, 章明奎2*
1.浙江省农业科学院 数字农业研究所，浙江 杭州310021；
2.浙江大学 环境与资源学院 浙江省亚热带土壤与植物营养重点研究实验室，浙江 杭州 310058
Reduction of solubility, bioavailability, and bioaccessibility of heavy metals in polluted soil by mineral amendments
MA Wan-zhu1, WANG Hao2, ZHANG Ming-kui2*
1. Institute of Digital Agriculture, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China; 2. Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
 全文: PDF(283 KB)   HTML ( ) 
摘要： 通过培养试验比较研究磷灰石、农用石灰、坡缕石、钙镁磷肥、沸石和氢氧化铁等6种矿物改良剂对酸性和石灰性等2种污染土壤中重金属的稳定性及其可溶性、植物有效性和生物可接受性的影响。吸附和解吸试验表明，6种矿物改良剂本身对Cd、Cu、Zn和Pb等4种重金属均有强烈的吸持作用，吸持率在97.2%以上；2次解吸后被保留在矿物上的重金属比例仍在96.8%以上。施用改良剂后，土壤中交换态重金属逐渐向碳酸盐结合态、氧化物结合态和残留态转化，但不同改良剂的转化方式和程度有较大差异。施用改良剂对降低土壤中水溶性重金属的效果最为明显，其次为植物有效态重金属，但降低生物可接受态重金属的效果较弱。酸性土壤上施用改良剂的效果明显高于石灰性土壤。总体上，各类改良剂在降低水溶性重金属的效果上较为相似，以施用钙镁磷肥、坡缕石或磷灰石为佳；在降低植物有效性重金属的效果上因重金属种类不同有所差异，Cd以施用钙镁磷肥为佳，Cu以施用坡缕石为佳，Zn以施用钙镁磷肥或坡缕石为佳，Pb以施用农用石灰、磷灰石或坡缕石为佳。施用氢氧化铁、沸石和钙镁磷肥对生物可接受态重金属有一定的降低作用。
Abstract: Heavy metal accumulation  in the topsoil  because traffic, industrial  wastes  and atmospheric deposition by sedimentation, impaction and interception is well documented. High concentrations of different heavy metals in soil may cause longterm risks to ecosystem  and humans. Metals can be mobilized in soil and taken up by edible plants or transported through  drainage waters. They can  have a direct influence on human health, as they can be transferred into the human body by different pathways, e.g.  inhalation of dust or contaminated suspended particles, soil ingestion, and dermal absorption by direct contact. Plant availability, bioaccessibility and solubility of metals in soil are related with these different pathways. Some techniques should be developed to achieve an enduring immobilization or insolubilization of metals in soil, especially when the pollution degree is not extremely high. Many researchers have reported a significant decrease of metal availability in  plants when amendments are added to polluted soils. However, little effort has been reported  in the literature to decrease metal bioaccessibility and solubility. Therefore, this study has the
objective to evaluate  the effects of several inexpensive, common mineral amendments on  the potential solubility, plant availability, and bioaccessibility of the most environmentally important metals in soils. Six mineral amendment effects  as potential immobilizers of heavy metals in two soils (acidic soil and calcareous soil) were  studied by monitoring metal availability. The EDTA extraction, simple bioaccessibility extraction test (SBET) and CaCl2 extraction were applied to measure the plant availability, bioaccessibility and solubility of heavy metals in the soils, respectively. The amendments were agricultural limestone, rock phosphate, palygorskite,  calcium magnesium phosphate  (Ca-Mg-P) fertilizer, zeolite, and Fe(OH)3, which were   applied to the soils at rate of 50 g/kg, respectively. Adsorption/desorption experiments of metals by isolated amendments showed that all amendments caused a strong retention of metals from solutions, with negligible release by dilution. The proportions of heavy metals adsorbed in six mineral materials were higher than 97.2%, and the proportions of heavy metals remained in the mineral materials were higher than 96.8% after the first and second desorption steps of the experiments of adsorption/desorption of metals in solution. Chemical fractions of Cd, Cu, Pb, and Zn in the soils were affected by application of the mineral materials. Treatments of the mineral materials reduced exchangeable metals in the soils. There were chemical transformations of heavy metal fractions in the soils from exchangeable fractions to carbonatebound, oxidebound, and residual fractions when the mineral materials were applied, and the transformation varied with different  types of amendments. The reduction effects of metal availability induced by amendment application decreased in the order of solubility > plant availability > bioaccessibility. The effects in acidic soil were greater than those in the calcareous soil. In general, Ca-Mg-P fertilizer, palygorskite or rock phosphate treatments were most suitable for decreasing water soluble heavy metals in the polluted soils. The most suitable mineral materials in decreasing plant availability were Ca-Mg-P fertilizer for Cd, palygorskite for Cu, Ca-Mg-P fertilizer or palygorskite for Zn, and agricultural limestone, rock phosphate or palygorskite for Pb. However, these amendments were scarcely efficient in reducing bioaccessibility of the metals, and the metals extracted by  SBET in all six amendment treatments were very similar to the  control treatment. Only Fe(OH)3, zeolite and Ca-Mg-P fertilizer had slight effects in reducing bioaccessibility of heavy metals of the soils. It is concluded that all six tested mineral amendments are effective to stabilize soluble metal fraction in the soils polluted with Cd, Cu, Pb, and Zn. These minerals are able to decrease water solubility and plant availability of the metals in the soils. However, plant availability and bioaccessibility are not synonymous. These amendments are  often used as metal immobilizers  and are of limited efficiency for decreasing bioaccessibility of the metals in the soils. Therefore other techniques are needed for controlling and  eventually  decreasing metal bioaccessibility in the soils.  
出版日期: 2012-09-20
CLC:  X 131  
服务　　
把本文推荐给朋友
加入引用管理器
E-mail Alert
RSS
作者相关文章　　

引用本文:

链接本文:

http://www.zjujournals.com/agr/CN/Y2012/V38/I5/629

No related articles found!