Abstract：
The majority of the studies on nanoscale zero-valent iron (nZVI) are conducted at a laboratory-scale, while field-scale evidence is scarce. The objective of this study was to compare the metal(loid) immobilization efficiency of selected Fe-based materials under field conditions for a period of one year. Two contrasting metal(loid) (As, Cd, Pb, Zn) enriched soils from a smelter-contaminated area were amended with sulfidized nZVI (S-nZVI) solely or combined with thermally stabilized sewage sludge and compared to amendment with microscale iron grit. In the soil with higher pH (7.5) and organic matter content (TOC = 12.7 %), the application of amendments resulted in a moderate increase in pH and reduced As, Cd, Pb, and Zn leaching after 1-year, with S-nZVI and sludge combined being the most efficient, followed by iron grit and S-nZVI alone. However, the amendments had adverse impacts on microbial biomass quantity, S-nZVI being the least damaging. In the soil with a lower pH (6.0) and organic matter content (TOC = 2.3 %), the results were mixed; 0.01 M CaCl2 extraction data showed only S-nZVI with sludge as remaining effective in reducing extractable concentrations of metals; on the other hand, Cd and Zn concentrations were increased in the extracted soil pore water solutions, in contrast to the two conventional amendments. Despite that, S-nZVI with sludge enhanced the quantity of microbial biomass in this soil. Additional earthworm avoidance data indicated that they generally avoided soil treated with all Fe-based materials, but the presence of sludge impacted their preferences somewhat. In summary, no significant differences between S-nZVI and iron grit were observed for metal(loid) immobilization, though sludge significantly improved the performance of S-nZVI in terms of soil health indicators. Therefore, this study indicates that S-nZVI amendment of soils alone should be avoided, though further field evidence from a broader range of soils is now required.
摘要：
大多数关于纳米零价铁（nZVI）的研究都是在实验室规模进行的，而现场规模的证据很少。这项研究的目的是比较选定的铁基材料在一年的野外条件下的金属（类）固定效率。两种对比金属(类)(As，Cd,Pb,用硫化的nZVI（S-nZVI）单独或与热稳定的污水污泥结合对冶炼厂污染区的富含Zn）的土壤进行了修正，并与微尺度铁砂的修正进行了比较。在pH（7.5）和有机质含量（TOC=12.7％）较高的土壤中，修正剂的应用导致pH值适度增加，砷含量降低，Cd,Pb,和锌在1年后浸出，S-NZVI和污泥组合是最有效的，其次是铁砂和S-nZVI。然而,修正案对微生物生物量产生了不利影响，S-nZVI是伤害最小的。在pH（6.0）和有机质含量（TOC=2.3％）较低的土壤中，结果是混合的；0.01MCaCl2萃取数据显示，只有带有污泥的S-nZVI在降低金属的可萃取浓度方面仍然有效；另一方面，提取的土壤孔隙水溶液中Cd和Zn的浓度增加，与这两项常规修正案相反。尽管如此,S-nZVI与污泥增加了该土壤中微生物生物量的数量。其他避免蚯蚓的数据表明，他们通常避免使用所有铁基材料处理的土壤，但是污泥的存在在一定程度上影响了他们的偏好。总之,S-nZVI和铁砂之间没有观察到金属（类）固定的显着差异，尽管污泥在土壤健康指标方面显着改善了S-nZVI的性能。因此,这项研究表明，应避免单独对土壤进行S-nZVI改良，尽管现在需要从更广泛的土壤中获得进一步的现场证据。
