Mineral Processing Division, Korea Institute of Geoscience and Mineral Resources (KIGAM), 124, Gwahak-ro, Yuseong-gu, Daejeon 34132, Republic of Korea; Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China.
Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China; Centre of Sustainable Design and Environment, Faculty of Design and Environment, Technological and Higher Education Institute of Hong Kong, Hong Kong, China.
Sci Total Environ. 2018 Mar;616-617:572-582. doi: 10.1016/j.scitotenv.2017.10.310. Epub 2017 Nov 9.
In this study, soil washing and stabilization as a two-step soil remediation strategy was performed to remediate Pb- and Cu-contaminated soils from shooting range and railway sites. Ferric nitrate (Fe(NO)) and [S,S]-ethylenediamine disuccinate (EDDS) were used as washing agents, whereas three types of sludge-derived biochars and phosphogypsum were employed as soil stabilizers. While Fe(NO) extracted larger amounts of metals compared to EDDS (84% Pb and 64% Cu from shooting range soil; 30% Pb and 40% Cu from railway site soil), it caused severe soil acidification. Both Fe(NO) and EDDS washing enhanced the mobility of residual metals in the two soils, which in most cases could be mitigated by subsequent 2-month stabilization by sludge-derived biochars or phosphogypsum. By contrast, the metal bioaccessibility could only be reduced by soil washing. Nutrient-rich sludge-derived biochar replenished available P and K in both soils, whereas Fe(NO) washing provided available nitrogen (N). Soil amendment enhanced acid phosphatase activity but marginally improved soil dehydrogenase and urease activity in the treated soils, possibly due to the influence of residual metals. This study supported the integration of soil washing (by Fe(NO) or EDDS) with soil stabilization (by sludge-derived biochars or phosphogypsum) for accomplishing the reduction of metal mobility and bioaccessibility, while restoring the environmental quality of the treated soils.
在这项研究中，采用土壤洗涤和稳定化两步土壤修复策略，修复来自射击场和铁路场地的 Pb 和 Cu 污染土壤。硝酸铁（Fe(NO)) 和[S,S]-乙二胺二琥珀酸（EDDS）被用作洗涤剂，而三种污泥衍生的生物炭和磷石膏被用作土壤稳定剂。虽然 Fe(NO) 比 EDDS 提取出更多的金属（来自射击场土壤的 84% Pb 和 64% Cu；来自铁路场地土壤的 30% Pb 和 40% Cu），但它会导致严重的土壤酸化。Fe(NO) 和 EDDS 洗涤均增强了两种土壤中残留金属的迁移性，在大多数情况下，后续用污泥衍生的生物炭或磷石膏稳定化 2 个月可以缓解这种情况。相比之下，金属生物可利用性只能通过土壤洗涤来降低。富含营养的污泥衍生生物炭补充了两种土壤中的有效磷和钾，而 Fe(NO) 洗涤提供了有效氮（N）。土壤改良剂提高了酸性磷酸酶的活性，但在处理过的土壤中，土壤脱氢酶和脲酶的活性仅略有提高，这可能是由于残留金属的影响。本研究支持将土壤洗涤（用 Fe(NO) 或 EDDS）与土壤稳定化（用污泥衍生的生物炭或磷石膏）相结合，以实现降低金属迁移性和生物可利用性，同时恢复处理土壤的环境质量。
