| 摘要: |
| 【目的】探讨石灰、硫化钠对铅 (Pb)污染土壤理化性质及作物生物量、Pb含量的影响，以探明石灰、硫化钠作为钝化剂修复Pb污染土壤的潜力，为中国北方地区重金属污染土地的安全利用提供依据。【方法】以陕西凤县Pb污染土壤为研究对象（农田平均Pb含量为172.1 mg/kg），向Pb污染土壤中分别施用了5，10，15 g/kg石灰和2，6，10 g/kg硫化钠，并以不添加钝化剂为对照（CK），稳定6个月后，于2021年5月开始种植作物，其中大豆和玉米为第1季作物，油菜和小麦为第2季作物，测定不同处理土壤的基础理化指标、Pb含量、有效态Pb含量以及作物生物量和茎叶、籽粒Pb含量，分析钝化处理后作物对Pb的富集情况，并对不同处理作物的食品安全风险进行了评价。【结果】与CK相比，石灰、硫化钠均提高了土壤pH，且土壤pH随着钝化剂施用量的增加而增大。石灰、硫化钠处理土壤有机质含量和阳离子交换量（CEC）与CK总体均无显著差异。相比CK，石灰、硫化钠处理玉米、大豆、小麦的总生物量总体增幅较大，而对油菜总生物量的影响较小。第1季和第2季作物收获后，与 CK对比，石灰、硫化钠处理作物根际土壤有效态Pb含量均明显减少。石灰和硫化钠处理4种作物茎叶中的Pb含量与CK相比均明显下降。与CK相比，石灰处理4种作物籽粒中的Pb含量均明显下降；除了玉米外，硫化钠处理大豆、油菜、小麦籽粒中的Pb含量较CK明显下降。不同含量石灰、硫化钠处理后，两季作物对Pb的富集能力差异较大，其中小麦对Pb的富集能力较强。对4种作物的食品安全风险进行了评价，结果显示，不同钝化剂处理作物可食用部分 (茎叶和籽粒)的Pb含量均超过了食品安全限值；石灰、硫化钠处理大豆、油菜所榨植物油中的Pb含量远远小于二者籽粒中的Pb含量，其中菜籽油满足了食品安全标准。【结论】在重金属Pb污染地区，石灰、硫化钠均提高了土壤pH，总体增加了作物生物量，减少了土壤和作物的Pb含量，可用于重金属污染土地的修复，且Pb污染地块经修复后可用作油菜籽种植基地。 |
| 关键词: 铅污染地区 石灰 硫化钠 土壤修复 |
| DOI：10.13207/j.cnki.jnwafu.2025.07.014 |
| 分类号: |
| 基金项目:陕西省秦创原“科学家+工程师”队伍建设项目 (2022KXJ-124) |
|
| Potential analysis and recommendations for in situ remediation of northern Pb contaminated soil with lime and sodium sulfide |
|
LÜ Xiaoyong1, WU Weilong2, ZHANG Han2, SHEN Feng2, WANG Ping2, WU Xuan2, ZHANG Zengqiang2, LI Ronghua2
|
|
1.Xi’an Engineering Investigation & Design Research Institute of China National Nonferrous Metals Industry Co.,LTD,Xi’an,Shaanxi 710054,China;2.College of Natural Resources and Environment,Northwest A&F University,Yangling,Shaanxi 712100,China
|
| Abstract: |
| 【Objective】This research aimed to investigate the influence of lime and sodium sulfide on the physicochemical properties of lead (Pb) contaminated soil,as well as on the biomass and Pb content of crops,in order to explore the potential of lime and sodium sulfide as passivating agents for the remediation of Pb contaminated soil and to provide a basis for the safe utilization of heavy metal polluted land in northern China.【Method】Lead-polluted soil from Fengxian,Shaanxi was used as the research subject (with an average Pb content of 172.1 mg/kg).Lime of 5,10,15 g/kg and sodium sulfide of 2,6,10 g/kg were applied respectively to the Pb-contaminated soil.Soil without passivating agent applied was used as the control(CK).After 6 months of stabilization,crops were planted in the treated soil in May 2021,with soybeans and corn as the first season crops,canola and wheat as the second-season crops.The basic physicochemical indicators,Pb content,available Pb content of the treated soils,as well as the biomass,and Pb content in stems,leaves and grains of the crops were determined.The enrichment of Pb in the crops after passivation treatment was analyzed,and the food safety risks of crops with different treatment were evaluated. 【Result】Compared to the control,the pH of the soil samples treated with lime and sodium sulfide both increased with the increase of application rate of passivating agent.The organic matter content and CEC of the soil samples treated with lime and sodium sulfide showed no significant differences compared to the control.The total biomass of corn,soybeans,and wheat of the soil treated with lime and sodium sulfide increased significantly compared to the control,while the biomass of canola showed no significant change.After the harvest of the first and second-season crops,the available Pb content in the crop rhizosphere soil treated with lime and sodium sulfide decreased significantly compared to the control.The Pb content in the stems and leaves of the four crops in the soil treated with lime and sodium sulfide also decreased significantly compared to the control.Additionally,the Pb content in the grains of soybean,canola and wheat in the soil treated with lime and sodium sulfide decreased significantly,while the Pb content decreased significantly in the grains of corn of lime treatment and remained similar with the control in the grains of corn of sodium sulfide treatment.Significant differences in the Pb enrichment of the two-season crops were observed after treatment with different amounts of lime and sodium sulfide,with wheat demonstrating a strong ability to accumulate Pb.Food safety risks of the four crops were evaluated according to relevant national standards,showing that the Pb content in the edible parts (stems/leaves and grains) of the crops in the soil treated with different passivating agents exceeded the food safety limits.However,the Pb content in the vegetable oil extracted from soybeans and canola planted in the soil treated with lime and sodium sulfide was much lower than the Pb content in the grains,with rapeseed oil meeting the food safety standards.【Conclusion】In heavy metal Pb polluted areas,lime and sodium sulfide increased the soil pH,increased the overall biomass of crops,and reduced the Pb content in the soil and crops.Therefore,they can be used for the remediation of heavy metal contaminated land.After remediation,the Pb-contaminated plots can be used as planting bases for producing edible oil from rapeseed. |
| Key words: lead-contaminated areas lime sodium sulfide soil remediation |
