生态环境学报 ›› 2022, Vol. 31 ›› Issue (11): 2216-2224.DOI: 10.16258/j.cnki.1674-5906.2022.11.013

• 研究论文 • 上一篇    下一篇

卫宁平原农用地土壤重金属污染特征与生态风险研究

刘志坚1,2(), 董元华2, 张琇3, 卿成实4   

  1. 1.宁夏回族自治区国土资源调查监测院,宁夏 银川 750002
    2.中国科学院南京土壤研究所土壤环境与污染修复重点实验室,江苏 南京 210008
    3.北方民族大学生物科学与工程学院,宁夏 银川 750021
    4.中国地质调查局成都地质调查中心,四川 成都 610081
  • 收稿日期:2022-06-13 出版日期:2022-11-18 发布日期:2022-12-22
  • 作者简介:刘志坚(1987年生),男,高级工程师,硕士,研究方向为环境地质。E-mail: Pannotia@qq.com
  • 基金资助:
    宁夏自然科学基金项目(2021AAC03424);宁夏财政计划项目(宁夏国土监项[2021]002号)

Contamination and Ecological Risk Assessment of Heavy Metals in the Soil of Agricultural Land in Weining Plain, Northwest China

LIU Zhijian1,2(), DONG Yuanhua2, ZHANG Xiu3, QING Chengshi4   

  1. 1. Ningxia Survey and Monitor Institute of Land and Resources, Yinchuan 750002, P. R. China
    2. Key Laboratory of Soil Environment and Contamination Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, P. R. China
    3. School of Biological Science and Engineering, North Minzu University, Yinchuan 750021, P. R. China
    4. Chengdu Center of China Geological Survey, Chengdu 610081, P. R. China
  • Received:2022-06-13 Online:2022-11-18 Published:2022-12-22

摘要:

卫宁平原是黄河流域上游的生态保护关键带,也是著名地理标志产品“中宁枸杞”的唯一原产地,在此开展区域性土壤重金属污染及潜在生态风险评价,对改善土壤生态系统功能,保护优质特色农业具有重要意义。该研究以卫宁平原农用地为主要研究对象,采集2830件表层土壤样品,检测As、Cd、Cr、Cu、Hg、Ni、Pb、Zn共8项重金属元素与Al、Li、Sc、Ti共4项地壳稳定元素的含量。运用标准化法计算重金属元素的基线值,并以此作为污染评价模型的参照值;采用污染负荷指数法和Hakanson潜在生态风险指数法研究农用地土壤重金属的污染程度和生态风险,基于空间分析阐明土壤重金属污染的空间分布格局。结果表明:卫宁平原表层土壤中As、Cd、Cr、Cu、Hg、Ni、Pb、Zn的环境地球化学基线值分别为14.51、0.29、79.61、0.05、34.57、26.42、23.95、73.49 mg·kg-1,土壤重金属平均含量均高于黄河流域土壤背景值;污染评价结果表明,土壤As、Cr、Ni污染程度较低,Cu、Pb、Zn污染程度较高,Cd、Hg污染程度最高,综合污染负荷指数总体以轻度污染为主;土壤重金属综合潜在生态风险以中度风险为主,Cd与Hg是导致潜在生态风险程度较高的最主要因子。空间分析表明,污染地块集中分布在城市-农用地交错带和工业园区-农用地交错带;密集的交通运输活动、钢铁冶炼和金属材料加工制造排放的废气及烟尘是土壤Cd、Cu、Pb和Zn污染的主要来源,乡镇企业及工业园区钢铁冶炼生产中的燃煤烟尘是土壤Hg污染的主要来源。该研究结果划定了因人为源输入而造成的重金属污染地块范围,可为黄河流域土壤重金属污染防治提供重要的数据支撑。

关键词: 卫宁平原, 农用地, 土壤, 重金属, 污染评价, 潜在生态风险

Abstract:

Weining Plain, which is the unique source area of the famous geographical indication product “Lycium barbarum”, is a key ecological protection zone in upstream of the Yellow River Basin. Regional heavy metal pollution and potential ecological risk assessments carried out here is of great significance to improve soil ecosystem functions and protect high-quality characteristic agriculture. In this research, the contents of heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn) and the crustal stable elements (Al, Li, Sc, and Ti) were assayed in a total of 2830 surface soil samples from the agricultural land. By using Al as the standard factor, the geochemical baseline values determined by the normalization procedure method were used as the reference of the contamination assessment model. The contamination load index and Hakanson potential ecological risk index were used to evaluate the contamination level and ecological risk of heavy metals in the soils of agricultural land. Based on the spatial analysis, the spatial distribution patterns of heavy metal contamination in soil were clarified. The results showed that the environmental geochemical baseline values of As, Cd, Cr, Cu, Hg, Ni, Pb and Zn in the surface soil of Weining Plain were 14.51, 0.29, 79.61, 0.05, 34.57, 26.42, 23.95 and 73.49 mg·kg-1, respectively, and all the average contents of heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn) were higher than the corresponding background values of heavy metals in the Yellow River Basin. There were low contamination levels of As, Cr and Ni, middle degrees of Cu, Pb and Zn, and high degrees of Cd and Hg. The total contamination level was low. The comprehensive potential ecological risk of soil heavy metals was at the moderate risk level, while Cd and Hg were the most essential factors leading to high potential ecological risks. The spatial analysis demonstrated that the contaminated plots was mainly in the urban-agricultural fringe and industrial-agricultural fringe. The main sources of Cd, Cu, Pb and Zn in soil were from exhaust gas and dust emitted by intensive transportation activities, steel smelting and metal material processing. The main source of Hg in soil was from soot during coal burning in township enterprises and steel smelting in industrial parks. The results of this research delineated that the range of heavy metal contamination caused by anthropogenic sources. It could provide important data for soil heavy metal pollution control in the Yellow River Basin.

Key words: Weining Plain, agricultural land, soil, heavy metals, contamination evaluation, potential ecological risks

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