生态环境学报 ›› 2022, Vol. 31 ›› Issue (8): 1629-1636.DOI: 10.16258/j.cnki.1674-5906.2022.08.015

• 研究论文 • 上一篇    下一篇

贵州汞矿区周边农田土壤汞镉复合污染特征空间分布及风险评估

李秀华1,2(), 赵玲1, 滕应1,*(), 骆永明1, 黄标1, 刘冲1, 刘本乐1,2, 赵其国1,*()   

  1. 1.中国科学院土壤环境与污染修复重点实验室(南京土壤研究所),江苏 南京 210008
    2.中国科学院大学资源与环境学院,北京 100049
  • 收稿日期:2021-12-09 出版日期:2022-08-18 发布日期:2022-10-10
  • 通讯作者: 赵其国,E-mail: qgzhao@issas.ac.cn
    * 滕应,E-mail: yteng@issas.ac.cn;
  • 作者简介:李秀华(1983年生),女,博士研究生,主要从事土壤污染治理与修复研究。E-mail: xhli@issas.ac.cn
  • 基金资助:
    国家土壤污染综合防治先行示范区项目(WHC18128-1);中国科学院学部咨询项目(2016ZWH002A-002)

Characteristics, Spatial Distribution and Risk Assessment of Combined Mercury and Cadmium Pollution in Farmland Soils Surrounding Mercury Mining Areas in Guizhou

LI Xiuhua1,2(), ZHAO Ling1, TENG Ying1,*(), LUO Yongming1, HUANG Biao1, LIU Chong1, LIU Benle1,2, ZHAO Qiguo1,*()   

  1. 1. CAS Key Laboratory of Soil Environment and Pollution Remediation(Institute of Soil Science), Nanjing 210008, P. R. China
    2. College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, P. R. China
  • Received:2021-12-09 Online:2022-08-18 Published:2022-10-10

摘要:

贵州汞矿开采和冶炼活动产生的“三废”,带来矿区周边农田土壤重金属污染问题,引起了国家及地方环保部门的高度关注。为探明研究区重金属污染分布,该研究采集了铜仁市敖寨乡农田表层土壤样品350个,双层样品19个,研究区剖面和对照剖面各1个,测定了土壤pH值、有机质(SOM)、总汞(Hg)和总镉(Cd)的含量;采用克里格插值法分析了空间分布特征;依据土壤环境质量农用地土壤污染风险管控标准(GB 15618—2018)、Hakanson潜在生态风险评价法、土壤重金属污染健康风险评估模型对研究区土壤重金属污染进行了安全性评估、潜在生态风险评估及人体健康风险评估。结果表明:该区域土壤pH值7.55±0.60,为弱碱性土壤;77.71%的点位土壤有机质含量高于30.0 g∙kg-1;表层土壤汞质量分数(20.20±19.31) mg∙kg-1和表层土壤镉质量分数 (1.17±0.33) mg∙kg-1的平均值均高于贵州省和全国背景值;空间分布上,中部和东北部区域以及敖寨河附近的汞和镉含量较高;相关性分析结果显示,土壤pH值和有机质含量均与土壤汞、镉含量呈显著正相关,土壤汞和镉含量也呈显著正相关关系。88.57%的点位土壤汞含量高于农用地土壤污染风险管制值,而镉含量基本介于农用地土壤污染风险筛选值和土壤污染风险管制值之间。研究区中部和东南部存在较强的镉潜在生态风险,大部分点位都存在极强的汞潜在生态风险。土壤汞和镉对儿童的非致癌健康风险明显高于成人,经口摄入途径对人体健康风险的危害指数最大,汞极有可能对成人和儿童的健康造成危害。鉴此,该研究区农田土壤汞镉复合污染较为严重,存在较强的生态风险和健康风险,亟需开展农田土壤污染风险管控与修复技术研究。

关键词: 农田土壤, 汞污染, 镉污染, 空间分布, 风险评估, 潜在生态风险, 人体健康风险

Abstract:

The “three wastes” (i.e., solid, water, and gas) generated by mercury (Hg) mining and smelting activities in Guizhou have caused heavy metal pollution in the surrounding farmland, therefore attracting great attention from the national and local environmental protection departments. To ascertain the pollution status and spatial distribution of heavy metals in the study area, we collected 350 surface soil samples, 19 double-layer samples, 1 profile sample of the study area, and 1 profile sample of the control in Aozhai Township, Tongren City, and measured soil pH, organic matter (SOM), and the contents of Hg and cadmium (Cd). The spatial distribution characteristics of Hg and Cd were analyzed by Kriging interpolation. Soil environmental quality risk control standard for soil contamination of agricultural land (GB 15618—2018), Hakanson potential ecological risk assessment method and a human health risk assessment model were used to assess the health safety, ecological and human health risks of heavy metals in this area. The results showed that the soil pH in this area was 7.55±0.60, indicating that the soil was weakly alkaline. 77.71% of the soil samples contained soil organic matter content higher than 30.0 g∙kg-1. the Hg content of the surface soil was (20.20±19.31) mg∙kg-1 and the Cd content was (1.17±0.33) mg∙kg-1, which were higher than the background metal content of Guizhou Province and China. In terms of spatial distribution, the central and northeast regions and the vicinity of the Aozhai river were observed with higher Hg and Cd. The correlation analyses showed that soil pH and organic matter content were significantly positively correlated with soil Hg and Cd contents, and soil Hg and Cd contents were significantly positively correlated. Soil Hg content in 88.57% of samples was higher than the risk intervention values for soil contamination of agricultural land, while the Cd content was basically between the risk screening values and risk intervention values for soil contamination of agricultural land. There were strong potential ecological risks for Cd in the central and southeastern parts of the study area, and the potential ecological risk of Hg in soils from most sites was very high. The non-carcinogenic health risks of soil Hg and Cd contents to children were significantly stronger than those to adults, and the oral intake route had the strongest risks to physical health. Hg pollution was most likely to cause health problems in adults and children. In summary, the combined pollution of Hg and Cd in this study area was particularly serious, and caused strong ecological and health risks. It is urgent to conduct soil risk intervention and fallow restoration.

Key words: farmland soil, mercury pollution, cadmium pollution, spatial distribution, risk assessment, potential ecological risks, human health risks

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