基于GIS的农田土壤重金属空间分布及污染评价 ——以南京市江宁区某乡镇为例
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1.南京农业大学;2.南京农业大学资源与环境科学学院

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国家自然科学基金项目(41771247)


GIS-Based Spatial Distribution and Risk Assessment of Heavy Metals in Farmland Soils:A Case Study of a Town of Jiangning,Nanjing
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NJAU

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National Natural Science Foundation of China(No. 41771247)

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    摘要:

    土壤污染近年来备受瞩目,我国已出台多项法律法规来规范防治,合理评价不同地区土壤重金属的污染情况,具有现实和长远意义。2017年11—12月在研究区采集的29个表层土壤(0~20 cm),分析测定土壤pH、有机质和8种重金属元素砷(As)、镉(Cd)、铬(Cr)、铜(Cu)、汞(Hg)、镍(Ni)、铅(Pb)和锌(Zn)的含量,采用最新发布的《土壤环境质量—农用地土壤污染风险管控标准(试行)》(GB 15618-2018)进行污染评价,运用GIS地统计学方法分析重金属空间分布特征。结果表明,研究区土壤pH呈现酸性至中性;有机质平均含量为17.73 mg•kg-1,较为缺乏;8种重金属元素(As、Cd、Cr、Cu、Hg、Ni、Pb、Zn)的平均含量分别为8.27、0.17、70.84、24.74、0.20、32.07、28.48和73.57 mg•kg-1,除As外,其他重金属含量均超过南京市江宁区土壤环境背景值,但未超过国家现行标准,总体无重金属污染。其中Cd、Cu和Hg元素在局部地区达到了警戒线,风险区主要分布在西南部和南部,呈现带状分布,农业生产上需引起重视。

    Abstract:

    【Objective】 Heavy metals pollution level in farmland soil is related to quality and safety of the agricultural produce and health of the farmland ecosystems. Spatial distribution and evaluation of heavy metal pollution of the soils has become the focus of concerns all over the world, and attracted wide attentions from the governments and scientists of all the countries. In recent years, the situation of soil heavy metal pollution in farmland in China is getting so serious that it has aroused country-wide concerns. To address the problem, China has promulgated the “Law of the People's Republic of China on Soil Pollution Prevention and Control”, which is an act of long-term realistic significance to regulation, control, and reasonable evaluation of the pollution of heavy metals in soils of China. 【Methods】Jiangning District of Nanjing City, the largest agricultural produce and sideline product logistics center in East China and the second in the country, has rarely been reported about the issue before. It is, therefore, necessary to perform investigations and evaluations of any heavy metal pollution problems in this region. For this study, samples of topsoil (0~20 cm) were collected from 29 pieces of farmland scattered in the region during November and December, 2017 for analysis of soil pH, organic matter and contents of 8 heavy metals, such as arsenic (As), cadmium (Cd) and chromium (Cr), Copper (Cu), mercury (Hg), nickel (Ni), lead (Pb) and zinc (Zn), and heavy metals pollution of the soil was evaluated in line with the newly released “Standards for Soil Environmental Quality and Risk Control of Agricultural Land Soil Pollution (Trial) (GB 15618-2018)” with a view to improving and optimizing the traditional evaluation methods for pollution assessment, and developing a more scientific and reasonable region-specific evaluation method, which combines the technical characteristics and spatial analysis function of GIS, and makes use of the geostatistics method in analyzing spatial distribution characteristics of the heavy metals pollution.【Results】Results show that the soils in the study area varied in the range from acidic to neutral in soil pH, lacked organic matter, and contained 8.27, 0.17, 70.84, 24.74, 0.20, 32.07, 28.48 and 73.57 mg•kg-1 of As, Cd, Cr, Cu, Hg, Ni, Pb and Zn, respectively, all of which except for As, were higher than their respective background values of the soil environment of the region, but still within the safe ranges specified in the current standards of the nation for agricultural environment quality. So on the whole, the region is not polluted with heavy metals.【Conclusion】In certain areas of the region, soil Cd, Cu and Hg has reached their respective alert threshold, posing pollution risks, which calls for serious attention in agricultural production. The risks are quite high in the southwest and south parts of the region, forming a band in distribution. In that band, Cd, Cr, Cu, Ni and Zn are found to have come from the same source, potentially the Lishui River running through the study area. The upper reaches of the Lishui River is the Qinhuai River flowing through the urban area of Nanjing. Further studies should be done as to specific sources of the risks. Comparison of the methods for evaluating heavy metal pollution in soil shows that the single factor index method is simple, intuitive and highly adoptable to determination of whether a single item of heavy metal in soil has surpassed the criterion in soil survey and to grading of the risk; the comprehensive index method is more scientific and reasonable for comprehensive evaluation of soil heavy metal pollution; The newly promulgated “Standards for Soil Environmental Quality and Risk Control of Agricultural Land Soil Pollution (Trial) (GB 15618-2018)” is aimed at soil pollution assessment of farmland in the light of soil pH and type of land use. The promulgation of the standard is of great significance to comprehensive risk assessment of soil heavy metal pollution of farmland soils, survey and grading of soil pollution and remediation of polluted soils.

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谢龙涛,潘剑君,白浩然,张培育,康 翔,王 飞,朱燕香.基于GIS的农田土壤重金属空间分布及污染评价 ——以南京市江宁区某乡镇为例[J].土壤学报,2020,57(2):316-325. DOI:10.11766/trxb201809010441 XIE Longtao, PAN Jianjun, BAI Haoran, ZHANG Peiyu, KANG Xiang, WANG Fei, ZHU Yanxiang. GIS-Based Spatial Distribution and Risk Assessment of Heavy Metals in Farmland Soils:A Case Study of a Town of Jiangning,Nanjing[J]. Acta Pedologica Sinica,2020,57(2):316-325.

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  • 收稿日期:2018-09-01
  • 最后修改日期:2018-11-23
  • 录用日期:2019-01-02
  • 在线发布日期: 2020-01-06
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