摘要
土壤一直是人类生存不可或缺的基本要素和重要资源。近年来，由于人为活动的加剧及受自然因素影响，大量重金属富集于土壤中，引起土壤质量下降并通过食物链逐级富集，直接危害人体健康。本论文以云南省某市的农用地土壤作为研究对象，通过地统计学基础、GIS技术及常规检测分析方法，分析了土壤中铅（Pb）、镍（Ni）、镉（Cd）、汞（Hg）、砷（As）、铜（Cu）、铬（Cr）、锌（Zn）8种重金属和pH、有机质（SOM）、阳离子交换量（CEC）3种化学性质的空间分布特征和相关性，评价了研究区8种土壤重金属的污染现状及潜在生态风险程度。主要研究结论为：（1）该市土壤pH、SOM和CEC属于中等变异。土壤pH均值为6.5，呈弱酸性。区域内土壤肥力较强，SOM总体属较高水平。CEC在5.4~52.5cmol(+)kg-1之间，说明该区域土壤保肥能力适中。土壤基本化学性质均表现出中等的空间自相关性，空间变异性程度较高。 （2）空间插值结果显示，该市土壤pH值基本呈低纬度低于高纬度，土壤SOM 含量具有较高的差异性，市西北边境处SOM最高。CEC在北部市中区最高，浓度从高到底逐渐向周边扩散。
（3）该市8种重金属污染情况总体表现为：Cd、As、Pb污染较重，Cu污染较轻，Zn、Cr、Ni三种重金属表现为清洁（安全）或尚清洁（警戒）状态。镀层厚度检测
（4）该市重金属多元素综合潜在生态风险指数为轻微潜在生态风险。土壤潜在风险程度不高，无重度污
染区，相对而言Cd、Hg和As的潜在生态风险较大。可采用植物修复、微生物修复等较温和的修复措施治理污染土壤。作为矿产的开发区，应当给予合理的管理措施，以保证生产的稳定增长和环境的可持续发展。
（5）该市土壤pH与Cr、Zn均呈现出显著正相关（P<0.05），与Ni呈现出极显著正相关（P<0.01）。SOM与各重金属含量均呈现不显著相关（P>0.05）。CEC 与Zn呈显著正相关（P<0.05），与Cu和Ni呈现极显著正相关（P<0.01）。pH与Pb、Ni单一污染指数及Cu、Pb、Ni潜在生态风险系数呈现极显著负相关(P＜0.01)。而SOM仅与Pb的单一污染指数和潜在生态风险系数呈现显著正相关性（P＜0.05）。CEC与单一污染指数和潜在生态风险系数均没有明显的相关性（P<0.05）。
自锁螺栓关键词：土壤；重金属；空间分布；污染评价
Abstract
Soil is the basic element and important resource for human survival.In recent years, due to a large number of artificial and natural factors,a large amount of heavy metals are enriched in the soil,causing the soil quality to decline and being gradually enriched through the food chain,directly jeopardizing people's health.This paper takes the agricultural land soil of a city in Yunnan Province as the research object,and analyzes8 soil heavy metals(Pb,Ni,Cd,Hg,As,Cu,Cr,Zn)through geostatist
ics basis,GIS technology and routine detection and analysis methods.The spatial distribution characteristics and correlation of three chemical properties(pH,SOM,CEC),then evaluated the pollution status and potential ecological risk of heavy metals in eight soils in the study area.The main research conclusions are:
(1)The soil pH,organic matter and cation exchange capacity of this city's soil were moderately varied.The soil pH average was6.519,which was weakly acidic.The soil in the area was relatively fertile,and the organic matter content was generally in the second-class high level.The soil cation exchange capacity was between5.4-52.5cmol(+). The basic physical and chemical properties of the soil all showed moderate spatial autocorrelation,resulting in a higher degree of spatial variability.
智能电位器(2)Spatial interpolation results showed that the soil pH value of the city was lower than those of the higher latitude,and the soil organic matter content was significantly different.The soil cation exchange capacity(CEC)was higher in the northeast and lower in the southwest.
(3)The overall manifestation of eight heavy metal pollution in the city was:the pollution of As,Cd,and Pb were heavy,Cu was relatively light,and three heavy metals,Cr, Zn,and Ni,appeared to be clean(safe)or clean enough(alert).
(4)The potential ecological risks of Cd and Hg in this city were relatively high,and As also showed potential ecological risks at some sampling points.The comprehensive ecological risk index of heavy metal multi-element indicated a slight potential ecological risk.The potential risk of agricultural land in this city was not high,and there was no
扩张网机serious pollution area.Plant restoration and microbial restoration could be used to manage contaminated soil.As a heavily exploited mineral zone,reasonable management measures should be taken to ensure stable growth of production and sustainable development of the environment.
(5)There was a significant positive correlation between pH and Cr and Zn(P<0.05), and a extremely significant positive correlation with Ni(P<0.01)in soil.There was no significant correlation between soil organic matter and heavy metal content(P>0.05). There was a significant positive correlation between soil cation and Zn(P<0.05),and a extremely significant positive correlation with Cu and Ni(P<0.01).There was a significant negative correlation between pH and Pb and Ni single pollution index and potential ecological risk factors of Pb,Cu and Ni(P<0.01).Soil organic matter only showed a significant positive correlation with Pb's single pollution index and potential ecological risk coefficient(P<0.05).There was no significant correlation between cation exchange capacity and single pollution index and potential ecological risk index(P<0.05).
Key words:soil;heavy metal;spatial distribution;pollution assessment
目录
摘要.........................................................................................................................................II 1绪论 (1)
1.1立题背景 (1)
1.2文献综述 (1)
1.2.1土壤重金属污染 (1)
1.2.2土壤重金属空间分布 (3)
1.2.3土壤重金属污染评价 (4)
1.3研究目标与研究内容 (10)
1.3.1研究目标 (10)
1.3.2研究内容 (10)
1.4技术路线 (11)
2材料与方法 (12)
2.1研究区概况 (12)
2.2研究方法 (12)
2.2.1野外调查与土壤样品采集 (12)
2.2.2土壤样品分析 (13)
2.2.3数据计算与分析 (13)
3结果与分析 (16)
3.1土壤化学性质空间分布特征 (16)
3.1.1土壤化学性质的描述性统计分析 (16)
3.1.2土壤化学性质空间分布特征 (17)
3.2土壤重金属空间分布特征 (19)
3.2.1重金属描述性统计 (19)
3.2.2土壤重金属空间变异 (20)
3.3土壤重金属污染评价 (27)
3.3.1单因子污染指数法 (27)
防撞钢梁3.3.2内梅罗综合指数法 (33)
3.4土壤重金属污染生态风险评价 (34)
3.4.1土壤重金属污染生态风险分级统计 (34)
3.4.2土壤重金属污染生态风险空间分布 (35)
3.5土壤化学性质与污染指数的相关性 (36)
3.5.1重金属元素间的相关性 (36)
3.5.2土壤化学性质与重金属的相关性 (37)
3.5.3土壤化学性质与重金属污染指数的相关性 (37)
4讨论 (39)
正火工艺5结论与展望 (42)
5.1结论 (42)
5.2展望 (42)
参考文献 (44)
致谢 (55)
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