昆山花桥镇土壤性状及变异规律毕业论文_林学毕业论文

昆山花桥镇土壤性状及变异规律毕业论文

2021-04-20更新

摘 要

为了解昆山花桥国际商务城土壤主要性状及重金属污染水平,选择商务城内耕地、荒草地、经济林地、人工林地、疏林草地、有林地6个土地利用类型作为研究对象,选取36个样点,分0-20、20-40两层分别取样,共采集72个土壤样品。采用酸分解法测定Cr,等离子体光电直读光谱仪ICP测定Pb、Cd、Zn、Cu含量,并测定了土壤容重、pH、有机质、全氮和全磷等反映土壤性状的指标。采用单因子污染指数、内梅罗综合污染指数评价重金属污染程度和以及Hakanson 潜在生态风险指数法对其污染程度和潜在风险性进行评价。结果表明:(1)花桥国际商务城土壤容重偏大,土壤偏碱性,随着土壤深度增加,有机质和全氮含量逐渐降低,全磷含量变化不大。(2)花桥国际商务城5种重金属平均值均超过江苏土壤背景值,其中Cd污染最为严重,比值达到2.94,各重金属元素之间存在显著相关性。(3)单因子污染指数评价表明,5种土壤重金属的污染程度大小为Cd>Pb>Cu>Zn>Cr。(4)内梅罗综合污染指数评价表明,不同土地利用类型污染程度大小为耕地>经济林地>有林地>疏林草地>人工林地>荒草地。(5)潜在生态风险评价表明,单个重金属的潜在生态风险指数的平均值的大小排列状况为Cd>Pb>Cu>Cr>Zn,综合潜在生态风险指数的大小状况为经济林地>耕地>有林地>疏林草地>人工林地>荒草地。

关键词:昆山花桥;土壤性状;重金属;生态风险评价

Variation of Soil Main Characters and Heavy Metals and Assessment of Ecological Risk in Huaqiao International Business City, Kunshan

Abstract

In order to understand the main soil properties and heavy metal pollution level of Huaqiao International Business City in Kunshan,Six land-use types of cultivated land, barren grassland, economic forest land, plantation forest land, sparse forest grassland and woodland in the commercial city were selected as the research objects. 36 sampling points were selected and sampled in 0-20 and 20-40 layers respectively. A total of 72 samples were collected. Chromium was determined by acid decomposition method and Pb, Cd, Zn and Cu were determined by ICP. The soil bulk density, pH, organic matter, total nitrogen and total phosphorus were also determined. The single factor pollution index, Nemerow comprehensive pollution index were used to evaluate the pollution degree of heavy metals and Hakanson potential ecological risk index were used to evaluate the pollution degree and potential risk. The results showed that: (1)In Huaqiao International Business City,Soil bulk density was high, soil alkalinity was low, organic matter and total nitrogen content decreased with the increase of soil depth, Total phosphorus content did not change much. (2)In Huaqiao International Business City, the average values of five heavy metals exceeded the background values of Jiangsu soil, and the Cd pollution was the most serious, with a ratio of 2.94. There was a significant correlation among the heavy metals. (3) The single factor pollution index evaluation showed that the pollution degree of heavy metals in five soils was Cd gt; Pb gt; Cu gt; Zn gt; Cr. (4) The evaluation of Nemerow comprehensive pollution index shows that the pollution degree in different land-use types is arable land gt; economic forest land gt; forested land gt; sparse forest grassland gt; artificial forest land gt; barren grassland. (5) Potential ecological risk assessment showed that the average value of potential ecological risk index of single heavy metal was Cd gt; Pb gt; Cu gt; Cr gt; Zn, and the comprehensive potential ecological risk index was economic forest land gt; cultivated land gt; forested land gt; sparse forest grassland gt; artificial forest land gt; barren grassland.

Key words: Flower Bridge in Kunshan; Soil Properties; Heavy Metals; Ecological Risk Assessment

目 录

1 绪论 1

1.1研究的背景及意义 1

1.2国内外研究现状 1

1.2.1城市土壤的特征 1

1.2.2城市土壤重金属污染的来源 1

1.2.3城市土壤重金属污染的特征 2

1.2.4城市土壤重金属污染的评价 3

2 研究方法 5

2.1研究区概况 5

2.2样品的采集与分析 5

2.2.1样品采集 5

2.2.2样品分析方法 6

2.3土壤重金属污染的生态风险评估方法 7

3 结果与分析 8

3.1土壤的主要性状及变异规律 8

3.2土壤重金属及变异规律 11

3.3土壤重金属污染的生态风险评估 16

4 结论与建议 18

5 致谢 19

参考文献 20

1 绪论

1.1研究的背景及意义

在城镇中,人类活动集中,人口密度密集,人类在利用自然资源的同时也产生大量的污染物,当污染物总量过大,超过了城镇的自然负荷时,就会对城镇造成破坏,影响当地的自然环境和人类的生存与发展。在中国经济社会不断发展的潮流下,城市化已经成为了中国发展不可避免地趋势。土壤作为城市复合生态系统的基本组成部分,对人类生产生活都具有重大的影响。随着城市化进程的加快,城市土壤重金属的含量逐步升高,这威胁着土壤环境质量及城市居民的生命健康安全。因此,有必要研究土壤主要性状、重金属变异规律及相应的生态风险评价,以确定土壤重金属污染状况、潜在生态风险状况,为风险预警、土壤修复和城市工业规划布局提供依据。现选区典型快速发展地区-花桥国际商务城,探讨其土壤主要性状等指标,为风险预警等提供依据。

1.2国内外研究现状

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