不同土地利用类型土壤中持久性有机污染物的分布特征与风险评价

发布时间：2018-06-02 16:44

  本文选题：有机氯农药 + 多环芳烃　； 参考：《南京师范大学》2015年硕士论文

【摘要】：环境中的持久性有机污染物(Persistent Organic Pollutants,简称POPs),是一类具有高毒性、持久性、易于在生物体内富集的有机化合物,POPs能够进行长距离的迁移和沉积,对源头附近或远处的环境造成污染,还会对人体造成危害,因此有必要开展POPs在环境中的分布和风险研究。本论文主要围绕POPs在滇池流域斗南地区几类农业土壤中的剖面分布特征及风险开展研究。考虑到不同土地利用类型,采集了大棚地(含不同种植年限)、露天菜地、撂荒地及居民区四类土地利用类型土壤样品,采用超声波萃取方法提取土壤样品中的OCPs及PAHs,用GC-MS进行了样品的测定,研究土壤中POPs的残留、来源及生态风险。应用SPSS等软件对数据进行数学统计,研究不同土地利用类型类型、土壤理化性质等因素与POPs分布之间的相关性。研究结果如下：斗南土壤中OCPs含量范围为32.38～134.42ng/g(干重),平均含量72.79ng/g；DDTs的含量为16.29～52.99ng/g,平均含量27.33ng/g; HCHs的含量范围为13.16～85.15ng/g,平均含量为45.46ng/g。不同土地利用类型土壤的土壤中OCPs含量从低到高为大棚地、居民区、撂荒地、露天菜地。DDTs及HCHs同分异构体的比值分析认为,斗南地区近期存在新的HCHs输入,可能是受到工业HCH的影响,DDTs则主要来自过去使用农药的残留。土壤剖面中,DDTs随深度变化其含量变化不明显,HCHs则在表层含量较高,随深度增加而逐渐降低。OCPs在土壤剖面的含量变化与TOC含量具有较显著的关系,与粘粒相关性不明显。HCHs和DDTs的残留量生态风险评价结果显示,HCHs潜在的生态风险较低,但DDTs具有一定的生态风险。斗南土壤中PAHs含量范围为566.16～2518.25ng/g,平均值为1641.53 ng/g。16种优控PAHs均有检出,其中三环和四环多环芳烃占主要地位。不同土地利用类型土壤的土壤受到不同程度的PAHs污染,居民区受PAHs污染程度要高于农业用地。土壤剖面中,土壤中TOC含量及粘粒含量与PAHs含量具有较显著的相关性。比值法及主成分来源解析发现,当地土壤中PAHs主要来源于燃烧源,尤其是机动车排放的尾气及居民燃煤,部分样品指示了石油源的存在。斗南地区土壤中PAHs的BaPeq浓度范围为92.25～155.22ng/g,与相关标准及同类研究相比,当地的潜在风险较小。
[Abstract]:Persistent organic pollutants (pops) in the environment are persistent Organic pollutants, a class of highly toxic, persistent and easily enriched organic compounds that can transport and deposit over long distances and pollute the environment near or far away from the source. It is necessary to study the distribution and risk of POPs in the environment. In this paper, the profile distribution and risk of POPs in several kinds of agricultural soils in Dianchi basin are studied. Taking into account different land use types, soil samples of four types of land use types, including greenhouse land (including different planting years, open vegetable fields, abandoned land and residential areas), have been collected, The OCPs and PAHs in soil samples were extracted by ultrasonic extraction. The samples were determined by GC-MS to study the residues, sources and ecological risks of POPs in soil. The correlation between POPs distribution and land use types, soil physicochemical properties and other factors was studied by using SPSS and other software. The results are as follows: the range of OCPs content in Dounan soil is 32.38 ~ 134.42 ng / g (dry weight = 72.79 ng / g / g), the average content of HCHs is 16.29 ~ 52.99 ng / g, the average content of HCHs is 27.33 ng / g, and the range of HCHs content is 13.1685.15 ng / g, with an average content of 45.46 ng / g. The ratios of OCPs contents in soils of different land use types from low to high to those in greenhouse land, residential area, abandoned land, open vegetable field and HCHs isomer showed that there were new HCHs inputs in Dounan area recently. It may be affected by industrial HCH mainly from pesticide residues in the past. In soil profile, the content of HCHs was higher in the surface layer than in the soil profile, and decreased gradually with the increase of depth. There was a significant relationship between the content change of TOC and the content of TOC in the soil profile. The results of ecological risk assessment of HCHS and DDTs showed that the potential ecological risk of HCHS was lower, but DDTs had some ecological risk. The range of PAHs content in Dounan soil was 566.16 ~ 2518.25 ng / g, and the average value was 1641.53 ng/g.16. All of them were identified by species-controlled PAHs, of which tricyclic and four-ring polycyclic aromatic hydrocarbons (PAHs) were dominant. The soil of different land use types was polluted by PAHs in different degree, and the degree of PAHs pollution in residential area was higher than that in agricultural land. In soil profile, TOC content, clay content and PAHs content were significantly correlated. Ratio method and principal component analysis showed that PAHs in local soil was mainly derived from combustion sources, especially exhaust emissions from motor vehicles and coal burning by residents, and some samples indicated the existence of oil sources. The range of BaPeq concentration of PAHs in soil is 92.25 ~ 155.22 ng / g in Dounan area. Compared with the related standards and similar studies, the local potential risk is relatively small.
【学位授予单位】：南京师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X53

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本文编号：1969465