【作者】 林舒；

【导师】 董岁明； 张淑贞；

【作者基本信息】 长安大学 ， 环境工程， 2009， 硕士

【摘要】 持久性有机污染物（POPs）作为新型污染物,由于其在土壤中残留时间长,亲脂性高,会对农作物质量和人类生命健康构成较大的安全隐患,已经引起了人们的广泛关注。而持久性有机污染物在土壤中的“老化”行为强烈影响其在环境中的迁移、转化、最终归宿及生物可利用性。本论文以三种多环芳烃（PAHs）菲、芘和苯并芘作为模型化合物,研究其在七种不同性质土壤中的吸附,吸附随时间的变化趋势,以及与土壤性质之间的关系。同时对比了几种不同的提取方法对土壤中多环芳烃的提取效率。本研究已取得以下几方面的成果:1)在七种土壤中加入三种多环芳烃,随着老化时间的延长,在经历一个短暂的快速吸附过程后,污染物进入慢吸附过程,缓慢地向致密的有机质和微孔内部迁移。土壤中各有机组分存在非均一性,对PAHs有不同的结合位点,两相一级动力学模型可以很好的描述PAHs在土壤中的迁移。2)使用0.01%CaCl₂溶液、正丁醇溶液和1:1的丙酮/二氯甲烷溶液为提取剂对土壤中的多环芳烃进行振荡提取,并与以1:1正己烷/二氯甲烷为溶剂的索式提取法进行比较。发现正丁醇最适合应用于有机污染物生物有效性评价,而1:1的丙酮/二氯甲烷振荡提取法可以替代索式提取法进行污染物总量的提取。3)土壤中可提取态多环芳烃与可溶解性有机碳（DOC）呈正相关关系,而与粘土成分（clay）成负相关关系。DOC含量的增加可以提高多环芳烃的迁移性,避免被束缚在土壤内部;而粘土成分因为其较大的吸附容量,在一定程度上阻止多环芳烃从土壤中的解吸。4)土壤有机碳中的硬碳成分决定PAHs在土壤中的慢迁移行为,有机污染物的慢迁移部分随着硬碳含量的增加而增加。硬碳对于土壤中有机污染物的吸附和最终归趋有着重大的意义。此外,土壤的粒径和污染物的分子体积对污染物在土壤中的老化也有一定的影响。更多还原

【Abstract】 The Persistent Organic Pollutants （POPs）, as a new type of pollutant, had attracted extensive attention because of its long time residues and high lipophilicity in the soil, which would bring grater security risks on crop quality and human health. The mobility, transformation and ultimate fate of POPs in the environment are strongly dependent on the aging and sequestration effect of the contaminants in soil. In this study, we used three kinds of polycyclic aromatic hydrocarbons （PAHs）, phenanthrene, pyrene and benzopyrene, as the model compounds to study the adsorption and the adsorption trends over time in seven different soils, as well as the relationship between sorption and soil character. Meanwhile we compared the efficiency of different extraction methods which were used to extract the PAHs from soil. The following results were obtained by the experiments:I) This study added three kinds of PAHs into seven soils and found with the extension of aging time, the pollutants entered into the slow process after a short-term rapid adsorption, and then migrated slowly to the condensed OM and the microporous internal. The SOM of soil existed non-homogeneous and had different binding sites to the PAHs. The two-compartment first order kinetic model could fit the migration perfectly.II) The study compared different extraction methods by using 0.01% CaCl₂ solution, butanol, 1:1 DCM/actone, and the soxhlet extraction （1:1 n-hexane/DCM） and found the butanol was most suitable for the bioavailability evaluation of organic pollutions, and the 1:1 DCM/actone could replace the soxhlet to extraction the total amount of pollutants.III) The extractable PAHs in the soil were positively correlated to dissolved organic carbon （DOC） and negatively correlated to clay. The increase of DOC could increase the mobility of PAHs and avoid them to be bounded in the soil internal, and the clay could prevent the PAHs desorption to some extent because of its large adsorption capacity. IV) The "hard carbon" in soil determined the slow migration behavior of PAHs, and the slow migration ratio increased with the increase of hard carbon. The hard carbon had great significance to the adsorption and final fate of organic pollutants in the soil. In addition, the soil particle size and the molecular bulk of pollutants had an appreciable effect to the pollutants aging in the soil.更多还原