【作者】 万寅婧；

【导师】 周立祥； 占新华；

【作者基本信息】 南京农业大学 ， 环境工程， 2006， 硕士

【摘要】 多环芳烃（Polycyclic aromatic hydrocarbons，PAHs）是指一类含有两个或两个以上苯环，以线状、角状或簇状排列的稠环型化合物。这类物质具有强烈的致癌、致畸、致突性，是一类持久性难降解有机污染物（Persistent Organic Pollutants，POPs），因此PAHs在环境中的生物地球化学行为备受关注。水溶性有机物（Dissolved organic matter，DOM）是陆地和水生生物系统中普遍存在的物质，在植物根际、有机肥料或有机废弃物施用地的土壤环境中含量尤其较高。它对土壤和水环境中养分和污染物的活化和迁移有较大的影响。研究环境中DOM与PAH的s相互关系对了解影响PAHs环境行为的因素和影响机制，以及科学地对PAHs的环境风险评价意义重大。本论文以农业上常用的有机物料-污泥、猪粪和绿肥为DOM的提取原料，以菲（Phe）为PAHs的代表，通过室内试验和水培生物学等试验研究了水溶性有机物对土壤-植物体系中多换芳烃的生物毒性的影响。 采用小麦根伸长抑制试验，研究了菲（Phe）、芘（Pyr）对土壤中小麦的生物毒性。结果表明，Phe、Pyr对小麦发芽与根伸长均有明显的抑制作用，土壤中Phe、Pyr浓度与小麦种子的发芽指数呈显著负相关性(r_Phe=-0.9708，r_Pyr=-0.9714)，与根伸长抑制率呈显著正相关性(r_Phe=0.9705，r_Pyr=0.9752)。Phe、Pyr对小麦根毒害的敏感区间浓度分别为0～200mg／kg和0～300mg／kg。Phe、Pyr污染土壤的小麦根伸长半数抑制浓度则分别为200mg／kg和500mg／kg。小麦对土壤中Phe的毒害更为敏感。PAHs对小麦发芽与根伸长的抑制程度与其结构和溶解度显著相关，且随着溶解度的增大和苯环数目的减少而增加。研究显示，PAHs因会降低土壤的土水势，且土水势降低的程度随着PAHs溶解度的增大而增大，这正是Phe、Pyr抑制小麦在土壤中发芽和根伸长的重要原因之一。 采用生物培养和物理化学试验，研究了水溶性有机物（DOM）对土壤中菲（Phe）生物毒性的影响。结果表明，DOM的存在会降低Phe的生物毒性，但是降低程度与其疏水性组分含量和表面活性有关，且Phe生物毒性的降低程度随DOM浓度的增大而增大。DOM降低土壤中Phe的生物毒性的重要原因是由于由于DOM均具有表面活性，DOM的存在可以提高Phe污染土壤的表层土水势所致。更多还原

【Abstract】 Polycyclic aromatic hydrocarbons （PAHs） are persistent organic pollutants （POPs） widely existing in the environment. They are a unique class of pollutants which are constituted by hundreds of individual substances. These compounds contain two or more fused aromatic rings made up of carbon and hydrogen atoms. PAHs have received popular and environmental attention due to their strongly recalcitrant degradability and the carcinogenic, mutagenic and tumorigenic properties. Dissolved organic matter （DOM）, one of the most active chemical components in terrestrial and water ecosystem, is ubiquitous in soil and aqueous environment. It has a great effect on the solubility, adsorption-desorption equilibrium, biodegradation and translocation of organic pollutants in soil and water. Increasing attention has been paid on influence of DOM on environmental behavior of PAHs, especially in soil-plant ecosystem. It has become an interdisciplinary focus in the fields of soil science, ecology and environmental science due to the important roles of DOM in PAHs uptake by plant, PAHs translocation in soils and waters, and PAHs bioremediation in soils. Consequently, this study was carried out to explore the influence of DOM derived from sewage sludge, pig manure and green manure on the biotoxicity of phenanthrene （Phe） in soil-plant ecosystem and the associated mechanism.Adopting biological culture experiments, the biotoxicity of phenanthrene （Phe） and pyrene （Pye） of wheat added in soil was studied. The results showed that there was a significant negative relationship between germination index and concentration of Phe and Pye (r_Phe=-0.9708, r_Pyr=-0.9714), a significant positive relationship between inhabitation rates of root elongation and concentration of Phe and Pye (r_Phe=0.9705, r_Pyr=0.9752). The sensitive range of inhibiting wheat root elongation was from 0 to 200mg/kg for Phe and from 0 to 300mg/kg for Pyr. The media half inhibition concentraton (IC₅₀) was 200mg/kg for Phe and 500mg/kg for Pyr. The biotoxicity of PAHs increased with the increase of its solubility and decrease of the benzene ring number. PAHs could reduce the soil water potential and the degree for this reduction increased with the increase of the solubility of更多还原