畜禽粪便及其堆肥中可溶态有机质对雌激素在土壤中归趋的影响

Natural steroid estrogens like 17β-estradiol（E2）in animal manure have the potential of disupting the endocine systems at low cnontrations (ng/L).Disposal of animal manure to agricultural land can lead to the transfer of steroid estrogens into surface and ground waters and affect human heath. It was widely recognized that binding with hydrophobic organic compounds onto dissolved organic matter(DOM) may significantly increase their ability of tansport.In this proposal, binding of DOM from animal manure with natural steriod estrogens was researched by fluorescence quenching, and the mechanism was further analyzed by Gaussian 09 program.Changes of fluorescence components,molecular distribution and functional groups and conformation in animal manure DOM during composting were by means of three dimentional excitation-emission matrix (EEM) ?uorescence spectroscopy,performance size-exclusion chromatography,13C CPMAS NMR spectroscopy and atomic force microscopy (AFM), and quantitative relationship was established beteween molecular components and fuctional groups of DOM and its adsorption of estrogens. Meanwhile, the degration of free estrogens and DOM bounded estrogens was also investigated in soil solution,and major environmental condition affecting the degration of DOM bounded estrogens was ascertained. These results contribute to the full understanding the adsorption and degration of estrogens in soils and providing the theoretical ground and alternative method for environmental risk control of estrogens.

畜禽粪便中类固醇雌激素如17-β-雌二醇（E2）在极低浓度下（ng/L）即具有极强的内分泌干扰性。农用过程中进入土壤，并向地表水和地下水体中迁移，进而威胁人体健康。环境中可溶态有机质（DOM）是有机污染物迁移的重要载体，本课题通过荧光猝灭法研究畜禽粪便中DOM与类固醇雌激素的结合特征，并利用高斯量子化学软件（Gaussian 09）分析畜禽粪便DOM与雌激素结合的主要机理，进一步通过三维荧光光谱、体积排阻色谱和核磁共振以及原子力显微镜联合表征堆肥过程中畜禽粪便DOM荧光组分、分子量、官能团和空间结构变化，定量分析堆肥过程对畜禽粪便DOM携带雌激素能力的影响；同时还研究了游离态和DOM结合态雌激素在土壤溶液中的降解特征，查明DOM结合态雌激素降解的主要控制因素，研究结果有助于深化认识雌激素在土壤中吸附和降解行为，为畜禽粪便雌激素污染风险控制提供理论依据和方法参考。

畜禽粪便中类固醇雌激素如17β -雌二醇（E2）在极低浓度下（ng/L）即具有极强的内分泌干扰性。农用过程中进入土壤，并向地表水和地下水体中迁移，进而威胁人体健康。环境中可溶态有机质（DOM）是有机污染物迁移的重要载体，本课题通过荧光猝灭法研究畜禽粪便中DOM 与类固醇雌激素的结合特征，进一步通过三维荧光光谱（EEM）、渗析以及原子力显微镜（AFM）联合表征堆肥过程中畜禽粪便DOM 荧光组分、分子量、空间结构变化，定量分析堆肥过程对畜禽粪便DOM 携带雌二醇（E2）和乙炔基雌二醇（EE2）能力的影响；还研究了雌激素在土壤中的吸附特征以及粪便及其堆肥可溶态有机质（DOM）对雌激素的吸附的影响，同时探讨了DOM对雌激素在土壤中的降解的影响。主要结论如下：.(1) 堆肥后，猪粪和牛粪DOM中类富里酸和类胡敏酸组分分别增加22.7% 和 11.8%。此外，通过AFM显示堆肥后DOM空间结构发生变化，形成了较大的团聚体，猪粪DOM中小分子量组分比例(MW<1000Da) 从52% 降到26.2%，大分子量组分(MW>14000Da)比例从23.2% 增到43.8%。DOM与雌激素的结合能力以结合系数（KDOC-e）表征，堆肥猪粪和牛粪的logKDOC-E2分别为4.65 和4.46，分别高于相应新鲜猪粪（4.60）和牛粪（4.40）。相关性分析结果表明KDOC-E2与类富里酸组分、1000Da-7000Da 和 7000Da-14000Da组分呈线性正相关。研究认为，雌激素E2与粪便及其堆肥DOM中1000Da-14000Da的富里酸组分结合增加了其向地表水体和地下水的迁移风险。.(2) E2、EE2在土壤中吸附符合Freundlich等温吸附方程。吸附系数Kf介于26.2~57.5和19.8~35.4，并与有机质含量呈显著正相关（P<0.05）。猪粪及其堆肥DOM显著抑制雌激素在土壤中的吸附，其中堆肥DOM的影响尤为显著。土壤中E2和EE2的降解速率可通过一级动力学模型模拟，E2的半衰期介于1.16~1.36天，EE2的降解半衰期为6.40~8.68天。降解速率随土壤含水量的增加而增加，而共存粪便DOM不总是促进E2的降解。.以上研究结果有助于深化认识雌激素在土壤中吸附和降解行为，为畜禽粪便雌激素污染风险控制提供理论依据和方法参考。.