主体化合物对有机污染物生物有效性过程的调控作用及其化学多样性

Bioavailability processes of organic pollutants involve a variety of individual physical, chemical, and biological interactions or processes, including speciation, mass transfer, and permeation across biological membrane. They have been recognized as limiting factors to biodegradation and bioremediation of organic compounds in soils or sediments. Host compounds (e.g., cyclodextrins) are increasingly applied to bioremediation of organic pollutants by improving their bioavailability. It is attributable to well recognized inclusion complexation through which organic pollutants are accommodated into the cavity of host compounds and form water soluble complexes. However, mechanisms by which host compounds mediate bioavailability processes of organic contaminants are poorly understood. To answer this question, both laboratory and field studies will be conducted about effects of host compounds on desorption, permeability, and biological reactivity of typical organic pollutants (e.g., pesticides and PAHs). Firstly, the experiments about adsorption and environmental stability of host compounds themselves and effects on soil microbes will be carried out to determine application rates of host compounds beyond which host compounds can lead to adverse effects on biological properties of soils. Secondarily, host compounds below these levels will be chosen for the following experiments including inclusion complexation, desorption, permeation across artificial biological membranes, and biological activities (e.g., soil degradation and earthworm bioconcentration). These experiments are aimed to investigate effects of host compounds on speciation, environmental/membrane transfer, and apparent bioavailability of structurally different organic pollutants. Finally, differences in inclusion complexation of host compounds with organic pollutants will be analyzed to classify these pollutants. And statistics analysis about effects of host compounds on desorption, permeability, and biological activities of organic pollutants will be done to reveal chemical diversity in mediation effects of host compounds. Overall, all the experiments are designated to obtain the information about effects of host compounds on speciation, environmental transfer, membrane transfer and biological activities of organic pollutants. These information are related to all the interactions or processes involved in bioavailability processes of organic pollutants, from the viewpoint of the definition "bioavailability processes of organic pollutants" advocated by the Annual Report of National Research Council. So, it is feasible to reach the goal of this project to reveal mediation of host compounds in bioavailability processes of organic pollutants.

生物有效性涵盖有机污染物的赋存、传质、生物膜吸收等作用或过程(统称为生物有效性过程)，通常是污染物生物降解与修复的限制性因素。主体化合物如环糊精，可通过包合作用提高污染物生物有效性，用于环境污染修复。现有研究受限于生物膜吸收资料缺乏、污染物选择单一等，难以阐明主体化合物对污染物生物有效性过程的影响机制。本研究基于生物有效性过程概念剖析，拟开展土壤模拟或现场测试，采用经典的环境化学实验技术并引入药物学的生物膜渗透测试技术，在排除主体化合物自身对环境扰动效应的前提下，考察它们对常见有机污染物脱附、模拟生物膜渗透、土壤降解或生物富集的影响，分别辨析它们对污染物环境赋存(含环境传质)、生物膜传质、生物活性的影响效应。同时，统计分析这些影响效应与污染物化学结构的关联及存在的化学多样性。本研究涵盖了生物有效性过程概念中的全部作用或过程，预计能阐明主体化合物对污染物生物有效性过程的调控机制。

生物有效性通常是污染物生物降解与修复的限制性因素。环糊精等主体化合物被证实能提高污染物生物有效性。本研究选取了农药、PAHs、抗生素、TBBPA等有机污染物，建立了环糊精对污染物生物膜渗透性能的影响评价模型，阐明了环糊精对有机污染物环境降解及蚯蚓生物富集的有效性调控与识别机制。.通过优化蛋黄卵磷脂、胆固醇等生物膜组分的含量及比例、成膜体系pH值，构建了两种可用于模拟胃、肠生物吸收的PAMPA技术，评价了130余种污染物的生物膜渗透性能。基于质量守恒、环糊精包合平衡及渗透平衡，构建了环糊精对污染物生物膜渗透性能影响的数学模型，其中环糊精浓度为唯一变量。污染物生物膜渗透性性能的变化，与化合物的包合稳定常数及环糊精种类和浓度相关。引入化合物的渗透性能，提高了污染物生物富集性能和急性毒理效应LC50的预测准确性，可用于评价环糊精对污染物生物积累和毒理特性的定量影响。.进一步开展了环糊精包合作用对PAHs蚯蚓富集生物有效性的识别与评价研究。发现PAHs的环糊精提取性能与BSAF都与土壤有机碳含量、土壤粘粒分数、粉粒分数、PAHs生物降解速率等相关，并且HPCD提取对土壤理化及结构特性的影响与蚯蚓吞食作用的影响相似。提出PAHs的蚯蚓体内浓度是环糊精提取浓度的幂函数，阐明了蚯蚓富集生物有效性的化学多样性。并构建一个适用于15种PAHs蚯蚓富集的生物有效性模型。该模型的3倍偏差预测准确性为98.4%，5倍偏差预测准确性为100%，优于目前所构建的生物有效性评价模型。.开展了环糊精单体和环糊精材料对污染物土壤降解和氧化降解的调控研究。发现环糊精通过包合洗脱-伪相捕捉作用，降低乙草胺等农药的土壤吸附作用，增加土壤中游离态农药的含量，不同程度上促进农药的土壤降解。发现环糊精材料通过类似于环糊精单体的包合作用，吸附抗生素和TBBPA。环糊精单体和材料的包合作用降低了TBBPA氧化降解性能，但没有改变其降解机制。CDP调控作用能有效消除环境体系中共存盐度离子、可溶性有机质的干扰效应。

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