典型PPCPs及其代谢、转化物的光降解基质效应与机理研究

Pharmaceuticals and personal care products (PPCPs) are receiving public concerns and scientific interest in the environmental occurrence, fate, toxicity, and ecological risk since they were included in the list of pollutants. The metabolites and environmental transformation products of PPCPs may pose greater threat to the aquatic ecosystem. However, until recently few studies are focused on their degradation and transformation in natural waters. The naturally occurring humic substances are ubiquitous in lakes, rivers, and oceans. It has been paid close attention to the studies of photosensitized degradation of pollutants by humic substances. According to our recent experimental results, the photodegradation of pollutants is affected by the coexisting environmental matrixes, such as metal ions and halide ions. The different photosensitization mechanisms, e.g., hydroxyl radicals attack, singlet oxygenation, and direct interaction between humic substances triplet states and pollutants, exhibit various effects on the reaction kinetics and photoproducts. Currently, few literatures are available on the matrix effects for the photosensitized degradation. This project aims to investigate the reaction kinetics, matrix effects, products, and mechanisms for the photodegradation of amitriptyline, imipramine and their demethyl-metabolites, and parabens along with the chlorinated derivatives (methyl-, ethyl-, propyl-, butyl-, 3-chloro-, and 3,5-dichloro paraben) in the humic substances solutions. This study will supply basic data for the explanation of the aquatic environmental behaviors, and evaluation of the ecological risk of these pollutants.

医药与个人护理品（PPCPs）自上世纪末被列为环境污染物以来，其浓度水平、迁移转化、环境毒性、生态风险等引起了公众和科学界的广泛关注。一些药物的代谢物和环境转化物对水生态环境影响可能更大，但迄今为止，较少文献报道它们在天然水中的降解转化。腐殖质广泛存在于湖泊、河流、海洋等水体，其对污染物的光敏化降解一直是研究的热点。根据最新的实验结果，腐殖质光化学活性易受水中共存的金属离子和卤离子等环境基质影响。不同的光敏机制，如羟基氧化、单线态氧作用、三线态腐殖质直接反应，其基质效应可能有所不同，因而影响光降解动力学和产物，目前这方面研究并不多见。本项目拟以阿米替林、丙咪嗪及其脱甲基代谢物和对羟基苯甲酸酯类（甲、乙、丙、丁酯）及其氯代物（3-、3,5-氯代物）为对象，研究其在腐殖质溶液中光降解动力学、基质效应、反应产物与作用机制，为揭示PPCPs及其代谢、转化物的环境行为与生态风险评估提供基础数据。

医药与个人护理品（PPCPs）自上世纪末被列为环境污染物以来，其浓度水平、迁移转化、环境毒性、生态风险等引起了公众和科学界的广泛关注。本项目考查了水中共存的金属离子和卤离子等环境基质对腐殖质光化学活性影响，阿米替林、丙咪嗪及其脱甲基代谢物和对羟基苯甲酸酯类（甲、乙、丙、丁酯）及其氯代物（3-、3,5-氯代物）在腐殖质作用下发生光敏化反应动力学与机制。研究表明：（1）金属离子的存在明显抑制腐殖质光致单线态氧的生成，阴离子对单线态氧生成无显著影响；（2）金属离子与腐殖质形成络合物，降低了腐殖质的氧化还原电位，阴离子的存在对腐殖质氧化还原电位影响不大；（3）阿米替林、丙咪嗪及其脱甲基代谢物和对羟基苯甲酸酯类（甲、乙、丙、丁酯）及其氯代物（3-、3,5-氯代物）与腐殖质发生光致电子转移反应；（4）胺类污染物降解与腐殖质电子接受能力(EAC)呈正相关；（5）在腐殖质作用下，胺类污染物发生氧化反应，生成有机自由基中间体，进而发生-H转移最终形成去甲基、去二甲基等系列产物。本项目通过研究腐殖质光敏化基质效应、胺类污染物光降解动力学、反应产物与作用机制，为揭示水环境中典型PPCPs及其代谢、转化物的环境行为与生态风险评估提供基础数据。