亚抑制状态下抗菌化合物的环境存在 浓度可能会导致抗药性细菌的进化，以及慢性疾病 饮用水中微量抗生素的暴露可能会增加过敏反应 对抗抗生素（Kummer 2001）。很容易去除抗菌母体化合物 通过氧化过程实现，但对氧化的抗菌活性知之甚少 在此过程中形成的中间体。因此 本研究的总体目标是系统地描述 顺序光化学/生物氧化法去除抗菌物质 天然水中的磺胺甲恶唑（SMX）和磺胺二甲嘧啶（SMZ）化合物。 具体的 本文所述研究阶段的目标包括:SMX的量化和 SMZ光解和UV/H₂O₂氧化速率；以及抗生素残留的评估 光氧化中间体的活性。 选择磺胺类药物SMX和SMZ作为模型抗菌剂 化合物。以下因素对SMX和SMZ氧化和矿化的影响 评估比率:pH；H₂O₂浓度；以及是否存在天然有机物 物质（名词）。分批光解和UV/H₂O₂氧化实验由 通过环形紫外线（UV）光反应器循环水。25瓦低压灯有一个 发射波长为254纳米。监测SMX和SMZ浓度，作为 时间和HPLC定量。进行总有机碳（TOC）分析以评估 SMX/SMZ矿化程度。实验在超纯水（DI）中进行 水）在pH值至少高于和低于溶液pKa两个pH单位的条件下进行缓冲 磺胺基；因此，SMX和SMZ的中性和阴离子形式的降解 进行了评估。在NOM存在的情况下，通过添加SMX和 SMZ进入惠勒湖水（北卡罗来纳州罗利），该湖水已通过0.45微米的过滤器过滤。这个 过滤后的惠勒湖水TOC为5.3 mg/L，pH为7.6，总碱度为 20毫克/升CaCO₃。 为了测试光氧化中间体是否具有抗菌活性，基于 实施了最小抑制浓度（MIC）的概念。对于磺胺类药物， MIC被记录为抑制80%生长的最低浓度 在没有添加抗菌化合物的情况下观察到。抗菌活性显著提高 通过采用Andrews（2001）描述的宏观稀释法和临床试验确定 以及实验室标准协会（CLSI）标准M7-A6。肠杆菌科生物E。 获取大肠杆菌ATCC®25922进行MIC测试。在MIC测试中，将大肠杆菌细胞添加到 Iso Sensitest肉汤产量为1x106个细胞/毫升。 然后，将1毫升接种物添加到8毫升培养基中 装有1毫升水中加入不同浓度抗菌剂或1 暴露于不同光解或UV/H₂O₂ 氧化时间。此外，在不添加抗菌剂的情况下制备阳性对照 代理人在37℃下孵育8小时后，在室温下测量每个样品的光密度 600纳米。为了获得小于0.6的吸光度，对样品进行稀释（2毫升样品+5毫升肉汤）。包括4个参考文献、表格和图表。

The environmental presence of antimicrobial compounds at sub-inhibitory concentrations may lead to the evolution of antimicrobial-resistant bacteria, and chronic exposure to antibiotics at trace levels in drinking water may contribute to increased allergies against antibiotics (Kummerer 2001). Removal of the antimicrobial parent compound is readily achieved by oxidation processes, but little is known about the antimicrobial activity of oxidation intermediates that are formed in the process. Therefore, the overall objective of this research is the systematic characterization of a sequential photochemical/biological oxidation process for the removal of the antimicrobial compounds sulfamethoxazole (SMX) and sulfamethazine (SMZ) from natural water. Specific objectives for the phase of the research described here included: quantification of SMX and SMZ photolysis and UV/H₂O₂ oxidation rates; and, assessment of residual antimicrobial activity of photooxidation intermediates. The sulfonamides SMX and SMZ were selected as model antimicrobial compounds. The effects of the following factors on SMX and SMZ oxidation and mineralization rates were evaluated: pH; H₂O₂ concentration; and, presence/absence of natural organic matter (NOM). Batch photolysis and UV/H₂O₂ oxidation experiments were conducted by recirculating water through an annular ultraviolet (UV) light reactor. The 25-W low pressure lamp had an emission wavelength of 254 nm. SMX and SMZ concentrations were monitored as a function of time and quantified by HPLC. Total organic carbon (TOC) analyses were performed to assess the extent of SMX/SMZ mineralization. Experiments were conducted in ultrapure water (DI water) buffered at pH values that were at least two pH units above and below the pKa of the sulfonamide group; thus, the degradation of the neutral and anionic forms of SMX and SMZ were evaluated. Tests conducted in the presence of NOM were performed by spiking SMX and SMZ into Lake Wheeler water (Raleigh, North Carolina) that had been filtered through a 0.45-µm filter. The TOC of filtered Lake Wheeler water was 5.3 mg/L, the pH was 7.6, and the total alkalinity was 20 mg/L as CaCO₃. To test whether photooxidation intermediates exhibit antimicrobial activity, a method based on the concept of minimum inhibitory concentrations (MICs) was implemented. For sulfonamides, the MIC is recorded as the lowest concentration that inhibits 80 % of the growth that would be observed in the absence of antimicrobial compound addition. The antimicrobial activity was determined by adapting the macrodilution method described by Andrews (2001) and the Clinical and Laboratory Standards Institute (CLSI) Standard M7-A6. The Enterobacteriaceae organism E. coli ATCC® 25922 was acquired to conduct MIC tests. In MIC tests, E. coli cells were added to Iso-Sensitest broth to yield 1x106 cells/mL. Then, 1 mL of this inoculum was added to 8-mL tubes containing 1 mL of water spiked with different concentrations of antimicrobial agent or 1 mL of antimicrobial-spiked water following exposure to different photolysis or UV/H₂O₂ oxidation times. Also, positive controls were prepared without the addition of antimicrobial agent. After incubating for 8 hours at 37ºC, the optical density of each sample was measured at 600 nm. To obtain an absorbance <0.6, samples were diluted (2 mL sample + 5 mL broth). Includes 4 references, tables, figures.