Department of Biological Sciences, Faculty of Science, Beirut Arab University, Debbieh, Lebanon.
Research Center for Environment and Development, Beirut Arab University, Bekaa, Lebanon.
Environ Monit Assess. 2023 Dec 26;196(1):90. doi: 10.1007/s10661-023-12267-6.
Antibiotic contamination in polluted rivers is well recognized as an environmental and public health challenge. In this study, the occurrence, distribution, and ecological risk assessment of three commonly used antibiotics (amoxicillin, ciprofloxacin, and azithromycin) were assessed in the Litani River, the most important and highly polluted river in Lebanon. Physicochemical and microbiological water quality parameters including the antibiotic-resistant ones were in parallel determined in the same sites. Water samples from five sites stretching across the river upper basin were analyzed for the antibiotics under study using high-performance liquid chromatography, with both fluorometric and UV detectors post-extraction using a solid-phase method with a hydrophilic-lipophilic balance cartridges. The disc diffusion method and standardized water quality methods were used for antibiotic-resistant bacteria and water quality assessment, respectively. Amoxicillin and ciprofloxacin were found at concentrations of 250 ng/L and 107.2 ng/L, while azithromycin was not detected in any of the sites under study. Varying levels of antibiotic resistance were detected with the isolated Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa) while the total coliforms showed resistance to multiple antibiotics. COD, TP, PO43-, TN, NO3-, NH4 + , E. coli, total coliform, P. aeruginosa, and Cd levels surpassed permissible levels. Correlation analysis with water quality parameters (COD, total phosphate, phosphate, total nitrogen, and cadmium) showed a significant positive correlation with ciprofloxacin (r > 0.5, p value < 0.05). Also, the resistant P. aeruginosa showed a significant positive correlation with cadmium (r > 0.5, p value < 0.05) while the resistant E. coli was positively correlated with total nitrogen, nitrate, and lead levels (r > 0.5, p value < 0.05). The ecological risk assessment revealed that all the tested antibiotics pose low risks (ecological risk quotient RQ < 0.1) except ciprofloxacin, which could pose a medium risk (0.1 < RQ < 1). Future research concerning the long-term assessment of antibiotics' residues and the identification of resistance genes in the river is recommended.
受污染河流中的抗生素污染是一个公认的环境和公共卫生挑战。在这项研究中，评估了三种常用抗生素（阿莫西林、环丙沙星和阿奇霉素）在黎巴嫩最重要和污染最严重的河流利塔尼河中的存在、分布和生态风险。在同一地点平行测定了包括抗生素抗性在内的理化和微生物水质参数。使用高效液相色谱法，对来自河流上游五个地点的水样进行了研究抗生素的分析，使用亲水-疏水平衡柱固相法提取后，使用荧光和紫外检测器。使用扩散法和标准化水质方法分别对抗生素抗性细菌和水质进行评估。在研究的所有地点均未检测到阿奇霉素，但检测到浓度为 250 ng/L 的阿莫西林和 107.2 ng/L 的环丙沙星。检测到不同水平的抗生素抗性，分离的大肠杆菌（E. coli）和铜绿假单胞菌（P. aeruginosa）表现出对多种抗生素的抗性，而总大肠菌群对多种抗生素表现出抗性。化学需氧量、总磷、正磷酸盐、总氮、硝酸盐、氨、大肠杆菌、总大肠菌群、铜绿假单胞菌和镉水平超过允许水平。与水质参数（化学需氧量、总磷酸盐、磷酸盐、总氮和镉）的相关分析表明，与环丙沙星呈显著正相关（r > 0.5，p 值 < 0.05）。此外，抗性铜绿假单胞菌与镉呈显著正相关（r > 0.5，p 值 < 0.05），而抗性大肠杆菌与总氮、硝酸盐和铅水平呈正相关（r > 0.5，p 值 < 0.05）。生态风险评估显示，除环丙沙星外，所有测试抗生素的风险均较低（生态风险商 RQ < 0.1），环丙沙星可能构成中等风险（0.1 < RQ < 1）。建议对河流中抗生素残留的长期评估和抗性基因的识别进行进一步研究。
