Abstract：
Sewage treatment plants (STPs) are primary sources of antibiotics in aquatic environments. However, limited research has been conducted on antibiotic attenuation in STPs and their downstream waters in low-urbanized areas. This study analyzed 15 antibiotics in the STP sewage and river water in the Zijiang River basin to quantify antibiotic transport and attenuation in the STPs and downstream. The results showed that 14 target antibiotics, except leucomycin, were detected in the STP sewage, dominated by amoxicillin (AMOX), ofloxacin, and roxithromycin. The total antibiotic concentration in the influent and effluent ranged from 158 to 1025 ng/L and 99.9 to 411 ng/L, respectively. The removal efficiency of total antibiotics ranged from 54.7 % to 75.7 % and was significantly correlated with total antibiotic concentration in the influent. The antibiotic emission from STPs into rivers was 78 kg/yr and 4.6 g/km2yr in the Zijiang River basin. The total antibiotic concentration downstream of the STP downstream was 23.6 to 213 ng/L and was significantly negatively correlated with the transport distance away from the STP outlets. Antibiotics may pose a high ecological risk to algae and low ecological risk to fish in the basin. The risk of AMOX and ciprofloxacin resistance for organisms in the basin was estimated to be moderate. This study established antibiotic removal and attenuation models in STPs and their downstream regions in a low-urbanized basin, which is important for simulating antibiotic transport in STPs and rivers worldwide.
摘要：
污水处理厂（STP）是水生环境中抗生素的主要来源。然而,在低城市化地区的STP及其下游水域中，对抗生素减毒进行了有限的研究。本研究分析了紫江流域STP污水和河水中的15种抗生素，以量化抗生素在STP和下游的运输和衰减。结果显示，14种目标抗生素，除了白霉素,在STP污水中检测到，以阿莫西林（AMOX）为主，氧氟沙星,和罗红霉素.进水和出水中的总抗生素浓度范围为158至1025ng/L和99.9至411ng/L，分别。总抗生素的去除效率为54.7%~75.7%,与进水中总抗生素浓度显著相关。紫江流域STP向河流的抗生素排放量分别为78kg/年和4.6g/km2yr。STP下游的总抗生素浓度为23.6至213ng/L，与远离STP出口的运输距离显着负相关。抗生素可能对藻类构成高生态风险，对流域鱼类构成低生态风险。估计流域生物对AMOX和环丙沙星耐药的风险是中等的。本研究建立了低城市化流域STP及其下游地区的抗生素去除和衰减模型，这对于模拟抗生素在全球STP和河流中的运输非常重要。
