小清河流域抗生素污染分布特征与生态风险评估

利用固相萃取、高效液相色谱-串联质谱法(HPLC-MS/MS)检测小清河流域地表水中4类抗生素的残留水平,分析其分布特征,结合土地利用类型探讨其可能的污染源,并通过计算风险商(RQs)来进行生态风险评估。结果表明:小清河流域地表水有13种抗生素检出,其中大环内酯类抗生素和甲氧苄啶的检出率为100%;20个采样点的大环内酯类、喹诺酮类、磺胺类和磺胺增效类的质量浓度范围分别是2.18~84.9、nd~1600、nd~845、1.88~3900 ng·L-1。高浓度的大环内酯类和喹诺酮类抗生素主要集中在人口密集区下游,在水产养殖密集的下游区域检测到较高浓度的磺胺类和磺胺增效药甲氧苄啶,表明生活污水和水产养殖废水仍是小清河流域抗生素污染的主要来源。生态风险评估结果显示,13种抗生素中处于高风险等级、中等风险等级、无风险等级的比例分别是38.5%、23.1%、38.5%,表明小清河流域部分水体抗生素污染具有较高的生态风险。

Distribution characteristics and ecological risk assessment of antibiotic pollution in Xiaoqing River watershed

Concentrations of 4 types of antibiotics in the surface water of Xiaoqing River watershed were determined using solid-phase ex traction (SPE) and high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS). The spatial distribution of these antibiotics was also examined. The potential pollution sources were explored in combination with land use characteristics of the watershed. Also, ecological risk assessment was performed using calculated risk quotients (RQs). Results showed that 13 antibiotics were detected in surface water samples, among which trimethoprim and macrolides were present in all water samples. The ranges of macrolides, quinolones, sulfonamides, and trimethoprim concentrations were respectively 2.18~84.9 ng·L^-1, nd~1600 ng·L^-1, nd~845 ng·L^-1, and 1.88~3900 ng·L^-1. Relatively high concentrations of macrolides and quinolones mainly occurred in the downstream of densely populated areas. Sulfonamides and trimethoprim were found in the downstream of areas with intensive aquaculture. The ecological risk level of 13 antibiotics was 38.5%, 23.1%, and 38.5% at heavy pollution, medium pollution, and safety, respectively. Our study suggested that antibiotic pollution in the Xiao qing River watershed was mainly caused by aquaculture wastewater and domestic sewage, and antibiotic pollution might pose threat to sensitive aquatic and benthic organisms in the watershed.