黄河济南段水体悬浮颗粒物中抗生素赋存特征

Occurrence and distribution of antibiotics in suspended particulate matters in the Yellow River(Jinan Section).

以黄河下游济南段为研究对象,采用微波消解提取-固相萃取结合高效液相色谱-质谱串联分析水体及其表层悬浮颗粒物(SPMs)中4类(磺胺类(FQs)、喹诺酮类(SAs)、大环内酯类(MLs)和四环素类(TCs))48种抗生素的赋存特征,并通过构建浊度vs.总悬浮固体量(TSS)和抗生素总浓度与浊度/TSS关系曲线预测水中溶解态(Cd)和SPMs结合态(CSPM)抗生素的分布.结果显示,黄河下游济南段可检出36种抗生素,其中MLs类抗生素检出率最高(97%~100%),FQs浓度水平最高(恩诺沙星达13.5µg/L),SAs的检出率和浓度(磺胺二甲异嘧啶达12.3µg/L)均较高,TCs普遍低于方法定量限;人为活动和畜禽养殖场是污染主要来源,水体浊度(11~724NTU)与TSS(3.2~914g/L)正相关,且二者与FQs和SAs在春季和冬季均表现出显著的线性关系.抗生素浓度与浊度/TSS线性关系计算结果显示,进入水体的FQs和SAs绝大部分会与SPMs结合(CSPM:3.2~27.2µg/g),Cd对其总量的贡献低于30%.各点位CSPM计算值和实测值拟合度较好,表明若根据抗生素总浓度进行校准,浊度/TSS可用于预测水体SPMs对FQs和SAs的负载能力.SPMs中抗生素在夏季空间分布均一,差异性较小(2.0~10.6µg/g);在冬季,下游(16.2~40.7µg/g)污染程度与上游(10.2~14.6µg/g)相比更严重;春季则表现为上游(38.2~49.5µg/g)显著高于下游(25.2~34.0µg/g).本研究结果表明黄河下游SPMs既是抗生素的重要“汇”,也是污染扩散至其他河流的“源”,值得进一步关注和研究.

The occurrence and distribution of 48 antibiotics belonging to four classes(including fluoroquinolones(FQs),sulfonamides(SAs),macrolides(MLs)and tetracyclines(TCs))in water bodies and suspended particulate matters(SPMs)collected from the Lower Reaches of Yellow Rives(Jinan Section)were investigated.The microwave-assisted extraction-solid phase extraction combined with high-performance liquid chromatography/mass spectrometry/mass spectrometry techniques were employed to quantify the concentrations of target antibiotics.Additionally,the correlations of turbidity and total suspended solids(TSS),as well as the relationships between total antibiotic concentrations and turbidity/TSS were established to determine the concentration levels of antibiotics in dissolved(Cd)and SPM-associated phases(CSPM).The results showed that a total of 36 target antibiotics were detected in all water samples.Among them,the MLs were detected at the highest frequencies(97%~100%).For the antibiotics in the FQs group,the highest concentrations were determined(up to 13.5µg/L for enrofloxacin),and the SAs were also detected at relatively high frequencies and concentrations(up to 12.3µg/L for sulfisomidine),which are mainly originated from anthropogenic activities and livestock farms.In the case of the TCs,most of them were below the limit of quantifications(LOQs).Furthermore,a reasonable linear relationship between turbidity and TSS,and a close to linear correlation of the total concentrations of FQs/SAs vs.turbidity/TSS was observed.From these regressions,the values of CSPM were calculated in the range of 3.2~27.2µg/g,suggesting the SPM-associated fractions accounted for most of the detected FQs/SAs antibiotics.While for the FQs/SAs dissolved in water,the Cd took up less than 30%of their total concentrations.Noteworthy,the calculated CSPM fitted well with the measured values,indicating the turbidity/TSS may be a useful proxy to evaluate the SAs/FQs adsorbed onto SPMs,if the total antibiotic concentrations used for calibration.Temporally,the concentrations of SPM-associated antibiotics insignificantly varied in summer(2.0~10.6µg/g).In winter,higher contamination levels of antibiotics in downstream SPMs than those in the upstream;while opposite patterns were observed for the temporal variations of the SPM-associated antibiotics in spring.In summary,the SPMs could represent as both an important reservoir and source of antibiotics in the Lower Reaches of Yellow River,which requires further attention and investigation.