沱江流域饮用水源地抗生素污染的时空变化、生态风险及人体暴露评估

为探讨抗生素在饮用水源地的分布现状，采用固相萃取-高效液相色谱质谱联用法对四川省沱江流域典型城市饮用水源地中35种抗生素进行了测定，并计算了风险商(RQ)及人体通过饮用水暴露于抗生素的量. 结果表明:① 沱江流域饮用水源地35种抗生素被广泛检出，在春季、夏季、秋季、冬季的浓度分别为n.d.(低于检出限)~114.696、n.d.~536.322、n.d.~69.488和n.d.~90.461 ng/L，检出率分别为0~85.7%、0~92.9%、0~100.0%和14.3%~100.0%. ② 抗生素在冬季检出率最高，达74.3%，喹诺酮类在各季节的平均浓度呈冬季≈夏季>春季>秋季的特征，四环素类在秋季浓度最低，其余5类抗生素未发现显著的时间变化. ③ 磺胺类和大环内酯类存在一定的空间分布特征，而其余抗生素未呈现显著空间分布差异. ④ 磺胺嘧啶在春季、秋季和冬季以及盐酸金霉素在夏季对生态系统有较高的生态风险. 氧氟沙星和盐酸四环素在春季、夏季和冬季的风险商介于0.10~1.00之间，在相应季节对沱江流域可能造成中等生态风险. ⑤ 短期内居民通过饮用沱江流域饮用水源地水暴露于抗生素的风险可以忽略不计，但长期低剂量暴露带来的健康风险问题有待进一步研究. 研究显示:抗生素污染广泛存在于沱江流域饮用水源水中，其中以兽用抗生素为主，表明农业活动可能对该流域抗生素污染贡献较大；沱江流域饮用水源地水中抗生素总体处于中低生态风险，基于该研究数据沱江流域内人群饮用水源水暴露于抗生素的量较低，相对安全. 

Spatial and Temporal Distribution,Ecological Risk and Human Exposure Assessment of Antibiotics in Drinking Water Sources in Tuojiang River Basin

The concentrations of 35 antibiotics were determined by solid phase extraction tandem high performance liquid chromatography-mass spectrometry to understand spatial and temporal distribution of the antibiotics in drinking water sources in typical cities in the Tuojiang River Basin, and their associated ecological and human exposure risks. The antibiotics were widely detected in typical urban drinking water samples, and the concentrations range was n.d. (no decision)-114.696, n.d.-536.322, n.d.-69.488, and n.d.-90.461 ng/L, the detection rates were 0-85.7%, 0-92.9%, 0-100.0% and 14.3%-100.0% in spring, summer, autumn, and winter, respectively. The average detection rate of antibiotics was the highest in winter, reaching 74.3%. The average concentration of quinolone antibiotics in different seasons was in the order of winter ≈ summer > spring > autumn. The concentration of tetracycline antibiotics was the lowest in autumn, and the other five antibiotics had no significant temporal variation. Spatial distribution of sulfadiazine and macrolide antibiotics was found, while the other antibiotics showed no significant spatial distribution. The risk assessment showed that sulfadiazine had high ecological risk to the ecosystem in spring, autumn and winter, while chlortetracycline hydrochloride showed high ecological risk in summer. The risk quotients of loxacin and tetracycline hydrochloride were between 0.10 and 1.00 in spring, summer and winter, indicating that these antibiotics might pose moderate ecological risk to the ecosystem in the corresponding seasons. The results of human exposure assessment showed that the risk of exposure to antibiotics through the drinking water was negligible in short term in Sichuan residents, but the health risk caused by long-term low-dose exposure needs further study. Based on the current study, the investigated 35 antibiotics occurred ubiquitously in the drinking water sources of typical cities in the Tuojiang River Basin, and veterinary antibiotics were the main pollutants, indicating agricultural activities might contribute to the antibiotic pollution in the studied areas. The ecological impact of the antibiotics on drinking water sources in the Tuojiang River Basin was generally at medium to low ecological risk, and the daily antibiotics intake via drinking water ingestion was safe for the local residents.