Revealing the hydrological transport and attenuation of 14 antibiotics in a low-flow stream

• Published in: The Science of the total environment Vol. 761; p. 143288
• Main Authors: Ding, Yan, Cui, Kangping, Lv, Kai, Li, Ruzhong, Chen, Yihan, Liu, Xiaowei
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 20.03.2021
• Subjects: Anti-Bacterial Agents - analysis; Antibiotic; Environmental Monitoring; Fluoroquinolones - analysis; Lagrangian sampling; Macrolides - analysis; OTIS; Tetracyclines - analysis; Tracer study; Transient storage; Lagrangian sampling; Tracer study; Antibiotic; OTIS; Transient storage
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2020.143288

The fate of antibiotics has mostly been studied in lab-scale systems. Few studies have precisely evaluated the attenuation of antibiotics in natural streams. We used Lagrangian sampling combined with a tracer test and one-dimensional transport with inflow and storage model (OTIS) to reveal the effects of dilution and self-attenuation processes, and diurnal variation of light on the degradation of 14 antibiotics in a 3.6 km low-flow stream. The results showed that the order of in-stream attenuation rates were macrolides (0.18–0.25 h−1) > tetracyclines (0.16–0.18 h−1) > fluoroquinolones (0.094–0.13 h−1) > sulfonamides (0.056–0.082 h−1); half of the mass of antibiotics were lost within 0.44–1.96 km. The dilution effect, including longitudinal dispersion and transient storage, accounted for 20.70%–91.60% of the total attenuation while self-attenuation processes accounted for 8.40%–79.30%. Over 60% of sulfonamides were dissipated by dilution, while over 68% of the removal of macrolides and tetracyclines was attributed to self-attenuation. A comparison of the attenuation rates between day and night demonstrated that photo-dependent attenuation played a dominant role, especially for sulfonamides, accounting for more than 50% of their self-attenuation. Photo-independent attenuation reduced most macrolides and tetracyclines. This in situ experiment increased our understanding of antibiotic attenuation in natural streams. [Display omitted] •In-stream attenuation of 14 antibiotics was studied using Lagrangian scheme.•Longitudinal dispersion and transient storage reduced most of antibiotics.•More than 60% of sulfonamides were dissipated by dilution effect.•The short half-life distances were partly attributed to the low flow.•Photodegradation plays an important role in 14-antibiotic attenuation.