Determination of Sulfamethoxazole Degradation Rate by an in Situ Experiment in a Reducing Alluvial Aquifer of the North China Plain

Abstract

Effluents from wastewater treatment facilities are reclaimed for environmental and landscaping use, resulting in infiltration to groundwater. Trace organic contaminants in these effluents have raised concerns, including the antibiotic resistance contributor sulfamethoxazole (SMX) detected frequently at concentrations exceeding 0.01 μg/L. A push–pull study to evaluate in situ degradation of SMX was undertaken in a shallow alluvial aquifer at the Tongzhou groundwater experimental site in southeast suburban Beijing. Ambient groundwater (1000 L) extracted from an experimental well at a depth of 10 m was spiked with SMX and NaBr, and then injected back into the same well. SMX and Br were “stored” over 15 days and monitored in the experimental well and 4 multilevel (depth: 10, 15, 17.5, 20, 25, and 30 m) observation wells located within 2–3 m distance. The concentration of SMX decreased faster than that of Br in the experimental and one observation well at 10 m depth; samples from all other depths contained little Br and SMX. The half-life of SMX degradation is estimated to be 3.1 ± 0.2 and 6.5 ± 0.6 days in the experimental well and observation well, respectively, under suboxic/anoxic conditions.

Linear Stochastic Analysis of the Partial Reversibility of Ensemble and Effective Dispersion in Heterogeneous Porous Media

“…Here, solutes (or heat) are introduced in the water injected into a well (push phase) and are extracted from the same well upon water extraction (pull phase). Push‐pull tests have been used to deduce various aquifer and transport properties (e.g., Kang et al., 2015; Leap & Kaplan, 1988; Paradis et al., 2018; Rasmusson et al., 2014; Vandenbohede et al., 2009), aside characterization of reactive transport (e.g., Istok et al., 1997; Kruisdijk & van Breukelen, 2021; Ma et al., 2019). Because of flow reversibility, the spread of a conservative‐tracer breakthrough curve is often considered to be unaffected by hydraulic heterogeneity, but the interpretation is hampered by ambient flow, mass‐exchange into zones of immobile porosity, and the interplay between advective spreading and diffusive mixing (Hansen et al., 2016).…”

Enhanced photoreactivity of MOFs by intercalating interlayer bands via simultaneous NCO and SCu modification

“…Antibiotics play an important role in protecting humans and animals from bacterial infection 1,2 . As one of two important subsets of antibiotics, sulfonamides (Sulfa) have been detected in the effluents and external soil of wastewater treatment plants worldwide 3–6 . Sulfamethoxazole (SMX) is the most common antibiotic used by humans, which means it is also widely present in urban wastewater 7 .…”

“…1,2 As one of two important subsets of antibiotics, sulfonamides (Sulfa) have been detected in the effluents and external soil of wastewater treatment plants worldwide. [3][4][5][6] Sulfamethoxazole (SMX) is the most common antibiotic used by humans, which means it is also widely present in urban wastewater. 7 Unfortunately, SMX cannot decompose naturally in water, and flora exposed to this antibiotic for extended periods of time may develop antibiotic resistance genes, which pose long-term threats to human pathogenic therapy and animal and plant growth.…”