Search

This study evaluated the ecotoxicity effects of effluent from an anaerobic fixed bed biofilm reactor (AFBBR) removing the sulfamethoxazole (SMX - 403 ± 104 ng L−1) and ciprofloxacin (CIP - 294 ± 123 ng L−1) antibiotics from domestic sewage in some microorganisms (Brevundimonas sp., Escherichia coli, Ochrobactrum sp., Sphingomonas sp.) and benthic organisms (Allonais inaequalis and Chironomus sancticaroli). The AFBBR showed high removal efficiency of SMX (85 ± 10%) and CIP (81 ± 16%) and completely eliminated the acute ecotoxicological effect on the C. sancticaroli insect larvae. The bioreactor effluent did not cause any inhibition on the cell growth of the microorganisms. Nonetheless, the A. inaequalis was extremely sensitive to the reactor effluent (100% mortality), probably due to the death of bacteria and algae essential to the nutrition of the Oligochaeta. Regarding the adult insect emergency of C. sancticaroli, a reduction of 50% was observed after 17 days of exposure to the effluent with 40 μgSMX L−1, inhibiting the larval development, which did not occur for CIP. The antimicrobial inhibition by CIP present in the domestic sewage resulted in EC50 (median effective concentration) values of 2.5, 0.9, 3.1 and 0.1 mgCIP L−1 for Ochrobactrum sp., Brevundimonas sp., Sphingomonas sp. and E. coli, respectively. Assessing the effect of antibiotics in the effluent on the microorganisms' growth by a disk diffusion test, only E. coli culture showed inhibition at the concentration of 5.0 mgCIP L−1. The study emphasized the potential of AFBBR to reduce ecotoxicity in the sewage on aquatic biota. [ABSTRACT FROM AUTHOR]

This study presents a column-switching solid-phase extraction online-coupled to a liquid chromatography/tandem mass spectrometry (SPE-LC-MS/MS) method for simultaneous analysis of 12 antibiotics (7 sulfonamides and 5 fluoroquinolones) and caffeine detected in the sewage and effluent of a pilot anaerobic reactor used in sewage treatment. After acidification and filtration, the samples were directly injected into a simple and conventional LC system. Backflush and foreflush modes were compared based on the theoretical plates and peak asymmetry observed. The method was tested in terms of detection (MDL) and quantification limit (MQL), linearity, relative recovery, and precision intra- and inter-day in lab-made sewage samples. The method presented suitable figures of merit in terms of detection, varying from 8.00 × 10 to 6.00 × 10 ng (0.800 up to 600 ng L; caffeine) with direct injection volume of only 100 μL and 13 min of total analysis time (sample preparation and chromatographic run). When the method was applied in the analysis of sewage and effluent of the anaerobic reactor ( n = 15), six antibiotics and caffeine were detected in concentrations ranging from 0.018 to 1097 μg L. To guarantee a reliable quantification, standard addition was used to overcome the matrix effect. [ABSTRACT FROM AUTHOR]