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Antibiotic residues, their mixture toxicity, and the potential selection for antibiotic-resistant bacteria could pose a problem for water use and the ecosystem of reservoirs. This study aims to provide a comprehensive understanding of the occurrence, concentration, distribution, and ecological risks associated with various antibiotics in the Cirata reservoir, Indonesia. In our water and sediment samples, we detected 24 out of the 65 antibiotic residues analyzed, revealing a diverse range of antibiotic classes present. Notably, sulphonamides, diaminopyrimidine, and lincosamides were frequently found in the water, while the sediment predominantly contained tetracyclines and fluoroquinolones. Most antibiotic classes reached their highest concentrations in the water during the dry season. However, fluoroquinolones and tetracyclines showed their highest concentrations in the water during the wet season. Ecotoxicological risk assessments indicated that the impact of most antibiotic residues on aquatic organisms was negligible, except for fluoroquinolones. Looking at the impact on cyanobacteria, however, varying risks were indicated, ranging from medium to critical, with antibiotics like sulfamethoxazole, ciprofloxacin, norfloxacin, and lincomycin posing substantial threats. Among these, ciprofloxacin emerged as the antibiotic with the strongest risk. Furthermore, fluoroquinolones may have the potential to contribute to the selection of antibiotic-resistant bacteria. The presence of mixtures of antibiotic residues during the wet season significantly impacted species loss, with Potentially Affected Fraction of Species (msPAF) values exceeding 0.75 in almost 90% of locations. However, the impact of mixtures of antibiotic residues in sediment remained consistently low across all locations and seasons. Based on their occurrences and associated risks, 12 priority antibiotic residues were identified for monitoring in the reservoir and its tributaries. Moreover, the study suggests that river inflow serves as the most significant source of antibiotic residues in the reservoir. Further investigations into the relative share attribution of antibiotic sources in the reservoir is recommended to help identify effective interventions.

RESUMEN

New anabolic steroids show up occasionally in sports doping and in veterinary control. The discovery of these designer steroids is facilitated by findings of illicit preparations, thus allowing bioactivity testing, structure elucidation using NMR and mass spectrometry, and final incorporation in urine testing. However, as long as these preparations remain undiscovered, new designer steroids are not screened for in routine sports doping or veterinary control urine tests since the established GC/MS and LC/MS/MS methods are set up for the monitoring of a few selected ions or MS/MS transitions of known substances only. In this study, the feasibility of androgen bioactivity testing and mass spectrometric identification is being investigated for trace analysis of designer steroids in urine. Following enzymatic deconjugation and a generic solid-phase extraction, the samples are analyzed by gradient LC with effluent splitting toward two identical 96-well fraction collectors. One well plate is used for androgen bioactivity detection using a novel robust yeast reporter gene bioassay yielding a biogram featuring a 20-s time resolution. The bioactive wells direct the identification efforts to the corresponding well numbers in the duplicate plate. These are subjected to high-resolution LC using a short column packed with 1.7-microm C18 material and coupled with electrospray quadrupole time-of-flight mass spectrometry (LC/QTOFMS) with accurate mass measurement. Element compositions are calculated and used to interrogate electronic substance databases. The feasibility of this approach for doping control is demonstrated via the screening of human urine samples spiked with the designer anabolic steroid tetrahydrogestrinone. Application of the proposed methodology, complementary to the established targeted urine screening for known anabolics, will increase the chance of finding unknown emerging designer steroids, rather then being solely dependent on findings of the illicit preparations themselves.

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The origin, i.e. natural occurrence or illegal treatment, of findings of 17alpha-boldenone (alpha-Bol) and 17beta-boldenone (beta-Bol) in urine and faeces of cattle is under debate within the European Union. A liquid chromatographic positive ion electrospray tandem mass spectrometric method is presented for the confirmatory analysis of 17beta-boldenone, 17alpha-boldenone and an important metabolite/precursor androsta-1,4-diene-3,17-dione (ADD), using deuterium-labelled 17beta-boldenone (beta-Bol-d3) as internal standard. Detailed sample preparation procedures were developed for a variety of sample matrices such as bovine urine, faeces, feed and skin swab samples. The method was validated as a quantitative confirmatory method according to the latest EU guidelines and shows good precision, linearity and accuracy data, and CCalpha and CCbeta values of 0.1-0.3 and 0.4-1.0 ng/ml, respectively. Currently, the method has been successfully applied to suspect urine samples for more than a year, and occasionally to faeces, feed and swab samples as well. Results obtained from untreated and treated animals are given and their impact on the debate about the origin of residues of 17beta-boldenone is critically discussed. Finally, preliminary data about the degree of conjugation of boldenone residues are presented and a simple procedure for discrimination between residues from abuse versus natural origin is proposed.

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