Veterinary pharmaceuticals are routinely used in livestock production to treat diseases, prevent infections, and promote growth. However, the potential release of pharmaceuticals from agricultural activities has raised concerns because they may pose detrimental effects to the ecosystems and human health, for example fostering the evolution of antibiotic-resistant bacteria in the natural environment. A better understanding of the environmental fate of veterinary pharmaceuticals is critical to properly assess and mitigate their risks. This dissertation focuses on a major group of veterinary pharmaceuticals, ionophore antibiotics (IPAs), which is sold at over 4 million kilograms per year and constitutes more than one third of the total antibiotic consumption by the livestock industry in the U.S. Despite the extensive usage of IPAs, their environmental fate was not well-understood. Therefore, this study aimed at achieving a comprehensive understanding of the occurrence, persistence, and transformation of IPAs from poultry litter before and after applications to the agricultural lands. Three of the most commonly used members of IPAs were investigated in this study: monensin (MON), salinomycin (SAL), and narasin (NAR). Based on the common management practices of poultry litter, the potential abiotic and biotic transformation reactions of IPAs were examined under varying conditions relevant to the water-soil-litter systems. This dissertation consists of three sections. First, a robust analytical method was developed to quantify IPAs in various environmental compartments, especially in high organic-containing matrices such as poultry litter, and soil and runoff from litter-fertilized lands. Efforts were made to optimize the analytical method with respect to improving extraction recovery, reducing matrix effects, and validating a surrogate standard. Second, lab-scale experiments were set up to determine the chemical properties of IPAs in aqueous environments and to study the abiotic transformation of IPAs, including hydrolysis and photolysis. The results showed that IPAs are prone to hydrolytic transformation in acidic environments, which are likely to be encountered in acidic soils, alum-amended litter (alum: Al₂(SO₄)₃•12H₂O), and acidic runoff. Multiple transformation pathways were proposed based on the identified hydrolysis products. It is also noteworthy that the hydrolysis products of MON still exhibited a toxic effect on the selected microorganism (Bacillus subtilis). SAL and NAR were found to undergo direct photolysis under both UV light and sunlight irradiation. In natural water matrix, IPAs were also degraded by indirect photolysis with hydroxyl radicals generated by light-excited nitrate. Dissolved organic matter can shield IPAs from light and slow down their photolysis. Third, the biodegradation potential of IPAs was first tested in litter and soil microcosms. Factor analysis was conducted to delineate the interaction of water and temperature on IPA degradation in the litter. Litter-fertilized and non-fertilized soil microcosms were compared on the degradation of MON and SAL. Furthermore, the inhibition and biotransformation potential of IPAs were assessed under different redox conditions with litter-enriched cultures. Inhibition tests focused on examining IPAs’ impact on microbial community functions, including denitrification, sulfate-reduction, and methane production. Biodegradation tests were conducted with different electron acceptors, including oxygen, nitrate, sulfate, and organic carbons, with efforts to elucidate primary biotransformation products. On the basis of the results obtained in this study, several recommendations on litter management and IPA selection were made to help mitigate the release and transport of IPAs, as well as enhance their degradation. Overall, this study significantly improved the understanding of the environmental fate of IPAs and the obtained knowledge can aid proper selection of IPAs and management strategies in future applications to minimize the risks of antibiotic micropollutants in the environment.

The use of veterinary drugs continues to be a challenge since some farmers use drugs for medicinal purposes, while others use them as growth promoters without observing the set withdrawal times. In emerging economies, challenges are experienced in residue testing to ensure residue free animal products. It is therefore necessary to develop a simple, environmentally friendly and cost effective extraction method for veterinary drugs residues. A dispersive liquid-liquid micro-extraction method for simultaneous determination of chloramphenicol, florfenicol and thiamphenicol residues in water, bovine muscle and milk was developed optimised and validated. Analysis was performed with liquid chromatography coupled to electron spray ionization tandem mass spectrometry in negative ion multiple reaction monitoring mode. Dispersive liquid-liquid micro-extraction method development involved optimisation of parameters such as type and volume of extraction solvent, type and volume of disperser solvent and pH. The optimum extraction solvent was dichloromethane at a volume of 250 μL while the optimum disperser solvent was acetonitrile (1 mL) Extraction was found to be optimum at pH 7. The developed method was validated according to Commission decision 2002/657/EC. Linearity. Linearity was observed for water, bovine milk and muscle in the ranges of 0.3 μg kg-1 to 0.9 μg kg-1, 25 μg kg-1 to 100 μg kg-1 and 50 μg kg-1 to 200 μg kg-1 for chloramphenicol, thiamphenicol and florfenicol respectively with regression coefficients ranging between 0.9941 and 0.9999. Limit of detections for CAP, FFC & THAP were 0.082, 3.31, and 2.21 μg kg-1 respectively while Limit of quantifications were 0.163, 7.51 and 6.84 μg kg-1 respectively. The recoveries for water, bovine milk and bovine muscle ranged between 87.2% and 102%. In this study the validated dispersive liquid-liquid micro-extraction has been found to perform very well not only in the water matrix but also in the more complex matrices like bovine milk and muscle. / Chemistry / M. Sc. (Chemistry)

Les flux journaliers et horaires de 15 molécules pharmaceutiques à l'entrée d'une station d'épuration ont été mesurés sur 3 ans et modélisés à la fois pour un bassin urbain de 16 000 habitants et un hôpital de 450 lits. Certaines molécules ne sont jamais ou rarement quantifiées. Les flux journaliers vont de 0,6 à 564 g/jour en fonction de la molécule et de la campagne de mesure 24h. Aucune dynamique saisonnière ou hebdomadaire n’a été identifiées. La dynamique des flux horaires des médicaments se distingue des autres polluants et du débit des eaux usées. Les flux horaires mesurés sont sévèrement impactés par le comportement aléatoire des patients lorsque la masse journalière consommée est faible. Ainsi, la dynamique moyenne est difficile à identifier. L'hypothèse principale pour modéliser les flux de médicaments dans les eaux usées est qu'ils résultent des étapes suivantes: ventes ou distributions de médicaments, consommation humaine, métabolisme et excrétion. Les ventes de médicaments pour le bassin urbain et les distributions de l'hôpital ont été collectées à différentes échelles spatiales et temporelles (respectivement 1, 6 et 223 pharmacies et journalières, hebdomadaires et mensuelles). Les plus grandes échelles sont plus fiables pour estimer les niveaux de consommations mais la variabilité des plus petites est plus proche de la variabilité observée dans les mesures. Les quantités de médicaments vendus ou distribués vont de 0,4 à 1 600 patients théoriques par jour en moyenne. En associant les flux journaliers mesurés aux ventes ou aux distributions, aucune corrélation linéaire n'a été trouvée. Un modèle stochastique au pas de temps de la minute est proposé et appliqué aux deux sites. Il produit des résultats fiables et précis pour les flux quotidiens et horaires. Cependant, les résultats sont difficiles à interpréter lorsque seuls quelques patients consomment un médicament. De plus, le modèle ne reproduit pas la spécificité inhérente de l'hôpital. En outre, le modèle est également capable de prédire avec précision le débit des eaux usées domestiques d'un bassin versant urbain, tant pour les volumes quotidiens que pour leurs dynamiques. / Daily and hourly loads of 15 pharmaceutical molecules at the inlet of a wastewater treatment plant have been measured over 3 years and modelled for both an urban catchment of 16 000 inhabitants and a hospital of 450 beds. Some molecules are never or rarely quantified. Daily loads range from 0.6 to 564 g/day depending of the molecule and the 24 h measurement campaign. Seasonal or weekly patterns are not identified. Pharmaceuticals hourly loads dynamics are distinctive from one another and from wastewater flow. The measured hourly loads are severely impacted by the random behaviour of the patients when the daily mass consumed is low. Thus, the average dynamics is difficult to identify. The main hypothesis to model pharmaceuticals loads in wastewater is that they result from the following steps: pharmaceuticals sales or distributions, human consumption, metabolism and excretion. Pharmaceuticals sales for the urban catchment and distribution for the hospital have been collected at different space and timescales (respectively 1, 6 and 223 pharmacies and daily, weekly and monthly). Larger scales are more reliable for magnitude but the variability of the smaller ones is closer to the variability observed in the measurements. The quantities of pharmaceuticals sold or distributed range from 0.4 to 1 600 theoretical patients per day. Associating measured daily loads with sales or distributions, no linear correlation is found. A minute time step stochastic model is proposed and applied to both sites. It produces reliable and accurate results for both daily and hourly loads. However, results are difficult to interpret when only a few patients are consuming a pharmaceutical. Also, the model does not reproduce the inherent specificity of the hospital. In addition, the model is also able to predict the domestic wastewater flow of an urban catchment with great accuracy for both daily volumes and dynamics.

Different sampling devices for paper spray - mass spectrometry (PS - MS) were investigated to improve the assay’s simplicity and sensitivity over traditional approaches. In the first one, pressure-sensitive adhesive paper was used as both sampling tool to collect drug residues on surfaces and paper substrate in PS - MS analysis. This method showed a significant improvement in drug collection on surfaces leading to low nano-gram level detection limits. Other sampling device being investigated was snap-in solid-phase extraction column, which demonstrated the ability to detect trace amounts of drugs in plasma while allowed easy transportation and the use of PS - MS automated system.

This work is based on the occurrence of drug residues in the environment. This study is focused on the development and optimization methods for determination of selected drugs in the surface water, aquatic sediment and sewage sludge from waste water treatment plant. From the group of drugs were chosen antibiotics. Antibiotics presented in the environment can cause adverse effects including toxic effects, immunity disorders and indirect bioalteration effects. Sulfonamide antibiotics, which are used in the treatment of urinary and respiratory tract infections as well as in the treatment of other infectious diseases, were chosen as a target compounds. Three optimized analytical methods for determination of sulfonamide antibiotics were developed. For the optimization of extraction were tested: solid phase extraction, pressurized solvent extraction, microwave extraction and ultrasonic extraction. For the final analysis was used liquid chromatography with two detectors - diode array detector and mass spectrometer. These optimized methods were applied for the analysis of real samples. The surface water and sediment samples were collected from two Moravian rivers (the Svratka river and the Svitava river). Samples of sewage sludge were collected from waste water treatment plant Brno-Modřice. Fish samples from the Svratka river were also collected. It was observed that all the selected sulfonamide antibiotics are present in real sediment samples (ug.kg-1). Simultaneously presence of some target analytes in real surface water (ug.l-1) and in sewage sludge (ug.kg-1) samples has been confirmed. In samples of surface water from the Svitava river and in fish samples sulfonamide antibiotics were not detected or their concentrations were below the limit of detection.

This work is based on the current issue of increasing concentrations of pharmaceutical residues in various components of the environment. These new environmental contaminants continuously enter the environment. The most affected environmental component is the aquatic environment. This study is focused on the development and optimization of reliable analytical method, which can determine selected drugs in the aquatic environment (waste waters and surface waters) qualitatively and quantitatively. The target compounds were selected mainly from the group of non-steroidal anti-inflammatory drugs (NSAID): salicylic acid, acetylsalicylic acid, clofibric acid, ibuprofen, acetaminophen, caffeine, naproxen, mefenamic acid, ketoprofen and diclofenac. NSAIDs are one of the most used drugs in Czech Republic. For the final analysis of this study was used the comprehensive two-dimensional gas chromatography with mass spectrometric detection Time-of-Flight (GCxGC-TOF MS). It is a very sensitive and reliable analytical method for trace and ultra-trace analysis. Simultaneously, solid phase extraction (SPE) and derivatization are optimized in this work. Optimized analytical method including SPE, derivatization with MSTFA (N-methyl-N-(trimethylsilyl) trifluoroacetamide) and final analysis by GCxGC-TOF MS were applied successfully for the analysis of real samples. Samples of waste water were collected from the waste water treatment plant in Brno – Modřice and samples of surface water were collected from two river streams Svratka and Svitava in Moravian region. The range of concentrations of selected drug residues varied from one to tens of g/L in wastewater and from tens to hundreds of ng/L in surface waters. The degree of wastewater and surface waters contamination by drug residues is assessed in conclusions of the work. Simultaneously, spontaneous degradation of selected drugs in water and removal efficiency of the wastewater treatment plant is assessed in conclusions of the work. The developed method is usable for monitoring and environmental analysis of water ecosystems. It is usable not only for selected drugs, but even for other organic compounds with similar properties.