The discovery of antibiotics is considered as one of the most significant scientific achievements of the 20th century – lives of millions of people and animals have been saved. Thenceforth, substantial amounts of administered antibiotics and their metabo-lites have been excreted into waste stream via urine and faeces. In this dissertation, primary focus is the qualitative balance of 14 antibiotics and one metabolite in urban water management and in urban waters, respectively. In particular, antibiotics pre-scribed to human beings are drained in the urban sewer system and finally enter the environment:
(i) Continuously via the effluent of the wastewater treatment plant after a partially effective removal or degradation or (ii) Intermittent via combined sewer overflow structures due to capacity limitations of the urban drainage system.
The fate and the potential effects and risks of these substances on ecosystems and hu-man health are of major concern – their direct toxic effect to all trophic levels as well as the global spread of antibiotic resistance genes are challenging. Hence, an assessment of microbial community activity due to antibiotic exposure is presented.
In particular, systematic work has been carried out to study the presence and character-istics of 14 antibiotics in urban waters. In detail, investigations were conducted to gain scientific knowledge with respect to adsorption, desorption, abiotic, biotic and photolyt-ic degradation as well as activity-inhibition of microorganism communities in sewage and of natural freshwater biofilm communities, respectively, due to inevitable urban drainage overflows.
In order to provide information to assist potential management strategies, which miti-gate surface water pollution and minimize the adverse impacts of antibiotics on activity of microorganism communities, the following specific topics were addressed:
⑴ The occurrence of 14 antibiotics and one metabolite were determined in sewag-es at three sampling sites in the city of Dresden, Germany.
⑵ The adsorption affinities of 14 antibiotics and one metabolite to size dependent sewer sediments were determined in experimental investigations, three sam-pling campaigns and subsequently an antibiotic-specific adsorption coefficient, normalized to organic content, was quantified.
⑶ The desorption affinity and -dynamics of 14 antibiotics and one metabolite were quantified in size dependent sewer sediments in experimental investigation and with statistical analysis.
⑷ The abiotic, biotic and photolytic degradation affinity of 14 antibiotics and one metabolite were quantified based on batch experiments with three different sewages at 7°C and 22°C, with artificial irradiation and different dilution ratios of the sewage at 30°C and subsequently a model framework decrypted ranges of abiotic, biotic and photolytic degradation coefficients.
⑸ The occurrence of three antibiotics, namely ciprofloxacin, clarithromycin and doxycycline was determined in sewage sampled during dry weather conditions in a small catchment of Dresden, which spills intermittently combined sewage (a mixture of sewage and storm water) to an adjacent brook in the case of capacity limitations of the urban drainage system during periods of intense rainfall and subsequently the three antibiotics were determined in the adjacent brook water.
⑹ Then, the activity-inhibition of microorganism community in sewage of this small catchment was quantified due to an exposition with three different antibiotics and three different antibiotic concentrations.
⑺ Last but not least, the activity-inhibition of natural freshwater biofilm communities in the adjacent brook was quantified via exposure to three antibiotics, which were individually dosed in three different concentrations, and also in mixture.
⑻ Finally, a two-dimensional hierarchical cluster analysis with dendrogram and heat map based on before mentioned activity inhibition of natural freshwater biofilm communities were conducted to identify hot spots of antibiotic tolerant and resistant bacterial subpopulations due to inevitable urban drainage system overflows.:List of Figures IV
List of Tables VIII
Symbols and Abbreviations XII
List of Publications on the Ph.D. topic XIX
1 General Introduction 2
1.1 Background 2
1.2 Aims and Objectives 3
1.3 Innovation and Contribution to the Knowledge 4
1.4 Outline of this Thesis 4
1.5 References 6
2 Adsorption and Desorption Affinity of 14 Antibiotics and One Metabolite for particulate components in urban drainage systems 10
2.1 Introduction 11
2.2 Materials and Methods 12
2.2.1 Study area 12
2.2.2 Sewer sediment and sewage sample collection 12
2.2.3 Sediment fractionation 13
2.2.4 Antibiotic determination in sewage and sediment 13
2.3 Results and Discussion 18
2.3.1 Antibiotics in composite sewage samples 18
2.3.2 Antibiotics adsorbed to sewer sediments 19
2.3.3 Organic-bound antibiotic load as a linear function of liquid concentration 20
2.3.4 Adsorption dynamics and adsorption coefficient determined by bath experiments 20
2.3.5 Mineral composition of sewer sediment SED#1B 23
2.3.6 Initial characteristics of sediment SED#1B 23
2.3.7 Desorption dynamics and desorption coefficient of SED#1B 24
2.4 Conclusions 25
2.5 References 26
3 Abiotic, Biotic and Photolytic Degradation Coefficients of 14 Antibiotics and One Metabolite 32
3.1 Introduction 34
3.2 Materials and Methods 35
3.2.1 Study area and sample collection 35
3.2.2 Experimental set up 35
3.2.3 Modelling framework 38
3.2.4 Procedure of model calibration 40
3.3 Results and Discussion 43
3.3.1 Primary metabolic parameter 43
3.3.2 Secondary metabolic parameter 44
3.4 Conclusions 50
3.5 References 50
4 Activity-Inhibition of Microorganisms due to an Exposition with different Antibiotics and Concentrations 56
4.1 Assessing Antibiotic Resistance of Microorganisms in Sanitary Sewage 56
4.1.1 Introduction 57
4.1.2 Material and Methods 58
4.1.2.1 Sampling Site and Antibiotic Agents 58
4.1.2.2 Analyzing Antibiotics 60
4.1.2.3 Respiration Rate 60
4.1.3 Results and Discussion 60
4.1.3.1 Concentration Range of Antibiotics and Typical Sewage Parameters 60
4.1.3.2 Oxygen Uptake Rate 62
4.1.4 Summary and Conclusions 63
4.1.5 References 64
4.2 Hot Spots of Antibiotic Tolerant and Resistant Bacterial Subpopulations in Natural Freshwater Biofilm Communities due to Inevitable Urban Drainage System Overflows 66
4.2.1 Introduction 68
4.2.2 Material and Methods 69
4.2.3 Results and Discussion 72
4.2.4 Conclusions 76
4.2.5 References 76
5 Summery and General Coclusions 82
5.1 Adsorption and Desorption Affinity 82
5.2 Abiotic, Biotic and Photolytic Degradation 83
5.3 Activity-Inhibition of Microorganism Communities due to Antibiotic Exposure 84
5.4 Enhancement of the Stockholm County Council (2014) assessment of antibiotics 84
5.5 References 87
6 Proposed Directions of Future Research 90
7 Appendixes 94
7.1 Chapters 94
7.2 Figures 95
7.3 Tables 115
7.4 References 139
| Identifer | oai:union.ndltd.org:DRESDEN/oai:qucosa:de:qucosa:72526 |
| Date | 27 October 2020 |
| Creators | Käseberg, Thomas |
| Contributors | Krebs, Peter, Tränckner, Jens, Rauch, Wolfgang, Technische Universität Dresden |
| Source Sets | Hochschulschriftenserver (HSSS) der SLUB Dresden |
| Language | English |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, doc-type:doctoralThesis, info:eu-repo/semantics/doctoralThesis, doc-type:Text |
| Rights | info:eu-repo/semantics/openAccess |
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