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Developing a rapid high throughput test to detect biodegradation of environmentally relevant chemicals
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Endersby, Katherine Amy (2023) Developing a rapid high throughput test to detect biodegradation of environmentally relevant chemicals. PhD thesis, University of Warwick.
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Official URL: http://webcat.warwick.ac.uk/record=b3985150
Abstract
Anthropogenic chemicals, including pharmaceuticals, are present in the aquatic environment as a consequence of their use by society, and their effects on aquatic biota are of growing concern. Determining the persistence of these chemicals in aquatic systems in a standardised and replicable test is crucial to understanding their potential to exert ecotoxicological impacts. These tests have been criticised for their high levels of variability and false negatives in which no degradation is detected where degradation of the chemical is possible, which is thought to be due to the ‘biodegradation lottery’, in which low cell abundance in freshwater test inocula decreases the chance of inclusion of a microorganism in a sample of inocula capable of biodegradation of the test chemical.
Centrifugation, membrane filtration, and tangential flow filtration methods were assessed for their ability to increase cell number, retain bacterial cell viability, and maintain a similar bacterial community composition, but also biodegrade common environmental pollutant p-Nitrophenol. Tangential flow filtration successfully overcame the biodegradation lottery and removed seasonal differences in the rates of biodegradation of p-Nitrophenol by freshwater bacterial communities, regardless of starting cell number.
Further investigation of pharmaceutical chemicals demonstrated temporal variation in the degradation rate of the chemicals. Acetazolamide, Chlorzoxazone, Indapamide, Hydrocortisone, Pentoxifylline, Theophylline and Warfarin were shown to be readily biodegradable by concentrated freshwater inocula. Methocarbamol may be biodegradable, while Ethosuximide, Lamotrigine, Letrozole and Lidocaine are not readily biodegradable according to this work. Chlorzoxazone is the only compound classified as readily biodegradable in both concentrated inocula and unaltered freshwater. Despite real environmental conditions not being static, some standardisations must be put in place to ensure that regulatory tests are carried out in a replicable and reliable manner. This study demonstrates the utility of increased cell number to overcome the biodegradation lottery and negate temporal differences in samples used for testing, to obtain data for the degradation of several pharmaceutical chemicals for which data was not previously known.
Item Type: | Thesis (PhD) | ||||
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Subjects: | Q Science > QD Chemistry Q Science > QH Natural history T Technology > TD Environmental technology. Sanitary engineering |
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Library of Congress Subject Headings (LCSH): | Pollutants -- Biodegradation, Biodegradation, Nitrophenols, Centrifugation, Membrane filters, Pollution prevention | ||||
Official Date: | March 2023 | ||||
Dates: |
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Institution: | University of Warwick | ||||
Theses Department: | School of Life Sciences | ||||
Thesis Type: | PhD | ||||
Publication Status: | Unpublished | ||||
Supervisor(s)/Advisor: | Bending, G. D. (Gary D.) ; Schäfer, Hendrik ; Snape, Jason | ||||
Sponsors: | AstraZeneca (Firm) ; Biotechnology and Biological Sciences Research Council (Great Britain) | ||||
Format of File: | |||||
Extent: | xii, 106 pages : colour illustrations | ||||
Language: | eng |
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