Microbial Source Tracking for Bathing Water Quality Assessment: E. coli and Bacterial Communities in Coastal Environment
(2025)- Abstract
- Microbial contamination in coastal environments and groundwater is explored within this thesis, focusing on
fecal contamination from anthropogenic sources and microbial community dynamics. The spread and
persistence of microbial contaminants in complex aquatic environments with multiple intermittent and point
sources of contamination, was studied in order to lay a groundwork for developing more robust monitoring
framework of water quality.
A combination of molecular methods, chemical analyses, and classical microbiological techniques was
utilized to study several different sites. In the first study, remediation strategies performed in a site
contaminated with chlorinated solvents were evaluated. Chemical... (More) - Microbial contamination in coastal environments and groundwater is explored within this thesis, focusing on
fecal contamination from anthropogenic sources and microbial community dynamics. The spread and
persistence of microbial contaminants in complex aquatic environments with multiple intermittent and point
sources of contamination, was studied in order to lay a groundwork for developing more robust monitoring
framework of water quality.
A combination of molecular methods, chemical analyses, and classical microbiological techniques was
utilized to study several different sites. In the first study, remediation strategies performed in a site
contaminated with chlorinated solvents were evaluated. Chemical monitoring, compound-specific isotope
analysis, and 16S rRNA gene sequencing were performed to assess remediation effectiveness and microbial
community shifts during biotic and abiotic degradation of contaminants. Subsequent studies were performed
in an urban coastal environment, where sediment and water microbial communities were investigated with
a particular focus on fecal indicator bacteria (Escherichia coli and intestinal enterococci) and other sewageassociated
taxa. Results indicate that sediments can act as reservoirs for E. coli, and that fecal indicator
bacteria monitoring could benefit from introduction of additional bacterial groups as sewage indicator
bacteria. Phenotypic and genotypic characterization of sediment-associated E. coli further revealed
adaptations that may facilitate survival in marine sediments, including virulence factors, biofilm formation,
and halotolerance. In a longitudinal study of sediment microbial communities, it was found that treated
effluent from a wastewater treatment plant was a significant source of both E. coli and sewage-associated
taxa, while combined sewer overflows caused a more localized and transient effect on the microbial
community. Additionally, the presence of sewage-associated taxa in sediments distant from known
discharge points suggested contribution from intermittent sources, such as stormwater. Analysis of microbial
communities in urban bathing water revealed that the microbial communities are influenced by environmental
parameters such as temperature and rainfall, and that sewage- and gut-associated bacterial groups have
complex spatial and temporal distribution. While the fecal and sewage indicator bacteria could be connected
to environmental parameters and anthropogenic influences to some degree, spatial sensitivity was very high.
E. coli was found to be an incomplete indicator of anthropogenic impact on coastal waters.
Overall, this thesis highlights the importance of combining microbial community analysis, source tracking,
and environmental data to achieve a more nuanced understanding of microbial contamination in aquatic
environments. The results contribute to the development of more effective monitoring and management
strategies for protecting water quality and public health in urban coastal areas. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/f3cdd567-9326-44ab-be36-83325bf6fae6
- author
- Frank, Ellinor LU
- opponent
-
- Prof. Werner, David, Newcastle University, United Kingdom.
- organization
- publishing date
- 2025-09-30
- type
- Thesis
- publication status
- published
- subject
- pages
- 94 pages
- publisher
- Department of Building and Environmental Technology, Lund University
- defense location
- Lecture Hall V:C, building V, Klas Anshelms väg 14, Faculty of Engineering LTH, Lund University, Lund.
- defense date
- 2025-10-24 10:15:00
- ISBN
- 978-91-8104-704-2
- 978-91-8104-703-5
- project
- Microbial Source Tracking for Bathing Water Quality Assessment: E. coli and Bacterial Communities in Coastal Environment
- language
- English
- LU publication?
- yes
- id
- f3cdd567-9326-44ab-be36-83325bf6fae6
- date added to LUP
- 2025-09-29 17:18:45
- date last changed
- 2025-10-02 09:12:59
@phdthesis{f3cdd567-9326-44ab-be36-83325bf6fae6,
abstract = {{Microbial contamination in coastal environments and groundwater is explored within this thesis, focusing on<br/>fecal contamination from anthropogenic sources and microbial community dynamics. The spread and<br/>persistence of microbial contaminants in complex aquatic environments with multiple intermittent and point<br/>sources of contamination, was studied in order to lay a groundwork for developing more robust monitoring<br/>framework of water quality.<br/>A combination of molecular methods, chemical analyses, and classical microbiological techniques was<br/>utilized to study several different sites. In the first study, remediation strategies performed in a site<br/>contaminated with chlorinated solvents were evaluated. Chemical monitoring, compound-specific isotope<br/>analysis, and 16S rRNA gene sequencing were performed to assess remediation effectiveness and microbial<br/>community shifts during biotic and abiotic degradation of contaminants. Subsequent studies were performed<br/>in an urban coastal environment, where sediment and water microbial communities were investigated with<br/>a particular focus on fecal indicator bacteria (Escherichia coli and intestinal enterococci) and other sewageassociated<br/>taxa. Results indicate that sediments can act as reservoirs for E. coli, and that fecal indicator<br/>bacteria monitoring could benefit from introduction of additional bacterial groups as sewage indicator<br/>bacteria. Phenotypic and genotypic characterization of sediment-associated E. coli further revealed<br/>adaptations that may facilitate survival in marine sediments, including virulence factors, biofilm formation,<br/>and halotolerance. In a longitudinal study of sediment microbial communities, it was found that treated<br/>effluent from a wastewater treatment plant was a significant source of both E. coli and sewage-associated<br/>taxa, while combined sewer overflows caused a more localized and transient effect on the microbial<br/>community. Additionally, the presence of sewage-associated taxa in sediments distant from known<br/>discharge points suggested contribution from intermittent sources, such as stormwater. Analysis of microbial<br/>communities in urban bathing water revealed that the microbial communities are influenced by environmental<br/>parameters such as temperature and rainfall, and that sewage- and gut-associated bacterial groups have<br/>complex spatial and temporal distribution. While the fecal and sewage indicator bacteria could be connected<br/>to environmental parameters and anthropogenic influences to some degree, spatial sensitivity was very high.<br/>E. coli was found to be an incomplete indicator of anthropogenic impact on coastal waters.<br/>Overall, this thesis highlights the importance of combining microbial community analysis, source tracking,<br/>and environmental data to achieve a more nuanced understanding of microbial contamination in aquatic<br/>environments. The results contribute to the development of more effective monitoring and management<br/>strategies for protecting water quality and public health in urban coastal areas.}},
author = {{Frank, Ellinor}},
isbn = {{978-91-8104-704-2}},
language = {{eng}},
month = {{09}},
publisher = {{Department of Building and Environmental Technology, Lund University}},
school = {{Lund University}},
title = {{Microbial Source Tracking for Bathing Water Quality Assessment: E. coli and Bacterial Communities in Coastal Environment}},
url = {{https://lup.lub.lu.se/search/files/228677544/e-spik_ex_Ellinor.pdf}},
year = {{2025}},
}