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Agricultural water quality and biofilm formation in water storage containers and irrigation pipes linked to fresh produce safety
Thesis (PhD (Microbiology))--University of Pretoria, 2016.
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| Format: | Thesis |
| Language: | English |
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2026
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| _version_ | 1867613450788667392 |
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| access_status_str | Open Access |
| author2 | Korsten, Lise |
| author_browse | Korsten, Lise |
| author_facet | Korsten, Lise |
| collection | Thesis |
| description | Thesis (PhD (Microbiology))--University of Pretoria, 2016. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/110014 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:36:20.940Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2026 |
| publishDateRange | 2026 |
| publishDateSort | 2026 |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/110014 Agricultural water quality and biofilm formation in water storage containers and irrigation pipes linked to fresh produce safety Korsten, Lise venessa.vdm@gmail.com Crossland, Venessa Irrigation Water Biofilm Water storage Thesis (PhD (Microbiology))--University of Pretoria, 2016. South Africa experiences semi-arid conditions and primary producers can therefore not be reliant on rainfall alone. They therefore also make use of water distribution systems to irrigate their crops from stored reserves. As access to superior quality irrigation water has decreased substantially with: water scarcity, licensing regulations and increased levels of pollution; producers are faced with potential crop contamination through the use of contaminated water. The quality of water for crop irrigation has therefore received considerable attention due to the closely associated links with crop contamination. The systems used to store and distribute the water have however received minimal consideration. The long term use of medium sized water storage tanks can lead to changes in the quality of the water and the development of vast biofilm structures. In order to determine the rate of water quality deterioration in large storage tanks, rain-, ground- and potable- water, and their resultant biofilms were monitored over an extended period. Findings showed that stored potable water declined in bacterial quality to levels below those observed for the stored ground water despite the ground water originally containing more heterotrophic bacteria. Rainwater which is usually considered as safe to use without treatment, displayed the highest levels of Escherichia coli contamination and bacterial biofilm content. In addition to the quality of the stored water, other factors have also been implicated to contribute towards water quality deterioration. In a separate study, water deterioration and biofilm formation inside tanks with different outside colouring was followed to determine if the tank properties had an effect of the rate of deterioration and biofilm v development. Closer monitoring of the tank properties indicated that the colour of the tanks exerted no effects on the rate of water deterioration and that changes in water quality were due to stagnation of the water and biofilm formation. Changes in water quality were also observed in irrigation water obtained from the Crocodile River during transport in on-farm distribution systems (IWDS). The majority of samples showed decreases in bacterial and thermotolerant coliform (FC) content whilst under 50% displayed increases. The development of biofilms within IWDS also appeared to occur relatively slowly with the entire biofilm collector surface only being covered after 52 weeks of exposure. It was also observed that the number of bacteria associated with the surfaces was higher than the number of bacteria present in the water; this was evident from as early as four weeks into the study. The presence of the indicator organism, E. coli, in the water and in the resultant biofilms was concerning however when considering the potential for crop contamination, no contamination of the lettuce crops was detected despite the high FC levels in the irrigation water. The findings of this study can therefore contribute to the adjustment of current irrigation water quality regulations and standards. Updated guidelines should also consider the quality of the irrigation water and the IWDS, rather than only consider the water as a potential source of crop contamination as it has been considered in the past. Microbiology and Plant Pathology PhD (Microbiology) 2026-05-15T17:26:04Z 2026-05-15T17:26:04Z 16/02/11 2016 Thesis http://hdl.handle.net/2263/110014 en application/pdf |
| spellingShingle | Irrigation Water Biofilm Water storage Agricultural water quality and biofilm formation in water storage containers and irrigation pipes linked to fresh produce safety |
| title | Agricultural water quality and biofilm formation in water storage containers and irrigation pipes linked to fresh produce safety |
| title_full | Agricultural water quality and biofilm formation in water storage containers and irrigation pipes linked to fresh produce safety |
| title_fullStr | Agricultural water quality and biofilm formation in water storage containers and irrigation pipes linked to fresh produce safety |
| title_full_unstemmed | Agricultural water quality and biofilm formation in water storage containers and irrigation pipes linked to fresh produce safety |
| title_short | Agricultural water quality and biofilm formation in water storage containers and irrigation pipes linked to fresh produce safety |
| title_sort | agricultural water quality and biofilm formation in water storage containers and irrigation pipes linked to fresh produce safety |
| topic | Irrigation Water Biofilm Water storage |
| url | http://hdl.handle.net/2263/110014 |