Thesis submitted in fulfilment of the requirements for the degree
Doctor of Technology: Biomedical Technology
in the Faculty of Health and Wellness Sciences
at the Cape Peninsula University of Technology
2008 / The quality of South Africa’s water sources is fast deteriorating due to an influx of
pollutants from industrial and agricultural areas. In addition, urbanisation has led to
the establishment of informal settlements along river systems. This study focuses on
the importance of maintaining water quality and the management of water resources
in order to ensure its sustainability in South Africa. The primary aim of this study was
to determine the extent of bacterial contamination in three rivers namely the Berg-,
Plankenburg- and Diep Rivers in the Western Cape, South Africa and to investigate
the application of a bioremediation system as a possible treatment technology.
Several aspects contributing to the contamination were addressed and different
approaches were studied and reviewed. In all three rivers, four sampling sites were
identified, which were sampled over a period of 9 to 12 months.
Contamination levels for the three rivers were evaluated by applying various
enumeration techniques, which could provide an accurate indication of the planktonic
bacterial pollution load in the river systems. The Most Probable Number (MPN)
technique was used to determine the level of faecal coliforms and E. coli. The
highest MPN, faecal coliform and E. coli counts of 3.5 x 107 micro-organisms/100 m ,
3.5 x 107 micro-organisms/100 m and 1.7 x 107 micro-organisms/100 m ,
respectively, were recorded at Site B2 in week 37 in the Berg River. Results showed
that in all the river water sampled and evaluated, the total MPN count mostly
exceeded the maximum limit of 2000 micro-organisms/100 m (SABS, 1984)
stipulated for river water throughout the study period. The heterotrophic plate count
(HPC) method was used to determine the number of culturable micro-organisms in
planktonic samples, while the flow cytometry (FCM) and epifluorescence microscopy
(EM) with different fluorochromes (Acridine orange and BacLight™ Live/Dead stain)
were employed to evaluate total bacterial counts in planktonic (water) samples. The
highest HPC at the various sites sampled was 1.04 x 106 micro-organisms/m (Berg
River, Site B2), 7.9 x 104 micro-organisms/m (Plankenbrug River, Site A) and
1.7 x 105 micro-organisms/m (Diep River, Site B). Total cell counts as high as
3.7 x 107 micro-organism/m (Berg River, Site B2), 5.5 x 108 micro-organism/m
(Plankenburg River, Site D) and 2.5 x 109 micro-organisms/m (Diep River, Site B)
were obtained by the FCM technique, which were significantly (p < 0.05) higher than
the total counts obtained by epifluorescence microscopy. The results thus show that
the FCM technique was the most reliable method for determining the total cell count
in river water samples. This technique makes use of computer software whereas
epifluorescence microscopy involves manual counting which may lead to human
error. In addition, the impact of residential, agricultural and industrial areas situated
along these rivers was also investigated. Even though exact point sources of
pollution could not be determined, it was found that all the sources, such as the storm
water drainage pipes, the industrial as well as the agricultural areas, could contribute
to increased MPN, heterotrophic and total bacterial counts.
This study also aimed at investigating and comparing the microbial
contamination levels at various sites in the Plankenburg and Diep Rivers in the
Western Cape, South Africa. Sampling of sites along the Plankenburg River started
in June 2004 and continued for a period of one year until June 2005. Sampling of the
Diep River sites started in March 2005 and continued for a period of nine months until
November 2005. Faecal coliform (FC) and E. coli (EC) counts were determined by
means of the Most Probable Number technique, the number of culturable cells were
determined using the heterotrophic plate count (HPC) technique and total microbial
counts were evaluated by Flow cytometric analysis (FCM). The highest microbial
counts for the Plankenburg River were observed at site B where the highest MPN,
FC, E. coli and total FCM counts of 9.2 x 106 (week 14), 3.5 x 106 (week 39) and
3.5 x 106 micro-organisms/100 m (week 39) and 2.1 x 108 micro-organisms/m
(weeks 1 and 39) respectively, were recorded. The highest HPC recorded for the
Plankenburg River was 7.9 x 106 micro-organisms/100 m (week 44, site A). Site B
is situated close to an informal settlement where waste effluents from storm water
drainage pipes enter the river system. In addition, other possible contamination
sources included agricultural (site A) and industrial (site C) areas bordering the
Plankenburg River. The highest total MPN, FC and E. coli counts in the Diep River
were 5.4 x 106 (week 23) and 1.6 x 106 micro-organisms/100 m [FC and E. coli,
respectively (both in week 23)], recorded at site B. The highest HPC and total FCM
counts of 1.7 x 107 micro-organisms/100 m (week 14) and 2.5 x 109 microorganisms/
m (week 23), respectively, were also recorded at site B. This site was
identified as the most contaminated site along the Diep River and served as an
accumulation point for waste effluents from the residential and industrial areas, which
included paint and machine manufacturers. Other sources situated along the Diep
River included storage and maintenance facilities for steel containers, a waste water
treatment plant and an oil-refinery. Most of the bacterial counts obtained for the
Plankenburg and Diep Rivers exceeded the accepted maximum limit for river water
for most of the sampling period.
Bacterial species from the Berg- and Plankenburg Rivers were isolated and
identified. The presence of various Enterobacteriaceae species isolated at all the
sites in both rivers confirmed faecal contamination of these water sources over the
entire sampling period. Opportunistic pathogens such as Klebsiella sp., Serratia sp.,
Enterobacter sp., Shewanella sp., Aeromonas sp., Pseudomonas sp., Acinetobacter
sp. and Citrobacter freundii as well as pathogens such as Bacillus cereus and
B. anthracis were also identified in both river systems.
All the respective articles are presented in the required format of the journal in
which the article has been published or submitted to.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:cput/oai:localhost:20.500.11838/1515 |
| Date | January 2008 |
| Creators | Paulse, Arnelia Natalie |
| Publisher | Cape Peninsula University of Technology |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Rights | http://creativecommons.org/licenses/by-nc-sa/3.0/za/ |
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