South Africa is a semi arid country and the provision of water clean water to a steadily
growing population is currently one of the major challenges facing governmental
organisations. Water resources in South Africa are subject to many forms of pollution.
resulting in eutrophication and salinisation. Hence, there is a need to monitor chemical and
organic pollution in South African rivers.
Chemical monitoring is expensive and not all the elements of water quality can be monitored
and measured in a particular sample. The synergistic effects of water quality determinants
cannot be demonstrated if only the chemical composition of a water resource is monitored.
Biological monitoring can provide a rapid indication of water quality and at a lower cost than
traditional monitoring. Organisms within a river are exposed to all water quality variables
present in a system and can provide an integrated reflection of the health of their
environment.
Diatoms are found in all aquatic ecosystems and have demonstrable responses to many of
the elements of water quality that have been identified as causing aquatic pollution. These
elements include total dissolved solids, pH and plant nutrients such as nitrates and
phosphates. The relationship between the structure of a given diatom community and the
water quality to which the community is exposed, has lead to the development of several
indices of water quality. Diatom indices of aquatic pollution have been developed in France,
Belgium, Germany, Britain and Japan. Existing diatom indices have been tested for use in
Finland, Poland, Britain, the Himalayas and South America.
Several diatom indices were tested in this study for application in the Vaal and Wilge Rivers.
The tested diatom indices correlated well with measured water quality variables such as pH
and the chemical variables responsible for eutrophication and salinisation. The
demonstrated correlations were comparable to those demonstrated by European authors.
Several indices proved successful in indicating general water quality, namely the Biological
Diatom lndex (BDI), the Specific Pollution sensitivity lndex (SPI) and the Generic Diatom
lndex (GDI). The Eutrophication and Pollution lndex (EPI) successfully indicated levels of
plant nutrients together with the ionic composition measured at various sites in the Vaal and Wilge Rivers. It is recommended that these indices be further tested in different regions within South Africa. / Thesis (M. Omgewingswetenskappe)--North-West University, Potchefstroom Campus, 2004.
| Identifer | oai:union.ndltd.org:NWUBOLOKA1/oai:dspace.nwu.ac.za:10394/66 |
| Date | January 2004 |
| Creators | Taylor, Jonathan Charles |
| Publisher | North-West University |
| Source Sets | North-West University |
| Detected Language | English |
| Type | Thesis |
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