The Wonderfontein Cave is located within the Witwatersrand Basin (Gauteng province,
South Africa) and is associated with the river banks of the Wonderfontein Spruit. This cave
system has for many years been subjected to the influx of polluted mine water. Since
subterranean environments remain poorly studied, it is unknown what the effect of this might
be on the associated ecosystem. Furthermore, water that enters the Wonderfontein Cave
poses a severe health threat as it drains into the underlying aquifer, which is abstracted for
human and animal use. The general aim of this study was to determine the extent of metal
pollution (enrichment), as well as to study the toxicity hazard potential of the soils and
sediments associated with the Wonderfontein Cave. The objectives of this study were to (1)
quantify the extent of anthropogenic metal pollution of water, soils and sediments associated
with the Wonderfontein Cave (2) and assessing the toxicity hazard potential of these
substrates; (3) determining whether nematode taxa and C. gariepinus individuals represent
isolated communities and a population within the Wonderfontein Cave, respectively; (4)
measuring the effect of mining-associated pollutants on the soil and sediment health of the
Wonderfontein Cave by making use of nematodes to serve as bioindicators; (5) evaluating
and comparing biomarker responses to metal bioaccumulation in C. gariepinus populations
associated with the Wonderfontein Cave and epigean (surface) environments and lastly (6)
comparing the results of the above identified assessments over both a temporal and spatial
scale. Sampling was undertaken during April (1st sampling interval) and September (2nd
sampling interval) 2013, which respectively represented the end of the high and low flow
periods. Also, sampling of the subterranean (Wonderfontein Cave) and associated surface
(Wonderfontein Spruit) environments were undertaken. The findings of this study suggested
that especially the sediments associated with the Wonderfontein Cave have been subjected
to severe nickel, copper, zinc, cobalt, aluminium, cadmium, lead and uranium enrichment.
Also, the concentrations of many of the studied metals exceeded the respective water, soil
and sediment environmental quality guidelines. Thus, also taking into consideration that
most of the sediments were classified as being toxic, a severe threat is posed to the health
of the associated biota. Although 60 nematode genera were identified from soil and
sediments samples collected from the respective sampling sites associated with the
Wonderfontein Cave and Spruit, it was concluded that most of these genera were likely only
temporary residents of the subterranean environment. Even though plant-parasitic and nonparasitic
nematodes were present, most of the collected soil and sediment samples were
dominated by bacterivores (non-parasitic nematodes). Zero genetic divergence was
recorded between the C. gariepinus populations associated with the Wonderfontein Cave and Stoffels Dam (Wonderfontein Spruit). However, significant temporal and spatial variation
was observed in some bioaccumulated metals and biomarker responses within and between
the respective C. gariepinus populations. Furthermore, the metal bioaccumulation levels
present in both these fish populations pose a substantial threat to human health and are
thus not fit for consumption. Also, no significant fish condition differences were observed
between the C. gariepinus populations associated with the Wonderfontein Cave and Spruit.
This study served as an initiative to create awareness and promote the conservation of
Africa’s karst landscapes. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2015
| Identifer | oai:union.ndltd.org:NWUBOLOKA1/oai:dspace.nwu.ac.za:10394/15933 |
| Date | January 2014 |
| Creators | Du Preez, Gerhard Cornelis |
| Source Sets | North-West University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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