Abstract
Ph.D.
Mining operations significantly influence the environment due to direct and indirect
discharges of waste products into the aquatic systems. The primary aim of this study
was to assess the current situation in the platinum mining area and develop a
management plan to ensure that existing and potential environmental impacts caused
by platinum mining and processing are mitigated.
To do this, an assessment was carried out to investigate changes in critical aquatic
invertebrate and fish community distributions and assess how they relate to measured
environmental factors. Five sites were selected, one reference site which is upstream of
heavy mining activities and four sites within heavy mining and processing activities.
Standard techniques for water, sediment, invertebrate and fish sampling were used.
Macro-invertebrates sampled were identified to family level whereas fish were identified
to species level.
Multivariate analysis used was cluster analysis by non-metric multidimensional scaling
(NMDS) for both macro-invertebrates and fish. Three methods of ordination were used
to analyze the biotic and abiotic data namely N-MDS, Correspondence Analysis (CA)
and Canonical Correspondence Analysis (CCA).
Cluster analysis of macro-invertebrates data revealed three major groups based on
sampling period (low flow or high flow) and the last cluster according to the locality.
Multidimensional scaling ordination of high and low flow for macro-invertebrate
communities confirmed the groupings detected by cluster analysis. Cluster analysis for
fish communities revealed two groups at 50% similarity; the first group is the
combination of reference and exposure sites for both high and low flow sampling
regimes. No fish were sampled at site 4 during both low and high flow regimes.
Multidimensional scaling ordination of high and low flow fish communities confirmed the
groupings detected by cluster analysis. Analysis using a similarity profile (SIMPROF)
test indicated that fish communities are statistically (p=5%) the same. It was found that
macro-invertebrates and fish respond differently to environmental variables.