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The use of diatoms to indicate water quality in wetlands : A South African perspective / by Malebo D. MatlalaMatlala, Malebo Desnet January 2010 (has links)
In a semi-arid country like South Africa, the availability and quality of water has always
played an important part in determining not only where people can live, but also their
quality of life. The supply of water is also becoming a restriction to the socio-economic
development of the country, in terms of both the quality and quantity of what is available.
Thus different monitoring techniques should be put in place to help inform the process of
conserving this precious commodity and to improve the quality of what is already
available.
Water quality monitoring has traditionally been by the means of physico-chemical
analysis; this has more recently been augmented with the use of biomonitoring techniques.
However, since the biota commonly used to indicate aquatic conditions are not always
present in wetlands; this study tested the use of diatoms as bio-indicators in wetlands.
Diatom samples were collected from thirteen wetlands in the Western Cape Province, and
cells from these communities were enumerated and diatom ?based indices were calculated
using version 3.1 of OMNIDIA. These indices were useful for indicating water quality
conditions when compared to the measured physico-chemical parameters. In addition,
most diatom species found were common to those found in riverine environments, making
the transfer of ecological optima possible.
The objective of the study was to provide a preliminary diatom-based index for wetlands,
however, given the relatively small study area and the strong bias towards coastal wetlands
it was deemed inadvisable to construct such an index, instead several indices are
recommended for interim use until further research that more comprehensively covers
wetlands in South Africa has been conducted. It is thus the recommendation of this study
that more data is collected for comparison to other wetlands and that in the interim, indices
such as SPI be applied for routine biomonitoring of these environments. / Thesis (M.Sc. (Botany))--North-West University, Potchefstroom Campus, 2010.
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The use of diatoms to indicate water quality in wetlands : A South African perspective / by Malebo D. MatlalaMatlala, Malebo Desnet January 2010 (has links)
In a semi-arid country like South Africa, the availability and quality of water has always
played an important part in determining not only where people can live, but also their
quality of life. The supply of water is also becoming a restriction to the socio-economic
development of the country, in terms of both the quality and quantity of what is available.
Thus different monitoring techniques should be put in place to help inform the process of
conserving this precious commodity and to improve the quality of what is already
available.
Water quality monitoring has traditionally been by the means of physico-chemical
analysis; this has more recently been augmented with the use of biomonitoring techniques.
However, since the biota commonly used to indicate aquatic conditions are not always
present in wetlands; this study tested the use of diatoms as bio-indicators in wetlands.
Diatom samples were collected from thirteen wetlands in the Western Cape Province, and
cells from these communities were enumerated and diatom ?based indices were calculated
using version 3.1 of OMNIDIA. These indices were useful for indicating water quality
conditions when compared to the measured physico-chemical parameters. In addition,
most diatom species found were common to those found in riverine environments, making
the transfer of ecological optima possible.
The objective of the study was to provide a preliminary diatom-based index for wetlands,
however, given the relatively small study area and the strong bias towards coastal wetlands
it was deemed inadvisable to construct such an index, instead several indices are
recommended for interim use until further research that more comprehensively covers
wetlands in South Africa has been conducted. It is thus the recommendation of this study
that more data is collected for comparison to other wetlands and that in the interim, indices
such as SPI be applied for routine biomonitoring of these environments. / Thesis (M.Sc. (Botany))--North-West University, Potchefstroom Campus, 2010.
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Investigating morphological changes in fish tissue, due to the presence of persistent organic pollutants and metals / W. Pheiffer.Pheiffer, Wihan January 2012 (has links)
Levels of selected metals and persistent organic pollutants (POPs) were investigated in sediment and fillet tissue of the sharptooth catfish (Clarias gariepinus), from sites along the Orange-Vaal River system, South Africa.
A histological assessment was done on the livers, kidneys, and gills of the fish sampled to determine morphological changes. The sediment and fish sampling sites were selected up- and downstream of major pollution sources such as mining, industrial and agriculture. The concentrations of the metals in the fish and sediment was determined with an inductively coupled plasma mass spectrometry and the POPs with a high resolution gas chromatographyhigh resolution mass spectrometer. Indices were calculated to describe the quality of the sediment The enrichment factor (Ef) of individual heavy metals evaluated elevation in levels above natural geology. The geo-accumulation index (Igeo) determined the degree of pollution by the enrichment levels of the individual metals. The pollution effect of the total mixture of the heavy metals was investigated by the metal pollution index (MPI) and pollution load index (PLI). Ecological risk was determined by calculating the sediment quality guideline index (SQG-I) and a sediment quality index (SQI) to determine the quality of the sediment. For the SQG-I and SQI, international sediment quality guidelines were used, since South Africa does not have them. The bio-accumulation factor (BF) was calculated between sediment and fish. A limited human health risk assessment was done for the consumption of Clarias gariepinus. A semi-quantitative histopathological assessment was preformed and alterations found were numerically described with the aid of mean organ indices.
The POPs values were very low. The Igeo and Ef of Se, Hg, Ag and Au were the highest at all the sites. Parys had the most metals that were enriched to different degrees, but Rooipoort had the highest MPI and PLI. The SQG-I indicated that the sites had a moderate chance of posing an ecological risk to its biota, except for Rooipoort that had a high toxic probability. The SQI classified Rooipoort as “fair” in terms of sediment quality and the rest of the sites as “good”. The semi-quantitative histology based assessment results showed that the mean organ and fish indices fell within class 1 (normal tissue structure with slight histological alterations) or class 2 (normal tissue structure with moderate histological alterations). The mean gill, -liver and kidney indices for all the sites fell in class 1. The mean fish index for all the sites however, fell in class 2. The human health risk assesment showed high risk for non-carcinogenic effects from Ag, Hg, As and Cr if fish from the sample sites were to be consumed.
The results from this study identified that the river system is polluted by anthropogenic activities. Results showed that the pollutants of concern in the system were ultimately Ag, Hg and PFOS. Although the morphology of Clarias gariepinus was not altered, the results indicated that the Orange-Vaal River system is polluted and that these fish is unsafe for human consumption. / Thesis (MSc (Environmental Sciences))--North-West University, Potchefstroom Campus, 2013.
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Investigating morphological changes in fish tissue, due to the presence of persistent organic pollutants and metals / W. Pheiffer.Pheiffer, Wihan January 2012 (has links)
Levels of selected metals and persistent organic pollutants (POPs) were investigated in sediment and fillet tissue of the sharptooth catfish (Clarias gariepinus), from sites along the Orange-Vaal River system, South Africa.
A histological assessment was done on the livers, kidneys, and gills of the fish sampled to determine morphological changes. The sediment and fish sampling sites were selected up- and downstream of major pollution sources such as mining, industrial and agriculture. The concentrations of the metals in the fish and sediment was determined with an inductively coupled plasma mass spectrometry and the POPs with a high resolution gas chromatographyhigh resolution mass spectrometer. Indices were calculated to describe the quality of the sediment The enrichment factor (Ef) of individual heavy metals evaluated elevation in levels above natural geology. The geo-accumulation index (Igeo) determined the degree of pollution by the enrichment levels of the individual metals. The pollution effect of the total mixture of the heavy metals was investigated by the metal pollution index (MPI) and pollution load index (PLI). Ecological risk was determined by calculating the sediment quality guideline index (SQG-I) and a sediment quality index (SQI) to determine the quality of the sediment. For the SQG-I and SQI, international sediment quality guidelines were used, since South Africa does not have them. The bio-accumulation factor (BF) was calculated between sediment and fish. A limited human health risk assessment was done for the consumption of Clarias gariepinus. A semi-quantitative histopathological assessment was preformed and alterations found were numerically described with the aid of mean organ indices.
The POPs values were very low. The Igeo and Ef of Se, Hg, Ag and Au were the highest at all the sites. Parys had the most metals that were enriched to different degrees, but Rooipoort had the highest MPI and PLI. The SQG-I indicated that the sites had a moderate chance of posing an ecological risk to its biota, except for Rooipoort that had a high toxic probability. The SQI classified Rooipoort as “fair” in terms of sediment quality and the rest of the sites as “good”. The semi-quantitative histology based assessment results showed that the mean organ and fish indices fell within class 1 (normal tissue structure with slight histological alterations) or class 2 (normal tissue structure with moderate histological alterations). The mean gill, -liver and kidney indices for all the sites fell in class 1. The mean fish index for all the sites however, fell in class 2. The human health risk assesment showed high risk for non-carcinogenic effects from Ag, Hg, As and Cr if fish from the sample sites were to be consumed.
The results from this study identified that the river system is polluted by anthropogenic activities. Results showed that the pollutants of concern in the system were ultimately Ag, Hg and PFOS. Although the morphology of Clarias gariepinus was not altered, the results indicated that the Orange-Vaal River system is polluted and that these fish is unsafe for human consumption. / Thesis (MSc (Environmental Sciences))--North-West University, Potchefstroom Campus, 2013.
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