An assessment of the ecological integrity of Reed Pans on the Mpumalanga Highveld
- Authors: De Klerk, Arno Reed
- Date: 2011-05-16T07:53:33Z
- Subjects: Pans (Geomorphology) , Ecological integrity , Lake ecology , Aquatic invertebrates , Water quality biological assessment , Mpumalanga (South Africa)
- Type: Thesis
- Identifier: uj:7074 , http://hdl.handle.net/10210/3637
- Description: M.Sc. , Mpumalanga, “the place where the sun rises”, sets the scene for one of the rarest wetland types in South Africa. They are formed on one of the last remnants of the ancient African land surface, contain peat and together with a variety of other pan types make up the Mpumalanga Lakes District. Of these approximately 320 pans, only ±2.3% are reed pans. These endorheic wetlands are unique from other pan types and peatlands in South Africa and support an abundant biodiversity. They perform vital functions such as water storage, filtering out impurities and carbon fixation, which prevents an excess release of CO2 into the atmosphere. There is very little known about these endorheic wetlands and thus they are constantly being threatened by various activities such as agriculture, livestock and mining. The objectives of this study were to determine the spatial and temporal variation of macroinvertebrate community structures of reed pans and the environmental factors, such as water quality, responsible for the maintenance of these structures; to determine the best method for sampling aquatic invertebrates in reed pans; as well as to determine the relationship between aquatic invertebrates and the water, sediment and habitat quality of a reed pan. Together with this the amphibian diversity as well as the occurrence of other biotic components was determined. Four reed pans were assessed during four different seasons over a one year period to account for the different hydrological extremes. Sub-surface water samples were analyzed for their suspended solid content, nutrient levels, metals and chlorophyll-a concentrations as well as in situ water quality parameters. Sediment samples were analyzed for metal concentrations, organic carbon and water content, as well as sediment size distribution. Invertebrates were collected using the following sampling techniques: aquatic light trap, terrestrial light trap, emergent trap, sweep net, plankton net, as well as benthic sampling using an Eckman grab.
- Full Text:
- Authors: De Klerk, Arno Reed
- Date: 2011-05-16T07:53:33Z
- Subjects: Pans (Geomorphology) , Ecological integrity , Lake ecology , Aquatic invertebrates , Water quality biological assessment , Mpumalanga (South Africa)
- Type: Thesis
- Identifier: uj:7074 , http://hdl.handle.net/10210/3637
- Description: M.Sc. , Mpumalanga, “the place where the sun rises”, sets the scene for one of the rarest wetland types in South Africa. They are formed on one of the last remnants of the ancient African land surface, contain peat and together with a variety of other pan types make up the Mpumalanga Lakes District. Of these approximately 320 pans, only ±2.3% are reed pans. These endorheic wetlands are unique from other pan types and peatlands in South Africa and support an abundant biodiversity. They perform vital functions such as water storage, filtering out impurities and carbon fixation, which prevents an excess release of CO2 into the atmosphere. There is very little known about these endorheic wetlands and thus they are constantly being threatened by various activities such as agriculture, livestock and mining. The objectives of this study were to determine the spatial and temporal variation of macroinvertebrate community structures of reed pans and the environmental factors, such as water quality, responsible for the maintenance of these structures; to determine the best method for sampling aquatic invertebrates in reed pans; as well as to determine the relationship between aquatic invertebrates and the water, sediment and habitat quality of a reed pan. Together with this the amphibian diversity as well as the occurrence of other biotic components was determined. Four reed pans were assessed during four different seasons over a one year period to account for the different hydrological extremes. Sub-surface water samples were analyzed for their suspended solid content, nutrient levels, metals and chlorophyll-a concentrations as well as in situ water quality parameters. Sediment samples were analyzed for metal concentrations, organic carbon and water content, as well as sediment size distribution. Invertebrates were collected using the following sampling techniques: aquatic light trap, terrestrial light trap, emergent trap, sweep net, plankton net, as well as benthic sampling using an Eckman grab.
- Full Text:
The use of selected freshwater gastropods as biomonitors to assess water quality
- Authors: Moolman, Liesel
- Date: 2008-10-14T11:28:49Z
- Subjects: Gastropoda , Water quality biological assessment , Biochemical markers
- Type: Thesis
- Identifier: uj:12178 , http://hdl.handle.net/10210/1191
- Description: M.Sc. , The health of aquatic ecosystems can be severely compromised by a variety of pollutants, such as heavy metals, which are related to anthropogenic activities. Increased recognition is given to the use of organisms, especially molluscs, in the biomonitoring of aquatic ecosystems. This promising approach complements the interpretation of the physico-chemical measurements of water quality. The bioaccumulation of pollutants as well as the resultant biological responses (biomarkers) in organisms can be used in assessing the spatial and temporal trends of chronically polluted environments. The aim of this study was to determine if selected freshwater gastropods (Melanoides tuberculata, Physa acuta, Helisoma duryi and Lymnaea columella) can be used as suitable biomonitors or indicators of water quality. Interspecies differences in metal bioaccumulation and biomarker responses were determined in order to select the most suitable biomonitor/indicator organism to be used. The bioaccumulation of metals was related to the biomarker responses of the organisms. This study was divided into an active biomonitoring (ABM) study and a laboratory exposure study. In the first study, the organisms, M. tuberculata and L. columella were chronically (two, four and six week period) exposed to field conditions. Metal bioaccumulation as well as the biomarker techniques, DNA damage, catalase (CAT) activity, reduced glutathione (GSH) content and cellular energy allocation (CEA) were measured in the organisms. These general biomarkers of exposure and effect, on the biochemical and cellular levels of biological organisation can give a rapid and sensitive assessment of organism health. The second study consisted of exposing the gastropods, M. tuberculata, P. acuta, H. duryi and L. columella to sub-lethal zinc and cadmium concentrations. The uptake and depuration kinetics of these metals were determined in M. tuberculata and H. duryi for a six hour and 48 hour period, respectively. The bioaccumulation of Zn and Cd as well as the biomarkers, DNA damage, CAT activity, GSH content and CEA were measured in all the species, after a two week exposure period. , Prof. J.H.J. van Vuren
- Full Text:
- Authors: Moolman, Liesel
- Date: 2008-10-14T11:28:49Z
- Subjects: Gastropoda , Water quality biological assessment , Biochemical markers
- Type: Thesis
- Identifier: uj:12178 , http://hdl.handle.net/10210/1191
- Description: M.Sc. , The health of aquatic ecosystems can be severely compromised by a variety of pollutants, such as heavy metals, which are related to anthropogenic activities. Increased recognition is given to the use of organisms, especially molluscs, in the biomonitoring of aquatic ecosystems. This promising approach complements the interpretation of the physico-chemical measurements of water quality. The bioaccumulation of pollutants as well as the resultant biological responses (biomarkers) in organisms can be used in assessing the spatial and temporal trends of chronically polluted environments. The aim of this study was to determine if selected freshwater gastropods (Melanoides tuberculata, Physa acuta, Helisoma duryi and Lymnaea columella) can be used as suitable biomonitors or indicators of water quality. Interspecies differences in metal bioaccumulation and biomarker responses were determined in order to select the most suitable biomonitor/indicator organism to be used. The bioaccumulation of metals was related to the biomarker responses of the organisms. This study was divided into an active biomonitoring (ABM) study and a laboratory exposure study. In the first study, the organisms, M. tuberculata and L. columella were chronically (two, four and six week period) exposed to field conditions. Metal bioaccumulation as well as the biomarker techniques, DNA damage, catalase (CAT) activity, reduced glutathione (GSH) content and cellular energy allocation (CEA) were measured in the organisms. These general biomarkers of exposure and effect, on the biochemical and cellular levels of biological organisation can give a rapid and sensitive assessment of organism health. The second study consisted of exposing the gastropods, M. tuberculata, P. acuta, H. duryi and L. columella to sub-lethal zinc and cadmium concentrations. The uptake and depuration kinetics of these metals were determined in M. tuberculata and H. duryi for a six hour and 48 hour period, respectively. The bioaccumulation of Zn and Cd as well as the biomarkers, DNA damage, CAT activity, GSH content and CEA were measured in all the species, after a two week exposure period. , Prof. J.H.J. van Vuren
- Full Text:
The use of transplanted brown mussels (Perna perna) as indicators of marine health in Richards Bay harbour
- Authors: Mills, Kerry Anne
- Date: 2008-10-14T11:38:07Z
- Subjects: Marine ecology , Water quality biological assessment , Mussels ecology , KwaZulu-Natal (South Africa)
- Type: Thesis
- Identifier: uj:12233 , http://hdl.handle.net/10210/1199
- Description: M.Sc. , Richards Bay Harbour is notably one of the fastest growing, economically important harbours in South Africa. However, this economic growth has lead to increased anthropogenic activities surrounding the harbour, which may result in higher contaminant, including metal, concentrations within the harbour. These contaminants may negatively influence the natural ecosystem functioning within the harbour. Consequently, assessment of the extent and effect of contamination, through continuous biomonitoring of Richards Bay Harbour, is essential. In the present study, the main aim was to assess the marine health in Richards Bay Harbour by studying spatial and temporal variation of bioaccumulation and biological responses within the mussel, Perna perna, using an active biomonitoring (ABM) approach. The ABM approach was preferred over the traditional passive biomonitoring of resident mussels since it eliminates several inherent factors that may mask the mussels’ true responses to the ambient environment. This approach entailed the transplantation of reference mussels from a relatively uncontaminated environment into Richards Bay Harbour, which is known to be contaminated by metals. In order to identify the reference mussel population for transplantation purposes, a study was undertaken to assess metal levels in two other P. perna populations within the same ecoregion as Richards Bay Harbour, namely Dawson’s Rocks and Sheffield Beach. The results showed that most metal concentrations were lower at Sheffield Beach, which consequently lead to the selection of this population as a reference. The effect of size differences on metal bioaccumulation was also assessed using the three latter mentioned mussel populations, which showed that, although local conditions strongly influence the relationship between metal bioaccumulation and size, utilisation of a narrow size range would minimise the size effect on bioaccumulation and should be used for ABM studies. , Prof. V. Wepener
- Full Text:
- Authors: Mills, Kerry Anne
- Date: 2008-10-14T11:38:07Z
- Subjects: Marine ecology , Water quality biological assessment , Mussels ecology , KwaZulu-Natal (South Africa)
- Type: Thesis
- Identifier: uj:12233 , http://hdl.handle.net/10210/1199
- Description: M.Sc. , Richards Bay Harbour is notably one of the fastest growing, economically important harbours in South Africa. However, this economic growth has lead to increased anthropogenic activities surrounding the harbour, which may result in higher contaminant, including metal, concentrations within the harbour. These contaminants may negatively influence the natural ecosystem functioning within the harbour. Consequently, assessment of the extent and effect of contamination, through continuous biomonitoring of Richards Bay Harbour, is essential. In the present study, the main aim was to assess the marine health in Richards Bay Harbour by studying spatial and temporal variation of bioaccumulation and biological responses within the mussel, Perna perna, using an active biomonitoring (ABM) approach. The ABM approach was preferred over the traditional passive biomonitoring of resident mussels since it eliminates several inherent factors that may mask the mussels’ true responses to the ambient environment. This approach entailed the transplantation of reference mussels from a relatively uncontaminated environment into Richards Bay Harbour, which is known to be contaminated by metals. In order to identify the reference mussel population for transplantation purposes, a study was undertaken to assess metal levels in two other P. perna populations within the same ecoregion as Richards Bay Harbour, namely Dawson’s Rocks and Sheffield Beach. The results showed that most metal concentrations were lower at Sheffield Beach, which consequently lead to the selection of this population as a reference. The effect of size differences on metal bioaccumulation was also assessed using the three latter mentioned mussel populations, which showed that, although local conditions strongly influence the relationship between metal bioaccumulation and size, utilisation of a narrow size range would minimise the size effect on bioaccumulation and should be used for ABM studies. , Prof. V. Wepener
- Full Text:
The current ecological state of the Lower Mvoti River, KwaZulu-Natal
- Authors: Malherbe, Charl Wynand
- Date: 2008-06-10T11:45:27Z
- Subjects: Aquatic ecology , Water quality biological assessment , Lower Mvoti River (South Africa)
- Type: Thesis
- Identifier: uj:9576 , http://hdl.handle.net/10210/599
- Description: The Reserve concept, introduced in the National Water Act, has led to an increasing use of biomonitoring techniques to assess the current ecological status of rivers in South Africa. The ecological status of a river provides vital information necessary to establish the amount and quality of water needed by the aquatic ecosystem. If the amount and quality of water is inadequate, then the water resource will not be able to provide the necessary goods and services to their respective water users. The biomonitoring of rivers gained impetus with the establishment of the River Health Programme (RHP) and its various objectives. The RHP led to the development and refinement of a range of biomonitoring indices to assess various components of the aquatic ecosystem. The components used to assess the current ecological status of a river include the physical habitat, riparian vegetation, water quality, as well as the macro-invertebrate and fish communities. The Mvoti River, in the vicinity of Stanger, is subjected to extensive water abstraction, which is then utilised for irrigation, industrial use, urban water requirements and various domestic uses by informal settlements. Previous studies on the river indicated that it is in a severely degraded state, especially below the confluences of the Nchaweni and Mbozambo rivers. Thus, this assessment of the current ecological status of the Mvoti River was undertaken to possibly identify the main causes of the degraded state. The study was undertaken during the high (February) and low flow (August) periods in 2005. Selected monitoring sites included sites used in previous studies on the Mvoti River as well as sites on the Nchaweni and Mbozambo tributaries. The methodology for this study was to implement the various indices used in the RHP for the different ecosystem components. The habitat indices implemented in this study were the Habitat Quality Index (HQI) and Integrated Habitat Assessment System (IHAS). Physicochemical water analyses were done during each sampling period to assess the water quality against the South African Water Quality Guidelines. The biotic indices used included the South African Scoring System 5 (SASS5) index to assess the macro-invertebrate community and the Fish Assemblage Integrity Index (FAII) to assess the fish community. Additionally, the newly developed EcoStatus indices for the fish and macro-invertebrate communities were implemented on the available fish and macro-invertebrate data. These indices were developed mainly to be used in Reserve determination assessments, where the assessments are built around the integration of all ecosystem components into a single value for the ecological status. The fish index is termed the Fish Response Assessment Index (FRAI) and the macro-invertebrate index the Macro-invertebrate Assessment Index (MIRAI)…. Multivariate statistical analyses were performed on the water quality as well as the macroinvertebrate and fish communities to establish any temporal and spatial trends together with any dominating water quality variables responsible for species composition at the different sites. PRIMER and CANOCO computer software were used to construct hierarchical clusters and NMDS plots for the biotic communities, while RDA and PCA bi-plots were used to represent the water quality variables and their effects on the biotic community structure. The Mvoti River is in a seriously degraded state and this degradation was particularly evident during the low flow period below the Sappi Stanger mill and the Stanger Sewage works effluent discharge points. The degraded state of the river is caused by the multitude of impacts on the river, which includes the local land-use, upstream land-use and effluent discharges in the vicinity of Stanger. The water quality in the vicinity of Stanger was in a poor state during the low flow, while the high flow was only slightly better. The upstream site is in a fair condition but, after the Nchaweni and Mbozambo rivers enter the Mvoti River, the water quality decreases. The variables found to be problematic included microbiological variables, chlorides and electrical conductivity in the Mvoti River. High nutrient values were found together with very high electrical conductivity in especially the Nchaweni River tributary. The lower Mvoti River contains very little habitat of good quality to support the biotic communities. The habitat is generally degraded due to the destruction of the riparian zone and the dominance of alien vegetation in the form of reeds. This, together with land-use and water abstraction activities, has caused high sediment loads in the lower Mvoti River which are continually moving. The IHAS and HQI results indicated the habitat in the lower Mvoti River is in a modified condition. The statistical analysis of the macro-invertebrate data showed that a definite spatial variation existed while no significant temporal variation was identified. There is a difference in the community structure between the Mvoti River and its tributaries, with the tributaries containing a very poor diversity. This lowered species diversity was attributed to the effects of, specifically, chlorides on the community structure but the origin of the chlorides could not be linked specifically to the Sappi Stanger mill’s activities. The SASS5 was similar with the Mvoti River sites having slightly higher scores, placing it in either a B or C class while most of the tributaries had a Class D. The community structure in the tributaries responded to nutrients and chlorides and these variables reduced the numbers of sensitive species and allowed hardy taxa to flourish. The results of the MIRAI index provided the same categories as identified by the SASS5 index. The fish community structure showed the same spatial differences identified in the macroinvertebrate communities, with the tributary sites containing different community structures than those found in the Mvoti River. The Mvoti River fish community is in a modified state with the majority of fish sampled being tolerant with very few sensitive species present. The FAII scores for the Mvoti River was a Category C, while the tributary sites scored a Category D or lower. The fish community is affected by the poor water quality, habitat and flow modifications in the lower Mvoti River. The FRAI index provided the lower Mvoti River and its tributaries with the same categories as identified with FAII. Overall, the Mvoti River is in a seriously degraded state with even the reference site being subjected to impacts that could potentially be harmful to the ecosystem. The ecological state of the river decreases as it moves past Stanger and is subjected to the impacts from the Nchaweni and Mbozambo rivers in the form of nutrients and salinity concentrations. The impacts on the Mvoti River have a multitude of different sources and if the aquatic ecosystem is to improve, only a collective effort will be of any value. , Prof. V. Wepener
- Full Text:
- Authors: Malherbe, Charl Wynand
- Date: 2008-06-10T11:45:27Z
- Subjects: Aquatic ecology , Water quality biological assessment , Lower Mvoti River (South Africa)
- Type: Thesis
- Identifier: uj:9576 , http://hdl.handle.net/10210/599
- Description: The Reserve concept, introduced in the National Water Act, has led to an increasing use of biomonitoring techniques to assess the current ecological status of rivers in South Africa. The ecological status of a river provides vital information necessary to establish the amount and quality of water needed by the aquatic ecosystem. If the amount and quality of water is inadequate, then the water resource will not be able to provide the necessary goods and services to their respective water users. The biomonitoring of rivers gained impetus with the establishment of the River Health Programme (RHP) and its various objectives. The RHP led to the development and refinement of a range of biomonitoring indices to assess various components of the aquatic ecosystem. The components used to assess the current ecological status of a river include the physical habitat, riparian vegetation, water quality, as well as the macro-invertebrate and fish communities. The Mvoti River, in the vicinity of Stanger, is subjected to extensive water abstraction, which is then utilised for irrigation, industrial use, urban water requirements and various domestic uses by informal settlements. Previous studies on the river indicated that it is in a severely degraded state, especially below the confluences of the Nchaweni and Mbozambo rivers. Thus, this assessment of the current ecological status of the Mvoti River was undertaken to possibly identify the main causes of the degraded state. The study was undertaken during the high (February) and low flow (August) periods in 2005. Selected monitoring sites included sites used in previous studies on the Mvoti River as well as sites on the Nchaweni and Mbozambo tributaries. The methodology for this study was to implement the various indices used in the RHP for the different ecosystem components. The habitat indices implemented in this study were the Habitat Quality Index (HQI) and Integrated Habitat Assessment System (IHAS). Physicochemical water analyses were done during each sampling period to assess the water quality against the South African Water Quality Guidelines. The biotic indices used included the South African Scoring System 5 (SASS5) index to assess the macro-invertebrate community and the Fish Assemblage Integrity Index (FAII) to assess the fish community. Additionally, the newly developed EcoStatus indices for the fish and macro-invertebrate communities were implemented on the available fish and macro-invertebrate data. These indices were developed mainly to be used in Reserve determination assessments, where the assessments are built around the integration of all ecosystem components into a single value for the ecological status. The fish index is termed the Fish Response Assessment Index (FRAI) and the macro-invertebrate index the Macro-invertebrate Assessment Index (MIRAI)…. Multivariate statistical analyses were performed on the water quality as well as the macroinvertebrate and fish communities to establish any temporal and spatial trends together with any dominating water quality variables responsible for species composition at the different sites. PRIMER and CANOCO computer software were used to construct hierarchical clusters and NMDS plots for the biotic communities, while RDA and PCA bi-plots were used to represent the water quality variables and their effects on the biotic community structure. The Mvoti River is in a seriously degraded state and this degradation was particularly evident during the low flow period below the Sappi Stanger mill and the Stanger Sewage works effluent discharge points. The degraded state of the river is caused by the multitude of impacts on the river, which includes the local land-use, upstream land-use and effluent discharges in the vicinity of Stanger. The water quality in the vicinity of Stanger was in a poor state during the low flow, while the high flow was only slightly better. The upstream site is in a fair condition but, after the Nchaweni and Mbozambo rivers enter the Mvoti River, the water quality decreases. The variables found to be problematic included microbiological variables, chlorides and electrical conductivity in the Mvoti River. High nutrient values were found together with very high electrical conductivity in especially the Nchaweni River tributary. The lower Mvoti River contains very little habitat of good quality to support the biotic communities. The habitat is generally degraded due to the destruction of the riparian zone and the dominance of alien vegetation in the form of reeds. This, together with land-use and water abstraction activities, has caused high sediment loads in the lower Mvoti River which are continually moving. The IHAS and HQI results indicated the habitat in the lower Mvoti River is in a modified condition. The statistical analysis of the macro-invertebrate data showed that a definite spatial variation existed while no significant temporal variation was identified. There is a difference in the community structure between the Mvoti River and its tributaries, with the tributaries containing a very poor diversity. This lowered species diversity was attributed to the effects of, specifically, chlorides on the community structure but the origin of the chlorides could not be linked specifically to the Sappi Stanger mill’s activities. The SASS5 was similar with the Mvoti River sites having slightly higher scores, placing it in either a B or C class while most of the tributaries had a Class D. The community structure in the tributaries responded to nutrients and chlorides and these variables reduced the numbers of sensitive species and allowed hardy taxa to flourish. The results of the MIRAI index provided the same categories as identified by the SASS5 index. The fish community structure showed the same spatial differences identified in the macroinvertebrate communities, with the tributary sites containing different community structures than those found in the Mvoti River. The Mvoti River fish community is in a modified state with the majority of fish sampled being tolerant with very few sensitive species present. The FAII scores for the Mvoti River was a Category C, while the tributary sites scored a Category D or lower. The fish community is affected by the poor water quality, habitat and flow modifications in the lower Mvoti River. The FRAI index provided the lower Mvoti River and its tributaries with the same categories as identified with FAII. Overall, the Mvoti River is in a seriously degraded state with even the reference site being subjected to impacts that could potentially be harmful to the ecosystem. The ecological state of the river decreases as it moves past Stanger and is subjected to the impacts from the Nchaweni and Mbozambo rivers in the form of nutrients and salinity concentrations. The impacts on the Mvoti River have a multitude of different sources and if the aquatic ecosystem is to improve, only a collective effort will be of any value. , Prof. V. Wepener
- Full Text:
The effect of environmental aspects on the biological communities of the Olifants and Luvuvhu Rivers in the Kruger National Park
- Authors: Renshaw, Christopher Ashby
- Date: 2012-05-02
- Subjects: Water quality biological assessment , River ecology management , Olifants River (South Africa) , Luvuvhu River (South Africa) , Kruger National Park Rivers Research Programme , Environmental impact analysis , Aquaculture - Environmental aspects
- Type: Mini-Dissertation
- Identifier: uj:2242 , http://hdl.handle.net/10210/4681
- Description: M.Sc. , The Department of Water Affairs (DWA) through the National Water Act 36 of 1998 (NWA) recognises that river management in South Africa is extremely important and consequently the ecological integrity of our river systems must be upheld. The conservation of our aquatic resources and aquatic ecosystems can only be achieved by the holistic management of the resources itself, and in turn the aquatic biodiversity. As such, the National River Health Programme (RHP) through the DWA has been formulated to identify and monitor the current ecological state of South African rivers (Balance et al., 2001). The Luvuvhu and Olifants Rivers in the Kruger National Park (KNP) have been monitored in terms of the River Health Programme, but little published literature is available on their biological communities as determined by the use of accepted indices such as the SASS5 protocol (Dickens and Graham, 2002) and the Fish Response Assessment Index (FRAI) (Kleynhans, 2007a). This project therefore studied the two rivers on an individual basis, as well as comparing them to each other. The working hypotheses for this project are that: (1) In comparison to the Luvuvhu River, the biological communities of the Olifants River in the KNP have been negatively affected by anthropogenic impacts; and (2) The ecological integrity of the biological communities improves as the Luvuvhu and Olifants Rivers flow though the KNP. To test these hypotheses the aims and objectives of this project were to: (1) Determine the fish and macroinvertebrate biological community structure in the Olifants and Luvuvhu Rivers in the KNP; (2) Determine the in situ water quality of the two rivers; and (3) Determine whether the changes in the biological communities along the two rivers can be related to anthropogenic stressors on the rivers from sources outside the KNP. The research methodology for this study was based on the implementation of the various indices used by the RHP for the biological communities sampled. Four sites in the Luvuvhu River and five sites in the Olifants River were selected based on data availability and site accessibility. The SASS5 protocol was used to assess the macroinvertebrates, and the Fish Response Assessment Index (FRAI) was used to assess the fish communities. In situ water quality parameters were assessed against South African Water Quality Guidelines for Freshwater Ecosystems (DWA, 1996) and the Kruger National Park’s thresholds of potential concern. This was done to determine the health of the biological communities in terms of Page 9 anthropogenic stressors, and then to assess the trends seen between the individual sites, and between the two rivers. Various univariate diversity indices were used to assess community structure. Multivariate statistical analyses were performed on the water quality as well as the macroinvertebrate and fish communities to establish any temporal and spatial trends. PRIMER and CANOCO computer software were used to construct hierarchical clusters and NMDS plots for the biotic communities, while PCA bi-plots were used to represent the water quality variables and their effects on the biotic community structure. The ecological integrity of the biological communities of the Olifants River has deteriorated. The fish and macroinvertebrate communities have declined in terms of species richness and abundance, as well as community structure. However, macroinvertebrates were not found to have diminished as drastically. This is due mainly to the fact that they respond rapidly to changes in conditions, and the 2010 season was a good one regarding habitat and water quality. As such they increased in diversity and number, but on the whole, this will change as the trend of decreasing species richness and abundance will continue. The decrease in water quality can be said to be a driver of these results, as the in situ variables revealed that the EC for the Olifants is extremely high. The abstraction of water upstream has led to an overall reduction in flow, and as such habitat availability is reduced, and fish and macroinvertebrate communities relying on these habitats have been negatively affected. There has been no increase in biological community integrity from the point where the Olifants River entered the park, to where it left the park. In fact, there has been a decrease in the integrity along the length of the river. The loss in biological community structure can therefore be attributed to habitat loss through water abstraction and the adverse water quality from the numerous anthropogenic influences upstream.
- Full Text:
- Authors: Renshaw, Christopher Ashby
- Date: 2012-05-02
- Subjects: Water quality biological assessment , River ecology management , Olifants River (South Africa) , Luvuvhu River (South Africa) , Kruger National Park Rivers Research Programme , Environmental impact analysis , Aquaculture - Environmental aspects
- Type: Mini-Dissertation
- Identifier: uj:2242 , http://hdl.handle.net/10210/4681
- Description: M.Sc. , The Department of Water Affairs (DWA) through the National Water Act 36 of 1998 (NWA) recognises that river management in South Africa is extremely important and consequently the ecological integrity of our river systems must be upheld. The conservation of our aquatic resources and aquatic ecosystems can only be achieved by the holistic management of the resources itself, and in turn the aquatic biodiversity. As such, the National River Health Programme (RHP) through the DWA has been formulated to identify and monitor the current ecological state of South African rivers (Balance et al., 2001). The Luvuvhu and Olifants Rivers in the Kruger National Park (KNP) have been monitored in terms of the River Health Programme, but little published literature is available on their biological communities as determined by the use of accepted indices such as the SASS5 protocol (Dickens and Graham, 2002) and the Fish Response Assessment Index (FRAI) (Kleynhans, 2007a). This project therefore studied the two rivers on an individual basis, as well as comparing them to each other. The working hypotheses for this project are that: (1) In comparison to the Luvuvhu River, the biological communities of the Olifants River in the KNP have been negatively affected by anthropogenic impacts; and (2) The ecological integrity of the biological communities improves as the Luvuvhu and Olifants Rivers flow though the KNP. To test these hypotheses the aims and objectives of this project were to: (1) Determine the fish and macroinvertebrate biological community structure in the Olifants and Luvuvhu Rivers in the KNP; (2) Determine the in situ water quality of the two rivers; and (3) Determine whether the changes in the biological communities along the two rivers can be related to anthropogenic stressors on the rivers from sources outside the KNP. The research methodology for this study was based on the implementation of the various indices used by the RHP for the biological communities sampled. Four sites in the Luvuvhu River and five sites in the Olifants River were selected based on data availability and site accessibility. The SASS5 protocol was used to assess the macroinvertebrates, and the Fish Response Assessment Index (FRAI) was used to assess the fish communities. In situ water quality parameters were assessed against South African Water Quality Guidelines for Freshwater Ecosystems (DWA, 1996) and the Kruger National Park’s thresholds of potential concern. This was done to determine the health of the biological communities in terms of Page 9 anthropogenic stressors, and then to assess the trends seen between the individual sites, and between the two rivers. Various univariate diversity indices were used to assess community structure. Multivariate statistical analyses were performed on the water quality as well as the macroinvertebrate and fish communities to establish any temporal and spatial trends. PRIMER and CANOCO computer software were used to construct hierarchical clusters and NMDS plots for the biotic communities, while PCA bi-plots were used to represent the water quality variables and their effects on the biotic community structure. The ecological integrity of the biological communities of the Olifants River has deteriorated. The fish and macroinvertebrate communities have declined in terms of species richness and abundance, as well as community structure. However, macroinvertebrates were not found to have diminished as drastically. This is due mainly to the fact that they respond rapidly to changes in conditions, and the 2010 season was a good one regarding habitat and water quality. As such they increased in diversity and number, but on the whole, this will change as the trend of decreasing species richness and abundance will continue. The decrease in water quality can be said to be a driver of these results, as the in situ variables revealed that the EC for the Olifants is extremely high. The abstraction of water upstream has led to an overall reduction in flow, and as such habitat availability is reduced, and fish and macroinvertebrate communities relying on these habitats have been negatively affected. There has been no increase in biological community integrity from the point where the Olifants River entered the park, to where it left the park. In fact, there has been a decrease in the integrity along the length of the river. The loss in biological community structure can therefore be attributed to habitat loss through water abstraction and the adverse water quality from the numerous anthropogenic influences upstream.
- Full Text:
Classifying and assessing the water quality of wetlands impacted by Eskom’s Matla Power Station in the Mpumalanga Province
- Authors: Mokobodi, Makoena Refilwe
- Date: 2015
- Subjects: Wetlands - Environmental aspects - South Africa , Wetland ecology - South Africa , Water - Pollution - South Africa , Water quality - South Africa - Analysis , Water quality biological assessment , Eskom (Firm)
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/58783 , uj:16490
- Description: Abstract: Please refer to full text to view abstract , M.Sc. (Environmental Management)
- Full Text:
- Authors: Mokobodi, Makoena Refilwe
- Date: 2015
- Subjects: Wetlands - Environmental aspects - South Africa , Wetland ecology - South Africa , Water - Pollution - South Africa , Water quality - South Africa - Analysis , Water quality biological assessment , Eskom (Firm)
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/58783 , uj:16490
- Description: Abstract: Please refer to full text to view abstract , M.Sc. (Environmental Management)
- Full Text:
The water quality and associated problems of the Hennops River and proposed rehabilitative measures
- Authors: Nawn, Ryan
- Date: 2009-02-05T07:14:45Z
- Subjects: Water quality biological assessment , Pollution , Urban runoff , Hennops River Valley (South Africa)
- Type: Thesis
- Identifier: http://ujcontent.uj.ac.za8080/10210/382278 , uj:8096 , http://hdl.handle.net/10210/2024
- Description: M.Sc. , This dissertation establishes the present – day condition of the Hennops River in terms of its water quality and hydrological status. The Hennops River is situated between Johannesburg and Pretoria within the provincial boundaries of Gauteng. The province has a high population density and is regarded as the economic powerhouse of South Africa. As such, rivers flowing through Gauteng have become polluted by the different land uses and activities present in the province. The Hennops River itself has lost most of its aesthetic appeal and has become less useful for recreational and agricultural uses. Furthermore, the Hennops River has become a liability and concern in suburbs south of Pretoria and, more importantly, has become less suitable for sustaining aquatic ecosystems in some of its sections. The Hennops River, therefore, has an effect not only on the environment itself, but also in terms of social and economic aspects. Because of these concerns it was deemed necessary to determine the actual water quality conditions and associated problems prevailing in the Hennops River. Being fed by tributaries, these problems could not be overlooked and were also included in this study. In order to achieve the aim of the study a literature review concerning the concept of water quality and the different physical and chemical constituents affecting aquatic ecosystems needed to be conducted. Added to this, attention had to be given to the study area’s physical features and land uses having an effect on the catchment’s water quality and associated problems. A literature review on existing knowledge of the Hennops River and its principal tributaries was also conducted so that it could be determined whether these rivers have deteriorated over the past three decades. The most recent water quality data was not only compared against existing knowledge, but also in terms of the Target Water Quality Range for Aquatic Ecosystems as stipulated by the Department of Water Affairs and Forestry. This study showed that deterioration of the Hennops River has occurred since rapid urbanisation within its catchment started during the 1970’s. Most of the River’s water quality and associated problems can be ascribed to problems occurring further upstream in the form of the Kaalspruit and Olifantspruit flowing through formal and informal settlements, industrial areas and agricultural land. The water quality of these rivers and the upper Hennops River is the least suitable of the whole study area for aquatic ecosystem well-being. Not only is this a concern but additional hydrological problems occur as well. These include problems such as erosional activity of riverbeds and riverbanks and the silting-up of Centurion Lake. An urgent need exists for holistic catchment management and rehabilitative measures to be implemented to improve the ecological state of these rivers. Rehabilitative measures were proposed and are aimed at improving the water quality and associated problems of the Hennops River and its affected tributaries. It is concluded, therefore, that the status of the Hennops River is not going to improve without the implementation of rehabilitative measures that should form part of an environmental management plan.
- Full Text:
- Authors: Nawn, Ryan
- Date: 2009-02-05T07:14:45Z
- Subjects: Water quality biological assessment , Pollution , Urban runoff , Hennops River Valley (South Africa)
- Type: Thesis
- Identifier: http://ujcontent.uj.ac.za8080/10210/382278 , uj:8096 , http://hdl.handle.net/10210/2024
- Description: M.Sc. , This dissertation establishes the present – day condition of the Hennops River in terms of its water quality and hydrological status. The Hennops River is situated between Johannesburg and Pretoria within the provincial boundaries of Gauteng. The province has a high population density and is regarded as the economic powerhouse of South Africa. As such, rivers flowing through Gauteng have become polluted by the different land uses and activities present in the province. The Hennops River itself has lost most of its aesthetic appeal and has become less useful for recreational and agricultural uses. Furthermore, the Hennops River has become a liability and concern in suburbs south of Pretoria and, more importantly, has become less suitable for sustaining aquatic ecosystems in some of its sections. The Hennops River, therefore, has an effect not only on the environment itself, but also in terms of social and economic aspects. Because of these concerns it was deemed necessary to determine the actual water quality conditions and associated problems prevailing in the Hennops River. Being fed by tributaries, these problems could not be overlooked and were also included in this study. In order to achieve the aim of the study a literature review concerning the concept of water quality and the different physical and chemical constituents affecting aquatic ecosystems needed to be conducted. Added to this, attention had to be given to the study area’s physical features and land uses having an effect on the catchment’s water quality and associated problems. A literature review on existing knowledge of the Hennops River and its principal tributaries was also conducted so that it could be determined whether these rivers have deteriorated over the past three decades. The most recent water quality data was not only compared against existing knowledge, but also in terms of the Target Water Quality Range for Aquatic Ecosystems as stipulated by the Department of Water Affairs and Forestry. This study showed that deterioration of the Hennops River has occurred since rapid urbanisation within its catchment started during the 1970’s. Most of the River’s water quality and associated problems can be ascribed to problems occurring further upstream in the form of the Kaalspruit and Olifantspruit flowing through formal and informal settlements, industrial areas and agricultural land. The water quality of these rivers and the upper Hennops River is the least suitable of the whole study area for aquatic ecosystem well-being. Not only is this a concern but additional hydrological problems occur as well. These include problems such as erosional activity of riverbeds and riverbanks and the silting-up of Centurion Lake. An urgent need exists for holistic catchment management and rehabilitative measures to be implemented to improve the ecological state of these rivers. Rehabilitative measures were proposed and are aimed at improving the water quality and associated problems of the Hennops River and its affected tributaries. It is concluded, therefore, that the status of the Hennops River is not going to improve without the implementation of rehabilitative measures that should form part of an environmental management plan.
- Full Text:
Degradation of cyanobacteria biotoxins in aquatic enviroments using dendrimer supported bimetallic nanocomposites immobilized in polyethersulfone membranes
- Authors: Nkonde, Mxolisi Absalom
- Date: 2018
- Subjects: Cyanobacterial toxins , Cyanobacterial blooms , Water quality biological assessment , Drinking water - Contamination , Dendrimers
- Language: Englsh
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/272824 , uj:29056
- Description: M.Tech. (Chemistry) , Abstract: Clean water is vital to the survival and health so the presences of cyanobacterial blooms have caused severe problems for humans, aquatic animals and wildlife. Cyanobacteria in surface and flowing waters used for potable water supplies have been the main cause to an ever increasing presence of cyano-toxins. Monitoring of these cyano-toxins in algae blooms from local Dams is important for evaluating the potential risk for people who rely on these Dams as a source for domestic water use. We report the synthesis of Fe/Ni-PES/DEN bimetallic nano-composites for use in degrading cyano-toxins. We also supported the bimetallic nano-composite in dendrimers and immobilised in polyethersulfone membranes. These membranes were characterised using scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) and Fourier transform infrared spectroscopy (FTIR).
- Full Text:
- Authors: Nkonde, Mxolisi Absalom
- Date: 2018
- Subjects: Cyanobacterial toxins , Cyanobacterial blooms , Water quality biological assessment , Drinking water - Contamination , Dendrimers
- Language: Englsh
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/272824 , uj:29056
- Description: M.Tech. (Chemistry) , Abstract: Clean water is vital to the survival and health so the presences of cyanobacterial blooms have caused severe problems for humans, aquatic animals and wildlife. Cyanobacteria in surface and flowing waters used for potable water supplies have been the main cause to an ever increasing presence of cyano-toxins. Monitoring of these cyano-toxins in algae blooms from local Dams is important for evaluating the potential risk for people who rely on these Dams as a source for domestic water use. We report the synthesis of Fe/Ni-PES/DEN bimetallic nano-composites for use in degrading cyano-toxins. We also supported the bimetallic nano-composite in dendrimers and immobilised in polyethersulfone membranes. These membranes were characterised using scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) and Fourier transform infrared spectroscopy (FTIR).
- Full Text:
Effects of dams on river water quality: a case study of Lesotho Highlands Water Project
- Authors: Nyakale, James Mogorosi
- Date: 2012-07-19
- Subjects: Lesotho Highlands Water Project , Water resources development , Water quality biological assessment
- Type: Mini-Dissertation
- Identifier: uj:8831 , http://hdl.handle.net/10210/5244
- Description: M.Sc. , The Senqu-Orange basin is the principal carrier of the mean annual runoff for the larger portion of South Africa, encompassing also Lesotho. The transformation of this river regime by inter-basin transfer from south-westerly flowing rivers to the northerly flowing Senqu-Orange system of water as a resource may have adverse impacts on freshwater quality of ecosystems. This report presents a case study of the Lesotho Highlands Water Project (Phase 1), investigating alterations of physical and chemical water quality caused by the three types of large infrastructure: a dam (Mohale Dam); a dam and weir (Katse Dam and Matsoku Weir); and a delivery tunnel (from ’Muela Dam to the Ash River Outfall). The aim of the study was to determine significant differences, if any, of selected water quality variables in water released or transported from the infrastructure, using water from an undisturbed sampling site located on the Senqu River as a reference. Analyses are carried out of longterm trends and variations of the following selected water quality variables: pH, conductivity, total nitrogen, magnesium and sodium. Sampling station sites, operated by South Africa Department of Water Affairs and Forestry from 1990 to 2003, are located at the Malibamatso, Senqunyane, Matsoku, Senqu and Ash rivers. Time series graphs were used for analysing long-term trends. ANOVA or the H-test and Scheffé multiple comparison statistical test methods were used to determine significant differences. Total suspended solids (TSS) and turbidity measurements, together with discharge rates, were made available from a study by the Lesotho Highlands Development Authority from January 1998 to September 1999, for two sites downstream of Matsoku Weir and Mohale Dam. Short-term temporal water quality effects due to dam discharges were assessed. pH values are uniform, and comply to target water quality range (TWQR) guidelines of the Department of Water Affairs and Forestry. There are no long-term trends for total nitrogen, conductivity, magnesium and sodium. There are records of intermittent episodes of total nitrogen exceeding TWQR, caused possibly by anoxic conditions of the artificial impoundments associated with the three types of large infrastructure. Total suspended solids were affected by discharge rates - concentrations increased with increasing flow ii discharge of surface water. Turbidity values increased in association with enhanced TSS concentrations, although this is not a causal relationship. From statistical evaluations, significant variations in pH were observed between each test site (dam, dam and weir, and delivery tunnel) and the reference site. The group means in pH at each test site were lower than the reference site. Scheffé test results indicted significant difference in total nitrogen between the dam, the delivery tunnel and the reference site, but not for the dam and weir in relation to the reference site. Similarly, mean concentrations of total nitrogen were lowest at delivery tunnel and the dam. Although, significant differences were observed for conductivity, sodium and magnesium between the dam and weir, and the reference location, such variations are attributable to the Senqu River valley and not the infrastructure of the transfer scheme. Thus, results from the assessment of significant differences in conductivity, sodium and magnesium at the dam and delivery tunnel were unreliable and discarded.
- Full Text:
- Authors: Nyakale, James Mogorosi
- Date: 2012-07-19
- Subjects: Lesotho Highlands Water Project , Water resources development , Water quality biological assessment
- Type: Mini-Dissertation
- Identifier: uj:8831 , http://hdl.handle.net/10210/5244
- Description: M.Sc. , The Senqu-Orange basin is the principal carrier of the mean annual runoff for the larger portion of South Africa, encompassing also Lesotho. The transformation of this river regime by inter-basin transfer from south-westerly flowing rivers to the northerly flowing Senqu-Orange system of water as a resource may have adverse impacts on freshwater quality of ecosystems. This report presents a case study of the Lesotho Highlands Water Project (Phase 1), investigating alterations of physical and chemical water quality caused by the three types of large infrastructure: a dam (Mohale Dam); a dam and weir (Katse Dam and Matsoku Weir); and a delivery tunnel (from ’Muela Dam to the Ash River Outfall). The aim of the study was to determine significant differences, if any, of selected water quality variables in water released or transported from the infrastructure, using water from an undisturbed sampling site located on the Senqu River as a reference. Analyses are carried out of longterm trends and variations of the following selected water quality variables: pH, conductivity, total nitrogen, magnesium and sodium. Sampling station sites, operated by South Africa Department of Water Affairs and Forestry from 1990 to 2003, are located at the Malibamatso, Senqunyane, Matsoku, Senqu and Ash rivers. Time series graphs were used for analysing long-term trends. ANOVA or the H-test and Scheffé multiple comparison statistical test methods were used to determine significant differences. Total suspended solids (TSS) and turbidity measurements, together with discharge rates, were made available from a study by the Lesotho Highlands Development Authority from January 1998 to September 1999, for two sites downstream of Matsoku Weir and Mohale Dam. Short-term temporal water quality effects due to dam discharges were assessed. pH values are uniform, and comply to target water quality range (TWQR) guidelines of the Department of Water Affairs and Forestry. There are no long-term trends for total nitrogen, conductivity, magnesium and sodium. There are records of intermittent episodes of total nitrogen exceeding TWQR, caused possibly by anoxic conditions of the artificial impoundments associated with the three types of large infrastructure. Total suspended solids were affected by discharge rates - concentrations increased with increasing flow ii discharge of surface water. Turbidity values increased in association with enhanced TSS concentrations, although this is not a causal relationship. From statistical evaluations, significant variations in pH were observed between each test site (dam, dam and weir, and delivery tunnel) and the reference site. The group means in pH at each test site were lower than the reference site. Scheffé test results indicted significant difference in total nitrogen between the dam, the delivery tunnel and the reference site, but not for the dam and weir in relation to the reference site. Similarly, mean concentrations of total nitrogen were lowest at delivery tunnel and the dam. Although, significant differences were observed for conductivity, sodium and magnesium between the dam and weir, and the reference location, such variations are attributable to the Senqu River valley and not the infrastructure of the transfer scheme. Thus, results from the assessment of significant differences in conductivity, sodium and magnesium at the dam and delivery tunnel were unreliable and discarded.
- Full Text:
Determining the pathogenicity and quantities of Escherichia coli in selected South African water types using molecular biology techniques
- Authors: Omar, Kousar Banu
- Date: 2008-08-15T07:42:36Z
- Subjects: Escherichia coli , Water quality biological assessment
- Type: Thesis
- Identifier: uj:7730 , http://hdl.handle.net/10210/859
- Description: Escherichia coli (E. coli) is a universally accepted indicator of faecal pollution in water, and can be divided into several groups of which one group would be commensal E. coli (generally the indicator organism), and five diarrhoeagenic E. coli types. Pathogenic E. coli offers attractive possibilities to model the pathogenicity of polluted water that people drink. To date, techniques used for the detection of these pathogens include standard culturing techniques, the use of molecular probes directed against known pathogens and polymerase chain reaction (PCR) for the amplification of known virulence genes, usually after a pre-culturing step. There is however a need to speed up the process and to accurately quantify (for risk purposes) the type and number of E. coli (commensal and pathogenic) present in any given water sample. The use of more recently developed techniques such as real-time PCR and competitive PCR (c-PCR) offers us a way of quantifying the target organism and has been successfully applied in various parts of the world. The aim of this study was to adapt and use developed methodologies that employs both c-PCR and multiplex PCR (m-PCR) to quantify total E. coli, detect and distinguish between the diarrhoeagenic E. coli patho-types present in selected South African water samples without prior culture or enrichment. Using E. coli as a model pathogen, a technique was developed for the concentration of bacteria from water samples, isolation of DNA from bacteria and performing PCR’s on the extracted DNA. Three m-PCR’s were developed directed towards the housekeeping (Mdh) and virulence (eaeA, Stx1, Stx2, ST, LT, Ial and Eagg) genes associated with entero-pathogenic E. coli. c-PCR was performed using the Mdh housekeeping gene, with our modified version of the PCR product used as competitor DNA. Results obtained lead to a protocol consisting of the filtration of 100 mℓ environmental water, DNA extraction directly from the membranes, followed by quantitative c-PCR to screen for PCR inhibition as well as to quantify isolated DNA, thereafter screening of the DNA for the presence of virulence genes with m-PCR. Initial testing with known pathogens showed that this methodology was a viable option. DNA could be recovered from the filters, yielding PCR-ready templates. A total of 49 water samples were collected, these samples included household containers from rural areas, river water from three provinces in South Africa and wastewater from 4 different wastewater treatment plants around Johannesburg (Gauteng province). These water samples were subjected to the above-mentioned protocol with 100 % (49/49) of the samples testing positive for presence of the E. coli Mdh house keeping gene. Of the samples tested, 57 % (28/49) tested positive for EAEC, 0 % (0/49) tested positive for EIEC, 92 % (45/49) tested positive for ETEC, 2 % (1/49) tested positive for atypical EHEC and 0 % (0/49) tested positive for atypical EPEC. 38 percent of the water samples could be successfully quantified by c-PCR and were able to detect as low as 3 cells/mℓ. However, the remaining 62 percent DNA samples (isolated from water samples) was diluted to overcome PCR inhibition but failed to be quantified by c-PCR because the level of target DNA was too low to detect which allowed over competition of the Mdh competitor DNA. In conclusion, this method could successfully isolate E. coli DNA from various water samples. The isolated DNA could be used as PCR template and PCR inhibition could be overcome in all the samples by either diluting the sample or adding PCR facilitators. The PCR was able to amplify low levels of isolated E. coli DNA from most of the water samples and the presence of pathogens could be detected in the water with the m-PCR. Molecular quantification could be used to quantify DNA isolated from the water samples, but one limitation is the detection of very low numbers of E. coli DNA due to the nature of c-PCR, i.e. co-amplification of the target and competitor DNA. , Prof. Paul Jagals Dr. T.G. Barnard Mr. K. Maclean
- Full Text:
- Authors: Omar, Kousar Banu
- Date: 2008-08-15T07:42:36Z
- Subjects: Escherichia coli , Water quality biological assessment
- Type: Thesis
- Identifier: uj:7730 , http://hdl.handle.net/10210/859
- Description: Escherichia coli (E. coli) is a universally accepted indicator of faecal pollution in water, and can be divided into several groups of which one group would be commensal E. coli (generally the indicator organism), and five diarrhoeagenic E. coli types. Pathogenic E. coli offers attractive possibilities to model the pathogenicity of polluted water that people drink. To date, techniques used for the detection of these pathogens include standard culturing techniques, the use of molecular probes directed against known pathogens and polymerase chain reaction (PCR) for the amplification of known virulence genes, usually after a pre-culturing step. There is however a need to speed up the process and to accurately quantify (for risk purposes) the type and number of E. coli (commensal and pathogenic) present in any given water sample. The use of more recently developed techniques such as real-time PCR and competitive PCR (c-PCR) offers us a way of quantifying the target organism and has been successfully applied in various parts of the world. The aim of this study was to adapt and use developed methodologies that employs both c-PCR and multiplex PCR (m-PCR) to quantify total E. coli, detect and distinguish between the diarrhoeagenic E. coli patho-types present in selected South African water samples without prior culture or enrichment. Using E. coli as a model pathogen, a technique was developed for the concentration of bacteria from water samples, isolation of DNA from bacteria and performing PCR’s on the extracted DNA. Three m-PCR’s were developed directed towards the housekeeping (Mdh) and virulence (eaeA, Stx1, Stx2, ST, LT, Ial and Eagg) genes associated with entero-pathogenic E. coli. c-PCR was performed using the Mdh housekeeping gene, with our modified version of the PCR product used as competitor DNA. Results obtained lead to a protocol consisting of the filtration of 100 mℓ environmental water, DNA extraction directly from the membranes, followed by quantitative c-PCR to screen for PCR inhibition as well as to quantify isolated DNA, thereafter screening of the DNA for the presence of virulence genes with m-PCR. Initial testing with known pathogens showed that this methodology was a viable option. DNA could be recovered from the filters, yielding PCR-ready templates. A total of 49 water samples were collected, these samples included household containers from rural areas, river water from three provinces in South Africa and wastewater from 4 different wastewater treatment plants around Johannesburg (Gauteng province). These water samples were subjected to the above-mentioned protocol with 100 % (49/49) of the samples testing positive for presence of the E. coli Mdh house keeping gene. Of the samples tested, 57 % (28/49) tested positive for EAEC, 0 % (0/49) tested positive for EIEC, 92 % (45/49) tested positive for ETEC, 2 % (1/49) tested positive for atypical EHEC and 0 % (0/49) tested positive for atypical EPEC. 38 percent of the water samples could be successfully quantified by c-PCR and were able to detect as low as 3 cells/mℓ. However, the remaining 62 percent DNA samples (isolated from water samples) was diluted to overcome PCR inhibition but failed to be quantified by c-PCR because the level of target DNA was too low to detect which allowed over competition of the Mdh competitor DNA. In conclusion, this method could successfully isolate E. coli DNA from various water samples. The isolated DNA could be used as PCR template and PCR inhibition could be overcome in all the samples by either diluting the sample or adding PCR facilitators. The PCR was able to amplify low levels of isolated E. coli DNA from most of the water samples and the presence of pathogens could be detected in the water with the m-PCR. Molecular quantification could be used to quantify DNA isolated from the water samples, but one limitation is the detection of very low numbers of E. coli DNA due to the nature of c-PCR, i.e. co-amplification of the target and competitor DNA. , Prof. Paul Jagals Dr. T.G. Barnard Mr. K. Maclean
- Full Text:
Detection of selected entero-pathogenic bacteria from stool specimens using a novel collection technique
- Authors: Mieta, Sumayya I. K.
- Date: 2010-04-08T08:39:18Z
- Subjects: Water quality biological assessment , Escherichia coli , Water quality bioassay
- Type: Thesis
- Identifier: uj:6757 , http://hdl.handle.net/10210/3164
- Description: M. Tech. , Diarrhoeal disease is an important public health problem worldwide as it is responsible for approximately 4 billion cases of diarrhoea per annum, of which 1.8 billion cases result in death. In most cases the causative agents are bacterial entero-pathogens such as Escherichia coli (E. coli), Salmonella, Shigella and Vibrio species. They enter the human body after consumption of contaminated water and food via the faecal-oral route of transmission. These pathogens are therefore identified from faecal matter with microbiological methods such as culture based techniques. There are however certain factors which negatively impact on the diagnosis. Recent literature has shown that bacterial pathogens may not be detected when they enter into a viable but non-culturable state (VBNC) making it difficult to detect the bacterial pathogens with culture based methods. The aim of the study was to detect entero-pathogenic bacteria from stool specimens using optimised protocols and a novel collection technique called the Bio-wipe kit. In the past sterile containers were used to collect and transport faecal matter to the WHRU laboratory for analysis. The disadvantage of this collection technique was that individuals were hesitant to provide faecal matter in a transparent container due to their social and moral status. The Bio-wipe kit eliminated some of the problems encountered with the previous collection technique as it is used in the same way as toilet tissue. Factors such as storage time and temperature was investigated for the recovery of faecal matter from the Bio-wipes since it was used in rural villages where the stool samples can not be refrigerated and transported to the lab immediately after the diarrhoeal episode. It was shown that the bacterial DNA can be recovered from the Bio-wipes within 5-10 days after usage when stored at 30°C and within 14 days after usage when stored at ambient temperature. Comparison of two in-house DNA extraction methods with the commercially available QIAamp® DNA stool mini kit indicated that the Guanidium thiocyanate without alpha casein method (GuSCN non ά-casein) could efficiently recover bacterial DNA from faecal matter free from the presence of inhibitors. This methodology could successfully recover amplifiable bacterial DNA in 92% (181/197) of the clinical Bio-wipes collected from individuals in the rural areas of the Vhembe region of the Limpopo province of South Africa. Various multiplex PCR’s (m-PCR) were optimised for this study for the detection and classification of diarrhoeagenic E. coli types, Salmonella, Shigella and Vibrio species. These m-PCR’s were proven to be very sensitive at detecting diarrhoegenic E.coli, Salmonella, Shigella and Vibrio species bacteria from the Bio-wipes. The extracted bacterial DNA from Bio-wipes recovered from clinical samples was amplified with the single genus specific multiplex PCR and 92% (181/197) of the samples tested positive for the E. coli mdh housekeeping gene, 3% (7/197) tested positive for the sodB housekeeping gene for V. cholerae spp, 5% (10/197) tested positive for the IpaH and Ial virulence genes for Shigella spp. and entero-invasive E. coli (EIEC) whereas none of the samples tested positive for the Salmonella virulence gene (IpaB). These results were confirmed with species specific multiplex PCR for each pathogen. It was concluded from this study that the Bio-wipe kit could be used for the collection of diarrhoeal and non-diarrhoeal faecal matter. The bacterial DNA could effectively be isolated from the recovered faecal matter using the GuSCN non α-casein DNA extraction method. The genus specific m-PCR was able to amplify low levels of bacterial DNA isolated from the Bio-wipes and thus the causative agents for diarrhoeal disease can successfully be diagnosed with the genus specific m-PCR. The Bio-wipe kit can be implemented for routine analysis and during diarrhoeal outbreaks as it is a cost effective, easy to use collection kit. The bacterial pathogens can easily and rapidly be diagnosed using the optimised molecular techniques instead of classical culture-based techniques.
- Full Text:
- Authors: Mieta, Sumayya I. K.
- Date: 2010-04-08T08:39:18Z
- Subjects: Water quality biological assessment , Escherichia coli , Water quality bioassay
- Type: Thesis
- Identifier: uj:6757 , http://hdl.handle.net/10210/3164
- Description: M. Tech. , Diarrhoeal disease is an important public health problem worldwide as it is responsible for approximately 4 billion cases of diarrhoea per annum, of which 1.8 billion cases result in death. In most cases the causative agents are bacterial entero-pathogens such as Escherichia coli (E. coli), Salmonella, Shigella and Vibrio species. They enter the human body after consumption of contaminated water and food via the faecal-oral route of transmission. These pathogens are therefore identified from faecal matter with microbiological methods such as culture based techniques. There are however certain factors which negatively impact on the diagnosis. Recent literature has shown that bacterial pathogens may not be detected when they enter into a viable but non-culturable state (VBNC) making it difficult to detect the bacterial pathogens with culture based methods. The aim of the study was to detect entero-pathogenic bacteria from stool specimens using optimised protocols and a novel collection technique called the Bio-wipe kit. In the past sterile containers were used to collect and transport faecal matter to the WHRU laboratory for analysis. The disadvantage of this collection technique was that individuals were hesitant to provide faecal matter in a transparent container due to their social and moral status. The Bio-wipe kit eliminated some of the problems encountered with the previous collection technique as it is used in the same way as toilet tissue. Factors such as storage time and temperature was investigated for the recovery of faecal matter from the Bio-wipes since it was used in rural villages where the stool samples can not be refrigerated and transported to the lab immediately after the diarrhoeal episode. It was shown that the bacterial DNA can be recovered from the Bio-wipes within 5-10 days after usage when stored at 30°C and within 14 days after usage when stored at ambient temperature. Comparison of two in-house DNA extraction methods with the commercially available QIAamp® DNA stool mini kit indicated that the Guanidium thiocyanate without alpha casein method (GuSCN non ά-casein) could efficiently recover bacterial DNA from faecal matter free from the presence of inhibitors. This methodology could successfully recover amplifiable bacterial DNA in 92% (181/197) of the clinical Bio-wipes collected from individuals in the rural areas of the Vhembe region of the Limpopo province of South Africa. Various multiplex PCR’s (m-PCR) were optimised for this study for the detection and classification of diarrhoeagenic E. coli types, Salmonella, Shigella and Vibrio species. These m-PCR’s were proven to be very sensitive at detecting diarrhoegenic E.coli, Salmonella, Shigella and Vibrio species bacteria from the Bio-wipes. The extracted bacterial DNA from Bio-wipes recovered from clinical samples was amplified with the single genus specific multiplex PCR and 92% (181/197) of the samples tested positive for the E. coli mdh housekeeping gene, 3% (7/197) tested positive for the sodB housekeeping gene for V. cholerae spp, 5% (10/197) tested positive for the IpaH and Ial virulence genes for Shigella spp. and entero-invasive E. coli (EIEC) whereas none of the samples tested positive for the Salmonella virulence gene (IpaB). These results were confirmed with species specific multiplex PCR for each pathogen. It was concluded from this study that the Bio-wipe kit could be used for the collection of diarrhoeal and non-diarrhoeal faecal matter. The bacterial DNA could effectively be isolated from the recovered faecal matter using the GuSCN non α-casein DNA extraction method. The genus specific m-PCR was able to amplify low levels of bacterial DNA isolated from the Bio-wipes and thus the causative agents for diarrhoeal disease can successfully be diagnosed with the genus specific m-PCR. The Bio-wipe kit can be implemented for routine analysis and during diarrhoeal outbreaks as it is a cost effective, easy to use collection kit. The bacterial pathogens can easily and rapidly be diagnosed using the optimised molecular techniques instead of classical culture-based techniques.
- Full Text:
An ecological risk assessment of pesticides using a probabilistic model and its implementation on the Crocodile and Magalies Rivers, South Africa
- Authors: Ansara-Ross, Tahla M.
- Date: 2012-07-31
- Subjects: Pesticides , Water quality biological assessment , Environmental monitoring , Crocodile River (South Africa) , Magalies River (South Africa)
- Type: Thesis
- Identifier: uj:8882 , http://hdl.handle.net/10210/5350
- Description: Ph.D. , South Africa is the highest produce-producing and therefore the highest pesticide consumer on the African continent. Although greatly beneficial to the industry, indiscriminate and over usage of these agrochemicals pose a risk to the aquatic ecosystems through non-point source pollution. Data on these risks are limited in the developing countries such as Africa since limited environmental monitoring of pesticides is undertaken. This is due to technical, logistical and economical constraints in determining the links between exposure and effect on non-target organisms. Methods that are able to screen for and monitor pesticides that could pose a risk according to site-specific scenarios are therefore necessary. Economical and easy-to-use predictive models incorporated into Preliminary Risk Assessments (PRA’s) are useful in this regard and have been developed and applied globally to assist in estimating the probability of risks of pesticides associated with aquatic ecosystems. Currently no such risk assessment model is applied in South Africa for this purpose. The main aim of the present study was to present and assess the suitability of selected PRA models as preliminary screening tools for estimating potential pesticide exposure and associated effects within aquatic ecosystems. To achieve this, the primary objectives were to apply and validate these models for assessing predicted risks and to relate these to actual ecological hazards by monitoring the exposure and effects of selected pesticides that were identified as potentially posing a risk. It was hypothesised that the data determined by these models would elucidate the association between potential risks of pesticides and actual environmental impacts and could therefore be applied and validated for South African conditions. A framework was thus developed using multidisciplinary approaches to predict the risks of agricultural pesticides to non-target aquatic organisms and to validate these risks in an area known to have a high pesticide usage, namely the Crocodile (west) Marico catchment. This area is representative of a typical farming community in the subtropical central area of South Africa. It is a catchment area that exhibits high urban and agricultural usage, which has compromised the overall ecological integrity of the aquatic systems. The focus of the study was on the Crocodile (west) and Magalies Rivers and the associated irrigation canal network systems. The present study was based on integrating multidisciplinary techniques following the implementation of a tiered approach for assessing the ecological risks of selected pesticides known to be used within the Crocodile (west) Marico catchment. Tier 1 starts with the PRA assuming a relatively worst-case scenario by identifying pesticides most commonly used (through surveys) and estimating exposures posing a potential risk to the aquatic environment using the PRIMET (Pesticide Risks In the tropics to Man, Environment and Trade) model. The second tier can establish a more realistic characterisation of risk for the pesticide application scenarios of interest by using models such as PERPEST (Predicting the Ecological Risks of PESTicides), PEARL (Pesticide Emission Assessment of Regional and Local Scales), TOXSWA (TOXic substances in Surface Waters), or SSDs (Species Sensitivity Distributions). Higher tiers then include comparing the results from the PRA model predictions to the actual hazards of pesticides and can determine if these risk models are valid under South Africa conditions. This can be achieved using a combination of laboratory- and field-based monitoring assessments in the form of a triad approach (using chemical, toxicological and ecological assessments) to construct several lines-of-evidence (LoEs). The risk assessment process ends with a summary and integration of the data based on the multiple LoEs gathered during monitoring using a weight-of-evidence (WoE) approach.
- Full Text:
- Authors: Ansara-Ross, Tahla M.
- Date: 2012-07-31
- Subjects: Pesticides , Water quality biological assessment , Environmental monitoring , Crocodile River (South Africa) , Magalies River (South Africa)
- Type: Thesis
- Identifier: uj:8882 , http://hdl.handle.net/10210/5350
- Description: Ph.D. , South Africa is the highest produce-producing and therefore the highest pesticide consumer on the African continent. Although greatly beneficial to the industry, indiscriminate and over usage of these agrochemicals pose a risk to the aquatic ecosystems through non-point source pollution. Data on these risks are limited in the developing countries such as Africa since limited environmental monitoring of pesticides is undertaken. This is due to technical, logistical and economical constraints in determining the links between exposure and effect on non-target organisms. Methods that are able to screen for and monitor pesticides that could pose a risk according to site-specific scenarios are therefore necessary. Economical and easy-to-use predictive models incorporated into Preliminary Risk Assessments (PRA’s) are useful in this regard and have been developed and applied globally to assist in estimating the probability of risks of pesticides associated with aquatic ecosystems. Currently no such risk assessment model is applied in South Africa for this purpose. The main aim of the present study was to present and assess the suitability of selected PRA models as preliminary screening tools for estimating potential pesticide exposure and associated effects within aquatic ecosystems. To achieve this, the primary objectives were to apply and validate these models for assessing predicted risks and to relate these to actual ecological hazards by monitoring the exposure and effects of selected pesticides that were identified as potentially posing a risk. It was hypothesised that the data determined by these models would elucidate the association between potential risks of pesticides and actual environmental impacts and could therefore be applied and validated for South African conditions. A framework was thus developed using multidisciplinary approaches to predict the risks of agricultural pesticides to non-target aquatic organisms and to validate these risks in an area known to have a high pesticide usage, namely the Crocodile (west) Marico catchment. This area is representative of a typical farming community in the subtropical central area of South Africa. It is a catchment area that exhibits high urban and agricultural usage, which has compromised the overall ecological integrity of the aquatic systems. The focus of the study was on the Crocodile (west) and Magalies Rivers and the associated irrigation canal network systems. The present study was based on integrating multidisciplinary techniques following the implementation of a tiered approach for assessing the ecological risks of selected pesticides known to be used within the Crocodile (west) Marico catchment. Tier 1 starts with the PRA assuming a relatively worst-case scenario by identifying pesticides most commonly used (through surveys) and estimating exposures posing a potential risk to the aquatic environment using the PRIMET (Pesticide Risks In the tropics to Man, Environment and Trade) model. The second tier can establish a more realistic characterisation of risk for the pesticide application scenarios of interest by using models such as PERPEST (Predicting the Ecological Risks of PESTicides), PEARL (Pesticide Emission Assessment of Regional and Local Scales), TOXSWA (TOXic substances in Surface Waters), or SSDs (Species Sensitivity Distributions). Higher tiers then include comparing the results from the PRA model predictions to the actual hazards of pesticides and can determine if these risk models are valid under South Africa conditions. This can be achieved using a combination of laboratory- and field-based monitoring assessments in the form of a triad approach (using chemical, toxicological and ecological assessments) to construct several lines-of-evidence (LoEs). The risk assessment process ends with a summary and integration of the data based on the multiple LoEs gathered during monitoring using a weight-of-evidence (WoE) approach.
- Full Text:
Diatom, macroinvertebrate and Riparian vegetation community structure responses in agriculturally impacted rivers
- Authors: Walsh, Gina
- Date: 2010-03-15T06:33:01Z
- Subjects: Riparian ecology , Water quality biological assessment , Water pollution , Crocodile River (South Africa)
- Type: Mini-Dissertation
- Identifier: uj:6676 , http://hdl.handle.net/10210/3080
- Description: M.Sc. , Pesticides and fertilizers, while allowing increases in food production, also have the ability to find their way into aquatic systems. Irrespective of their route of entry into an aquatic ecosystem, they may affect aquatic biota by influencing survival, growth and reproduction. Secondary effects may occur in which populations of organisms are impacted due to a reduction or elimination of pollution-susceptible species which results in a disturbance of biological processes and interactions due to water quality impacts associated with agricultural practices. Biomonitoring techniques are used to assess the integrity of aquatic ecosystems and provide information on the environmental conditions that have prevailed within a river. Because aquatic organisms are exposed to their environment and all pollutants and toxicants thereof, they will cumulatively reflect the conditions which they are exposed to. This study aims to assess community structure, biotic integrity and feeding traits of aquatic communities at river sites that have varying adjacent land uses. The chosen study area falls within the Crocodile (West) Marico Water Management Area (WMA). Study sites were selected on the Magalies and Crocodile rivers which form Hartbeespoort Dam at their confluence. Agricultural intensity in North West Province is high and irrigation farming tends to be located on the large floodplains associated with the middle Crocodile River. The main economic activity of the WMA occurs in Gauteng, and is generated by the intense urban and industrial activities of northern Johannesburg. These practices ensure that water pollution from agriculture and urban land use is a major problem along segments of the rivers under investigation. Study sites were chosen based on their adjacent land use and consisted of sites related to agricultural, urban and natural activities. Environmental driver components that were assessed included water quality and habitat integrity (IHAS). Biotic response indices were implemented to assess the integrity of diatom (GDI, SPI, BDI, EPI and %PTV), macroinvertebrate (SASS5 and MIRAI) and riparian vegetation (VEGRAI) communities. Principal Component Analysis (PCA) analyses were undertaken on water quality data using Primer version 6 to determine patterns in water quality between sites. Multivariate (CLUSTER, NMDS and RDA) and univariate (Margalef’s index, Shannon-Wiener diversity index and Pielou’s evenness) analyses were performed on macroinvertebrate family data, macroinvertebrate FFG data, diatom species data and riparian vegetation data using Primer version 6 and Canoco version 4.5 in order to elucidate differences in community structure per land use. Results indicated that particular water quality and habitat impacts were present for each land use. Comparison of community structure of diatoms taken from sites with varying land uses showed differences from one another. Relative reference diatom communities comprised of diatom species that had preferences for clean water, whilst community structures of diatoms were modified and showed specific change in relation to agricultural and urban water quality impacts. An increased diversity in air breathing macroinvertebrates was shown at sites with agricultural practices at high flow, where urban sites were differentiated from agricultural sites due to the presence of the Hydropsychidae and Hirudinea families. At low flow macroinvertebrate families making up communities overlapped between land uses. A difference noted at low flow was that the contribution of the Chironomidae was higher at urban sites in comparison to agricultural sites, indicating organic water pollution. The statistical comparison of macroinvertebrate communities, FFGs and riparian vegetation showed that differences between sites with different land uses were not significant. Nonetheless, some differences in refined data were noted for the varying land uses. Considering the macroinvertebrate community make up of the relative reference site, which was comprised of macroinvertebrate families that were more sensitive and showed preferences for higher water quality, community structures of macroinvertebrates were modified and showed change in relation to land use. Macroinvertebrate FFGs indicated that a change in the input of UPOM at agricultural sites, and a change in the presence of FPOM at urban sites were responsible for a shift in the FFG dominance. A difference in riparian integrity was noted between relative reference and test sites, but could not be easily distinguished between test sites with different land uses. Riparian integrity was more predictive of macroinvertebrate FFG structure than actual macroinvertebrate community structure. This indicates that riparian integrity and comparison with biological traits such as FFGs were useful in showing impacts due to organic matter inputs. Overall biotic indices were less useful in distinguishing between urban and agricultural land uses. It appeared that biotic indices masked the changes in the actual taxonomic components, erroneously suggesting that sites with different land uses are similar in terms of ecosystem integrity. It must be noted that integrity indices certainly have an important place in management of aquatic systems, but it appears to be more useful to utilise taxonomic make up and biological traits (in this case of FFGs) to show specific impacts, as these are factors which can be compared across a relatively broad spatial scale. It can be concluded that sites could be separated according to land use based on community structure of diatoms and macroinvertebrates, and biological trait analysis of feeding groups. It was noted that diatom communities were more defined in their response to land use practices in comparison to macroinvertebrate communities.
- Full Text:
- Authors: Walsh, Gina
- Date: 2010-03-15T06:33:01Z
- Subjects: Riparian ecology , Water quality biological assessment , Water pollution , Crocodile River (South Africa)
- Type: Mini-Dissertation
- Identifier: uj:6676 , http://hdl.handle.net/10210/3080
- Description: M.Sc. , Pesticides and fertilizers, while allowing increases in food production, also have the ability to find their way into aquatic systems. Irrespective of their route of entry into an aquatic ecosystem, they may affect aquatic biota by influencing survival, growth and reproduction. Secondary effects may occur in which populations of organisms are impacted due to a reduction or elimination of pollution-susceptible species which results in a disturbance of biological processes and interactions due to water quality impacts associated with agricultural practices. Biomonitoring techniques are used to assess the integrity of aquatic ecosystems and provide information on the environmental conditions that have prevailed within a river. Because aquatic organisms are exposed to their environment and all pollutants and toxicants thereof, they will cumulatively reflect the conditions which they are exposed to. This study aims to assess community structure, biotic integrity and feeding traits of aquatic communities at river sites that have varying adjacent land uses. The chosen study area falls within the Crocodile (West) Marico Water Management Area (WMA). Study sites were selected on the Magalies and Crocodile rivers which form Hartbeespoort Dam at their confluence. Agricultural intensity in North West Province is high and irrigation farming tends to be located on the large floodplains associated with the middle Crocodile River. The main economic activity of the WMA occurs in Gauteng, and is generated by the intense urban and industrial activities of northern Johannesburg. These practices ensure that water pollution from agriculture and urban land use is a major problem along segments of the rivers under investigation. Study sites were chosen based on their adjacent land use and consisted of sites related to agricultural, urban and natural activities. Environmental driver components that were assessed included water quality and habitat integrity (IHAS). Biotic response indices were implemented to assess the integrity of diatom (GDI, SPI, BDI, EPI and %PTV), macroinvertebrate (SASS5 and MIRAI) and riparian vegetation (VEGRAI) communities. Principal Component Analysis (PCA) analyses were undertaken on water quality data using Primer version 6 to determine patterns in water quality between sites. Multivariate (CLUSTER, NMDS and RDA) and univariate (Margalef’s index, Shannon-Wiener diversity index and Pielou’s evenness) analyses were performed on macroinvertebrate family data, macroinvertebrate FFG data, diatom species data and riparian vegetation data using Primer version 6 and Canoco version 4.5 in order to elucidate differences in community structure per land use. Results indicated that particular water quality and habitat impacts were present for each land use. Comparison of community structure of diatoms taken from sites with varying land uses showed differences from one another. Relative reference diatom communities comprised of diatom species that had preferences for clean water, whilst community structures of diatoms were modified and showed specific change in relation to agricultural and urban water quality impacts. An increased diversity in air breathing macroinvertebrates was shown at sites with agricultural practices at high flow, where urban sites were differentiated from agricultural sites due to the presence of the Hydropsychidae and Hirudinea families. At low flow macroinvertebrate families making up communities overlapped between land uses. A difference noted at low flow was that the contribution of the Chironomidae was higher at urban sites in comparison to agricultural sites, indicating organic water pollution. The statistical comparison of macroinvertebrate communities, FFGs and riparian vegetation showed that differences between sites with different land uses were not significant. Nonetheless, some differences in refined data were noted for the varying land uses. Considering the macroinvertebrate community make up of the relative reference site, which was comprised of macroinvertebrate families that were more sensitive and showed preferences for higher water quality, community structures of macroinvertebrates were modified and showed change in relation to land use. Macroinvertebrate FFGs indicated that a change in the input of UPOM at agricultural sites, and a change in the presence of FPOM at urban sites were responsible for a shift in the FFG dominance. A difference in riparian integrity was noted between relative reference and test sites, but could not be easily distinguished between test sites with different land uses. Riparian integrity was more predictive of macroinvertebrate FFG structure than actual macroinvertebrate community structure. This indicates that riparian integrity and comparison with biological traits such as FFGs were useful in showing impacts due to organic matter inputs. Overall biotic indices were less useful in distinguishing between urban and agricultural land uses. It appeared that biotic indices masked the changes in the actual taxonomic components, erroneously suggesting that sites with different land uses are similar in terms of ecosystem integrity. It must be noted that integrity indices certainly have an important place in management of aquatic systems, but it appears to be more useful to utilise taxonomic make up and biological traits (in this case of FFGs) to show specific impacts, as these are factors which can be compared across a relatively broad spatial scale. It can be concluded that sites could be separated according to land use based on community structure of diatoms and macroinvertebrates, and biological trait analysis of feeding groups. It was noted that diatom communities were more defined in their response to land use practices in comparison to macroinvertebrate communities.
- Full Text:
The bacterial pathogenicity of source waters based on enterovirulent Escherichia coli as model pathogens
- Madzivhandila, Tshimangadzo Lucky
- Authors: Madzivhandila, Tshimangadzo Lucky
- Date: 2008-08-18T07:40:21Z
- Subjects: Escherichia coli , Water quality biological assessment
- Type: Thesis
- Identifier: uj:7965 , http://hdl.handle.net/10210/887
- Description: This study assessed the pathogenicity of source waters in the Nwanedi River catchment surface waters including rivers as well as its related non perennial tributaries (storm run-off) by determining the presence of diarrhoeagenic Escherichia coli pathotypes namely Enteropathogenic Escherichia coli, Enterotoxigenic Escherichia coli, Enterohaemorrhagic Escherichia coli, Enteroaggregative Escherichia coli and Enteroinvasive Escherichia coli. The faecal pollution levels in the surface waters was assessed by measuring indicator Escherichia coli numbers in water samples at various sampling sites carried from its land-based faecal sources into the receiving surface water bodies. Sampling sites were selected to represent the human, livestock as well as wildlife sources of faecal generation and the possible infection risk posed to domestic, full body contact, agriculture uses as well as for abstraction intended for drinking were determined by comparing the Escherichia coli numbers with the guidelines summarised in Table 2.6: Chapter 2. A total of 199 proposed water samples were collected and analysed by the Miniaturised Most Probable Numbers method using 96-well micro-titre plates to enumerate Escherichia coli from the water samples. Twenty eight of 199 water samples were also analysed with a multiplex polymerase chain reaction using specific primers for the identification of diarrhoeagenic Escherichia coli related virulent genes namely – Mdh for commensal E. coli, Eagg and pCVD for Enteroaggregative E. coli, ST1 and LT1 for Enterotoxigenic E. coli, Stx1 and Stx2 for Enterohaemorrhaegic E. coli, EaeA for Enteropathogenic E. coli and Enterohaemorrhagic E. coli, Ial for Enteroinvasive E. coli. River water samples were directly filtered and 100-mℓ of filtered water samples were extracted while 1-mℓ pre-cultured Escherichia coli from storm run-off samples were extracted for use in the multiplex polymerase chain reaction. Because of the villages along the Nwanedi River catchment, Enteropathogenic E. coli followed by Enterotoxigenic E. coli was suspected to be the dominant diarrhoeagenic Escherichia coli. Contrary to this Enteroaggregative E. coli (54%) was dominant followed by Enterohaemorrhaegic E. coli (29%), Enteroinvasive E. coli (7%), Enteropathogenic E. coli (4%) and Enterotoxigenic E. coli (4%) respectively, in the surface water samples. The Escherichia coli numbers were significantly higher in storm run-off compared to the river water samples. Literature report Enteroaggregative E. coli to be associated with diarrhoea in HIV/AIDS patients, to whom its dominance in the surface water samples could pose serious infection risk to the Nwanedi River catchment communities, more especially the young, elderly and the immuno-compromised at the period of sampling if the waters are used untreated. The high Escherichia coli numbers could possibly be the results of continuous faecal contamination into the water sources and the rain storm events carrying faecal materials from land surface. Results show that Nwanedi River catchment waters harbour pathogens indicated by diarrhoeagenic Escherichia coli occurrence as well as commensal Escherichia coli numbers , which suggest the possible infection risk posed to the consumers if the waters are used untreated. , Prof. P. Jagals Dr. T.G. Barnard
- Full Text:
- Authors: Madzivhandila, Tshimangadzo Lucky
- Date: 2008-08-18T07:40:21Z
- Subjects: Escherichia coli , Water quality biological assessment
- Type: Thesis
- Identifier: uj:7965 , http://hdl.handle.net/10210/887
- Description: This study assessed the pathogenicity of source waters in the Nwanedi River catchment surface waters including rivers as well as its related non perennial tributaries (storm run-off) by determining the presence of diarrhoeagenic Escherichia coli pathotypes namely Enteropathogenic Escherichia coli, Enterotoxigenic Escherichia coli, Enterohaemorrhagic Escherichia coli, Enteroaggregative Escherichia coli and Enteroinvasive Escherichia coli. The faecal pollution levels in the surface waters was assessed by measuring indicator Escherichia coli numbers in water samples at various sampling sites carried from its land-based faecal sources into the receiving surface water bodies. Sampling sites were selected to represent the human, livestock as well as wildlife sources of faecal generation and the possible infection risk posed to domestic, full body contact, agriculture uses as well as for abstraction intended for drinking were determined by comparing the Escherichia coli numbers with the guidelines summarised in Table 2.6: Chapter 2. A total of 199 proposed water samples were collected and analysed by the Miniaturised Most Probable Numbers method using 96-well micro-titre plates to enumerate Escherichia coli from the water samples. Twenty eight of 199 water samples were also analysed with a multiplex polymerase chain reaction using specific primers for the identification of diarrhoeagenic Escherichia coli related virulent genes namely – Mdh for commensal E. coli, Eagg and pCVD for Enteroaggregative E. coli, ST1 and LT1 for Enterotoxigenic E. coli, Stx1 and Stx2 for Enterohaemorrhaegic E. coli, EaeA for Enteropathogenic E. coli and Enterohaemorrhagic E. coli, Ial for Enteroinvasive E. coli. River water samples were directly filtered and 100-mℓ of filtered water samples were extracted while 1-mℓ pre-cultured Escherichia coli from storm run-off samples were extracted for use in the multiplex polymerase chain reaction. Because of the villages along the Nwanedi River catchment, Enteropathogenic E. coli followed by Enterotoxigenic E. coli was suspected to be the dominant diarrhoeagenic Escherichia coli. Contrary to this Enteroaggregative E. coli (54%) was dominant followed by Enterohaemorrhaegic E. coli (29%), Enteroinvasive E. coli (7%), Enteropathogenic E. coli (4%) and Enterotoxigenic E. coli (4%) respectively, in the surface water samples. The Escherichia coli numbers were significantly higher in storm run-off compared to the river water samples. Literature report Enteroaggregative E. coli to be associated with diarrhoea in HIV/AIDS patients, to whom its dominance in the surface water samples could pose serious infection risk to the Nwanedi River catchment communities, more especially the young, elderly and the immuno-compromised at the period of sampling if the waters are used untreated. The high Escherichia coli numbers could possibly be the results of continuous faecal contamination into the water sources and the rain storm events carrying faecal materials from land surface. Results show that Nwanedi River catchment waters harbour pathogens indicated by diarrhoeagenic Escherichia coli occurrence as well as commensal Escherichia coli numbers , which suggest the possible infection risk posed to the consumers if the waters are used untreated. , Prof. P. Jagals Dr. T.G. Barnard
- Full Text:
Birds as bio-indicators of the ecological integrity of the Sabie River, Mpumalanga
- Authors: Sudlow, Bronwyn Elisabeth
- Date: 2008-10-16T05:49:50Z
- Subjects: Water quality biological assessment , Birds ecology , Mpumalanga (South Africa)
- Type: Thesis
- Identifier: uj:12387 , http://hdl.handle.net/10210/1216
- Description: M.Sc. , Rivers always borrow a great part of their character from the terrestrial ecosystems – the catchments – through which they flow. A multitude of natural factors determines the health of a river ecosystem, however, together with these natural factors, the combined influences of urban development, pollution, bank erosion, deforestation (and ironically many forms of afforestation), and poor agricultural practices have so degraded our rivers that they are under severe threat. One particular group of organisms within river ecosystems that are affected by human-induced changes, are birds. Birds are rather adaptable organisms; many species are able to inhabit human environments very successfully. However, some bird species are highly specialized and adapted to specific environments, like riparian and riverine zones, and their absence or presence is a useful aid in indicating the ecological integrity of an area. In the past, management of aquatic ecosystems was based primarily on chemical water quality monitoring. However, it is impractical to monitor each component of river make-up in detail, therefore monitoring of biological components (biomonitoring) was also incorporated; using selected ecological indices that are representative of the larger ecosystem, and that are practical to measure. Common examples of biotic assemblages that have been incorporated into biomonitoring and used in biotic indices are aquatic macroinvertebrates, fish, plants and algae. Each assemblage is useful in its own particular way in providing us with an integrated view of the integrity of the ecological system as a whole. However, little research has been done on the potential of using birds in a suitable index to monitor changes in the environment. Because birds are so easily observed, their species so easily identified, and their distribution so widespread, it seems viable that birds could also be incorporated into an index of biotic integrity, and used for short- or long-term monitoring of river ecosystems. The river that was selected for the purposes of this study was the Sabie River, in Mpumalanga, South Africa. The Sabie River catchment falls within the Incomati River basin, which is an international drainage basin occupied by South Africa, Swaziland and Mozambique. Land use in the catchment is characterized by forestry, rural community activities (subsistence and small scale farming of livestock and fruit), and conservation activities, in particular the Kruger National Park. In order to gain better understanding of the functioning and composition of the instream and riparian zones of the Sabie River, certain indices were applied, namely the SASS 5 aquatic invertebrate index, together with the Index of Habitat Integrity (IHI). , Dr. G.M. Pieterse
- Full Text:
- Authors: Sudlow, Bronwyn Elisabeth
- Date: 2008-10-16T05:49:50Z
- Subjects: Water quality biological assessment , Birds ecology , Mpumalanga (South Africa)
- Type: Thesis
- Identifier: uj:12387 , http://hdl.handle.net/10210/1216
- Description: M.Sc. , Rivers always borrow a great part of their character from the terrestrial ecosystems – the catchments – through which they flow. A multitude of natural factors determines the health of a river ecosystem, however, together with these natural factors, the combined influences of urban development, pollution, bank erosion, deforestation (and ironically many forms of afforestation), and poor agricultural practices have so degraded our rivers that they are under severe threat. One particular group of organisms within river ecosystems that are affected by human-induced changes, are birds. Birds are rather adaptable organisms; many species are able to inhabit human environments very successfully. However, some bird species are highly specialized and adapted to specific environments, like riparian and riverine zones, and their absence or presence is a useful aid in indicating the ecological integrity of an area. In the past, management of aquatic ecosystems was based primarily on chemical water quality monitoring. However, it is impractical to monitor each component of river make-up in detail, therefore monitoring of biological components (biomonitoring) was also incorporated; using selected ecological indices that are representative of the larger ecosystem, and that are practical to measure. Common examples of biotic assemblages that have been incorporated into biomonitoring and used in biotic indices are aquatic macroinvertebrates, fish, plants and algae. Each assemblage is useful in its own particular way in providing us with an integrated view of the integrity of the ecological system as a whole. However, little research has been done on the potential of using birds in a suitable index to monitor changes in the environment. Because birds are so easily observed, their species so easily identified, and their distribution so widespread, it seems viable that birds could also be incorporated into an index of biotic integrity, and used for short- or long-term monitoring of river ecosystems. The river that was selected for the purposes of this study was the Sabie River, in Mpumalanga, South Africa. The Sabie River catchment falls within the Incomati River basin, which is an international drainage basin occupied by South Africa, Swaziland and Mozambique. Land use in the catchment is characterized by forestry, rural community activities (subsistence and small scale farming of livestock and fruit), and conservation activities, in particular the Kruger National Park. In order to gain better understanding of the functioning and composition of the instream and riparian zones of the Sabie River, certain indices were applied, namely the SASS 5 aquatic invertebrate index, together with the Index of Habitat Integrity (IHI). , Dr. G.M. Pieterse
- Full Text:
The use of biomarker responses to assess pesticide exposure in the Crocodile- and Olifants River systems
- Authors: Visser, Zola
- Date: 2010-05-27T06:05:13Z
- Subjects: Biochemical markers , Environmental monitoring , Water quality biological assessment , Pesticides
- Type: Thesis
- Identifier: uj:6846 , http://hdl.handle.net/10210/3278
- Description: M.Sc. , The Hartbeespoort Dam is located in the North-West Province, downstream of the confluence of the Crocodile River and the Magalies River. The dam was originally built for agricultural purposes and the surrounding area has many canals for irrigation. The use of pesticides for agricultural practices within the area which are transported by the canals, are of great concern. It is well known that residues of persistent pesticides (especially those of organochlorine) and insecticides are found in terrestrial and aquatic environments as well as in the organisms occupying these niches. Such xenobiotics are highly lipid soluble and lengthy exposure to them results in their high accumulation in non-target organisms, all contributing to adverse effects on the ecosystem. The upper Olifants River catchment comprises the drainage areas of the Olifants River, Klein Olifants River and Wilge River, with tributaries down to the Loskop Dam. Over the past few years, the Olifants River has been systematically impaired because of an increase in agricultural and mining activities, industrial development and urbanisation. Recent fish kills in the Loskop Dam has lead to many controversies about the water quality in the Olifants River. The aim of this study was to determine through the use of biomarker responses if it would be possible to identify whether sub-lethal pesticide exposure occurs in fish populations in the Crocodile- and Olifants River systems. Both active biomonitoring (ABM) and passive biomonitoring (PBM) were carried out at selected sites in the Crocodile River system. The ABM technique involved the transplantation of bioindicator organisms, in this case fish, and exposing them for a period of four weeks. The ABM and PBM exposures were carried out during different pesticide spraying regimes, which also coincided with high (summer) and low (winter) flow conditions. Following the exposure period, the organisms were removed and assessed for biological responses (biomarkers). General biomarker responses used in pesticide exposure i.e. acetylcholinesterase (AChE), malondialdehyde (MDA), catalase activity (CAT), protein carbonyls (PC), cellular energy allocation (CEA) and condition factor (CF) were determined. The same suite of biomarkers used in the Crocodile River system was used to determine responses in resident fish species in the Olifants River system.
- Full Text:
- Authors: Visser, Zola
- Date: 2010-05-27T06:05:13Z
- Subjects: Biochemical markers , Environmental monitoring , Water quality biological assessment , Pesticides
- Type: Thesis
- Identifier: uj:6846 , http://hdl.handle.net/10210/3278
- Description: M.Sc. , The Hartbeespoort Dam is located in the North-West Province, downstream of the confluence of the Crocodile River and the Magalies River. The dam was originally built for agricultural purposes and the surrounding area has many canals for irrigation. The use of pesticides for agricultural practices within the area which are transported by the canals, are of great concern. It is well known that residues of persistent pesticides (especially those of organochlorine) and insecticides are found in terrestrial and aquatic environments as well as in the organisms occupying these niches. Such xenobiotics are highly lipid soluble and lengthy exposure to them results in their high accumulation in non-target organisms, all contributing to adverse effects on the ecosystem. The upper Olifants River catchment comprises the drainage areas of the Olifants River, Klein Olifants River and Wilge River, with tributaries down to the Loskop Dam. Over the past few years, the Olifants River has been systematically impaired because of an increase in agricultural and mining activities, industrial development and urbanisation. Recent fish kills in the Loskop Dam has lead to many controversies about the water quality in the Olifants River. The aim of this study was to determine through the use of biomarker responses if it would be possible to identify whether sub-lethal pesticide exposure occurs in fish populations in the Crocodile- and Olifants River systems. Both active biomonitoring (ABM) and passive biomonitoring (PBM) were carried out at selected sites in the Crocodile River system. The ABM technique involved the transplantation of bioindicator organisms, in this case fish, and exposing them for a period of four weeks. The ABM and PBM exposures were carried out during different pesticide spraying regimes, which also coincided with high (summer) and low (winter) flow conditions. Following the exposure period, the organisms were removed and assessed for biological responses (biomarkers). General biomarker responses used in pesticide exposure i.e. acetylcholinesterase (AChE), malondialdehyde (MDA), catalase activity (CAT), protein carbonyls (PC), cellular energy allocation (CEA) and condition factor (CF) were determined. The same suite of biomarkers used in the Crocodile River system was used to determine responses in resident fish species in the Olifants River system.
- Full Text:
Optimisation of culture methods for the selective isolation of diarrhoeagenic Escherichia coli from water
- Authors: Heine, Lee
- Date: 2008-08-13T12:19:12Z
- Subjects: Escherichia coli , Water quality biological assessment , Water purification
- Type: Thesis
- Identifier: uj:7661 , http://hdl.handle.net/10210/852
- Description: Diarrhoea caused by strains of Escherichia coli is recognised as a significant cause of morbidity and mortality world-wide. Efficient isolation of these bacteria from water is necessary for effective management of available water sources and for the control and prevention of waterborne disease. Methods that are currently available do not allow for the efficient isolation of the diarrhoeagenic E. coli. Therefore, the aims of the current study were: to determine the efficacy of Chromocult® Coliformen Agar for identification of diarrhoeagenic E. coli; correlate virulence gene carriage with biochemical profiles of diarrhoeagenic E. coli; and develop an enrichment method for the selective isolation of diarrhoeagenic E. coli. Chromocult® Coliformen Agar proved unreliable for identifying diarrhoeagenic E. coli – 30% of strains would have been incorrectly identified using this medium. The carriage of pathotype-specific virulence genes by enteroaggregative E. coli strains was associated with the production of ornithine decarboxylase and the fermentation of sucrose. The enrichment procedure detailed in this study was an improvement upon an existing method. In addition, the improved method proved effective for the isolation of five diarrhoeagenic E. coli pathotypes. In contrast, the original procedure was only shown to be effective when isolating enterohaemorrhagic E. coli. The improved method was applied on environmental water and two samples yielded colonies positive for genes carried by enteropathogenic E. coli and enterotoxigenic E. coli, respectively. As confirmation of these results PCR products were sequenced and corresponded to published sequences of the virulence genes. , Ms. P.S. Kay Dr. T. G. Barnard Prof. P. Jagals
- Full Text:
- Authors: Heine, Lee
- Date: 2008-08-13T12:19:12Z
- Subjects: Escherichia coli , Water quality biological assessment , Water purification
- Type: Thesis
- Identifier: uj:7661 , http://hdl.handle.net/10210/852
- Description: Diarrhoea caused by strains of Escherichia coli is recognised as a significant cause of morbidity and mortality world-wide. Efficient isolation of these bacteria from water is necessary for effective management of available water sources and for the control and prevention of waterborne disease. Methods that are currently available do not allow for the efficient isolation of the diarrhoeagenic E. coli. Therefore, the aims of the current study were: to determine the efficacy of Chromocult® Coliformen Agar for identification of diarrhoeagenic E. coli; correlate virulence gene carriage with biochemical profiles of diarrhoeagenic E. coli; and develop an enrichment method for the selective isolation of diarrhoeagenic E. coli. Chromocult® Coliformen Agar proved unreliable for identifying diarrhoeagenic E. coli – 30% of strains would have been incorrectly identified using this medium. The carriage of pathotype-specific virulence genes by enteroaggregative E. coli strains was associated with the production of ornithine decarboxylase and the fermentation of sucrose. The enrichment procedure detailed in this study was an improvement upon an existing method. In addition, the improved method proved effective for the isolation of five diarrhoeagenic E. coli pathotypes. In contrast, the original procedure was only shown to be effective when isolating enterohaemorrhagic E. coli. The improved method was applied on environmental water and two samples yielded colonies positive for genes carried by enteropathogenic E. coli and enterotoxigenic E. coli, respectively. As confirmation of these results PCR products were sequenced and corresponded to published sequences of the virulence genes. , Ms. P.S. Kay Dr. T. G. Barnard Prof. P. Jagals
- Full Text:
A baseline assessment of selected seasonal pans in the Kruger National Park, South Africa
- Authors: Taylor, Shaun
- Date: 2012-06-07
- Subjects: Kruger National Park (South Africa) , Pans (Geomorphology) - Environmental aspects , Wetland ecology , Water quality biological assessment
- Type: Mini-Dissertation
- Identifier: uj:8681 , http://hdl.handle.net/10210/5036
- Description: M.Sc. , Owing mostly to the ephemeral nature, pan wetlands aren’t afforded the attention that other (arguably) more attractive or functional wetland types entertain. In the Kruger National Park, the study of its freshwater resources has focused mainly on the water quality of its rivers leaving pans almost entirely unaccounted for, until now. The aims of this study were to determine a baseline assessment of the structural, hydrological, physico-chemical and biological characteristics of eight selected seasonal pans in the Kruger National Park. The results of this study show that the pans are relatively small (<1.3 hectares), shallow (from 0.4 to 1.1metres), of various shapes and can hold a greater volume of water where greater depth and increasingly concave basin profiles are present. The physico-chemical characteristics typically showed high summer sub-surface water temperatures (up to 38°C), anaerobic conditions, pH values of 6.2 to 7, low alkalinity, varied conductivity, turbid conditions and generally could be described as oligotrophic in terms of nutrients. The dominant anion in most cases was sulphate. Iron was the dominant metal in the water chemistry of the pans. Several dissolved metals in the water chemistry of the pans were relatively high in concentration including aluminium, zinc, copper, cadmium, lead and selenium when evaluated against national water quality standards. Overall, limited spatial and temporal similarities were observed between the pans in terms of the physico-chemical characteristics of the water. The sediment of the pans can be considered as high in organic content, generally moist and comprising of predominantly either very fine sand sediments or coarse sand with appreciable amounts of medium coarse sediments. In general, manganese was the most abundant metal in the sediments, followed by relatively high concentrations of chromium, nickel, copper and zinc when compared with international sediment quality standards. Correlations between metal concentrations, sediment size and organic content were not strong.Lastly, the degree of grass cover for some pans show remarkably similar variation in the degree of change with distance from the brim of the pans outward. The trees immediately surrounding the pans however, are diverse and generally correspond with earlier studies of the vegetation of the Kruger National Park.
- Full Text:
- Authors: Taylor, Shaun
- Date: 2012-06-07
- Subjects: Kruger National Park (South Africa) , Pans (Geomorphology) - Environmental aspects , Wetland ecology , Water quality biological assessment
- Type: Mini-Dissertation
- Identifier: uj:8681 , http://hdl.handle.net/10210/5036
- Description: M.Sc. , Owing mostly to the ephemeral nature, pan wetlands aren’t afforded the attention that other (arguably) more attractive or functional wetland types entertain. In the Kruger National Park, the study of its freshwater resources has focused mainly on the water quality of its rivers leaving pans almost entirely unaccounted for, until now. The aims of this study were to determine a baseline assessment of the structural, hydrological, physico-chemical and biological characteristics of eight selected seasonal pans in the Kruger National Park. The results of this study show that the pans are relatively small (<1.3 hectares), shallow (from 0.4 to 1.1metres), of various shapes and can hold a greater volume of water where greater depth and increasingly concave basin profiles are present. The physico-chemical characteristics typically showed high summer sub-surface water temperatures (up to 38°C), anaerobic conditions, pH values of 6.2 to 7, low alkalinity, varied conductivity, turbid conditions and generally could be described as oligotrophic in terms of nutrients. The dominant anion in most cases was sulphate. Iron was the dominant metal in the water chemistry of the pans. Several dissolved metals in the water chemistry of the pans were relatively high in concentration including aluminium, zinc, copper, cadmium, lead and selenium when evaluated against national water quality standards. Overall, limited spatial and temporal similarities were observed between the pans in terms of the physico-chemical characteristics of the water. The sediment of the pans can be considered as high in organic content, generally moist and comprising of predominantly either very fine sand sediments or coarse sand with appreciable amounts of medium coarse sediments. In general, manganese was the most abundant metal in the sediments, followed by relatively high concentrations of chromium, nickel, copper and zinc when compared with international sediment quality standards. Correlations between metal concentrations, sediment size and organic content were not strong.Lastly, the degree of grass cover for some pans show remarkably similar variation in the degree of change with distance from the brim of the pans outward. The trees immediately surrounding the pans however, are diverse and generally correspond with earlier studies of the vegetation of the Kruger National Park.
- Full Text:
Determining the influences of land use patterns on the diatom, macroinvertebrate and riparian vegetation integrity of the Lower Harts/Vaal River systems
- Authors: Ferreira, Linette
- Date: 2010-05-26T06:13:04Z
- Subjects: Vaalharts Irrigation Scheme , Water quality management , Water quality biological assessment , Effect of water pollution on diatoms
- Type: Thesis
- Identifier: uj:6835 , http://hdl.handle.net/10210/3268
- Description: M.Sc. , Water resources in South Africa are scarce and need to be protected and managed in a sustainable way for future generations. Food supply is a great priority worldwide and the pressure to produce enough food has resulted in the expansion of irrigation and the steadily increasing use of fertilizers and pesticides to achieve higher yields. Rivers are impacted by agriculture through increased suspended sediment loads (which affects primary production, habitat reduction and introduction of absorbed pollutants), elevated nutrient inputs (which may increase the abundances of algae and aquatic plants), salinization and pesticide runoff (which eliminates species intolerant to these conditions and therefore impacts on the normal production of the river system). Aquatic biota plays an integral part in the functioning of aquatic ecosystems. Biological monitoring is used to assess ecosystem health and integrity. Biological communities reflect the overall integrity of the river ecosystem by integrating various stressors and therefore provide a broad measure of their synergistic effects. The research area falls within the Lower Vaal Water Management Area (WMA), which lies in the North-West and Northern Cape Provinces. The lower Vaal River and the Harts River (one of the tributaries of the Vaal) are the river systems under investigation in this study. Farming activities ranges from extensive livestock production and rain fed cultivation to intensive irrigation enterprises at Vaalharts (such as maize, cotton and groundnuts). The Vaalharts is the largest irrigation scheme in South Africa. Salinity is of concern in the lower reaches of the Harts- and Vaal Rivers, due to saline leachate from the Vaalharts irrigation scheme. Agricultural inputs are known to affect aquatic communities and chemicals (e.g. pesticides, herbicides, fertilizers) are extensively used in the Vaalharts irrigation scheme. At present there are no data on the effect of these chemicals on the aquatic biota of the lower Harts- and Vaal Rivers. The aims of this study were to assess the diatom- and macroinvertebrate community structures, ecosystem integrity and macroinvertebrate feeding traits (functional feeding groups – FFGs) in relation to land use.
- Full Text:
- Authors: Ferreira, Linette
- Date: 2010-05-26T06:13:04Z
- Subjects: Vaalharts Irrigation Scheme , Water quality management , Water quality biological assessment , Effect of water pollution on diatoms
- Type: Thesis
- Identifier: uj:6835 , http://hdl.handle.net/10210/3268
- Description: M.Sc. , Water resources in South Africa are scarce and need to be protected and managed in a sustainable way for future generations. Food supply is a great priority worldwide and the pressure to produce enough food has resulted in the expansion of irrigation and the steadily increasing use of fertilizers and pesticides to achieve higher yields. Rivers are impacted by agriculture through increased suspended sediment loads (which affects primary production, habitat reduction and introduction of absorbed pollutants), elevated nutrient inputs (which may increase the abundances of algae and aquatic plants), salinization and pesticide runoff (which eliminates species intolerant to these conditions and therefore impacts on the normal production of the river system). Aquatic biota plays an integral part in the functioning of aquatic ecosystems. Biological monitoring is used to assess ecosystem health and integrity. Biological communities reflect the overall integrity of the river ecosystem by integrating various stressors and therefore provide a broad measure of their synergistic effects. The research area falls within the Lower Vaal Water Management Area (WMA), which lies in the North-West and Northern Cape Provinces. The lower Vaal River and the Harts River (one of the tributaries of the Vaal) are the river systems under investigation in this study. Farming activities ranges from extensive livestock production and rain fed cultivation to intensive irrigation enterprises at Vaalharts (such as maize, cotton and groundnuts). The Vaalharts is the largest irrigation scheme in South Africa. Salinity is of concern in the lower reaches of the Harts- and Vaal Rivers, due to saline leachate from the Vaalharts irrigation scheme. Agricultural inputs are known to affect aquatic communities and chemicals (e.g. pesticides, herbicides, fertilizers) are extensively used in the Vaalharts irrigation scheme. At present there are no data on the effect of these chemicals on the aquatic biota of the lower Harts- and Vaal Rivers. The aims of this study were to assess the diatom- and macroinvertebrate community structures, ecosystem integrity and macroinvertebrate feeding traits (functional feeding groups – FFGs) in relation to land use.
- Full Text:
- «
- ‹
- 1
- ›
- »