The development and validation of a homologous tilapia vitellogenin enzyme linked immunosorbent assay (t-VTG-ELISA) as biomarker of estrogenic exposure
- Authors: Mbazo, Dimakatjo Surprise
- Date: 2008-06-17T13:38:04Z
- Subjects: Water quality bioassay , Indicators (Biology)
- Type: Thesis
- Identifier: uj:2877 , http://hdl.handle.net/10210/630
- Description: Water is essential to all life but many freshwater resources are polluted through human activities. Humans and wildlife are exposed to a wide range of contaminants through their water, many of which pose a risk to health. Some of the contaminants released into the environment have been reported to have the capability to disrupt the endocrine functions in humans and wildlife and they can mimic or antagonise the action of estrogenic. These endocrine disrupting chemicals (EDCs) interact with physiological systems and cause alterations in development, growth and reproduction in wildlife and humans. To achieve some measure of assessing the potential harm that the contaminants pose, we need to know the environmental concentration of the chemical concerned and to monitor their effect on the organisms. The water supply sector need to include EDCs in standard systems of routine water source monitoring which include indicator bacteria and nutrient species but before the system can be incorporated, methods to measure the occurrence of EDCs in aquatic environment need to be developed and validated and a reliable guidelines data need to be in place. The aim of this study was to develop an enzyme-linked immunosorbent assay (ELISA) to quantify vitellogenin (VTG) in Oreochromis mossambicus (Mozambique tilapia) VTG has been used successfully as a biomarker for estrogenic contamination in different studies. For this study, VTG was isolated and purified from plasma of 17β-estradiol exposed tilapia by gel filtration chromatography. The purity of the VTG isolate was confirmed by polyacrylamide gel electrophoreses (SDS-PAGE). Polyclonal antibodies against t-VTG were raised in rabbits and the specificity of the anti-t-VTG was confirmed by western blot. Using purified t-VTG as a standard and anti-t-VTG antibody, a homologous competitive ELISA was developed and validated. The standard curves of the ELISA, which were generated on different days, were identical which indicate that the assay is reliable, reproducible and repeatable. The intra-assay and inter-assay coefficient variation was 2.41 (n = 4) and 8.71 (n = 10) respectively. The serial dilution of plasma VTG from exposed tilapia showed a good parallelism with the standard t-VTG within the working range of the assay. The serial dilution of the reference fish did not cover the whole range of the t-VTG standard curve. By using the standard curve and the dilution of the exposed plasma, we were able to demonstrate that the ELISA was able to quantify VTG. With good laboratory practise, this ELISA can be use to quantify VTG in chemically exposed fish. It will also be ideal to continue analyzing the antibody to determine the appropriate dilutions necessary to ensure that the assay work its optimal capabilities. , Dr. I. Barnhoorn Prof. P. Jagals Prof. J.H.J. Van Vuren
- Full Text:
- Authors: Mbazo, Dimakatjo Surprise
- Date: 2008-06-17T13:38:04Z
- Subjects: Water quality bioassay , Indicators (Biology)
- Type: Thesis
- Identifier: uj:2877 , http://hdl.handle.net/10210/630
- Description: Water is essential to all life but many freshwater resources are polluted through human activities. Humans and wildlife are exposed to a wide range of contaminants through their water, many of which pose a risk to health. Some of the contaminants released into the environment have been reported to have the capability to disrupt the endocrine functions in humans and wildlife and they can mimic or antagonise the action of estrogenic. These endocrine disrupting chemicals (EDCs) interact with physiological systems and cause alterations in development, growth and reproduction in wildlife and humans. To achieve some measure of assessing the potential harm that the contaminants pose, we need to know the environmental concentration of the chemical concerned and to monitor their effect on the organisms. The water supply sector need to include EDCs in standard systems of routine water source monitoring which include indicator bacteria and nutrient species but before the system can be incorporated, methods to measure the occurrence of EDCs in aquatic environment need to be developed and validated and a reliable guidelines data need to be in place. The aim of this study was to develop an enzyme-linked immunosorbent assay (ELISA) to quantify vitellogenin (VTG) in Oreochromis mossambicus (Mozambique tilapia) VTG has been used successfully as a biomarker for estrogenic contamination in different studies. For this study, VTG was isolated and purified from plasma of 17β-estradiol exposed tilapia by gel filtration chromatography. The purity of the VTG isolate was confirmed by polyacrylamide gel electrophoreses (SDS-PAGE). Polyclonal antibodies against t-VTG were raised in rabbits and the specificity of the anti-t-VTG was confirmed by western blot. Using purified t-VTG as a standard and anti-t-VTG antibody, a homologous competitive ELISA was developed and validated. The standard curves of the ELISA, which were generated on different days, were identical which indicate that the assay is reliable, reproducible and repeatable. The intra-assay and inter-assay coefficient variation was 2.41 (n = 4) and 8.71 (n = 10) respectively. The serial dilution of plasma VTG from exposed tilapia showed a good parallelism with the standard t-VTG within the working range of the assay. The serial dilution of the reference fish did not cover the whole range of the t-VTG standard curve. By using the standard curve and the dilution of the exposed plasma, we were able to demonstrate that the ELISA was able to quantify VTG. With good laboratory practise, this ELISA can be use to quantify VTG in chemically exposed fish. It will also be ideal to continue analyzing the antibody to determine the appropriate dilutions necessary to ensure that the assay work its optimal capabilities. , Dr. I. Barnhoorn Prof. P. Jagals Prof. J.H.J. Van Vuren
- Full Text:
Development of a passive, in situ, integrative sampler for monitoring biotoxins in aquatic environments
- Authors: Nyoni, Hlengilizwe
- Date: 2015-11-09
- Subjects: Water - Pollution - Toxicology , Water quality bioassay , Aquatic ecology , Fishes - Effect of water pollution on
- Type: Thesis
- Identifier: uj:14526 , http://hdl.handle.net/10210/15056
- Description: PhD. (Chemistry) , This thesis focuses on functionalising the silicone membrane by filling it with synthesised γ-Fe2O3 nanoparticles for the purpose of using it as a passive sampling device for monitoring microcystins and cylindrospermopsin in aquatic environments. The identity and purity of the synthesised nanoparticles was verified by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscope (SEM), surface zeta potential analyser and Brunauer-Emmet-Teller (BET). There was no chemical uptake of microcystin compounds into the silicone membrane without a suspension of maghemite nanoparticles. But, a linear uptake of microcystin compounds was observed into the functionalised silicone membrane passive sampler throughout the exposure period. These findings suggest that the silicone membrane filled with a suspension of synthesised γ-Fe2O3 nanoparticles can be an efficient, green and less costly instrument useful in estimating biotoxin concentrations in South African waters and the world at large.
- Full Text:
- Authors: Nyoni, Hlengilizwe
- Date: 2015-11-09
- Subjects: Water - Pollution - Toxicology , Water quality bioassay , Aquatic ecology , Fishes - Effect of water pollution on
- Type: Thesis
- Identifier: uj:14526 , http://hdl.handle.net/10210/15056
- Description: PhD. (Chemistry) , This thesis focuses on functionalising the silicone membrane by filling it with synthesised γ-Fe2O3 nanoparticles for the purpose of using it as a passive sampling device for monitoring microcystins and cylindrospermopsin in aquatic environments. The identity and purity of the synthesised nanoparticles was verified by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscope (SEM), surface zeta potential analyser and Brunauer-Emmet-Teller (BET). There was no chemical uptake of microcystin compounds into the silicone membrane without a suspension of maghemite nanoparticles. But, a linear uptake of microcystin compounds was observed into the functionalised silicone membrane passive sampler throughout the exposure period. These findings suggest that the silicone membrane filled with a suspension of synthesised γ-Fe2O3 nanoparticles can be an efficient, green and less costly instrument useful in estimating biotoxin concentrations in South African waters and the world at large.
- Full Text:
The aquatic toxicology of gold nanoparticles
- Authors: Botha, Tarryn Lee
- Date: 2015
- Subjects: Aquatic toxicology , Gold nanoparticles , Water quality bioassay , Water - Pollution - Toxicology
- Language: English
- Type: Doctoral (Thesis)
- Identifier: http://hdl.handle.net/10210/58665 , uj:16485
- Description: Abstract: Toxicity laboratory tests are used world-wide to manage environmental resources such as water quality and are considered to be the first step in a tiered approach in establishing guidelines for setting maximum acceptable concentrations of specific pollutants. The aim of this study was to evaluate the aquatic toxicology of gold nanoparticles (nAu) using a combination of acute and chronic ecotoxicological bioassays. Particle distribution and agglomeration in the reconstituted water medium was evaluated using several microscopy techniques as well as characterization tools which included dynamic light scattering and Fourier transform infrared spectrometery. Range finding exposure tests were done to determine the LC50 of nAu in Pseudokirchneriella subcapitata, Daphnia pulex, Daphnia magna and 14 day old Danio rerio using standard OECD protocols where ionic gold and solvent controls were also included. The acute toxicity showed a bimodal response for nAu and an LC50 was only calculated for D. pulex at 75.314mg/l while ionic gold concentrations had an LC50 with a 95% confidence level at 0.01mg/l and 4.85mg/l daphnia and 14 day old zebrafish respectively. The in vivo nAu distribution and mechanical effect was observed using several microscopy techniques which showed the attachment of nAu to the surface of algae and daphnia, uptake via the gills and storage in cartilage and muscle tissue in zebrafish as well as nAu ingestion of agglomerates visible to the naked eye (40mg/l and 45mg/l). A reproductive study in D. magna to determine the effect of nAu on molting patterns related to reproduction showed that as exposure concentrations increased daphnia molting also increased and a lower correlation was seen between reproduction and molting as concentrations increased. Sub lethal testing was done by exposing adult zebrafish (D. rerio) to nAu for 96 hours at a concentration range of 5mg/l to 45mg/l with a 5mg/l interval between concentrations. Male fish livers were stored in RNA later and grouped samples were used for DNA microarray. Real time polymerase chain reactions (RT-PCR) were used to determine changes in gene expression in the liver comparing male fish to female fish. The results obtained from scanning the gene chip gave an indication of events in the cell based on 15 618 genes being regulated. The gene ontology was further investigated using ArrayStar® to show pathway interactions as well as the clustering of genes. The 20mg/l and 25mg/l nAu concentrations showed similar genetic clustering and these were related to 40mg/; and 45mg/l respectively. By using a process of elimination genes were narrowed down to 75, genes that are not yet properly understood in the zebra fish genome and genes that had a fold change less than threefold were eliminated. Pathways were then looked at and the following genes were focused on and used... , D.Phil. (Aquatic Health)
- Full Text:
- Authors: Botha, Tarryn Lee
- Date: 2015
- Subjects: Aquatic toxicology , Gold nanoparticles , Water quality bioassay , Water - Pollution - Toxicology
- Language: English
- Type: Doctoral (Thesis)
- Identifier: http://hdl.handle.net/10210/58665 , uj:16485
- Description: Abstract: Toxicity laboratory tests are used world-wide to manage environmental resources such as water quality and are considered to be the first step in a tiered approach in establishing guidelines for setting maximum acceptable concentrations of specific pollutants. The aim of this study was to evaluate the aquatic toxicology of gold nanoparticles (nAu) using a combination of acute and chronic ecotoxicological bioassays. Particle distribution and agglomeration in the reconstituted water medium was evaluated using several microscopy techniques as well as characterization tools which included dynamic light scattering and Fourier transform infrared spectrometery. Range finding exposure tests were done to determine the LC50 of nAu in Pseudokirchneriella subcapitata, Daphnia pulex, Daphnia magna and 14 day old Danio rerio using standard OECD protocols where ionic gold and solvent controls were also included. The acute toxicity showed a bimodal response for nAu and an LC50 was only calculated for D. pulex at 75.314mg/l while ionic gold concentrations had an LC50 with a 95% confidence level at 0.01mg/l and 4.85mg/l daphnia and 14 day old zebrafish respectively. The in vivo nAu distribution and mechanical effect was observed using several microscopy techniques which showed the attachment of nAu to the surface of algae and daphnia, uptake via the gills and storage in cartilage and muscle tissue in zebrafish as well as nAu ingestion of agglomerates visible to the naked eye (40mg/l and 45mg/l). A reproductive study in D. magna to determine the effect of nAu on molting patterns related to reproduction showed that as exposure concentrations increased daphnia molting also increased and a lower correlation was seen between reproduction and molting as concentrations increased. Sub lethal testing was done by exposing adult zebrafish (D. rerio) to nAu for 96 hours at a concentration range of 5mg/l to 45mg/l with a 5mg/l interval between concentrations. Male fish livers were stored in RNA later and grouped samples were used for DNA microarray. Real time polymerase chain reactions (RT-PCR) were used to determine changes in gene expression in the liver comparing male fish to female fish. The results obtained from scanning the gene chip gave an indication of events in the cell based on 15 618 genes being regulated. The gene ontology was further investigated using ArrayStar® to show pathway interactions as well as the clustering of genes. The 20mg/l and 25mg/l nAu concentrations showed similar genetic clustering and these were related to 40mg/; and 45mg/l respectively. By using a process of elimination genes were narrowed down to 75, genes that are not yet properly understood in the zebra fish genome and genes that had a fold change less than threefold were eliminated. Pathways were then looked at and the following genes were focused on and used... , D.Phil. (Aquatic Health)
- 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:
Bioaccumulation of metals and the general health of fish from the Vaal Dam and Vaal River Barrage
- Authors: Groenewald, Marinka
- Date: 2012-01-25
- Subjects: Water quality bioassay , Bioaccumulation , Freshwater fish diseases , Freshwater fishes , Effect of metals on freshwater fishes
- Type: Thesis
- Identifier: uj:1963 , http://hdl.handle.net/10210/4320
- Description: M.Sc. , The water quality in the Vaal River system has deteriorated due to increasing industrial, mining and agricultural activities in the Vaal Dam and Vaal River Barrage catchment areas. This study was undertaken to determine the water quality in the Vaal Dam, and three localities within the Vaal River Barrage reservoir (i.e. the Riviera Aquatic Club, Abrahamsrust Pleasure Resort and at the Barrage structure). The objectives of this study, was to determine the fish population species composition, evaluate the general health of the selected fish species and obtain site specific metal bioaccumulation data for each locality. Suggestions and proposals for future monitoring and management of these waterbodies were also made. Metereological information on the Vaal River Barrage area was supplied by Rand Water, as well as physical and chemical data of fixed localities, sampled fortnightly (January 1997 to September 1998). In addition, water samples were collected at the Vaal Dam and the three Vaal River Barrage localities mentioned above, during February, May, August and November 1997. These samples were analysed by the Chemistry Department of the Rand Afrikaans University in accordance with standard methods. The chemical and physical characteristics and metal concentrations (aluminium, cadmium, calcium, copper, iron, magnesium, manganese, nickel, strontium and zinc) of these separate sets of data were then compared with Rand Water's Raw Water Quality Criteria. The aluminium, ammonia, chromium, copper, dissolved organic carbon, fluoride, iron, lead, manganese, nitrate, sulphate, total hardness and turbidity variables did not comply with the recommended guideline values. No guideline levels for strontium are available, however. Sedimentation, turbidity, salination and eutrophication within the Vaal River system play an important role in the bioaccumulation of metals by benthic organisms. Metals that adsorb to sediment particles, through various processes, are generally more persistent and less mobile than those in the overlying water and pose a severe long-lasting threat to the aquatic environment. Generally, the highest metal concentrations (AI, Cd, Cu, Fe, Mn, Ni, Pb, Sr and Zn) in the sediment samples collected at the four localities and seasons, were found in the finer sediment classes (class D). The Riviera Aquatic Club locality had the highest overall concentrations of the metals analysed. The adult fish communities within the Vaal Dam and Vaal River Barrage were assessed, as it is believed that the fish community structure is indicative of environmental conditions. Adult Labeo capensis, Labeo umbratus, Cyprinus carpio, Clarias gariepinus, Barbus aeneus and Micropterus sa/moides, were collected (using gill nets) to determine the adult fish community composition and age. When compared with a study conducted by Mulder (1971), it is clear that Labeo capensis has remained the most abundant species within the system, but that Barbus aeneus has now been replaced by Labeo umbratus as the second most abundant species. Furthermore, age determination tables (Mulder, 1971) were used to classify the fish population between the ages of 2 and 7 years. This indicates a healthy, dynamic community structure where recruitment is taking place. The Health Assessment Index (HAl) was used to determine the general health of the two fish species selected for metal analysis (i.e. Labeo capensis and Labeo umbratus). Except for moderate to severe gill damage recorded, no damage to external variables, were of concern. However, both Labeo capensis and Labeo umbratus had high percentages (89% and 93%, respecii tively) of abnormal livers. Using the Plascon Colour Chart (Watson, personal communication), these livers were classified as ranging from tan to "coffee with cream" in colour. High haematocrit and plasma protein levels were observed and could be due to environmental stress, while the White Blood Cell Counts were within normal ranges. Generally speaking, only mild to moderate parasite infections were observed and probably do not pose a serious health threat to the fish host. Total HAl values for Labeo capensis indicate that this this fish population was in relatively good health, but too few Labeo umbratus individuals were collected to make accurate assumptions about this population. Metal analysis (AI, Cd, Cu, Fe, Mn, Ni, Pb, Sr and Zn) was carried out on the tissues and organs (skin, muscle, gill filaments, gill arches, liver, hindgut content, gonads and vertebrae) of Labeo capensis and Labeo umbratus, collected during the study period. Only aluminium, iron and strontium are discussed. Aluminium concentrations were relatively high at all of the localities, but as pH values were mostly alkaline, aluminium is rendered biologically unavailable and as for iron, was mostly accumulated in the non-edible portion and viscera of the fish. Strontium accumulates in bony tissues due to its similarity with calcium, but is not essential for bone formation. The human health risks of these metals in the edible portion of the fish still have to be refined and communicated to the general public of South Africa. In conclusion, this baseline study has determined the metal concentrations in the aquatic environment (due to anthropogenic activities) that may be accumulated by fish and may affect the adult fish community structures and their general health.
- Full Text:
- Authors: Groenewald, Marinka
- Date: 2012-01-25
- Subjects: Water quality bioassay , Bioaccumulation , Freshwater fish diseases , Freshwater fishes , Effect of metals on freshwater fishes
- Type: Thesis
- Identifier: uj:1963 , http://hdl.handle.net/10210/4320
- Description: M.Sc. , The water quality in the Vaal River system has deteriorated due to increasing industrial, mining and agricultural activities in the Vaal Dam and Vaal River Barrage catchment areas. This study was undertaken to determine the water quality in the Vaal Dam, and three localities within the Vaal River Barrage reservoir (i.e. the Riviera Aquatic Club, Abrahamsrust Pleasure Resort and at the Barrage structure). The objectives of this study, was to determine the fish population species composition, evaluate the general health of the selected fish species and obtain site specific metal bioaccumulation data for each locality. Suggestions and proposals for future monitoring and management of these waterbodies were also made. Metereological information on the Vaal River Barrage area was supplied by Rand Water, as well as physical and chemical data of fixed localities, sampled fortnightly (January 1997 to September 1998). In addition, water samples were collected at the Vaal Dam and the three Vaal River Barrage localities mentioned above, during February, May, August and November 1997. These samples were analysed by the Chemistry Department of the Rand Afrikaans University in accordance with standard methods. The chemical and physical characteristics and metal concentrations (aluminium, cadmium, calcium, copper, iron, magnesium, manganese, nickel, strontium and zinc) of these separate sets of data were then compared with Rand Water's Raw Water Quality Criteria. The aluminium, ammonia, chromium, copper, dissolved organic carbon, fluoride, iron, lead, manganese, nitrate, sulphate, total hardness and turbidity variables did not comply with the recommended guideline values. No guideline levels for strontium are available, however. Sedimentation, turbidity, salination and eutrophication within the Vaal River system play an important role in the bioaccumulation of metals by benthic organisms. Metals that adsorb to sediment particles, through various processes, are generally more persistent and less mobile than those in the overlying water and pose a severe long-lasting threat to the aquatic environment. Generally, the highest metal concentrations (AI, Cd, Cu, Fe, Mn, Ni, Pb, Sr and Zn) in the sediment samples collected at the four localities and seasons, were found in the finer sediment classes (class D). The Riviera Aquatic Club locality had the highest overall concentrations of the metals analysed. The adult fish communities within the Vaal Dam and Vaal River Barrage were assessed, as it is believed that the fish community structure is indicative of environmental conditions. Adult Labeo capensis, Labeo umbratus, Cyprinus carpio, Clarias gariepinus, Barbus aeneus and Micropterus sa/moides, were collected (using gill nets) to determine the adult fish community composition and age. When compared with a study conducted by Mulder (1971), it is clear that Labeo capensis has remained the most abundant species within the system, but that Barbus aeneus has now been replaced by Labeo umbratus as the second most abundant species. Furthermore, age determination tables (Mulder, 1971) were used to classify the fish population between the ages of 2 and 7 years. This indicates a healthy, dynamic community structure where recruitment is taking place. The Health Assessment Index (HAl) was used to determine the general health of the two fish species selected for metal analysis (i.e. Labeo capensis and Labeo umbratus). Except for moderate to severe gill damage recorded, no damage to external variables, were of concern. However, both Labeo capensis and Labeo umbratus had high percentages (89% and 93%, respecii tively) of abnormal livers. Using the Plascon Colour Chart (Watson, personal communication), these livers were classified as ranging from tan to "coffee with cream" in colour. High haematocrit and plasma protein levels were observed and could be due to environmental stress, while the White Blood Cell Counts were within normal ranges. Generally speaking, only mild to moderate parasite infections were observed and probably do not pose a serious health threat to the fish host. Total HAl values for Labeo capensis indicate that this this fish population was in relatively good health, but too few Labeo umbratus individuals were collected to make accurate assumptions about this population. Metal analysis (AI, Cd, Cu, Fe, Mn, Ni, Pb, Sr and Zn) was carried out on the tissues and organs (skin, muscle, gill filaments, gill arches, liver, hindgut content, gonads and vertebrae) of Labeo capensis and Labeo umbratus, collected during the study period. Only aluminium, iron and strontium are discussed. Aluminium concentrations were relatively high at all of the localities, but as pH values were mostly alkaline, aluminium is rendered biologically unavailable and as for iron, was mostly accumulated in the non-edible portion and viscera of the fish. Strontium accumulates in bony tissues due to its similarity with calcium, but is not essential for bone formation. The human health risks of these metals in the edible portion of the fish still have to be refined and communicated to the general public of South Africa. In conclusion, this baseline study has determined the metal concentrations in the aquatic environment (due to anthropogenic activities) that may be accumulated by fish and may affect the adult fish community structures and their general health.
- Full Text:
Pro-inflammatory cytokines as biomarkers of infection caused by human exposure to diarrhoeagenic Escherichia coli
- Authors: Hong, Heather Alanna
- Date: 2008-08-20T09:44:57Z
- Subjects: Escherichia coli , Water quality bioassay
- Type: Thesis
- Identifier: uj:7992 , http://hdl.handle.net/10210/892
- Description: Prof. Paul Jagals Dr. Hafsatou Ndama Traoré
- Full Text:
- Authors: Hong, Heather Alanna
- Date: 2008-08-20T09:44:57Z
- Subjects: Escherichia coli , Water quality bioassay
- Type: Thesis
- Identifier: uj:7992 , http://hdl.handle.net/10210/892
- Description: Prof. Paul Jagals Dr. Hafsatou Ndama Traoré
- Full Text:
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