Thesis (Ph.D. (Zoology))--North-West University, Potchefstroom Campus, 2008.

Persistent organic pollutants (POPs) are a threat to the environment and human health because they are ubiquitous, resistant to degradation, can bio-accumulate in organisms and bio-magnify in food chains. They have a detrimental effect on the reproductive, nervous and immunity systems of vertebrates. An international treaty, the Stockholm Convention on POPs, came into force in 2004 and aims to limit and eventually prohibit any use and unintentional production of POPs. South Africa ratified the Convention in 2002. Those compounds currently listed by the Stockholm Convention as POPs include chlorinated pesticides such as dichlorodiphenyltrichlorethane (DDT), chlordane and dieldrin, and industry-related compounds such as polychlorinated biphenyls (PCBs) and hexachlorobenzene. Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) are also regarded as POPs but - together with some PCBs - they are the unintentional result of anthropogenic activity. This study focussed on the PCDDs, PCDFs and dioxin-like PCBs in the aquatic environment of South Africa particularly because the water resources in this country are under pressure. Despite the fact that South Africa has the sources of these compounds, little is known about the levels of these three groups of compounds. The concentration of twelve dioxin-like PCBs, seven PCDDs and ten PCDFs were determined for 22 sites selected on the grounds of their proximity to possible pollution sources. Analytical determinations included gas chromatography/mass spectrometry and a cell-based bio-assay, the H4IIE-/17C reporter gene assay. Possible sources of the observed pollution were inferred using the following statistical investigative methods: principal component and hierarchical cluster analysis. Seven of the sites had levels higher than the threshold effect concentration of Canada's sediment quality guidelines of 0.85 ngTEQ kg'1 (Toxic Equivalency Quotient). The other sites had lower levels. The highest concentration, 17.8 ng TEQ kg"1, was measured at a site in the southern Gauteng Province. Most of the PCDD/F pollution seemed to have come from combustion sources related to human activity, rather than industrial combustion. Most of the dioxin-like PCB pollution seemed to have been from commercial PCB preparations. Future research would require better characterisation of the sources in order to reduce the formation of these compounds, but also to better understand the exposure and risk scenarios, if humans are to be in close contact with these sources. / Thesis (Ph.D. (Zoology))--North-West University, Potchefstroom Campus, 2008.

Water resources in South Africa are scarce, and should therefore be protected against pollutants, also from persistent organic pollutants (POPs). POPs are a global concern due to their ubiquitous presence, persistence and toxicity. This is emphasised by the Stockholm Convention on POPs, which aims at reducing and ultimately eliminating them. South Africa signed and ratified the treaty, and it became international law on 17 May 2004, but there is still a lack of information regarding POPs in South Africa. This study focussed on establishing the levels of POPs and other organic pollutants, which included various organochlorine pesticides (OCPs), polycyclic aromatic hydrocarbons (PAHs), dioxin-like compounds (DLCs), non-dioxin-like polychlorinated biphenyls (PCBs) and polybrominated diphenyl ether (PBDE). Sampling regions included the industrial cities – Cape Town, Richards Bay, Durban and Bloemfontein, and low-income, high density residential areas surrounding a wetland in Soweto/Lenasia and Botshabelo. Additionally, rivers flowing into neighbouring countries, rivers in the vicinity of paper and pulp producers and high altitude rivers were included. Sediment samples were firstly screened for the presence of DLCs by the H4IIE-luc bio-assay, whereafter sites eliciting quantifiable responses were selected for further chemical analysis by high resolution gas chromatography-high resolution mass spectrometry (HRGC/HRMS). Of the 96 sites, only 23 had quantifiable levels of DLCs. These sites were mainly of industrial, semi-industrial or low-income residential nature. PAHs were the predominant class of compounds at most of the sites, while OCPs and PCBs were present in moderate concentrations and PBDEs in minor concentrations. The concentration of pollutants measured in South African soils and sediments were intermediate when compared to the levels measured in some European, Asian and Scandinavian countries, with the exception of a few sites where exceptionally high levels of compounds were measured. The carbon content normalized concentrations of certain compounds at some of the sites exceeded the Canadian sediment quality guidelines. The estimated cancer risk associated with dermal absorption of OCPs measured in this study was negligible when compared to the background cancer risk expected for South Africans due to life style factors. However, it was estimated that dermal exposure to PCBs, DLCs and PAHs may lead to severe increases in cancer cases, and may seriously impact on human health. / Thesis (Ph.D. (Environmental Science))--North-West University, Potchefstroom Campus, 2011.

Water resources in South Africa are scarce, and should therefore be protected against pollutants, also from persistent organic pollutants (POPs). POPs are a global concern due to their ubiquitous presence, persistence and toxicity. This is emphasised by the Stockholm Convention on POPs, which aims at reducing and ultimately eliminating them. South Africa signed and ratified the treaty, and it became international law on 17 May 2004, but there is still a lack of information regarding POPs in South Africa. This study focussed on establishing the levels of POPs and other organic pollutants, which included various organochlorine pesticides (OCPs), polycyclic aromatic hydrocarbons (PAHs), dioxin-like compounds (DLCs), non-dioxin-like polychlorinated biphenyls (PCBs) and polybrominated diphenyl ether (PBDE). Sampling regions included the industrial cities – Cape Town, Richards Bay, Durban and Bloemfontein, and low-income, high density residential areas surrounding a wetland in Soweto/Lenasia and Botshabelo. Additionally, rivers flowing into neighbouring countries, rivers in the vicinity of paper and pulp producers and high altitude rivers were included. Sediment samples were firstly screened for the presence of DLCs by the H4IIE-luc bio-assay, whereafter sites eliciting quantifiable responses were selected for further chemical analysis by high resolution gas chromatography-high resolution mass spectrometry (HRGC/HRMS). Of the 96 sites, only 23 had quantifiable levels of DLCs. These sites were mainly of industrial, semi-industrial or low-income residential nature. PAHs were the predominant class of compounds at most of the sites, while OCPs and PCBs were present in moderate concentrations and PBDEs in minor concentrations. The concentration of pollutants measured in South African soils and sediments were intermediate when compared to the levels measured in some European, Asian and Scandinavian countries, with the exception of a few sites where exceptionally high levels of compounds were measured. The carbon content normalized concentrations of certain compounds at some of the sites exceeded the Canadian sediment quality guidelines. The estimated cancer risk associated with dermal absorption of OCPs measured in this study was negligible when compared to the background cancer risk expected for South Africans due to life style factors. However, it was estimated that dermal exposure to PCBs, DLCs and PAHs may lead to severe increases in cancer cases, and may seriously impact on human health. / Thesis (Ph.D. (Environmental Science))--North-West University, Potchefstroom Campus, 2011.

Persistent organic pollutants (POPs) are a threat to the environment and human health because they are ubiquitous, resistant to degradation, can bio-accumulate in organisms and bio-magnify in food chains. They have a detrimental effect on the reproductive, nervous and immunity systems of vertebrates. An international treaty, the Stockholm Convention on POPs, came into force in 2004 and aims to limit and eventually prohibit any use and unintentional production of POPs. South Africa ratified the Convention in 2002. Those compounds currently listed by the Stockholm Convention as POPs include chlorinated pesticides such as dichlorodiphenyltrichlorethane (DDT), chlordane and dieldrin, and industry-related compounds such as polychlorinated biphenyls (PCBs) and hexachlorobenzene. Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) are also regarded as POPs but - together with some PCBs - they are the unintentional result of anthropogenic activity. This study focussed on the PCDDs, PCDFs and dioxin-like PCBs in the aquatic environment of South Africa particularly because the water resources in this country are under pressure. Despite the fact that South Africa has the sources of these compounds, little is known about the levels of these three groups of compounds. The concentration of twelve dioxin-like PCBs, seven PCDDs and ten PCDFs were determined for 22 sites selected on the grounds of their proximity to possible pollution sources. Analytical determinations included gas chromatography/mass spectrometry and a cell-based bio-assay, the H4IIE-/17C reporter gene assay. Possible sources of the observed pollution were inferred using the following statistical investigative methods: principal component and hierarchical cluster analysis. Seven of the sites had levels higher than the threshold effect concentration of Canada's sediment quality guidelines of 0.85 ngTEQ kg'1 (Toxic Equivalency Quotient). The other sites had lower levels. The highest concentration, 17.8 ng TEQ kg"1, was measured at a site in the southern Gauteng Province. Most of the PCDD/F pollution seemed to have come from combustion sources related to human activity, rather than industrial combustion. Most of the dioxin-like PCB pollution seemed to have been from commercial PCB preparations. Future research would require better characterisation of the sources in order to reduce the formation of these compounds, but also to better understand the exposure and risk scenarios, if humans are to be in close contact with these sources. / Thesis (Ph.D. (Zoology))--North-West University, Potchefstroom Campus, 2008.

Contaminated soils are a worldwide problem. Polycyclic aromatic hydrocarbons (PAHs) are common contaminants in soil at former industrial areas, especially at old gasworks sites, gas stations and former wood impregnation facilities. Risk assessments of PAHs in contaminated soils are usually based on chemical analysis of a small number of individual PAHs, which only constitute a small part of the complex cocktail of hundreds of PAHs and other related polycyclic aromatic compounds (PACs) in the soils. Generally, the mixture composition of PAH-contaminated soils is rarely known and the mechanisms of toxicity and interactions between the pollutants are far from fully understood. The main objective of this thesis was to characterize remediated PAHcontaminated soils by use of a chemical and bioanalytical approach. Bioassay specific relative potency (REP) values for 38 PAHs and related PACs were developed in the sensitive H4IIE-luc bioassay and used in massbalance analysis of remediated PAH contaminated soils, to assess the contribution of chemically quantified compounds to the overall aryl hydrocarbon receptor (AhR)-mediated activity observed in the H4IIE-luc bioassay. Mixtures studies showed additive AhR-mediated effects of PACs, including PAHs, oxy PAHs, methylated PAHs and azaarenes, in the bioassay, which supports the use of REP values in risk assessment. The results from the chemical and bioassay analysis showed that PAH-contaminated soils contained a large fraction of AhR activating compounds whose effect could not be explained by chemical analysis of the 16 priority PAHs. Further chemical identification and biological studies are necessary to determine whether these unknown substances pose a risk to human health or the environment. Results presented in this thesis are an important step in the development of AhR-based bioassay analysis and risk assessment of complex PAH-contaminated samples. / <p>Other funders: Sparbanksstiftelsen Nya and Ångpanneföreningen</p>

Concern on a global scale gave rise to the founding of the Stockholm Convention on persistent organic pollutants (POPs) with a view to restrict the use and production of these toxic chemicals. As a signatory, South Africa is legally bound to abide to the Convention’s objectives, including participating in relevant research and monitoring. However, developing countries such as South Africa have limited information concerning POPs, partially because these countries do not have sufficient analytical capabilities, and thus method development and refinement are necessary. One group of POPs consisting of polychlorinated dibenzo-pdioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (dl-PCBs), collectively referred to as dioxins, are of particular concern due to their high toxicity and persistence. Additionally, the analysis of dioxins is recognised as one of the most analytically challenging of its kind. This study investigated the effect of different preparatory protocols on the semi-quantification of dioxins using the H4IIE-luc-reporter gene assay. The protocols evaluated were either Soxhlet or pressurised liquid extraction (PLE) combined with a manual acid digestion, gel permeation chromatography (GPC) and Florisil fractionation clean-up procedure as well as the automated Total Rapid Prep™(TRP) system which makes use of a PLE combined with a multi-layer silica, alumina and carbon column clean-up procedure. To evaluate the protocols, an eight point matrix matched calibration curve, two soil samples and a certified reference material (CRM) were used. The extracts were semi-quantified by the H4IIE-luc bio-assay. During the course of the assay, the appropriateness of different standards was investigated, and a mixed standard containing all 17 toxic PCDD/Fs was chosen for quantification. During the data review process, higher bioassay equivalent (BEQ) values were obtained from PLE compared to Soxhlet extraction, while no statistically significant difference (Kruskal-Wallis ANOVA: p > 0.05) was found between the assay quantifications for the different preparatory techniques. However, the results of the H4IIE bio-assay were larger than the expected values. The identity of the chemicals that were in all likelihood responsible for the higher response was investigated through instrumental analysis using comprehensive two-dimensional gas chromatography coupled to time of flight mass spectrometry (GCxGC-TOFMS). Instrumental results indicated a high level of PAHs in the extracts, which could lead to super induction of the aryl hydrocarbon receptor (AhR) and therefore, to a positive bias in the results. Instrumental screening proved that all selected preparatory protocols were inadequate at removing interfering compounds and not sufficiently selective for PCDD/Fs, although the TRP was more successful in removing interferences. The high matrix interference hindered peak identification. Additionally, as indicated by instrumental analysis, the weak recovery of PCDD/Fs could be ascribed to high evaporation temperatures. The effect of different reference standards in the H4IIE bio-assay used during semi-quantification needs further investigation; similarly, the optimisation of extraction, evaporation and clean-up protocols and the use of different GCxGC-TOFMS column combinations aimed at more efficient separation needs to be investigated. The assistance of the National Metrology Institute (funded through the Department of Trade and Industry) towards this research is hereby acknowledged. / Thesis (MSc (Environmental Sciences))--North-West University, Potchefstroom Campus, 2013.

Concern on a global scale gave rise to the founding of the Stockholm Convention on persistent organic pollutants (POPs) with a view to restrict the use and production of these toxic chemicals. As a signatory, South Africa is legally bound to abide to the Convention’s objectives, including participating in relevant research and monitoring. However, developing countries such as South Africa have limited information concerning POPs, partially because these countries do not have sufficient analytical capabilities, and thus method development and refinement are necessary. One group of POPs consisting of polychlorinated dibenzo-pdioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (dl-PCBs), collectively referred to as dioxins, are of particular concern due to their high toxicity and persistence. Additionally, the analysis of dioxins is recognised as one of the most analytically challenging of its kind. This study investigated the effect of different preparatory protocols on the semi-quantification of dioxins using the H4IIE-luc-reporter gene assay. The protocols evaluated were either Soxhlet or pressurised liquid extraction (PLE) combined with a manual acid digestion, gel permeation chromatography (GPC) and Florisil fractionation clean-up procedure as well as the automated Total Rapid Prep™(TRP) system which makes use of a PLE combined with a multi-layer silica, alumina and carbon column clean-up procedure. To evaluate the protocols, an eight point matrix matched calibration curve, two soil samples and a certified reference material (CRM) were used. The extracts were semi-quantified by the H4IIE-luc bio-assay. During the course of the assay, the appropriateness of different standards was investigated, and a mixed standard containing all 17 toxic PCDD/Fs was chosen for quantification. During the data review process, higher bioassay equivalent (BEQ) values were obtained from PLE compared to Soxhlet extraction, while no statistically significant difference (Kruskal-Wallis ANOVA: p > 0.05) was found between the assay quantifications for the different preparatory techniques. However, the results of the H4IIE bio-assay were larger than the expected values. The identity of the chemicals that were in all likelihood responsible for the higher response was investigated through instrumental analysis using comprehensive two-dimensional gas chromatography coupled to time of flight mass spectrometry (GCxGC-TOFMS). Instrumental results indicated a high level of PAHs in the extracts, which could lead to super induction of the aryl hydrocarbon receptor (AhR) and therefore, to a positive bias in the results. Instrumental screening proved that all selected preparatory protocols were inadequate at removing interfering compounds and not sufficiently selective for PCDD/Fs, although the TRP was more successful in removing interferences. The high matrix interference hindered peak identification. Additionally, as indicated by instrumental analysis, the weak recovery of PCDD/Fs could be ascribed to high evaporation temperatures. The effect of different reference standards in the H4IIE bio-assay used during semi-quantification needs further investigation; similarly, the optimisation of extraction, evaporation and clean-up protocols and the use of different GCxGC-TOFMS column combinations aimed at more efficient separation needs to be investigated. The assistance of the National Metrology Institute (funded through the Department of Trade and Industry) towards this research is hereby acknowledged. / Thesis (MSc (Environmental Sciences))--North-West University, Potchefstroom Campus, 2013.

Polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) are common contaminants of sediment, soils and biological tissues. These compounds pose a significant risk to biological and ecosystem health and functioning due to these compounds being mutagenic, carcinogenic and are known to disrupt the endocrine system. The bioaccumulation and biomagnification potential that these compounds possess mean that they are capable of affecting the entire food chain and are not limited to the organisms that are directly in contact with the compounds Even though there has been an increase in the attention on identifying the presence and impacts that these compounds may have in South Africa, the level of attention is lower than what it is in other countries around the world. Although South Africa has guidelines in place for other pollutants, such as metals, there are no such guidelines in place to monitor PAHs and PCBs.. Industries are known to release both PAHs and PCBs, mainly from incomplete burning processes and the release of oils and fuels in the case of PAHs, and from heat transfer fluids in the case of PCBs. Durban Bay and surrounding areas of eThekwini, KwaZulu-Natal are highly industrialised with many aquatic systems, in which these contaminants are likely to deposit. The aim of this research was to determine the concentrations of these compounds by means of chemical analysis and additionally biological analysis, using the H4IIE-luc bioassay and compare these levels to international guideline levels. It was found that the concentrations of the 23 analysed PAHs were 6.5–3 235.6 ng.g-1 and the concentration of the PCBs analysed were 0–113.83 ng.g-1. Many sites were found to be in exceedance of the guideline limits, particularly in the harbour. Toxic equivalency factors (TEF) were used to gauge the toxic equivalency (TEQ) of the PAHs and PCBs that were found. The TEQs were generally low, and were below any guideline levels. The assay revealed the extract containing the PCBs had a bioassay equivalence (BEQ) of 0–93.54 pgTCDDeq. g-1 and the extract containing the PAHs of 0–776.08 pgTCDD-eq.g-1. With a proportion of the sites exceeding guideline limits. The BEQ results were two to three orders of magnitude greater than the TEQs calculated from the concentrations determined by the instrumental analysis, however, followed a similar trend. Additionally chemical analysis was not performed on a full suite of compounds that are able to elicit a response from the cells, which could be a reason why the BEQ and TEQ did not follow a similar trend among some of the samples. It would have been more beneficial to have performed chemical analysis on the 16 priority PAHs (as determined by the United States Environmental Protection Agency), the dioxin-like PCBs and polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDFs) which are all capable of eliciting a response from the cells and have TEF values. The areas that were most affected by contamination of these compounds was the harbour and surrounding canals, and there was point source contamination along the Umhlatuzana, Umbilo, and Amanzimnyana Rivers. All dl-PCBs should be chemically analysed at all the sample areas, as these cause adverse effects to biota. In addition to this, biota should be sampled to determine concentrations of the compounds to determine bioavailability and the degree of bioaccumulation in the food chain. Utilising biomarkers it would be possible to determine stresses of fish. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2014

Polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) are common contaminants of sediment, soils and biological tissues. These compounds pose a significant risk to biological and ecosystem health and functioning due to these compounds being mutagenic, carcinogenic and are known to disrupt the endocrine system. The bioaccumulation and biomagnification potential that these compounds possess mean that they are capable of affecting the entire food chain and are not limited to the organisms that are directly in contact with the compounds Even though there has been an increase in the attention on identifying the presence and impacts that these compounds may have in South Africa, the level of attention is lower than what it is in other countries around the world. Although South Africa has guidelines in place for other pollutants, such as metals, there are no such guidelines in place to monitor PAHs and PCBs.. Industries are known to release both PAHs and PCBs, mainly from incomplete burning processes and the release of oils and fuels in the case of PAHs, and from heat transfer fluids in the case of PCBs. Durban Bay and surrounding areas of eThekwini, KwaZulu-Natal are highly industrialised with many aquatic systems, in which these contaminants are likely to deposit. The aim of this research was to determine the concentrations of these compounds by means of chemical analysis and additionally biological analysis, using the H4IIE-luc bioassay and compare these levels to international guideline levels. It was found that the concentrations of the 23 analysed PAHs were 6.5–3 235.6 ng.g-1 and the concentration of the PCBs analysed were 0–113.83 ng.g-1. Many sites were found to be in exceedance of the guideline limits, particularly in the harbour. Toxic equivalency factors (TEF) were used to gauge the toxic equivalency (TEQ) of the PAHs and PCBs that were found. The TEQs were generally low, and were below any guideline levels. The assay revealed the extract containing the PCBs had a bioassay equivalence (BEQ) of 0–93.54 pgTCDDeq. g-1 and the extract containing the PAHs of 0–776.08 pgTCDD-eq.g-1. With a proportion of the sites exceeding guideline limits. The BEQ results were two to three orders of magnitude greater than the TEQs calculated from the concentrations determined by the instrumental analysis, however, followed a similar trend. Additionally chemical analysis was not performed on a full suite of compounds that are able to elicit a response from the cells, which could be a reason why the BEQ and TEQ did not follow a similar trend among some of the samples. It would have been more beneficial to have performed chemical analysis on the 16 priority PAHs (as determined by the United States Environmental Protection Agency), the dioxin-like PCBs and polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDFs) which are all capable of eliciting a response from the cells and have TEF values. The areas that were most affected by contamination of these compounds was the harbour and surrounding canals, and there was point source contamination along the Umhlatuzana, Umbilo, and Amanzimnyana Rivers. All dl-PCBs should be chemically analysed at all the sample areas, as these cause adverse effects to biota. In addition to this, biota should be sampled to determine concentrations of the compounds to determine bioavailability and the degree of bioaccumulation in the food chain. Utilising biomarkers it would be possible to determine stresses of fish. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2014