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dc.contributor.advisorBouwman, H.
dc.contributor.advisorQuinn, L.
dc.contributor.authorSwiegelaar, Caitlin Reneé
dc.date.accessioned2017-10-19T10:42:44Z
dc.date.available2017-10-19T10:42:44Z
dc.date.issued2017
dc.identifier.urihttp://hdl.handle.net/10394/25873
dc.descriptionPhD (Environmental Sciences), North-West University, Potchefstroom Campus, 2017en_US
dc.description.abstractPersistent organic pollutants (POPs) can be classified as widely distributed organic compounds, sharing a suite of physical and chemical properties, occurring in all environmental compartments with serious toxicological potential. Due to the properties and potential danger associated with POPs, they have come under scientific scrutiny and have commanded attention from governmental and non-governmental groups alike. The global recognition of the inherent risk of POPs culminated in the development of the Stockholm Convention (SC). The main aim of the SC is to protect humans and the environment from chemicals that are persistent, bio-accumulate and tend to become widely geographically distributed. South Africa, as a signatory of the SC has the responsibility to undertake appropriate research, development, monitoring and cooperation pertaining to persistent organic pollutants. There is growing concern over the toxicity, environmental distribution and bio-accumulation of a group of POPs, namely perfluorinated compounds (PFCs). These compounds are widespread toxic POPs that are used extensively in various industrial applications. Contrary to the bio-accumulative pattern of most POPs that partition into fatty tissues, PFCs bind to proteins. Although data concerning PFCs is limited for the South African environment, these compounds have been detected in human and wildlife populations. This study focussed on the analysis of selected PFCs from multiple environmental matrices in the Orange-Senqu River basin (OSRB), the largest river systems in South Africa. Matrices analysed included fresh water, sediment and waste streams, fresh water fish, as well as birds nesting in aquatic environments. The aim of the project was to determine the levels of twelve PFCs [perfluorobutanesulfonic acid (PFBS), perfluorohexanoic acid (PFHxA), perfluoroheptanoic acid (PFHpA), perfluorohexanesulfonic acid (PFHxS), perflurooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA) perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnA), perfluorododecanoic acid (PFDoA), perfluorotridecanoic acid (PFTrDA) and perfluototetradecanoic acid (PFTA)] in the Orange River Basin where high concentrations were found previously, and to establish possible sources, pathways, exposures and hazards of the PFCs identified and quantified. Water samples contained quantifiable concentrations of PFBS (0.24 ng/L) and PFUnA (0.17 ng/L). The presence of these compounds is likely from use in crop farming, or as surfactants in mining or in the textiles and upholstery industries. In the case of sediments and tailings, only six samples contained PFCs. In sediment PFOS (2 – 4 ng/g) and PFHxA (5 ng/g) was detected, and in tailing I found PFHxA (4 ng/g) and PFOA (8 ng/g). Possible sources identified include aviation, mining and/or wastewater treatment plants. None of the fish samples analysed had detectable concentrations, whereas all PFCs analysed for were detected in eggs. However, the detection frequency varied from one compound in a single sample to PFOS with a 95% detection rate in eggs. The PFOS concentrations ranged from 0.3 – 2800 ng/g wm, with the highest median PFOS concentration detected in African Darter eggs (1100 ng/g wm). The lowest concentrations were in African Sacred Ibis eggs (10 ng/g wm). As reported in literature, I found that long-chain PFSAs were predominant in wild bird eggs followed by long-chain PFCAs, short-chain PFCAs and short-chain PFSAs. This pattern is likely due to differences in the bio-accumulation potential of PFCs based on their chain length. To further investigate the concentrations and patterns of PFCs in wild bird eggs, multivariate statistical analysis was performed. A cluster analysis indicated a grouping where PFOS was separated from all the other congeners. This coincides with literature, as PFOS is the main congener found in biota. The congener profile of PFCs in individual species were compared. PFOS was the dominant congener detected in all bird species. However, PFNA, PFDA and PFUnA concentrations were statistically significantly different between the bird species. The significance of congeners could be contributed to the foraging method and/or type of diet. The African Darter had the highest concentrations of PFCs compared to any other species, followed by the Reed Cormorant and White-breasted Cormorant. The congener profiles of PFCs in bird eggs were further investigated using principle component analysis (PCA) indicating that PFCs varied depending on species, feeding habitat, and collection site. Additionally, the concentrations of PFCs differed significantly between species. These differences could be attributed to multiple factors such as exposure routes (diet, feeding habitat, and area of sampling) and differences in toxicokinetics (absorption, distribution, transformation, and elimination) of PFCs. The distribution of congeners at different sites were further investigated. Welverdiend had the highest frequency of detection of PFC congeners. The possible sources associated with these congeners in the surrounding area are WWTP, farmlands, active and abandoned mines. However, ratios of PFHpA, PFOA, and PFNA indicated precursor breakdown and precipitation as a contributing source. Schoemansdrift had higher concentrations of PFNA and PFDA than any other site. The high concentrations of PFOS were found in Orkney and could be due to mining utilised in the surrounding area. Upington had the highest levels of PFTrDA that seems to be associated with a WWTP. Toxicological data is dependent on which no-observed-adverse-effect level (NOEL) is used from literature. If the least conservative option is chosen, with maximum PFOS levels: African Darter, Reed Cormorant, White-breasted Cormorant, Grey Heron, Cattle Egret, Glossy Ibis and Black-headed Heron will all have levels above the NOEL. In conclusion; PFCs are present in the South African environment, with high concentration levels found in bird eggs. Although there is not yet consensus on the toxicological no-observed-adverse-effect level (NOELs) for PFCs in birds, the PFC exposure in conjunction with exposure to other POPs and organic toxicants may have detrimental effects on the South African aquatic bird population. The combined toxicological effect of these chemical loadings on bird populations may be a cause for concernen_US
dc.language.isoenen_US
dc.publisherNorth-West University (South Africa), Potchefstroom Campusen_US
dc.subjectPOPsen_US
dc.subjectPerfluorinated compoundsen_US
dc.subjectPFOSen_US
dc.subjectWateren_US
dc.subjectSedimenten_US
dc.subjectFishen_US
dc.subjectWild bird eggsen_US
dc.subjectSouth Africaen_US
dc.titleSources, pathways, exposures and hazards of perfluorinated chemicals in the Orange River Catchmenten_US
dc.typeThesisen_US
dc.description.thesistypeDoctoralen_US
dc.contributor.researchID10063773 - Bouwman, Hindrik (Supervisor)
dc.contributor.researchID12243531 - Quinn, Laura Penelope (Supervisor)


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