Thesis (M.Sc. (Zoology)) --University of Limpopo, 2014 / Contamination of aquatic ecosystems by agricultural and mining activities, as well as by industrial discharges and urbanization in the catchment of the South African river systems has been the cause of increasing public concern. These activities may result in water pollution. One such river is the Olifants River System in Mpumalanga and Limpopo provinces which is highly impacted. The main aim of the study was to assess the impact of the water and sediment quality on the health of Clarias gariepinus and Labeo rosae and human risk when the fish is consumed at the Phalaborwa Barrage in the Lower Olifants River, Limpopo Province. This was achieved by assessing the water and sediment quality of the barrage at the three sampling sites; assessing the condition of the fish and the fish parasites by applying the fish HAI (Health Assessment Index) and PI (Parasite Index); determining the bioaccumulation of selected metals in the muscle tissue of the two fish species; and to determine the Human health risk factor upon consumption of fish contaminated with metals at the barrage. Ten fish from each fish species were collected seasonally at each site using gill nets of different mesh sizes. Standards methods were followed when testing selected water and sediment constituents. For water quality sampling, the water samples were collected over four seasons (autumn, winter, spring and summer) at three sites (inflow, wall and below wall) from April 2010 to January 2011. Sediment samples were also collected using a Friedlinger mudgrab (225cm3) at the three sites during winter and summer. Fish hosts were examined for mobile ectoparasites, weighed and measured. Blood samples were drawn and skin smears were made. Fish were killed, dissected and all external and internal organs were examined as prescribed in the fish health assessment index. The condition factor was determined for each fish population. All parasites were collected, fixed and preserved using standard methods. The highest water temperature (28.5 ºC) was in spring and lowest in winter (18 ºC). Overall pH was in an alkaline condition as it ranged from 7.4 to 8.7. Most water quality parameters were recorded at higher concentration in spring which includes; water temperature, pH, conductivity, salinity, TDS, alkalinity, and turbidity. Major ions (cations and anions) recorded were all within the TWQR. Sulphates concentrations were all within the TWQR. Calcium concentration levels exceeded the typical concentration limit in spring but the levels were still within the TWQR for domestic use. Nutrients levels (nitrate, nitrite, sulphate) were very low which indicate oligotrophic conditions. Highest total nitrogen was recorded in spring which is an indicative of eutrophic conditions. Highest phosphorous concentrations were recorded in winter, spring and summer which are an indicative of eutrophic conditions. Noticeable elevated levels were recorded at the inflow in summer which is an indicative of hypertrophic conditions. The results of the metals concentrations analysed demonstrated that metals within the barrage are present in trace amounts in the water. Analysis of the metal concentrations in water, sediment and fish muscle tissue revealed that the sediment contained the highest concentrations of metals followed by fish tissue and then the water. Metals that were detected in the water column includes; aluminium, antimony, arsenic, barium, boron, iron, manganese, selenium, strontium and tin. Metals that were detected at concentrations above the TWQR for aquatic ecosystem were; aluminium, antimony and selenium. Arsenic, cadmium and chromium were recorded at concentrations above the detection limit as suggested by CCME. Zinc concentrations were recorded at levels below suggested detection limit. Aluminium, barium, boron, cadmium, chromium, manganese, selenium and strontium were all detected at elevated levels in water and above the TWQR. Among the metals recorded in the water column, significant seasonal variations in concentration were found for aluminium, barium, boron, lead selenium and strontium whereas only boron showed a significant variation between sites. In comparison to the metals concentrations accumulated in the muscle tissue of both fish species. It was noted that C.gariepinus accumulated more metals than L. rosae; however L. rosae accumulated more metals at elevated concentrations than C. gariepinus. The metals that were accumulated at elevated levels in C. gariepinus were barium, boron, zinc and selenium. In L. rosae, iron, aluminium, strontium, titanium, vanadium and arsenic accumulated at elevated levels. All these metals pose a high risk to fish and human’s health. The highest population HAI was recorded in summer for both fish species. The lowest HAI value was recorded in autumn for both fish species. Although a high HAI population value was recorded higher in summer for both fish species, in general both fish species from the barrage were in a normal condition. A high number of ectoparasites were recorded in L. rosae than in C. gariepinus while high numbers of endoparasites were recorded in C. gariepinus than L. rosae. The dominating ectoparasites for both species were from the class monogenea. Although the prevalence for Contracaecum sp. in C. gariepinus was 100% in all season, it did not influence the condition of the host. None of the parasites identified from both fish species neither reached alarmingly infection levels nor caused any visible damage to the host. In conclusion, the water quality at the Phalaborwa Barrage is slightly polluted based on the water quality parameter(phosphorous) presence and recorded of some metals at the inflow that were recorded at elevated levels above the TWQR. Further recommendations are refereed such as extension of this study to all tributaries and to include other fish species in addition to constant monitoring of the impoundment.

This study was carried out in the Souris and Turtle Rivers in North Dakota. The aim of this study was to develop multi-element fingerprints of the Souris River and Turtle River sediments and to evaluate the suitability of these fingerprints to assess the geographic origin of potential pollutants of the two rivers. Preliminary analysis of Souris River sediment samples confirmed that the multi-element fingerprinting can be used to assess the sediment and contaminant loading patterns. Laboratory experiments were performed to assess the validity of linear mixing assumption in multi-element fingerprinting studies. The results of these experiments verified the assumptions and showed that there is a statistically significant spatial and temporal variation in the element concentrations depending on their mobility and re-deposition. Field studies were conducted in the Souris River and Turtle River to assess the variation of element concentrations in the top riverbed samples along the main rivers and their tributaries. The sediment contribution from the tributaries and the phosphorus concentrations in the main channel were used to calculate the phosphorus contributions from the tributary sediments to the Souris River. The differences in phosphorus contributions from tributaries were related to land use, underlying geology, and the size of the watersheds of the tributaries in the Souris River watershed. Similar analysis was used in the Turtle River to calculate Arsenic, Cadmium and Selenium contribution from the tributaries to the Turtle River. The differences in the contribution of these elements were related to the underlying geology and the size of the watersheds. This study provides a detailed analysis of element concentrations and relative sediments and element loading rates from the tributaries to the main rivers along the Souris and Turtle Rivers in North Dakota. The multi-element fingerprinting technique can be successfully used as a tool to identify the relative contribution of sediments and assessing and tracing pollution sources in rivers. Multi-element fingerprinting provides a relatively low cost, rapid tool for sediment tracking, without the need for addition of exotic chemicals such radio-tracers or dyes to natural ecosystems. / North Dakota State University. College of Science and Mathematics / North Dakota State University. Department of Biological Sciences. Environmental Conservation Sciences Program / North Dakota Department of Health / ND INBRE / North Dakota Water Resources Research Institute / North Dakota State Water Commission

Thesis (MscEng)--University of Stellenbosch, 2005. / ENGLISH ABSTRACT: The environmental impacts of manmade changes to rivers are, in modern days, extremely important. The impact needs to be quantified in order to predict future happenings and to assist in determining preventative measures. Dam construction forms an essential part of modern life to provide the necessary water demand for the ever increasing population. One manmade change that has a major impact on rivers is large dam developments in the upper reaches of rivers. These developments normally have the following effects on the lower reaches of the river due to the change in flow regime: • Narrower main channel, • Deeper main channel, • Reduced sediment transport, • Changes in sediment erosion and deposition patterns, • Less frequent flood plain inundation, • Overgrown flood plains, • Changes in ecological and biological parameters. All the above mentioned factors play an important part in the stability of the ecological and biological parameters. Prior to construction of a dam, however, the baseline ecological, physical Ichemical, hydrological, hydraulic and social conditions of the river system, including its associated groundwater, estuarine and floodplain components, would need to be established, to allow clear identification of future changes as a result of implementation of the instream flow requirements (lFR), as well as to guide the post-construction monitoring programme itself. The discharge and sediment transport changes that might occur as a result of the Berg River Dam development was thoroughly investigated in this reseach. The physical processes and mathematical modelling that formed part of this investigation are discussed in this thesis. The mathematical modelling was carried out using MIKE 11, software developed by the Danish Hydraulic Institute for Water and Environment. This program was developed especially for one dimensional modelling of hydrodynamics and sediment transport within a river system. The results obtained from the simulations were used to calculate a hydrodynamic and sediment mass balance for both the pre and post dam scenarios in the Berg River, Western Cape. The influence of artificial flood releases from the Berg River Dam which is currently under construction was also investigated. Most of the data needed for the calibration and verification of the mathematical model was obtained from field work. Suspended and bed load sediment samples were taken in order to aid in the calibration of the sediment transport model. The bed roughness coefficients of the various sections of the river were calibrated against actual recorded water levels measured during flood events that occurred in 2003 and 2004. An intensive study of the incipient motion of cobbles and boulders in the upper reaches of the Berg River was carried out. Unfortunately it has to be stated that the transport of cobbles and boulders cannot be simulated by most computer programs as almost all the transport models available are only defined up to a maximum diameter of 20mm. The lack of consistent sediment load data as well as the low rainfall during 2003 and 2004 presented problems during the calibration of the sediment transport model; it is therefore recommended that sediment load sampling is continued for at least two years in order to verify the calculated sediment yield for the various catchments. From this study it can be concluded that the Berg River Dam will have a significant effect on the downstream river morphology of the first 70 kilometres of the river. Thereafter the effect will decrease to a minimum. The proposed artifical flood releases are effective in reinstating the river to its present state. This study also showed that a fully hydrodynamic model of a large river system such as the Berg River can be calibrated and validated. / AFRIKAANSE OPSOMMING: Die omgewingsimpak van mensgemaakte veranderinge in natuurlike riviere raak meer en meer belangrik. Hierdie impak moet gekwantifiseer word om sodoende toekomstige gebeurtenisse te verstaan en om die nodige voorkomingsmaatreëls in werking te stel. Om aan die waterbehoefte te voldoen vorm damkonstruksie 'n belangrike deel van die hedendaagse samelewing. Damme is moontlik een van die veranderinge aan die ewewig van riviere wat die grootste impak op die stroomaf dele van die rivier het. Die volgende veranderinge ten opsigte van die hoofkanaal word meestalopgemerk na die konstrukie van 'n dam in die hoërliggende dele van riviere: • Nouer hoofkanaal, • Dieper hoofkanaal, • Afname in die volume sediment wat vervoer word, • Veranderinge ten opsigte van die erosiepatrone, • Vloedvlaktes word minder oorstroom, • Toegegroeide vloedvlaktes, • Veranderings aan die ekologiese en biologiese parameters. Die bogenoemde faktore speel 'n belangrike rol ten opsigte van die stabiliteit van die ekologiese en biologiese veranderlikes. Alvorens die konstruksie begin moet die natuurlike ewewigstoestand van die rivier ten opsigte van die ekologiese, fisiese, chemiese, hidrologiese, hidrouliese, en sosiale faktore gemeet word. Dit moet gedoen word om sodoende toekomstige veranderinge wat moontlik mag plaasvind as gevolg van die damkonstruksie en die omgewingsloslatings te kwantifiseer. Hierdie metings word ook gebruik om die na - konstruksie monitering te evalueer. Die veranderinge ten opsigte van vloei en sedimentvervoer wat moontlik mag plaasvind as gevolg van die Berg Rivier Dam konstruksie is noukeuring ondersoek. Die fisiese prosesse as ook die wiskundige modelle wat gedurende hierdie studie aangewend is word in hierdie tesis bespreek. Al die wiskundige modellering is met MIKE 11 wat deur die Deense Instituut vir Water en Omgewing ontwikkel is, uitgevoer. Hierdie sagteware is spesifiek vir die een dimensionele simulasie van hidrodinamika en sediment vervoer van riviere ontwikkel. Die resultate wat verkry is, is gebruik om 'n hidrodinamiese en sedimentvervoer massabalans vir beide die voor - en na - dam toestande op te stel. Die effek van beheerde, kunsmatige vloede is ook ondersoek. Die meeste van die data wat benodig word om die wiskundige model the kalibreer is verkry deur fisiese veldwerk te doen. Sediment monsters is geneem gedurende die winter seisoen van 2003 en 2004. Hierdie data is gebruik om die sediment vervoer model te kalibreer. Die bodemruheid van die verskillende dele van die rivier is gekalibreer teen gemete vloedhoogtes tydens 2003 en 2004. 'n Deeglik studie van die begin van beweging van die groter partikels wat in die bolope van die Berg rivier aangetref word is uitgevoer. Ongelukkig moet dit genoem word dat hierdie een van die groot tekortkominge is van die model aangesien dit nie in die sedimentvervoer model ingekorporeer kan word nie omdat die meeste van die sedimentteorieë wat tans beskikbaar is net gedefinieer is tot 'n partikel groote van 20 mm. Die tekort aan deurlopende sediment lading data as ook die lae reënval gedurende 2003 en 2004 het probleme veroorsaak tydens die kalibrasie van die sedimentvervoer model. As gevolg hiervan word daar aanbeveel dat die insameling van sedimentdata vir ten minste nog twee jaar volgehou word ten einde die beskikbaarheid van sediment in die verskeie opvanggebiede deeglik na te gaan. Uit hierdie studie kan afgelei word dat die Berg rivier dam 'n beduidende effek op die morfologie van die eeste 70 kilometer van die Berg Rivier sal hê. Verder stoomaf sal die effek minder sigbaar wees. The beheerde kunsmatige vloedloslatings speel 'n beduidende rol in die normalisering van die sedimentvervoer van die Berg rivier. Hierdie studie toon dat 'n volledige hidrodinamiese model van 'n groot rivierstelsel gekalibreer kan word.

The Columbia River is the largest fluvially dominated estuary in the Pacific Northwest, yet the Holocene transgressive fill of this system has not previously been studied. Nearly 1500 industry borehole and water well records in the lower Columbia River basin (LCRB) were analyzed. These records document the sedimentary infilling of the lower 120 miles of the drowned river valley that occurred during the Holocene marine transgression (10-0 ka) . Of particular importance is a key stratigraphic marker horizon of volcanic tephra that has been identified throughout the LCRB. INAA was used to determine the geochemical composition of the target tephra layer. The tephra geochemistry was then compared to geochemical data from potential Cascade source volcanos to determine whether the tephra layers are geochemically related, and the possible age and source of the tephra. The geochemical comparisons indicate that the suspect tephra horizon was derived from the climax eruption of Mount Mazama approximately 6845 years ago. Cross-sections have been constructed that record the lateral and longitudinal depositional development of the river basin. Sediment grain size distribution data have also been compiled and shows that grain size distribution does not change with respect to subsurface elevation within the LCRB. The results indicate that the LCRB has been dominated by fine sand deposition throughout the Holocene period, and silt and clay sized fractions were bypassed through the system to be deposited offshore. A total volume of 74.6 km3 of sediment has accumulated in the basin since the time of the catastrophic floods 12,700 years ago. Sediment volume analysis was used to predict past fluvial sediment supply rates and sediment retention. The volume of sediment deposition from early to late Holocene time has decreased by a factor of 2.4. Sedimentation rates in the basin are estimated from a basin isopach of the Holocene fill and from an extrapolated sediment sea-level curve. Basin sedimentation rates ranged from 12. 6 mm/yr-1 for the early Holocene to 2. 5 mm/yr-1 for the late Holocene period. This factor of 5 decrease in the sedimentation rate also indicates that the Columbia River bypassed much of its fine grained fraction through to the marine environment during the mid-late Holocene.

Thesis (M.Sc. (Zoology)) --University Limpopo, 2013 / Major anthropogenic activities such as, mining, coal-fired power stations and intensive agricultural practices in the upper catchment area of the Olifants River, have a dramatic impact on the water quality downstream. As a result the river is presently the third most polluted river in South Africa. The aim of this study was to assess the impact of water and sediment quality on the health of Labeo rosae and Schilbe intermedius. The aim was accomplished by applying the Fish Health Assessment Index (HAI) which includes the Parasite Index (PI) at Flag Boshielo Dam in the Middle Olifants River, Limpopo Province. This was achieved through; assessing the water quality of the dam by determining the levels of physical and chemical constituents in the water at three sampling sites, determining the bioaccumulation of selected metals in the muscle tissue of the two fish species, assessing the fish health (including the fish condition factor) and the fish parasites in the dam by using the fish HAI and PI, and ascertaining the Human Health risk factor upon consumption of fish contaminated with metals from the dam. The water and sediment quality were seasonally sampled at three sites in the dam: inflow, middle and wall. Dorsal muscle tissues from both fish species were collected for metal bioaccumulation analyses. The water, sediment and fish muscle tissue samples were analysed by an accredited laboratory by means of ICP-OES spectrometry. For the fish health and parasites, ten fish per species were collected seasonally (July 2009 to April 2010) by means of gill nets and examined at a field laboratory using the HAI and PI protocol. Generally the water quality of Flag Boshielo Dam was acceptable for aquatic ecosystems according to the SAWQG with the exception of phosphorus and some metals at the inflow area. The pH ranged between slightly acidic to alkaline values; water temperature: 15°C to 26°C; water hardness medium soft, salinity within the freshwater range; turbidity in the clear water range. The TDS and major ions (salts) were acceptable for the duration of the study. The highest concentrations of nutrients (specifically phosphorus) as well as metals (aluminium, cadmium, copper, iron and lead) were recorded at the inflow area of the dam. The nutrients were very low except the eutrophic range phosphorus concentrations recorded at the inflow whereby, the Elands River may be an additional source of nutrients into Flag Boshielo Dam. The metals that were recorded above TWQR are; aluminium, cadmium, copper, iron and lead, of which were mostly recorded at the inflow. However, statistically there was no significant difference among the three sampling sites. The metal concentrations at the inflow were recorded only slightly higher than the middle and the dam wall. The main source of the metals may be the water coming from catchment area of the dam given the intensive agricultural activities taking place between Loskop Dam and Flag Boshielo Dam. Sediment and bioaccumulation: All the metals were recorded at higher concentrations in the sediment than in the water and fish muscle tissue, except antimony, selenium and strontium. The most abundant metals recorded in the sediment were iron and aluminium. However, the concentrations above the TEL were cadmium, nickel and zinc. The elevated metal concentrations in the sediment are indicating that the metal load in the sediment of Flag Boshielo Dam could be a potential risk for the aquatic biota if they become bioavailable. Antimony, selenium and strontium metal concentrations were recorded at higher concentrations in the muscle tissue of both fish species than in the sediment and water. Iron was the most accumulated metal in the muscle tissue of both fish species. In terms of numbers, more metals were recorded in the muscle tissue of S. intermedius than in L. rosae however the metal concentrations were higher in the latter. This can be attributed to their different trophic levels in the food chain; L. rosae is a primary consumer while S. intermedius is a tertiary consumer. However, the metals that accumulated in the fish muscle tissue were indicative of bio-availability of the toxic metals in the dam and not water/sediment pollution. According to a Human Health risk assessment (Chapter 3), metals that may have risks upon consumption of L. rosae are; antimony, arsenic, chromium, iron and vanadium; for S. intermedius are; antimony, chromium, iron, vanadium and arsenic (in descending order). These metals may pose toxic and carcinogenic risks to humans. Therefore, the rednose labeo (L. rosae) and to a lesser extend the silver catfish (S. intermedius) fish species from Flag Boshielo Dam may not be suitable for humans if consumed above 350 g per week. Fish health and parasites: The Health Assessment Index (HAI) values of the two fish species differed significantly with higher index values recorded for S. intermedius than L. rosae. Besides the Parasite Index (PI), abnormal haematocrit readings, liver conditions, skin lesions and clubbed gills are the necropsy anomalies that contributed predominantly to the HAI. Overall, the PI contributed mostly to the total HAI value. The parasite load and therefore also the mean intensity, mean abundance and prevalence of S. intermedius were higher during all seasons than that of L. rosae. The dominant ectoparasites for both species were from the Class Monogenea and the dominant endoparasites were nematodes. Out of 40 L. rosae sampled, 139 parasites were retrieved; five parasite species were ectoparasites and two endoparasites. From the 40 S. intermedius sampled, 2473 parasites were retrieved, from which two species (one genus) were ectoparasites and three species were endoparasites. The condition factor is used to compare the “condition”, “fatness” or wellbeing of fish and it is based on the hypothesis that heavier fish of a particular length are in a better physiological condition. The L. rosae had a better condition factor, recorded at values less than (2) as compared to S. intermedius (>2). The cause of the HAI necropsy anomalies may have been also from parasite load other than the metals in the water and sediment. However, the HAI alone cannot be used for metal pollution, unless it is done in conjunction with a histopathological study of the tissues/organs. Therefore, the cause of the recorded anomalies from both fish species is inconclusive. On the hand, fish can be used as bioindicators because the accumulated metals in the fish tissues are indicative of the bioavailability of metals in Flag Boshielo Dam.

Thesis (Ph. D.)--University of Hong Kong, 2010. / Includes bibliographical references (p. 199-216). Also available in print.

published_or_final_version / abstract / toc / Geography / Doctoral / Doctor of Philosophy

This study represents an integrated and holistic assessment of the eziMbokodweni Estuary’s water and sediment quality. The estuary was once relatively un-impacted but now flows through a highly anthropogenically-modified catchment, comprising industrial and residential developments (formal and informal), and the eziMbokodweni Wastewater Treatment Works, furthermore the floodplain has been completely transformed to accommodate the Amanzimtoti golf course. Flow from the highly degraded Isipingo River and Estuary is occasionally diverted into the eziMbokodweni and the Southern Sewage Works Outfall, one of the largest deep sea sewage outfalls in the eThekwini Municipality, is located at sea, approximately 1.5 km south of the estuary mouth. Estuarine health can be studied on various fronts, in this study, the following variables were monitored in the water and sediment columns, seasonally for spring and neap tides: heavy metals, nutrients, bacteria and selected physico-chemical parameters. The results demonstrated that the eziMbokodweni catchment was a major contributor of heavy metals and nutrients to the estuarine system. The quantity of the majority of heavy metals and nutrients transported by the river at the upper estuary exceeded the amount exported to sea at the estuary mouth-nearshore interface, resulting in the estuary accruing large quantities of material seasonality. It was noted that the nearshore waters are enriched, as a variety of heavy metals and nutrients entered the estuary mouth during flood tide episodes. A range of heavy metals were detected within the sediment profiles obtained from the estuary, with fine to medium grained sediment exhibiting greater heavy metal content, in some cases, multi-fold higher than that detected in medium to coarse grained sediment. Geochemical indices were employed to ascertain the extent to which these metals constituted a pollution threat to the environment. The contamination factor calculated for all sediment layers and sampling sites implied low contamination. The enrichment factor calculated for the majority of heavy metals alluded to natural causes while some heavy metals exhibited significant to extremely high levels of enrichment thus implicating anthropogenic causes as likely sources of these heavy metals. The degree of contamination of the estuary was classified as low. Overall, the heavy metal and nutrient content detected in the sediments were low as compared to the large quantities detected from the budget. This indicates that natural mechanisms exist which facilitate the utilization or removal of these heavy metals and nutrients from the estuary. It is proposed that the most significant manner by which these heavy metals and nutrients are eliminated from the estuary is through episodic flood events that scour and strip fine grained sediment from the estuary bed. The pH assessment of the estuary revealed that this environment was slightly basic through most of the year with mildly acidic conditions noted during winter. The average Dissolved Oxygen levels were within acceptable levels, with the exception of winter when levels were very close to hypoxic conditions. The average Total Dissolved Solid content indicated that the estuary was compliant with the target water quality range for domestic use on selected seasonal-tidal cycles, and the average Electrical Conductivity levels were compliant with the ideal target water quality range for aquatic ecosystems and domestic use as per the South African water quality guidelines (DWAF, 1996a-e). A salinity gradient was evident in the estuary, as salinity levels decreased with distance from the estuary mouth. The saline nature of the lower estuary provided for the flocculation of material, which was alarming as large quantities of heavy metals and nutrients were detected in the estuary. The lower estuary is therefore susceptible to contamination due to the salinity regime and the dominance of fine grained sediment. The demand for oxygen in the estuary was high during summer, autumn and spring, and within acceptable levels for natural waters during winter. Extremely high levels of Chemical Oxygen Demand were recorded in the estuary which provides prime growth and survival opportunities for bacteria. This correlated with the results from microbiological investigations as high levels of bacteria were noted within the estuary, in both the sediment and water columns. The detected quantities of Total Coliforms, Faecal Coliforms and Escherichia Coliforms exceeded the target water quality thresholds for domestic and full contact recreational use. While at selected sites, the recorded Faecal Coliforms and Escherichia Coliforms levels were deemed compliant for intermediate contact recreational use. However, these sites were not compliant throughout the sampling period. Overall, the upper and mid-estuary exhibited greater counts of bacteria, in both the sediment and water column, than the estuary mouth and was attributed to factors such as flushing, sediment particle size, salinity and the ‘dilution effect’. Furthermore, the sediment of the eziMbokodweni Estuary is serving as a reservoir for bacteria. A number of options have been proposed to improve the degraded state of the eziMbokodweni Estuary and are ultimately aimed at curbing the anthropogenic input of these contaminants. The insight gained from this study provides the database from which more integrated and holistic estuarine management strategies can stem, that are applicable not just to the eziMbokodweni Estuary but estuaries in general. / M.Sc. University of KwaZulu-Natal, Durban 2013.

Thesis (Ph. D.)--Utrecht University, 2007. / Vita. Includes bibliographical references (p. 197-209).

Thesis (M.Sc.)--York University, 2005. Graduate Programme in Earth and Space Science. / Typescript. Includes bibliographical references (leaves 136-151). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:MR19718