Thesis (M.Sc. (Zoology)) -- University of Limpopo, 2018 / This study aimed to determine the effects of water and sediment quality on fish and the effects of land-use on the water and sediment quality of the Steelpoort River system. To achieve these aims, a few objectives had to be met. The water and sediment quality, the level of metal bioaccumulation of two fish species, the level of acetylcholine esterase inhibition in fish brain tissue, as well as changes in land-use over time. The study adds value in the scientific knowledge of the Steelpoort catchment given that there’s little information about it. It is thus a good baseline, which gives direction for further studies conducted within this catchment. The Steelpoort River, is a tributary of the Olifants River system. The Olifants River (Mpumalanga and Limpopo provinces) is a river stressed by anthropogenic activities with the Steelpoort River being a major sub-catchment. The Steelpoort catchment is filled with mines, agricultural activities, and other developments, such as, the construction of a new dam (De Hoop Dam opened 2014), residential areas and malls. The mines within the catchment are mostly platinum and chrome mines. Sampling was conducted for high and low flow at five sampling sites: Two upstream sites, 1 and 2, and three downstream sites 3, 4, and 5. Site 1 is the reference site for the study as this section (ecoregion) was described as “least threatened”. It was hypothesised that high concentrations of metals and nutrients would be present in the water and sediment, and that the metal would be present in fish tissue and would have an effect on human health, that the biomarker AChE would show signs of inhibition within brain tissue, and lastly that land-use characteristics would have an effect on the water and sediment quality, and inhibition of AChE. Water and sediment samples were collected quarterly over a period of a year at five sites, whereas fish samples (Chiloglanis pretoriae and Labeobarbus marequensis) were only collected bi-annually at three sites. The physico-chemical, nutrients, cations and ions, and metals and metalloids were determined. The two fish species were used for metal bioaccumulation and AChE analyses. Human health risk and bio-concentration factor (BCF) analyses were conducted. Using the land-cover details obtained from South African National Biodiversity Institute (SANBI), Department of Environmental Affairs (DEA) and The Council for Scientific and Industrial Research (CSIR), land-use characteristics were determined and evaluated. The in-situ physico-chemical parameters assessed in this study were found to be within acceptable limits of the Target Water Quality Range (TWQR) at all the sites. The Electrical Confuctivity (EC) and Total Disolved Solids (TDS) parameters were highest at Site 5 and lowest at Site 1, this could be due to Site 5 being the last site before the Steelpoort River connects to the Olifants River, hence this site recieves all the ions and solutes from upstream; and the lowest value at Site 1 could be attributed to this site having the least number of lan-use effects. For nutrients, the highest total nitrogen concentration was recorded at Site 5 and the highest phosphate concentration at Site. This river is mesotrophic according to both the total inorganic nitrogen and phosphorus levels. Metals in the water column that were above DWAF guidelines for Aquatic Ecosystems were Al, Ba, Mn and Zn. In the sediment the following metals were above the Canadian sediment quality guidelines: Cd, Cu, Cr and Zn, which can pose a threat to the health of fish through biomagnification through the food chain. Both C. pretoriae and L. marequensis had bioaccumulated metals from the river system. The concentrations of metals in the muscle tissue of C. pretoriae where higher and this could be due to the fact that unskinned samples were used in the case of C. pretoriae. A variety of metals were present in both fish species but Al, Fe, Sr and Zn were present in higher concentrations. Concentrations of metals were highest in samples from Site 5 The human health risk assessment revealed that Pb could cause health related impacts to the humans who consume a single 150 g fish meal once a week in C. pretoriae; and that Co could cause potential risks in the near future. The BCF values revealed that there were more bioconcentrated metals in C. pretoriae than in L. marequensis and this could also be due to different diets. The AChE activity was higher for L. marequensis during high flow at all sites and higher at Site 1 during low flow but lower at Site 5 and equivalent at Site 2 than the AChE activity recorded for C. pretoriae. This could be due to the ability of L. marequensis to expel pesticides from their system before the pesticides affect brain activity by decreasing the function of AChE. Both fish species had more AChE activity during low flow for sites 1 and 2 than during high flow. The high flow AChE activity was higher for Site 5 in both fish species. The results confirm the hypotheses were that metals would be present in fish tissue and would have an effect on human health; and that the biomarker AChE would show signs of inhibition within brain tissue. The agricultural activity has decreased over time within the catchment, from 2000 to 2014 and this could be due to a decrease of fertile land. There has also been a decrease in the mining activity from 2000 to 2009 and then an increase during 2014, where the decrease could be due to the closure of mines at the end of their life span; and the increase in 2014 could be due to the opening of new mines. Residential areas have increased from 2000 through to 2014. The availability of water decreased from 2000 to 2009, and then increased drastically in 2014. The drastic increase is due to the multiple dams that have been built over time in order to provide water resources to the increased population, and also for mining and irrigation purposes. The water quality showed an increase in the NO3, SO4 and PO4; meanwhile the EC has decreased over time. The decrease in EC means that there are fewer ions in the river. The increase in phosphates and nitrates could mean there is a lot of fertilizers and pesticides being used in agriculture even with the decrease in agricultural land-use over the years. The pesticides can also be due to the increase in residential areas, where pesticides are also used to get rid of pests.

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Stream transport is an important process in the dispersion of radioactive material that has been released by man into his environment. Some portion of the radionuclides that enter the stream system may remain in solution. However, a significant amount will become associated with aquatic organisms and sediments in the stream. The relative distribution will depend upon the particular radionuclide and the environmental factors of the stream system. Contemporary sediment samples from preselected locations in the Guadalupe River drainage basin were analyzed for their mineral composition, ion exchange capacity, and radionuclide sorption. The clay minerals were the most significant agents in the radionuclide sorption processes. X-ray diffraction patterns of the clay-sized particles show the presence of a heterogeneous mixed-layered clay mineral complex of poor crystallinity. The degraded nature of these crystallites is suggested by the low intensities and the broad and diffuse diffraction maxima. Ion exchange capacity measurements gave values of 10 to 47 meq/100 grams and projected values of 20 to 73 meq/100 grams of clay material. Radionuclide sorption studies using cesium-137 and strontium-89 were made on the naturally occurring sediments and sediments from which the organic fraction had been removed. Sorption values were compared with mineralogy and ion exchange capacity to obtain points of correlation. Rates of radionuclide sorption and release were highest during the first few moments of contact, but totals slowly continued to increase throughout the seven-day duration of the experiments. Sediments containing the naturally occurring organic fraction had the highest sorption values both for strontium-89 and cesium-137. The organic fraction contributes to the over-all sorption capacity of the sediments, even though some of the organic molecules may block exchange sites on the clay minerals against exchange with the radionuclide. These laboratory experiments indicated that radionuclide sorption in the dynamic fluvial environment was temporary. When the contaminated sediments were placed in conditions simulating a marine environment, 43 percent of the cesium-137 and 42 percent of the strontium-89 were released because of competition for the exchange sites from the more abundant ions in sea water. Even though fluvial releases are considered an acceptable means of radionuclide disposal, it should be emphasized that all stream systems are dynamic, and this disposal is at best temporary. The brief respite gained today may be overshadowed by the ultimate contamination of tomorrow. / text

Increased urbanization in the United States and the rest of the world, has led to more research on the effects it has on the local ecology. Urbanization can be defined as the creation of impervious cover in areas previously covered by natural vegetation (forest, grassland or farmland) as well as the potential influence of sewage treatment plants. Small increases in impervious cover can cause noticeable changes in stream chemistry. The goal of this study is to quantify the impact of smaller industrial cities on water and sediment geochemistry in a largely agricultural watershed. The study area is in east-central Indiana along the west fork of the White River and includes the cities of Winchester, Muncie and Anderson. This area is dominated by agriculture and the impact of cities in the region on water chemistry has not been studied. To evaluate this impact, sampling sites were selected up- and downstream of the three cities to characterize White River water chemistry before and after it flows through the cities as well as sewage treatment plants. Sampling was done over the course of one year to obtain samples characteristic of high and low flow river conditions. Samples were analyzed for major cation and anion concentrations as well as total suspended solids. Metals data was also obtained in sediments, although sampled only twice throughout the study. Results show that sediment load, on average, increases on the downstream side as the river flows through urbanized areas. Chemical analyses show that major cations and anions, Na, K, SO4 and Cl, have distinct spikes in concentration on the downstream side of the cities, as well. Na and Cl are specifically linked to human and urbanized activity, and were up to four times higher downstream of urbanized cities. The concentration of other major ions, including Ca, Mg and NO3, was mostly due to agricultural land use and local bedrock geology. Trace metals characteristic of pollution from automobiles, including Cd, Cr and Zn, showed large increases downstream of urban areas as well. This indicates that even in an area that is largely dominated by agriculture, smaller cities have a quantifiable impact to White River water quality. / Department of Geology

Thesis (M.S.)--University of Tennessee, Knoxville, 2008. / Title from title page screen (viewed on Sept. 23, 2009). Thesis advisor: John S. Schwartz. Vita. Includes bibliographical references.

Thesis (M.S.) -- University of Tennessee, Knoxville, 2006. / Title from title page screen (viewed on Sept. 19, 2006). Thesis advisor: Joanne Logan. Vita. Includes bibliographical references.

The soil usage as well its occupation tend to be increasingly influenced by a number of pressures emanating from its relationship with the environment. This is due to the urgency to maintain the balance between natural ecosystems and the increasing demand to occupy new territorial areas. The cover has important role in the process of securing land and favor maintaining the quantity and quality of water. The areas occupied by agriculture and pasture are more likely to suffer from erosion processes. In these environments the watercourses may also be affected by excess sediment and pollutant particles. The aim of this study was to analyze the dynamics of hydrosedimentological Poxim-Açu/SE river basin by monitoring water quantity and quality. Thus, we intended to present the general characteristics on the environment and sustainability contemplating systemic method in studies of interdisciplinary slant facing watersheds. We used the SWAT model in this study. We have also chosen four usage scenario and ground cover for the watershed. In the survey highlighted that the watershed of river Poxim Acu presents potential areas in the production process of sediments that are linked to both the use and occupation of land, as the topography of the land, and limiting how much water production, since there are few areas covered by native vegetation, where agriculture and pasture dominate the landscape by adding 84% of the occupied area. Mention was also made by using the parameters analyzed the good quality of the river water Poxim-Açu, being classified as Class 1, requiring only simple treatment as determined by CONAMA Resolution 357/05 for this type of class. Regarding the environmental profile of the villagers and Caroba Cajueiro, it was found that the male nature is intense, but respondents still perceive the environment as something separated from the experience of each. / O uso e ocupação do solo tendem a ser cada vez mais influenciados por um conjunto de pressões que emanam do seu relacionamento com o meio ambiente. Isso deve-se pela urgência em manter o equilíbrio dos ecossistemas naturais e pela demanda cada vez maior de ocupar novas áreas territoriais. A cobertura vegetal tem papel muito importante no processo de proteção dos solos e favorecem na manutenção da quantidade e qualidade das águas. As áreas ocupadas por agricultura e pastagens tem maior tendência a sofrer com os processos erosivos. Nesses ambientes os cursos de água também podem ser afetados por excesso de partículas poluidoras e sedimentos. O objetivo dessa pesquisa foi analisar a dinâmica hidrossedimentológica da bacia hidrográfica do rio Poxim-Açu/SE por meio do monitoramento quantitativo e qualitativo da água. Dessa forma pretendeu-se apresentar as características gerais sobre o meio ambiente e sustentabilidade contemplando o método sistêmico nos estudos de cunho interdisciplinar voltado para bacias hidrográficas. Nesse estudo foi utilizado o modelo SWAT, onde foi escolhido quatro cenário de uso e cobertura do solo para a bacia hidrográfica . Na pesquisa destacou-se que a bacia hidrográfica do rio Poxim-Açu apresenta áreas potenciais no processo de produção de sedimentos que estão relacionadas tanto com o uso e ocupação do solo, quanto à topografia do terreno, e limitantes quanto a produção de água, visto que são poucas as áreas coberta por vegetação nativa, onde a agricultura e a pastagem dominam a paisagem somando 84% de área ocupada. Destacou-se também, por meio dos parâmetros analisados a boa qualidade da água do rio Poxim-Açu, podendo ser classificada como Classe 1, necessitando apenas tratamento simples como determina a resolução CONAMA 357/05 para esse tipo de Classe. No tocante ao perfil socioambiental dos moradores dos povoados Caroba e Cajueiro verificou-se que a relação homem natureza é intensa, porém os entrevistados ainda percebem o meio ambiente como algo dissociado da vivência de cada um deles.

M.Sc. / The study looks into the sediment-bound metals (Fe, Mn, Cu, Cr, Cd, Co, Pb, Ni, Zn and Hg) of the Leeu/Taaibospruit catchment, which is impacted by agricultural, industrial and urban development. A number of chemical procedures, including total metal determination, the Tessier-sequential extraction scheme, the BCR Protocol, evaluation of the % TOC and determination of AVS to SEM ratios were applied to sediment samples collected from eight sites along the two rivers in the study area. Samples were collected during both high flow (summer) and low flow (winter) conditions. Following the chemical characterisation, bioaccumulation testing was conducted by exposing chironomid larvae to the sediment samples collected in from the study sites and determining their metal uptake relative to control specimens in uncontaminated sediments. These bioaccumulation results were then considered in conjunction with the chemical parameters in an attempt to identify any trends and correlations. Significant spatial and temporal differences were found in the metal concentrations from the study area. The total extraction results indicated that abundant amounts of Cr and Fe are present throughout the system. This was expected based on the make-up of the underlying geology. In addition, one of the sites, which is in close proximity to the town of Sasolburg, was identified as a potentially contaminated site. This site had significantly higher concentrations of Zn, Cu, Pb and, most notably, Hg when compared to the other sites. The elevated metal concentrations are most evident in samples collected under low flow conditions, but are also seen in the high flow Hg concentrations. Sequential extractions showed that Fe and Cr are concentrated in the residual phases of the sediment. Copper is largely present in the oxidisable fraction under low flow conditions, but also has considerable residual and reducible chemical forms. Manganese and Zn are distributed among all the different chemical phases and are therefore likely to be readily available for uptake by benthic organisms. The TOC was found to be highest during low flow conditions and at those sites with observable amounts of organic debris from the surrounding reeds and other vegetation. The AVS/SEM ratios were used to predict that due to the formation of insoluble metal sulphides, Cd, Cu, Hg, Ni, Pb and Zn are unlikely to be bioavailable at certain sites, i.e. the contaminated site 1 and at site 5, which only has agricultural impacts. In general, the bioaccumulation of Fe, Co, Ni, Cr and Mn was higher in the test larvae than the control larvae. Bioaccumulation of Cu, Pb, Zn and Hg levels were only higher than the control worms at sites where contamination was suspected to have taken place. Average bioaccumulation factors indicated that Hg is the metal that is most readily available for bioaccumulation, followed by Cu, Zn and Mn. All of these metals were bioconcentrated in the tissues of the test chironomids, while levels of Fe, Ni, Cr and Pb were found to be lower in the organisms than in the sediments. Although many of the chemical fractions were found to correlate significantly with the uptake of the different metals, the best overall correlation existed between the bioaccumulated metal and the total non-residual fraction. In fact, the sum of the first four steps of the Tessier-scheme correlated significantly with the bioaccumulated metal for all elements considered in the calculation, except for Pb. Additionally, the predictions made by the AVS model were found to be useful in justifying the behaviour and accumulation patterns of Hg, Zn and Cu at certain sites. The correlations and bioavailability clearly differed spatially, temporally and among the different elements. It is therefore suggested that prediction of the bioavailability and subsequent uptake of sediment-bound metals will require as many chemical and environmental factors as possible, and should include bioaccumulation and toxicity testing in order to examine the validity and completeness of these predictions.

Sediments in the Trinity River were chemically, physically and biologically characterized and assessed for toxicity. Laboratory bioassays were conducted to identify sediments which induced toxic responses in test organisms and to document these responses through time. Metal and organic contaminant concentrations in bottom sediments were measured. Relationships between these concentrations and biological responses observed in laboratory bioassays were determined. Toxicity identification / reduction methods were used to characterize sediment toxicants. Sediment oxygen demand was also measured in resuspended and undisturbed bottom sediments through time. The Background Sediment Chemistry Approach and the Sediment Bioassay Approach were used to assess sediment quality. Sediment toxicity was observed in whole sediment bioassays using Chironomus tentans as the test species. A relationship between sediment contaminant concentration and toxicity was observed in approximately sixty percent of the sediments. Oxygen demand of resuspended sediments was elevated in sediments at two locations on the river. Oxygen demand of undisturbed sediments was elevated at one location on the river. Characterization of sediment toxicants was conducted using EDTA, pH, and carbon treatments and manipulations of the sediments. Aeration tests were also used to evaluate the contribution of volatile organic contaminants to observed toxicity.

Thesis (MSc. (Chemistry)) -- University of Limpopo, 2021 / Surface water from the rivers serves as a source of water for many purposes including drinking, irrigation and animal farming. The quality of surface water deteriorates due to human, animals and industrial waste. Amongst these wastes, selenium and other trace elements contaminants are included. Selenium can either be essential or toxic depending on the concentration and oxidation state. The aim of this current study was to determine the concentrations of inorganic selenium [Se(IV) and Se(VI)] in water and sediment samples collected from Blood and Mokolo Rivers in Limpopo Province, South Africa. Water and sediment samples were collected from 10 different sampling sites from down to upstream of each river. Water samples were acidified with 1% ultra-pure HNO3 and analysed directly for total selenium concentration. The accuracy of the method was validated using SRM1643f (trace elements in water reference material). Sediment samples were digested using microwave assisted acid digestion for the determination of total concentration of selenium. The accuracy of the method was evaluated using SRM 8704 (sediment standard reference material). Total concentration of selenium in both water and sediment samples were quantified using ICP-MS. The total concentration of selenium in water samples from Blood and Mokolo River were found to be in the range of 0.0682 to 2.72 μg/L and 0.0851 to 25.4 μg/L respectively. The selenium concentrations in all sediment samples were found to be below instrument detection limit of 0.0571 ng/g in both rivers. An adopted SPE method using Dowex 1 x 2 resin (chloride form) as an adsorbent material to preconcentrate and separate Se(IV) and Se(VI) was used for the speciation in water samples. Both Se(IV) and Se(VI) were retained on the column. The retained Se(IV) and Se(VI) were eluted using 15 mL 1 M HNO3 and 3 M HNO3 respectively at a flow rate of 2 ml/min and diluted to the final volume of 20 mL. The instrument detection limit was 0.192 μg/L and 0.108 μg/L for Se(IV) and Se(VI) respectively. The validation of the method was performed by using SRM 1643f and solutions of known concentrations. The water samples were adjusted to an optimum pH of 6 throughout the speciation analysis. The Se(IV) had higher percentage recoveries of 95 – 114% than Se(VI) with 53%. vi Concentrations of Se(IV) and Se(VI) in Blood River ranged from 0.0411 to 0.820 μg/L and 0.0811 to 1.75 μg/L respectively. Concentrations of Se(IV) and Se(VI) in Mokolo River ranged from 0.135 to 2.79 μg/L and 0.0961 to 14.8 μg/L respectively. The inorganic selenium species in water samples were also determined by using the adopted online mode of HPLC-ICP-MS with Hamilton PRP-X100 column. The separation of the two species was achieved by using isocratic elution of 100 mM NH4NO3 at pH 8.5 in 8 min. The method was successfully validated using SRM 1643f. The LOD of 0.842 μg/L and LOQ of 2.81 μg/L for Se(IV) were achieved. The LOD of 0.690 μg/L and LOQ of 2.30 μg/L for Se(VI) were achieved. The Se(IV) and Se(VI) concentrations determined using HPLC-ICP-MS were found to be in good agreement with Se(IV) and Se(VI) concentrations obtained using SPE in both rivers. The presence of Se(IV) and Se(VI) in water samples in Blood and Mokolo Rivers indicates that industrial and agricultural activities taking place near the rivers have an effect on the quality of the water. The selenium in water may be due to wastes from industrial, municipal and agricultural runoffs. The absence of selenium in sediment samples suggests that the area where the rivers are located is not rich in selenium.