• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 59
  • 2
  • 1
  • Tagged with
  • 76
  • 76
  • 76
  • 76
  • 39
  • 27
  • 26
  • 20
  • 17
  • 16
  • 14
  • 13
  • 12
  • 9
  • 9
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Comparison of water quality between sources and between selected villages in the Waterberg District of Limpopo Province; South Africa: with special reference to chemical and microbial quality.

Makgoka, Seretloane Japhtaline January 2005 (has links)
Thesis (MPH)--University of Limpopo, 2005 / Water and sanitation inadequacy is still an environmental health challenge in several regions worldwide and a billion people lack access to safe water, while 2.4 billion people have inadequate sanitation [2]. Assessment of water quality by its chemistry includes measures of elements and molecules dissolved or suspended in water. Commonly measured chemical parameters include arsenic, cadmium, calcium, chloride, fluoride, total hardness, nitrate, and potassium [16]. Water quality can also be assessed by the presence of waterborne microorganisms from human and animals’ faecal wastes. These wastes contain a wide range of bacteria, viruses and protozoa that may be washed into drinking water supplies [21]. Three villages were selected for water quality analysis, based on their critical situation regarding access to water and sanitation: namely, Matlou, Sekuruwe and Taolome villages, situated in the Mogalakwena Local Municipality within the Waterberg district of the Limpopo Province, South Africa. A proposal was written to the Province of North Holland (PNH) and was approved for funding to start with the implementation of those projects, with 20% of each village’s budget allocated for water quality research [26]. This was a cross sectional, analytical study to investigate the chemical and microbial quality of water in Matlou, Sekuruwe and Taolome villages. The study was also conducted to explore methods used by household members to store and handle water in storage tanks. Water samples were collected and analysed according to the standard operating procedures (SOPs) of the Polokwane Municipality Wastewater Purification Plant in Ladanna, Polokwane City of South Africa. The questionnaire used was adopted from the one used for cholera outbreak in the Eastern Cape Province of South Africa. Results show that water from all sources in all the villages had increased total hardness concentration. Water from the borehole in Matlou village had increased number of total coliform bacteria. There were increased total and faecal coliform bacteria in storage tanks samples from Matlou village. Water samples from reservoirs in Sekuruwe and Taolome villages did not test positive for any microbial contamination. Water from xiv informally connected yard taps in Sekuruwe village had increased total coliform bacteria, while increased total and faecal coliforms were found in households’ storage tanks. Water samples from communal taps in Taolome village had minimal number of total coliform bacteria, while water from storage tanks had both increased total and faecal coliform bacteria. Matlou village was the only place with increased nitrate concentration at the households’ storage tanks. While all the villages had microbial contamination, Taolome village had the least number of coliform bacteria in water samples from households’ storage tanks as compared to Matlou and Sekuruwe villages. It is concluded that water from sources supplied by the municipalities are safe to be consumed by humans while water from informally connected taps and households’ storage tanks are not safe to be used without treatment. It is recommended that a health and hygiene education package be prepared for all the villages, so that handling of water from the main source into their storage tanks can be improved. Secondly, it is recommended that water in all sources be treated for total hardness and water in storage tanks in Matlou village be treated for nitrate. Thirdly, it is recommended that water be accessed everyday of the week, so that people do not use unsafe water supplies. / The Province of North Holland, Netherlands.
22

The remediation of surface water contamination: Wonderfonteinspruit

Opperman, Ilze 29 February 2008 (has links)
When mining activities in some parts of the Witwatersrand were discontinued in 2000, the defunct workings started to flood. In September 2002 the mine water started to decant from the West Rand Mine Basin (WRB) next to the Tweelopie East Stream. Treated water is currently used in the mine's metallurgical plants and 15Ml per day of treated water is disposed firstly into the Cooke Attenuation Dam and then discharged into the Wonderfonteinspruit. The aim of this study was to find and provide remediation measures as a result of acid mine drainage and other impacting factors on the water quality and volume in the Wonderfonteinspruit. Conductivity and total dissolved solids (TDS) were highest at the point where the tailings dam leached into the Wonderfonteinspruit. Sulphate was very high as was expected due to acid mine drainage. The best way to treat the high sulphate levels is with sulphate-reducing bacteria. To avoid the fatal flaw of many other constructed wetlands, a continuous carbon source is provided to the bacteria in the form of activated sewage from the Flip Human sewage treatment plant. Iron and other heavy metals are being precipitated through oxidation reactions to form oxides and hydroxides from the aerobic cell in the wetland. The wetlands are also known for their ability to reduce nitrate and microbial values with great success. In the remediation, four elements that currently do not comply with the SABS criteria for class 0 water, were chosen for improvement: conductivity, dissolved solids, sulphate and iron. Conductivity falls within class 1 and has a maximum of 178 mS/m @25ºC that should be reduced to under 70 mS/m. Total dissolved solids have a value of 1585 mg/l, which is much higher than the prescribed 450 ml/l, making it class 2 water. The last two problematic elements are both considered as class 2 water: sulphate peaks at 592 mg/l where the preferred value is 200 mg/l, and iron should be 0.01 mg/l, not the staggering 0.3mg/l. iv Alternative mitigation methods were identified and analysed for the impacts of the five major contaminators and ultimately the solution comes down to constructed wetlands. This is not a straightforward solution, however, and a specific design to accommodate all the different pollutants and water quality ranges was proposed. The other mitigation methods include a cut-off trench and pump-back system for the tailings dam, as well as the implementation of a monitoring programme. The sewage works should be optimised and better managed. Both the settlement and agricultural sector need to be educated on their representative impacts on the environment and government assistance should be available. / ENVIRONMENTAL SCIENCES / MSC (ENVIRON MANAGEMENT)
23

Assessment of the effects of gold-mine effluent on the natural aquatic environment

Venter, Andries J.A. 21 May 2014 (has links)
D.Phil. (Zoology) / South Africa is a major gold-producing country with the 43 larger mines processing approximately 120 x 106 ton of milled and processed ore and about 30 x I06 ton of mined waste rock. Pollution of both surface and ground water, which can be attributed to the influences of gold-mining, are well known. Acid mine drainage, characterized by a low pH and high concentrations of dissolved metals, and seepage, from active and disused mine-tailings, are two of the main environmental problems associated with gold mining operations in South Africa. A growing concern for the environment and a stricter approach to water pollution by government agencies have made it necessary to investigate the type of effects which the gold mining industry is responsible for, and to develop action to reduce these impacts. The present study focused on procedures to access the effect of gold-mining effluent on the natural surface environment. The study is divided into three separate identities. The mine represented as Ccse study Mine One is considered to be a major contributor of salt loads to the natural stream on the property of the mine. This stream confluences with the Klip River outside the mined area. This mine has only one discharge point of underground mine service water, and is considered to be the main point source of pollution for the mine. As the mine makes use of an open water circuit, the quality and quantity of effluent have a direct effect on the downstream users. It appears that one of the main water quality problems of this open water circuit is the creation of surface water with a very low pH. Part of the problem is the geology of the area which consists of shales, which has a natural low buffering capacity. Because of the low pH the wetlands are not very effective. Metal concentration changes are possibly the direct result of the low pH of the both the water column and sediment. Improving the pH of the surface water can leads to reduced metal concentrations in the water, with possible increased concentrations in the sediment and wetland vegetation. Case Study Mine Two was conducted at a gold mine in the Far West Rand Mine region. The mine can be classified as having a closed water circuit, in that only excess water is discharged. The volume of water discharged is dependent on a number of factors, such as rainfall, wash-down service water and changing demands in sewage treatment systems. The advantage in this type of circuit is that water which has accidentally been spilled can be retained in one of the boundary dams, without the possibility of endangering the downstream users. From the assessment it appears that although the mining activities have influenced the water within the mining area this impact is only confirmed to certain areas. Biotic environmental conditions at certain sites resemble the conditions of the two control sites while other, notably those in contact with processing plants (e.g. metallurgical plant), are far more deteriorated. pH does not seem to be a problem at this specific mine. The main reasons are that the underlying geology of the mine is dolomitic in nature, while the sulphate concentration in the ore appears to be lower than those' found at the Witwatersrand mines. Case study Mine Three is situated in the Klerksdorp gold-mining region. The mine has a complex water circuit as a percentage of the service water is being reused or/and discharged via effluent streams into the Vaal River. Metal concentrations in the sediment core samples indicate a large variability between seasons, sites and depth. Sites in close proximity of slimes dams have high iron and manganese concentrations, whilst those in contact with effluent water from metallurgical plants have relatively high nickel, copper and in concentrations. This can be related to the type of processing material used in the gold-mining process.
24

Investigation of coagulant properties and efficiency of Diceriocaryum Eriocarpum Plant for turbidity removal and biosorbent for heavy metals uptake in aqueous solution

Bassey, Odo James 23 July 2015 (has links)
MESCH / Department of Hydrology and Water Resources
25

Assessment of the impact of water and sediment quality on aquatic macroinvertebrate assemblages in the Blyde River of the Olifants River System, Limpopo Province

Malakane, Karabo Concelia January 2019 (has links)
Thesis (M.Sc. (Zoology) -- University of Limpopo, 2019 / The Olifants River is one of the major river systems in South Africa, providing water for industries, mines, agricultural and domestic activities. Consequently, the river has turned out to be one of the most polluted rivers in South Africa. The Blyde River is an important tributary of the Olifants River, known for its continuous flow and good water quality. However, the recent increase in human activities such as, commercial agricultural and large-scale forestry practices in the catchment may have a negative impact on the quality of the water, which may consequently affect the aquatic biota community structure. The aim of the study was to assess the water and sediment quality of the Blyde River using aquatic macroinvertebrates as bioindicators and the South African Scoring System version 5 (SASS5) protocol was followed. Seven sampling sites were selected at Blyde River and five samples were collected per site. Collected macroinvertebrates were identified to family level and classified according to their tolerance levels to pollution at the University of Limpopo Biodiversity Laboratory. In addition, seasonal readings of the physico-chemical parameters such as, pH, dissolved oxygen (DO), temperature, salinity, total dissolved solutes (TDS) and electrical conductivity (EC) were recorded in situ using YSI Model 554 Datalogger with a 4 m multiprobe and a Mettler Toledo SevenGo™. Most of the physico-chemical parameters recorded at Blyde River were within the South African water quality guidelines for aquatic ecosystems. Metals such as, As, Al, Ba, B, Cd, Cr, Co, Cu, Fe, Pb, Mn, Ni, Se, Ag, Sr, Sn, Ti, V, and Zn were tested from the water column, sediments and macroinvertebrate tissue. Almost all the metals analysed from the water column and sediments were within the quality guidelines. Out of the twenty tested metals, As, Ag, Cu, and Zn exceeded the recommended quality guidelines in the water column at some sites. Only As, Cr and Cu exceeded the recommended quality guidelines in the sediments. The most abundant macroinvertebrates were from the orders Ephemeroptera, Diptera, and Trichoptera at all sites. There was a similar macroinvertebrate community structure across the sites, supported by the positive correlation analysis among the sites (r > 0.4). Wildlife Estate and Wildrivers Estate had the highest and lowest numbers of sensitive macroinvertebrates respectively. The highest percentage of iv sensitive macroinvertebrate taxa was recorded in winter and the highest percentage of tolerant species was recorded in summer. This was also supported by the SASS indices, the SASS score, number of taxa and average score per taxon (ASPT) were highest in winter, followed by autumn, spring and lowest in summer. The overall SASS indices showed that the water quality condition at most of the sites at Blyde River could be considered as good. All the seven sites on average fell under ecological band A and B, except for the Wildrivers Estate, thus, the water quality status of the river could be described as unmodified and largely natural with few modifications. / VLIR
26

Prediction and ecotoxicological effects of runoff induced pesticide contamination in agricultural surface waters : a risk assessment using GIS and microcosms

Dabrowski, James Michael 12 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2001. / ENGLISH ABSTRACT: Runoff is generally regarded as one of the most important routes of nonpoint source pesticide pollution in agricultural surface waters. Of major concern is the fact that low, sub-lethal levels of pesticide exposure are responsible for negative ecotoxicological effects, stressing the need for methods capable of identifying problem areas where populations could be at risk. Predicted average losses of three pesticides in tributaries of nine sub-catchments of the Lourens River were calculated through use of a GIS-based runoff model. There was a significant (p < 0.005) positive correlation between the predicted average loss and mean measured concentrations of the insecticides both in water and suspended sediments (R2 between 0.75 and 0.9), indicating that the model could serve as a powerful tool for the risk assessment and management of surface waters in South African orchard areas. Based on field relevant exposure scenanos, the potential effects of azinphos-methyl on macroinvertebrate communities were evaluated in a combined microcosm and field approach. Microcosms were contaminated for 1 h with AZP (control, 0.2; 1,5and 20 ug/L; three replicates each) and acute effects on survival were evaluated 6 days after exposure. The sensitivity or tolerance of 12 core taxa was determined based on their response to the exposure scenarios and compared to field tolerance/sensitivity as was established by a field investigation at a control and contaminated site of the Lourens River. The sensitivity/tolerance of ten of the 12 taxa corresponded to that which was found in the field. Thus microcosm studies employing a field relevant design can be successfully linked to field studies and indicate that transient pesticide contamination affects the aquatic communities of the Lourens River. / AFRIKAANSE OPSOMMING Afloop word oor die algemeen beskou as een van die belangrikste roetes van niepuntbron pestisiedbesoedeling in landbou oppervlakwaters. Die feit dat lae, sub-letale vlakke van pestisiedblootstelling negatiewe ektoksikologiese gevolge kan hê, is van groot belang. Dit beklemtoon die behoefte aan metodes om probleemgebiede te kan identifiseer waar bevolkings aan risiko onderhewig is. 'n GIS-gebaseerde afloopmodel is gebruik om die gemidddelde verlies van drie pestisiede in die sytakke van nege sub-opvangsgebiede van die Lourensrivier te voorspel. Daar was 'n beduidende (p < 0.005) positiewe korrelasie tussen die voorspelde gemiddelde verlies en gemete konsentrasies van insektisiede in beide die water en sediment (R2 between 0.75 and 0.9) fases, wat aandui dat die model as 'n kragtige hulpmiddel vir risikobestuur van oppervlakwaters in Suid Afrikaanse boord-gebiede kan dien. Die potensiële gevolge van azinfos-rnetiel (AZP) op makroinvertebraat gemeenskappe is deur middel van 'n gekombineerde mikrokosmos (wat op veldrelevante blootstellings gebaseer is) en veldbenadering bepaal. Mikrokosmosse is vir 1 h met AZP gekontamineer (kontrole; 1; 0.2; 1; 5 en 20 ~g1L; drie replikate elk), en die akute gevolge op oorlewing is ge-evalueer na ses dae van blootstelling. Die sensitiwiteit of toleransie van 12 sleutel taksa is deur middel van hulle respons op die blootstellingsreeks bepaal, en met hulle veldtoleransie/sensitiwiteit vergelyk wat in 'n veldstudie by 'n kontrole- en gekontamineerde gebied in die Lourensrivier bepaal is. Die sensitiwiteit/toleransie van 10 van die 12 taksa in die mikrokosmos eksperimente het ooreengestem met die wat in die veld gevind is. Mikrokosmosstudies wat op 'n veldrelevante ontwerp gebaseer is, kan dus suksesvol aan veldstudies gekoppel word, en dui aan dat oorgedraagde pestisiedkontaminasie die akwatiese gemeenskap van die Lourensrivier beinvloed.
27

An assessment of the social impacts of water pollution on children in informal settlement : the case of Kliptown informal settlement, Soweto, Johannesburg

Kamusono, Jennifer Tadzei 09 1900 (has links)
The study investigated the causes of water pollution in Kliptown, an informal settlement 17km south of Johannesburg. The study further examined the impact of water pollution, sanitation and inadequate and low quality water provision on children’s social life, health and well-being in informal settlements. The subject of water pollution due to inadequate water supply and sanitation is one that brings a lot of debate, due to the overwhelming impacts it has on children’s social life as well as their health. In informal settlements, social impacts arising from inadequate water supply and sanitation such as the prevalence of water-related diseases like diarrhoea, skin rashes and eye infections have become a permanent feature. This study aimed at assessing the social impacts of water pollution in Kliptown’s Tamatievlei, Mandela View and Valentine Village informal settlements. It also looked at the factors that contribute to the social impacts of water pollution and propose recommendations on how to minimise the social impacts of water pollution on children in Kliptown’s informal settlements. The study applied a mixed method approach, utilising exploratory and descriptive questions to extrapolate both qualitative and quantitative data, which was also presented in quality and quantity form. Outcomes of the investigation indicated that diarrhoea is a major waterborne disease that affects children, mostly under-five years of age, in the informal settlements and that children sometimes missed school due to their being treated for diarrhoea and other water-related illnesses. It was also found that children lived in unhygienic conditions with smelling bucket system toilets and rotting garbage. The study established that children congregated for water at water points for long periods and in the process, they were deprived of time to take part in other social activities. The study recommends mitigating inadequate, low quality water supply, water pollution and sanitation in an integrated manner to gradually eliminate the negative social impacts on children’s social life, health and well-being in Kliptown informal settlement. / Environmental Science / M.Sc. (Environmental Management)
28

The quality of water entering Loskop Dam, Mpumalanga, South Africa.

Moyo, Stanley. January 2013 (has links)
D. Tech. Chemistry / The increase in industrialisation in South Africa has led to an increase in coal mining and coal utilisation in Mpumalanga. This has resulted in the deterioration in the quality of water upstream of Loskop Dam. Little or no information is available on the occurrence or fractionation of trace metals in sediments, which are reservoirs for pollutants. Furthermore, no information is available concerning the occurrence of polycyclic aromatic hydrocarbons (PAHs), known for their carcinogenic and mutagenic effects, in rivers in the area. The possible impact of leaching of elements and organic compounds from South African coals has not been exhaustively researched. The general objectives of the study were to: 1) assess the impact of potentially toxic metals and organic compounds leaching from coal, on the quality of surface waters via simulated leaching experiments; 2) determine the extent of pollution by trace metals and polycyclic aromatic hydrocarbons of the Olifants, Klein Olifants and Wilge rivers, at selected points in the upper catchment area; and 3) identify and apportion sources of polycyclic aromatic hydrocarbons in the sediment samples from the study area.
29

An investigation into the negative external impact of water pollution, public policy options and coping strategies --with specific references to the Lotus River Catchment area

Moses, Mariana January 2005 (has links)
The main purpose of this study was to assess the negative external impact of water pollution upon water resources and the users thereof within urban areas.
30

An investigation into the negative external impact of water pollution, public policy options and coping strategies --with specific references to the Lotus River Catchment area

Moses, Mariana January 2005 (has links)
The main purpose of this study was to assess the negative external impact of water pollution upon water resources and the users thereof within urban areas.

Page generated in 0.1266 seconds