Domestic water wells in Eastern Ontario were identified in potentially vulnerable fractured and karst bedrock aquifers using geologic and geochemical data. A novel methodology is presented that evaluates ¹³⁷Cs and ²¹⁰Pbₑₓ as local indicators of groundwater vulnerability. The method is designed to determine the vulnerability of a specific well. Suspended sediment samples and well-bottom sediment samples were collected from both potentially vulnerable and non-vulnerable wells. Surface soil samples were also collected from West Rural Ottawa and the Township of Alfred & Plantagenet in Ontario, Canada. Gamma spectroscopy was used to analyze the samples and quantify the presence of the radionuclides in cps and cps/g. The spectral data indicate no significant difference in the activities of ²¹⁰Pbₑₓ among samples, but a significant difference in the activities of ¹³⁷Cs was observed between surface soil samples and well-bottom sediment samples collected from vulnerable wells. The data suggest that ²¹⁰Pbₑₓ does not act as a good indicator of vulnerable aquifers because of its geogenic origin. The anthropogenic origin of ¹³⁷Cs precludes this issue, and while ¹³⁷Cs was detected in measurable quantities at the surface, its use as an indicator of vulnerable aquifers is limited by hydrologic and geologic controls that prevent infiltration in vulnerable terrains.

For this study, I have constructed a logistic regression model, using existing datasets of environmental parameters to predict the probability of As concentrations above 5 parts per billion (ppb) in Virginia groundwater and to evaluate if geologic or other characteristics are linked to elevated As concentrations. Measured As concentrations in groundwater from the Virginia Tech Biological Systems Engineering (BSE) Household Water Quality dataset were used as the dependent variable to train (calibrate) the model. Geologic units, lithology, soil series and texture, land use, and physiographic province were used as regressors in the model. Initial models included all regressors, but during model refinement, attention was focused solely on geologic units. Two geologic units, Triassic-aged sedimentary rocks and Devonian-aged shales/sandstones, were identified as significant in the model; the presence of these units at a spatial location results in a higher probability for As occurrences in groundwater. Measured As concentrations in groundwater from an independent dataset collected by the Virginia Department of Health were used to test (validate) the model. Due to the structure of the As datasets, which included As concentrations mostly (95-99%) = 5 ppb, and thus few (1-5%) data in the range > 5 ppb, the regression model cannot be used reliably to predict As concentrations in other parts of the state. However, our results are useful for identifying areas of Virginia, defined by underlying geology, that are more likely to have elevated As concentrations in groundwater. Results of this work suggest that homeowners with wells installed in these geologic units have their wells tested for As and regulators closely monitor public supply wells in these areas for As. / Master of Science

Aggregate mining in Ontario is a highly contentious landuse activity between many stakeholder groups. Land use activities, within a watershed, including anthropogenic infrastructure and anthropogenic changes to the natural infrastructure (such as aggregate pits and quarries), may increase susceptibility of an aquifer by modifying contaminant migration pathways, which is an issue of water security. The purpose of this research is to apply the Vulnerability Scoring Tool to test its utility in the field of water security. The methodology is applied to an aggregate extraction site in the Grand River Watershed in Ontario, and presents an example of how changing land use may change exposure pathways. In particular, the case study results indicate an increase in vulnerability once the aquitard had been penetrated, through aggregate excavation. Applying vulnerability and risk models to future aggregate mining sites can be a useful decision-making tool when investigating impacts of aggregate extraction sites on water security. / Canadian Water Network

Made available in DSpace on 2014-06-11T19:33:34Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-03-16Bitstream added on 2014-06-13T19:23:43Z : No. of bitstreams: 1 bovolato_le_dr_prud.pdf: 1892227 bytes, checksum: a9aeb196221c260182c29cb5bbb47456 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A água subterrânea é de grande importância em termos econômicos e de saúde pública, tanto em áreas urbanas como em zonas rurais. A expansão urbana e as atividades associadas, principalmente para aquelas cidades cujo abastecimento é feito exclusivamente a partir da captação subterrânea, têm provocado transformações físicas e químicas nas reservas de água subterrânea, principalmente porque os efeitos da ocupação territorial estão diretamente ligados ao suprimento de água potável e à prática de disposição de efluentes no solo. A variabilidade e a intensidade da poluição das águas subterrâneas guarda relação com a vulnerabilidade do aqüífero, com as características dos esgotos e do arranjo dos sistemas de saneamento. A degradação da qualidade da água subterrânea por sua vez impacta a disponibilidade de suprimento de água. Este trabalho permitiu analisar a qualidade das águas subterrâneas na cidade de Araguaína frente ao processo de expansão urbana, cidade esta desprovida de um sistema de esgotamento sanitário. Utilizando uma metodologia já consagrada na literatura para a estimativa da vulnerabilidade à contaminaçào de aquíferos, produziu-se uma carta de vulnerabilidade para a área urbana de Araguaína e seu entorno. Esta carta de vulnerabilidade à contaminação poderá ser utilizada como ferramenta auxiliar em estudos de ordenamento territorial e planejamento urbano. / Groundwater is a matter of great concern with regard to economic issues and public health such in urban areas as in agricultural zones. The urban expansion and the related activities, mainly for those cities whose supply is made exclusively from the underground withdrawal, have raised physical and chemical transformations in the underground water wells, mainly because the territorial occupation effects are directly related to drinkable water supply and the practice that discharge effluent into the ground. The groundwater pollution variability and intensity is related to the aquifer vulnerability, sewers features and sanitation systems arrangement. Consequently, the degradation of underground water quality impacts the water supply availability. In this paper was possible to analyze the underground water quality in Araguaína city according to the urban expansion process. Beside, this city doesn't have a sewage system. Using a well-known literature methodology to estimate the aquifer contamination wear point, it was developed a vulnerability chart to Araguaina urban area and its around. This chart of vulnerability to contamination could be used as an auxiliary tool in studies of territorial ordering and urban planning.

Philosophiae Doctor - PhD / The need to ensure groundwater security is vital, particularly in urban areas. Assessing the impact of land use and climate variables on groundwater quality can help improve sustainable management. The vulnerability mapping of groundwater contamination identifies high-risk areas. Using models and technologies that forecast the distribution of contamination risk over time and place can help prioritize groundwater monitoring. Based on such needs, the Cape Flats aquifer in Cape Town, South Africa, was chosen as the case study for assessing the potential for groundwater contamination risk in urban and coastal hydrogeological settings. The Cape Flats aquifer has been highlighted as an alternate water supply source to augment current supply sources in Cape Town. However, the shallow aquifer is under pressure from agricultural and industrial activities and long-term climate variables, among other factors.

Orientador: João Osvaldo Rodrigues Nunes / Banca: José Tadeu Tommaselli / Banca: Encarnita Salas Martin / Banca: Antonio Carlos Vitte / Banca: Marcos Tadeu de Freitas Suita / Resumo: A água subterrânea é de grande importância em termos econômicos e de saúde pública, tanto em áreas urbanas como em zonas rurais. A expansão urbana e as atividades associadas, principalmente para aquelas cidades cujo abastecimento é feito exclusivamente a partir da captação subterrânea, têm provocado transformações físicas e químicas nas reservas de água subterrânea, principalmente porque os efeitos da ocupação territorial estão diretamente ligados ao suprimento de água potável e à prática de disposição de efluentes no solo. A variabilidade e a intensidade da poluição das águas subterrâneas guarda relação com a vulnerabilidade do aqüífero, com as características dos esgotos e do arranjo dos sistemas de saneamento. A degradação da qualidade da água subterrânea por sua vez impacta a disponibilidade de suprimento de água. Este trabalho permitiu analisar a qualidade das águas subterrâneas na cidade de Araguaína frente ao processo de expansão urbana, cidade esta desprovida de um sistema de esgotamento sanitário. Utilizando uma metodologia já consagrada na literatura para a estimativa da vulnerabilidade à contaminaçào de aquíferos, produziu-se uma carta de vulnerabilidade para a área urbana de Araguaína e seu entorno. Esta carta de vulnerabilidade à contaminação poderá ser utilizada como ferramenta auxiliar em estudos de ordenamento territorial e planejamento urbano. / Abstract: Groundwater is a matter of great concern with regard to economic issues and public health such in urban areas as in agricultural zones. The urban expansion and the related activities, mainly for those cities whose supply is made exclusively from the underground withdrawal, have raised physical and chemical transformations in the underground water wells, mainly because the territorial occupation effects are directly related to drinkable water supply and the practice that discharge effluent into the ground. The groundwater pollution variability and intensity is related to the aquifer vulnerability, sewers features and sanitation systems arrangement. Consequently, the degradation of underground water quality impacts the water supply availability. In this paper was possible to analyze the underground water quality in Araguaína city according to the urban expansion process. Beside, this city doesn't have a sewage system. Using a well-known literature methodology to estimate the aquifer contamination wear point, it was developed a vulnerability chart to Araguaina urban area and its around. This chart of vulnerability to contamination could be used as an auxiliary tool in studies of territorial ordering and urban planning. / Doutor

Submitted by Jordan (jordanbiblio@gmail.com) on 2017-03-18T14:08:53Z No. of bitstreams: 1 DISS_2015_ Suzy Darley de Lima.pdf: 2045410 bytes, checksum: 8cfe92b2773538f714b8fb98ccefcc13 (MD5) / Approved for entry into archive by Jordan (jordanbiblio@gmail.com) on 2017-03-18T15:14:37Z (GMT) No. of bitstreams: 1 DISS_2015_ Suzy Darley de Lima.pdf: 2045410 bytes, checksum: 8cfe92b2773538f714b8fb98ccefcc13 (MD5) / Made available in DSpace on 2017-03-18T15:14:37Z (GMT). No. of bitstreams: 1 DISS_2015_ Suzy Darley de Lima.pdf: 2045410 bytes, checksum: 8cfe92b2773538f714b8fb98ccefcc13 (MD5) Previous issue date: 2015-11-27 / CAPES / A avaliação dos riscos à contaminação dos aquíferos, tem sido uma ferramenta de gestão muito estudada nos dias atuais, devido principalmente, à escassez hídrica, fazendo com que o homem recorra, cada vez mais, ao uso das águas subterrâneas para consumo humano. Um dos contaminantes dessas águas, que tem levantado diversas discussões, são os hidrocarbonetos pouco solúveis em água. O objetivo desta pesquisa foi apontar a necessidade da implantação de políticas públicas direcionadas ao processo de gestão das áreas contaminadas por postos de combustíveis no Estado de Mato Grosso, visto que estes contaminantes são fortemente danosos ao meio ambiente e à saúde humana. A pesquisa foi dividida em três etapas, onde a primeira abordou o levantamento das áreas contaminadas por postos de combustíveis no município de Cuiabá, Mato Grosso, a fim de discutir a importância do inventário para a gestão dessas áreas. A segunda etapa avaliou o risco de contaminação do aquífero, no município de Alta Floresta, Mato Grosso, com intuito de contribuir para definição de áreas que necessitam receber um tratamento prioritário, quanto à sua proteção ou a possíveis investigações adicionais, bem como a escolha do melhor local para instalações dos poços de abastecimento ou instalação de uma rede de monitoramento de qualidade das águas subterrâneas. A terceira e última etapa, foi o isolamento e caracterização de bactérias degradadoras de Diesel, encontradas em amostras de água subterrânea coletadas em um posto de combustível no município de Alta Floresta, com intuito de aplicar a técnica de biorremediação em áreas contaminadas por combustíveis derivados de petróleo. / The risk assessment to the contamination of water supplies has been a management tool widely studied today, mainly due to water shortages, causing the man resorted increasingly to the use of groundwater for human consumption. A contaminant of groundwater, which has raised several discussions, are poorly soluble hydrocarbons in water. The aim of this study was to point out the need to implement public policies directed to the process of management of areas contaminated by gas stations in the state of Mato Grosso, as these contaminants are highly damaging to the environment and human health. The research was divided into three stages, where the first addressed survey the areas contaminated by gas stations in the city of Cuiabá, Mato Grosso, to discuss the importance of inventory for the management of these areas. The second step assessed the risk of aquifer contamination in the municipality of Alta Floresta, Mato Grosso, aiming to contribute to defining areas in need receive priority treatment for their protection or possible additional investigations, as well as the choice of best place for installations of supply wells or installation of a network monitoring groundwater quality. The third and final step was the isolation and characterization of degrading bacteria Diesel, found in groundwater samples collected at a gas station in the municipality of Alta Floresta, aiming to apply the bioremediation technique in contaminated areas derived fuel oil.

Submitted by Biblioteca de Pós-Graduação em Geoquímica BGQ (bgq@ndc.uff.br) on 2017-09-04T16:36:01Z No. of bitstreams: 1 Dissertação Final.pdf: 7209490 bytes, checksum: 9fde93c2a4d5f0c380d9e7f1afb93c0b (MD5) / Made available in DSpace on 2017-09-04T16:36:01Z (GMT). No. of bitstreams: 1 Dissertação Final.pdf: 7209490 bytes, checksum: 9fde93c2a4d5f0c380d9e7f1afb93c0b (MD5) / Universidade Federal Fluminense. Instituto de Química. Programa de Pós-Graduação em Geoquímica, Niterói, RJ / Visando à caracterização hidrogeoquímica das águas subterrâneas à partir de amostras obtidas em poços tubulares profundos, poços rasos e fontes naturais existentes na região litorânea de Niterói, Estado do Rio de Janeiro, foram analisadas águas de origem subterrâneas, recolhidas em 43 poços tubulares profundos, 14 poços rasos escavados e 5 fontes naturais, em ambientes geológicos distintos, distribuídos na área que compreende os bairros de Pendotiba, Maria Paula, Itaipu, Itacoatiara, Piratininga e Camboinhas. As análises permitiram reconhecer diferenças composicionais entre os diversos setores amostrados. As águas encontradas nas baixadas lagunares e litorâneas demonstraram bastante complexidade, que pôde ser relacionada à diversidade dos ambientes geológicos. Por outro lado, as águas das áreas mais internas apresentaram maior homogeneidade química e relação mais intíma com a litologia da região, principalmente aquelas que possuem influência dos diques de rochas básicas. A aplicação dos diagramas de Piper permitiu a caracterização de um fácie bicarbonatado-cloretado-sódico-cálcico, predominante, podendo localmente apresentar tendências magnesianas e sulfatadas. O emprego de razões iônicas possibilitou, em alguns casos, estabelecer o relacionamento com a litologia, bem como perceber indícios de salinização nas águas sujeitas à contaminação por águas salinas. Entretanto, foi observado que, mesmo em áreas situadas nas proximidades das lagoas e dos cordões litorâneos, poços profundos que atingiram as rochas cristalinas apresentaram águas com boas condições de consumo. Concentrações de Nitrato, acima dos limites permitidos, foram observadas na maioria dos poços rasos. Contudo o maior índice de contaminação ( 248,67 mg NO3=/l ) foi determinado em poço tubular profundo. A falta de cuidados técnicos durante a perfuração e exploração das águas subterrâneas, associada às elevadas concentrações de ferro (e manganês), proporciona condições ideais à proliferação de ferro-bactérias, que são observadas em proporções endêmicas, tornando frequentes as paralisações em determinados poços. Análises das condições geoambientais possibilitaram a definição da vulnerabilidade característica para cada setor pré-determinado, indicando áreas de alta vulnerabilidade porém de baixo risco a poluição , e outras áreas que, embora possuíssem baixa vulnerabilidade, apresentaram elevado risco à contaminação, em função da carga contaminante. O estudo da área apontou ainda para a necessidade de uma série de iniciativas a que se devem proceder para melhor encaminhar uma política de controle e gerenciamento dos recursos hídricos subterrâneos da região. / Groundwater, the water present in the subsoil, occupying the interstices, granules, fractures, faults or channels existing in the different geological systems, under conditions of flow, obeying the principles of hydraulics. Many people in developing countries rely upon untreated groundwater supplies for their drinking water. These supplies are obtained from drilled boreholes or tubewells, dugwells and springs. Such sources are usually of good quality and much better than some traditional sources of supply, for example ponds and streams. In general, due to the practicality of obtaining good quality, groundwater is highly sought after to serve a wide range of human purposes. However, groundwater can be quite vulnerable to various forms of environmental degradation. The oceanic region of Niterói there is no public supply of water and due to this fact the groundwater is the only source of supply for the population. Hydrogeochemical characterization of groundwater from samples obtained from deep tubular wells, shallow wells and springs in the oceanic region of Niterói, State of Rio de Janeiro, were analyzed ground water collected in 43 deep tubular wells, 14 shallow wells excavated and 5 springs, in different geological environments and the results of the chemical analyzes were interpreted using diagrams, ionic ratios, graphs and estatistical analyses. Integrated to the hydrogeochemical studies was carried out the evaluation of the vulnerability of the region, indicating areas with high risk of contamination. Finally, it was possible to observe that the lack of technical care during the drilling and exploitation of groundwater and the natural vulnerability of the aquifer is responsible for wells with contamination up to 248,67 mg NO3/L.

<p>The analysis of geologic, hydrologic and hydrogeologic data interpreted to give the characteristics of the Cape Flats aquifer showed the quality of groundwater from the aquifer is suitable for development as a water resource. The conceptual model of the Cape Flats sand shows an unconfined sandy aquifer, grading into semi-confined conditions in some places where thick lenses of clay and peat exists. Recharge rates through the saturated zone of the Cape Flats aquifer have been determined by water table fluctuation (WTF), rainfall-recharge relationship, soil water balance and chloride mass balance methods (CMB). Recharge rates using the WTF vary considerably between wet and dry years and between locations, with a range of 17.3% to 47.5%. Values obtained from empirical rainfall-recharge equation (method 2) agree with those of the WTF. Recharge estimates from the water balance model are comparatively lower but are within the range calculated using empirical method 2 (i.e. 87 &ndash / 194 mm or 4 &ndash / 21% of MAP). These recharge rates also agree with estimates from the series of other methods applied to sites located in the north-western coast of Western Cape and are comparable to recharge rates obtained elsewhere in the world.</p>

Protection of groundwater sources has become an important issue in Canada. Over the last decade many approaches to the protection of groundwater sources have evolved. Some approaches provide qualitative information while others give quantitative values with respect to protection measures. The objective of the thesis is to examine the existing approaches of source water protection (SWP) using a complex geological setting, and introduce new methodologies towards the quantitative measurement of the various steps of SWP. The information obtained from the studies can be used to set up future guidelines for SWP. The first step in SWP is to assess the vulnerability of an aquifer. In this thesis, we compare three approaches for evaluating aquifer vulnerability: the Index Approach (Intrinsic Susceptibility Index, or ISI), the Hydraulic Resistance (HR) Approach (similar to the Aquifer Vulnerability Index, or AVI) and the Travel Time Approach (Surface to Aquifer Advective Time, or SAAT). The ISI approach uses the thickness and vertical hydraulic conductivity of the layers overlying an aquifer, and the vulnerability is expressed as a numerical score which is related to these parameters but is not physically based. The HR approach is physically based, uses the same parameters as ISI with the addition of porosity, and results are in the form of travel time under a unit gradient. SAAT extends the physically based approach by including the unsaturated zone and using the actual downward gradient; results are given in terms of advective travel time from surface to aquifer. These three approaches are compared, using two different aquifer systems. The second step in SWP is the delineation of wellhead protection areas (WHPAs). The WHPA delineates the area within which a source of contamination could have an impact on the well. The actual impact on the well depends not only on the source, but also on the characteristics of the groundwater system. Important considerations include the dimensionality of the system, the uncertainty in the system characteristics, and the physical processes that could affect the impact. The conventional approach is to define different time of travel (TOT) zones based on backward advective particle tracking. An alternative approach is to apply backward advective-dispersive solute transport modelling, in which dispersion can be taken as representing the uncertainty in defining the hydrogeologic characteristics (e.g. hydraulic conductivity) of the aquifer. The outlines of the TOT zones in the backward advective particle tracking approach is obtained by drawing an envelope around the respective tracks, which may require considerable guesswork. In the backward-in-time transport modelling, the outline of the TOT zones are developed using mass balance principles. The third step is the assessment of well vulnerability. Well vulnerability is based on the source-pathway-receptor concept which analyses the transport and fate of the contaminants along its path from the source to the receptor, and the interaction of the well itself with the flow system, and thus determines the actual impact on the well. The impact can be expressed in terms of the contaminant concentration in the well water. The mapping of the impact can be carried out by using a standard advective-dispersive transport model in either a forward-in-time mode (for a known contaminant source) or in a backward-in-time mode (for unknown sources). Thus, the well vulnerability concept goes beyond the conventional approach of WHPA, which is based solely on advective transport, neglecting dispersion and chemical processes. For any known point or non-point time-varying contaminant sources located arbitrarily within the well capture zone, the expected concentration at the well can simply be evaluated by convoluting the source mass with the results of the well vulnerability without further use of the model. Convolution is a well-known and effective superposition method to deal with arbitrary inputs in time and space for linear systems. The information of the contaminant concentration in the well water can be used to quantify the risk of a well becoming contaminated. Risk can be expressed in terms of the exposure value of the contaminant concentration exceeding the allowable limit and the time frame within which the well becomes contaminated. The exposure value can be integrated with the time element to set up a ranking of priorities, or to calculate the investment that must be made today in order to have the required funds available for remediation at the time it becomes necessary. The concept is applied to a well using hypothetical contaminant sources located arbitrarily within the capture zone. Well vulnerability maps can be used as a powerful tool to identify the optimal locations for Beneficial Management Practices (BMPs). A case study addressing the problem of elevated nitrate levels in a drinking water supply well is used to demonstrate the principle. The reduction of nitrate input concentration within the most vulnerable areas shows the largest impact at the well.