Dissertations / Theses on the topic 'Heavy metals Groundwater'

Thesis (Ph.D )--Tufts University, 2002.
Adviser: Samuel P. Kounaves. Submitted to the Dept. of Chemistry. Includes bibliographical references (leaves 104-111). Access restricted to members of the Tufts University community. Also available via the World Wide Web;

As much as 80 000 sites, including landfills from glass production industries, are estimated to be contaminated in Sweden. One of these landfills is located near the glassworks factory of Pukeberg, in the municipality of Nybro, Southeast Sweden. It has been found to be severely contaminated with heavy metals, which have toxic effects to humans and biota. The aim of this study is to investigate hydrologic properties at Pukeberg, including groundwater velocities and their potential (spatial) heterogeneity that would affect the transport of metals. Metal concentrations in soil, pore water and groundwater were measured to investigate such metal transport and retention at the site. Slug tests were conducted at the site to determine local discharges and water velocities. For comparison, total groundwater flows through the landfill were estimated by considering water balances of the upstream catchment. Results showed a much higher groundwater flow through the landfill at Pukeberg when estimated from water balance constraints of the upstream catchment, compared to when up-scaled from local measurements of hydraulic conductivities and gradients within the landfill. This points to the existence of aquifer heterogeneity, including preferential flow paths and low-flow zones. Depending on flow path, transport velocities of heavy metals could therefore differ considerably. With a pH of 7 in pore water, and relatively low DOC (dissolved organic carbon) concentrations, environmental conditions were found likely to favour a strong retention for most of the metals investigated. This conclusion is supported by our estimates of Kd (the soil-water partitioning coefficient), derived from the in-situ ratio between soil concentrations and pore water concentrations at the landfill. These estimates were consistently higher than previously reported laboratory results from leaching tests, as well as guideline values from the Swedish EPA. For instance, Kd for Pb and As was found to be 50600 l/kg and 16400 l/kg, respectively. Thus, for most metals, a limited transport downstream could be expected. Indications of high aquifer heterogeneity within the limited area investigated in this study however give rise to uncertainties, for instance regarding the representativeness of the taken samples. Possible future analyses of extended sampling schemes could decrease these uncertainties.

The aim of this study was to make an inventory of the open dumping site Jhumjhumpur in Jessore, Bangladesh, in order to investigate whether spreading of heavy metals had occurred to surrounding soil and groundwater. The study is based on a thorough literature study as well as a field study, including soil and groundwater sampling, at the dumping site Jhumjhumpur. The literature study covers the current waste management system in three cities of Bangladesh: Dhaka, Jessore and Khulna. The results from the field study indicate that metals from the dumping site have been transported and spread to the groundwater in connection to the site and the agricultural land south of the site. A more complete investigation is needed to be able to determine how big a risk the open dumping site is for the surrounding environment. Measurements for avoiding further contamination of the groundwater and the agricultural land should be implemented.

La dépollution des eaux souterraines est actuellement une des principaux défis environnementaux, considérant le nombre de sites contaminés et le risque posé à la santé humaine et à l'environnement par l'exposition à la contamination des eaux souterraines. La barrière réactive perméable (PRB) est une technologie in situ passive pour la remédiation des eaux souterraines contaminées. Il se compose d'une barrière placée perpendiculairement à l'écoulement des contaminants et constituée d'un matériau réactif qui traite la panache de contaminants le traversant sous le gradient hydraulique naturel. C’est la technologie de remédiation des eaux souterraines la plus rentable ; elle permet l'utilisation des terres de surface et réduit l'exposition des travailleurs aux polluants. Le matériau réactif le plus utilisé est le fer à valence zéro (ZVI), qui peut dépolluer l'eau souterraine contaminée par une large gamme de contaminants au moyen de mécanismes chimiques et physiques différents. Le problème principal de l'utilisation de ZVI granulaire est la réduction de la porosité du milieu poreux, en raison de la nature expansive de produits de corrosion, des précipités et la formation de gaz. Pour surmonter ce problème, des mélanges de matériaux granulaires et ZVI ont été testés afin de déterminer leur efficacité de dépollution et le comportement hydraulique à long terme. L'utilisation de Lapillus volcaniques à mélanger avec ZVI pour dépolluer les eaux souterraines contaminées par métaux lourds est proposée dans ce travail. Des essais sur Lapillus ont montré une efficacité d'élimination de métaux lourds non négligeable, tandis que les tests en colonne effectuée en utilisant des mélanges n’ont pas montré une réduction élevée de la conductivité hydraulique au cours du temps.La modélisation des essais batch et colonne en tant qu’outil pour la compréhension des mécanismes impliqués dans les milieux poreux réactifs a été mis en place. L’étude de la sensibilité des paramètres des modèles sur leurs réponses a également été explorée
Groundwater remediation is currently one of the major environmental challenges, considering the number of contaminated sites and the risk posed to human health and to the environment by exposure to groundwater contamination. Permeable reactive barrier (PRB) is a passive in situ technology for the remediation of contaminated groundwater. It consists of a barrier placed perpendicularly to the contaminant flow and made of reactive material that treats contaminant plume flowing through it under the natural hydraulic gradient. It is the most cost-effective groundwater remediation technology; it allows the use of surface land and reduces the exposure of workers to contaminants. The most used reactive material is Zero Valent Iron (ZVI), which is able to remediate groundwater contaminated by a large range of contaminants by means of different chemical and physical mechanisms. The main issue of granular ZVI use regards the reduction of the porous medium porosity, because of the expansive nature of corrosion products, precipitates and gas formation. To overcome this problem, mixtures of ZVI and granular materials were tested to investigate their long-term removal efficiency and hydraulic behavior. The use of volcanic Lapillus to be mixed with ZVI to remediate heavy-metals contaminated groundwater is proposed in this work. Tests on Lapillus showed a not negligible heavy metal removal efficiency of the volcanic material, while the hydraulic monitoring of column tests performed using mixtures showed a not high reduction of hydraulic conductivity over time.Modelling batch and column tests as a tool for understanding the mechanisms involved in the reactive porous media has been set up. The analysis of the sensitivity of the models response with respect to the input parameters has also been explored

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
It is known that the leachate from the decomposition of organic waste represents a danger to the environment, and it is highly pollutant. Therefore, this study aims to evaluate the quality of groundwater around the landfill in the municipality of Visconde do Rio Branco (MG). Results indicate high levels superior than those recommended by CONAMA resolution No. 396/08 of the parameters color, turbidity, biochemical oxygen demand, dissolved oxygen, Lead, Manganese, Chromium, Nickel and E. Coli. This fact indicates that waste management is being done incorrectly and there are sources of contamination within the mass of waste. The origin of this behavior can be justified by the malfunctioning of the manure treatment lagoons. It can be also observed that the variation of water level follows the trend of rain intensity and that the phreatic groundwater flow coincides with the superficial flow.
É de conhecimento que o percolado proveniente da decomposição da matéria orgânica do lixo pode representar um perigo ao meio ambiente, pois é altamente poluidor. Logo, este trabalho objetiva avaliar a qualidade da água subterrânea no entorno do aterro sanitário do município de Visconde do Rio Branco (MG). Resultados obtidos indicam teores superiores aos estipulados pela resolução CONAMA 396/08 dos parâmetros Cor, Turbidez, DBO, OD, Chumbo , Manganês , Crômio, Níquel, E.Coli. Este fato indica que o manejo do lixo está sendo feito de maneira incorreta e que existem fontes pontuais de contaminação dentro da massa de resíduos. A origem deste comportamento também pode ser justificada pelo funcionamento inadequado das lagoas de tratamento do chorume. Também foi observado que a variação do nível d água (NA) segue a tendência de intensidade de chuvas da região e que o fluxo subterrâneo coincide com o fluxo superficial.

Metal contamination in groundwater aquifers poses risks to human health as well as other life forms. Previous laboratory experiments have demonstrated that bacteria found in geologic settings like aquifers are likely to adsorb metal contaminants and attenuate metal migration. However, as bacteria can also migrate through the groundwater aquifer a better understanding of the combined effect of these two processes is required. The aim of this laboratory study was to a) explore the affinity bacteria exhibit towards metals and porous media of varying composition, b) investigate the effect of mineral and solution composition on the bacterial filtration and c) use the combined data to predict the impact of microbes on metal mobility in porous media. Pantoea Agglomerans was used as a model bacterium while column materials consisted of quartz sand and iron-oxide coated sand (IOCS). Bacteria were characterised using potentiometric titrations to identify the type and concentration of sites present on their bacterial wall. Particular attention was paid to the effect of kinetics of proton and metal adsorption due to the variable contact times that solutions have with bacteria in columns. It was found that increasing the contact time between cell surfaces and protons during potentiometric titrations resulted in less reproducible results. This was due to the release of cell exudates under high pH conditions rather than cell death. Exudates were also found to adsorb protons. Moreover, zinc adsorption onto cell surfaces is higher after 60 to 90 minutes of contact time, while there is a decline in adsorption for longer contact times due to release of cell exudates in the solution. Stability constants for the adsorption of zinc onto cell surface sites, quartz and IOCS materials were determined through batch adsorption experiments, providing a mechanistic explanation of the adsorption process. Reactive transport models incorporating kinetics and surface complexation are developed to describe zinc movement through packed columns. Batch kinetic studies showed that significant Zn sorption to IOCS takes place gradually during the first two hours of contact time. Adsorption continues to take place at a slower rate for an additional 10 hours. This kinetic effect is manifested also during flow-through experiments (column dimensions: length 0.12 m, diameter 0.025 m) with a Darcian velocity 6.1·10-3 cm s-1, which is comparable to natural groundwater flow rates through sand porous media. A pseudo-second order kinetic adsorption model is combined with a numerical advection dispersion model for the first time to predict Zn transport. Model output results are of mixed quality as the model cannot successfully describe contaminant arrival time and breakthrough curve shape simultaneously. Moreover, a mechanistic surface complexation reactive transport model is capable of predicting Zn sorption under varying pH conditions demonstrating the versatility of mechanistic models. However, these models do not account for kinetics and therefore they are not intended to fit the dispersion of the contaminant due to kinetic effects of adsorption. Experiments in mixed zinc/cell systems demonstrate that transport through IOCS is dominated by the adsorption to the porous medium. This is consistent with the batch surface complexation predictions for the system. Adsorption to bacteria is reversible and zinc is stripped from the cells and redistributed onto the IOCS. Adsorption onto cells becomes significant and plays a role in mobile metal speciation only once the column is saturated with zinc.

In the year 2000, 170 countries decided to stand together and solve some primary and common global problems like poor health, water, and sanitation. Obtaining access to safe drinking water is every individual’s right. The UN defines safe drinking water as “the water required for each personal or domestic use must be safe, therefore free from micro-organisms, chemical substances and radiological hazards that constitute a threat to a person's health” (UNDESA, 2014). This thesis focuses on identifying the number of people who potentially receive spring water from a piped source in rural mountainous areas. There are three significant steps and data requirements which are necessary to meet this study’s objective. These are to: 1) obtain data classifying the various sources of drinking water in each country by specifying the percentage of population served by a particular water in rural and urban areas, 2) determine the number of countries which are undeveloped or developing, and 3) identify specific countries which are defined as mountainous (and thus likely to have spring fed piped water systems) based on elevation and slope in order to estimate the number of people living in mountainous areas. Results show that 183.54 (million) people were estimated to receive piped water from the springs in mountainous areas. Approximately, 34% of the population is from the Eastern Asia and South-Eastern Asia regions, and 33% reside in the Latin America and Caribbean Islands. These were followed by Western Asia and North Africa Regions with 15% and Central Asia and Southern Asia Regions with 14% of their population estimated to receive piped spring water.

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Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico
The groundwater represents the most important freshwater supply of planet. Dailly, in all world a great amount of toxic and genotoxic material reaches the aquatic systems, mainly the aquifers. The Barreiras aquifer through of five water wells is responsible for the supplying of Universidade Federal do Rio Grande do Norte (UFRN). All water wells are polluted with nitrate and some heavy metals, two of them were disabled. The genotoxicity of groundwater samples from Barreiras Aquifer in UFRN was assessed using the Allium cepa test, the Ames test and the Salmonella typhymurium microsuspension test (Kado test). For the Allium cepa test the influence of the groundwater samples collected on macroscopic (root length, colour and form) and microscopic (root tip mitotic index, chromosome aberrations and micronucleus) parameters was examined. All water samples caused a significant increase of the chromosome and mitotic aberration frequency and reduction on the rooth growth compared to negative control. Bridges and chromosome stickness were the most frequent kind of aberration in dividing cells. Furthermore, breaks were also observed. No significant increase in the number of micronuclei was found in relation to the negative controls. For Ames test were used the Salmonella typhymurium strains TA98 and TA100 without metabolic activation, applying the direct method. Prior to the Kado test, organic fractions from the water samples were obtained through XAD resin concentration. The mutagenicity organic extracts were evaluated by Kado test using TA98 and TA100 strains, in the absence and presence of S9 mix (metabolic activation). The concentrations of seven heavy metal ions were measured in water samples, but only Ni, Cu and Cr levels exceeded the permissible maximum concentration for the natural reservoirs. The results obtained for mutagenic activity using the Ames test were negative in all raw water samples analyzed. Positive results in XAD4 extracts of water samples were obtained for TA98 in the presence of S9 mix for two stations. Concentrations of heavy metals and nitrate can be correlated with the toxicity and genotoxicity of water analyzed. The mutagenic effect detected with TA98 strain suggested that organic compounds (after metabolization) are involved with the mutagenicity detected in the samples analyzed. The data set obtained in this work indicated the presence of at least two classes of mutagens: organic and inorganic compounds
As ?guas subterr?neas representam o suprimento mais importante de ?gua doce do planeta. Diariamente, em todo planeta, uma grande quantidade de material t?xico e genot?xico atingem os sistemas aqu?ticos, principalmente os aq??feros. O aq??fero Barreiras, atrav?s de cinco po?os, ? respons?vel pelo abastecimento da Universidade Federal do Rio Grande do Norte (UFRN). Todos os po?os encontram-se contaminados com nitrato e alguns metais pesados. Dois deles foram desativados. A genotoxicidade das amostras das ?guas subterr?neas do aq??fero Barreiras na UFRN foi avaliada usando os teste Allium cepa, o teste de Ames e o teste de microsuspens?o com Salmonella typhimurium (Teste de kado). Para o teste Allium cepa a influ?ncia das amostras de ?gua subterr?neas coletadas nos par?metros macrosc?picos (crescimento, colora??o e forma da raiz), microsc?pico (?ndice mit?tico, aberra??es cromoss?micas e micron?cleo) foram examinadas. Todas as amostras de ?gua causaram aumento significante na freq??ncia de aberra??es cromoss?micas e mit?ticas e redu??o no crescimento das ra?zes comparando com o controle negativo. Pontes e cromossomos stickness foram os tipos de aberra??es mais freq?entes nas c?lulas em divis?o. Al?m disso, quebras de DNA tamb?m foram observadas. N?o foi encontrado aumento significante no n?mero de micron?cleos comparando com o controle negativo. Para execu??o do teste de Ames, aplicando o m?todo direto foram usadas ?s linhagens de Salmonella typhymurium TA98 e TA100 sem ativa??o metab?lica. As amostras de ?gua foram submetidas ao processo de concentra??o em resina XAD antes do teste de Kado. Extra??o org?nica foi realizada em colunas contendo resina XAD4 que absorve uma grande classe de compostos mutag?nicos. A mutagenicidade dos extratos org?nicos foi avaliada pelo teste de Kado usando as linhagens TA98 e TA100, na aus?ncia e na presen?a da fra??o S9 (ativa??o metab?lica). As concentra??es de sete metais pesados foram medidas nas amostras de ?gua, apenas os n?veis de Ni, Cu e Cr excederam os n?veis m?ximos de concentra??es permitidas para os reservat?rios naturais. Os resultados obtidos para a atividade mutag?nica usando o teste de Ames foi negativo em todas amostras de ?gua bruta analisadas. Resultados positivos com o extrato da resina XAD4 das amostras de ?gua foram obtidos para cepa TA98 na presen?a da fra??o S9 para duas amostras. Metais pesados e nitrato podem estar correlacionadas com a toxicidade e genotoxicidade observada nas amostras de ?gua analisadas. O efeito mutag?nico detectado com a linhagem TA98 sugere que compostos org?nicos (depois de metabolizados) causaram a mutagenicidade detectada nas amostras analisadas. Em conjunto, os dados obtidos neste trabalho indicam a presen?a de pelo menos duas classes de mut?genos: compostos org?nicos e inorg?nicos

Natural contamination of groundwater by arsenic (As) has become a critical public health threat in many parts of the world. The well-known regions associated with As contamination of groundwater are Bangladesh and West Bengal, India where approximately 100 million people are exposed to high levels of arsenic by drinking arsenic-contaminated groundwater and about 35 million are already affected. Long-term drinking of arsenic-contaminated water leads to arsenicosis, which is characterized by cancers of the skin, organ disease and certain other types of cancer. Affected developing communities are at higher risk because they may not have access to conventional water treatment facilities. This problem has focused research efforts on providing accessible arsenic removal technologies. In this study, cactus mucilage, an extract from the Opuntia ficus-indica (also known as Nopal and Prickly Pear cactus), is investigated as a natural agent for As removal from water. Cactus mucilage is a natural hydrocolloid with known flocculant abilities and a demonstrated interaction with As. Two mucilage fractions were extracted - a gelling extract (GE) and a non-gelling extract (NE). Two As removal systems were studied: the cactus mucilage acting alone and a hybrid mucilage and iron treatment system. The mechanism of action of the mucilage's interaction with arsenic was also studied. Batch experiments were used to study the arsenic removal systems. Total As was determined with Hydride Generation - Atomic Fluorescence Spectroscopy (HGAFS) and Inductively Coupled Plasma - Mass Spectroscopy (ICPMS). In the hybrid system, iron (Fe) was also determined by ICP-MS. Total Organic Carbon (TOC) analysis was used to determine mucilage concentration. Attenuated Total Reflectance - Fourier Transform Infrared Spectroscopy (ATR-FTIR) and Ultraviolet-Visible Spectroscopy (UVVIS) were used to study the molecular composition. Additionally, the mucilage was characterized by Transmission Electron Microscopy (TEM) for physical morphology and by Laser-induced Breakdown Spectroscopy (LIBS) and High Performance Liquid Chromatography (HPLC) for inorganics and sugars composition. Both cactus extracts showed an interaction with As by binding and transporting As to the air-water interface of the treatment container, with GE and NE causing a 14% and 9% respective increase in As concentration at the air-water interface. TOC analysis showed that the mucilage migrated to the top of the treatment container but also settled on the bottom. This interaction with As was shown to be pH dependent - optimal performance was at pH 5.5 and 9. The mucilage interaction with As was also dependent on the ionic strength of the solution. ATR-FTIR showed the role of the carboxyl functional group as the binding site for the As(V). The hybrid iron-mucilage treatment system was studied in order to capitalize on the strong affinity of iron for As, as well as to exploit the flocculant properties of the mucilage. Mucilage was successfully applied as a coagulant aid in the removal of As by Fe(III) salt, achieving between 75% to 96% As removal. The process depended on the hydrolysis of the Fe(III) salt to form iron hydroxides and oxyhydroxides, which reacted with and adsorbed the dissolved As(V). The iron arsenate colloidal precipitate which formed was then adsorbed onto the mucilage surface forming larger, heavier, denser flocs. The As removal increased with increasing mucilage concentration reaching a maximum at 100 mg/L GE. Increasing Fe(III) concentration increased the As removal reaching an optimum concentration at 40 mg/L Fe. The As removal had rapid kinetics, achieving visual separation within 10 minutes and completing the majority of the removal within 30 minutes. These results are important because they demonstrate that the mucilage is the versatile basis for an As removal treatment, being able to interact as a complexant for the arsenic as well as an effective coagulant aid for iron arsenate precipitation.

Des 85 000 hectares de terres agricoles à l'île Maurice, prés de 85% est occupé par la canne à sucre, le reste étant composé de maraîchage et des cultures fruitières. Pour assurer sa pérennité et sa viabilité économique à long terme, l'industrie cannière s'appuie dans son programme de réforme sur une revalorisation de ses sous produits en développant une industrie d'éthanol à partir de la mélasse et en utilisant plus efficacement la bagasse durant la période de récolte pour produire l'électricité. Cependant ces deux filières génèrent beaucoup de déchets (400 000 T/an de vinasse durant la distillation d'éthanol, et 40 000 T/an de la cendre de charbon/bagasse durant la production d'énergie électrique), qu'il faudrait valoriser et gérer avec le moins d'effet néfaste possible sur l'environnement. Parmi les moyens disponibles pour la gestion de ces déchets, le recyclage agricole semble être le plus attrayant du point de vue agronomique et également sous l'aspect de protection de l'environnement. Dans ce contexte pour valider cette pratique de recyclage agricole à l'Île Maurice, une étude a été entreprise pour connaître les effets de l'épandage de fortes doses de vinasse et des cendres de bagasse/charbon sur les sols, la culture de la canne à sucre et sur la qualité des ressources en eau. L'analyse de la vinasse et de la cendre de charbon et de bagasse échantillonnées à intervalle régulier de trois mois entre 2005 et 2008 a montré que leur composition chimique est très variable. Néanmoins la caractérisation de la vinasse a confirmé qu'avec sa teneur en K (moyenne de 9.37 g/L), elle est utile principalement comme engrais potassique quoiqu'à un taux de 100 m3/ha son apport en termes d'azote (moyenne de 122 kg N/ha) et en matière organique (8-15% de matière sèche) sera aussi appréciable. Des métaux lourds (Cu, Zn, Ni, Mn, Pb) étaient également présents dans la vinasse mais leurs concentrations étaient négligeables et ne dépassaient souvent pas la limite de détection du spectrophotomètre d'absorption atomique utilisé pour la mesure (5 mg/kg pour le Cu, Zn, Ni, Pb, 10 mg/Kg pour le Mn) A l'opposé de la vinasse qui est acide (pH de 4.5 en moyenne), la cendre de bagasse ou de charbon possède un pH alcalin variant entre 7.5 à 11.5, et peut de ce fait, être utilisée comme amendement pour corriger l'acidité dans les sols. Appliquée à un taux de 100 T/ha, la cendre de charbon représenterait une source importante de potassium (moyenne de 139 kg K/ha) et surtout de phosphore (moyenne de 298 kg P/ha) à la canne à sucre. Contenant très peu de métaux lourds (Cu, Zn, Ni, Mn, Pb et Hg) et en général pas de micropolluants organiques, la cendre de charbon ne risque pas d'accentuer la présence de ces polluants organiques ou inorganiques dans le sol, dans la canne à sucre ou dans la nappe phréatique. Les études au laboratoire ont par contre démontré que la cendre de bagasse/charbon était capable de fortement immobiliser par adsorption, les herbicides atrazine et hexazinone avec des valeurs de Km (coefficients de sorption) de 0.13 pour atrazine et 0.32 pour hexazinone, rendant minime le risque de transfert de ces herbicides vers la nappe souterraine. Les analyses de sol ont confirmé que l'apport de la vinasse baissait le pH (de 5.9 à 5.4 en moyenne), mais cette baisse n'était que temporaire et pas assez significative pour affecter la croissance de la canne. Le pH du sol retournait à sa valeur initiale peu de temps après l'épandage de 100 m3/ha de la vinasse. La cendre de charbon avait eu un effet inverse en augmentant le pH du sol quoique cette hausse ne fût également pas significative pour la culture de la canne. Epandues à 100 m3/ha et à 100 T/ha la vinasse et la cendre de charbon, respectivement, avaient tendance à hausser la salinité du sol qui restait toutefois bien en dessous du seuil de 1700 RS/cm acceptable pour la culture de la canne à sucre. Si la vinasse à 100 m3/ha augmentait le carbone organique dans certains sols, tel ne fut cependant pas le cas pour la cendre de charbon à 100 T/ha. La vinasse comme la cendre de charbon avait un effet positif sur le niveau de calcium et de magnésium échangeables dans le sol. Ainsi à 100 T/ha la cendre de charbon augmentait dans le sol de Pamplemousses le Ca échangeable de 3.40 à 6.61 cmol+/kg après 12 mois, tandis que durant cette même période la vinasse à 100 m3/ha, et malgré sa forte teneur en potassium, portait le Ca échangeable de 1.66 à 1.83 cmol+/kg dans le sol de Union Park. Les essais aux champs établis dans quatre localités avec des doses croissantes de vinasse (25, 50 et 100 m3/ha) ont montré que le rendement de la canne à sucre que ce soit sous forme de canne ou de sucre n'était pas affecté de façon négative par ce déchet. Au contraire les résultats obtenus durant les trois années d'étude, qui ont permis de récolter une canne vierge et deux repousses, ont démontré que la vinasse avait donné un meilleur rendement en canne (moyenne de 84.9 T/ha annuellement pour les quatre sites) que le traitement recevant NPK uniquement sous forme d'engrais minéraux (moyenne de 77.3 T/ha annuellement pour les quatre sites). Puisque tous les traitements avaient reçu le même taux d'azote et de phosphate, ce rendement plus élevé de la vinasse était A part une meilleure nutrition potassique, probablement dû à une amélioration de la qualité du sol grâce aux matières organiques apportées par la vinasse. D'autre part, la cendre de charbon à 100 T/ha était définitivement néfaste à la canne à sucre comme indiqué par le rendement en canne plus faible (moyenne de 67.5 T/ha annuellement pour les quatre sites). A 50 T/ha, l'effet de la cendre de charbon sur le rendement dépendait du type de sol, étant plus affecté dans les sols lessivés comme à Belle Rive que dans les sols moins lessivés de la zone sous humide comme à Pamplemousses. En raison de leur faible teneur en métaux lourds, la vinasse aussi bien que la cendre de charbon n'ont pas d'effet sur la concentration des métaux lourds présents dans la canne à sucre. Pour connaître l'effet de l'épandage de 100 m3/ha de vinasse et de 100 T/ha de cendre de bagasse sur la qualité des eaux souterraines, l'eau percolant après chaque grosse pluie à un mètre de profondeur sous des lysimètres établis sur deux sites avec une pluviométrie différente (1500 mm/an à Réduit et plus de 3500 mm/an à Belle Rive) avait été recueillie et analysée durant la période 2005 à 2008. Les résultats ont montré que la vinasse à 100 m3/ha n'accentuait pas les pertes d'azote sous forme de nitrate. Les métaux lourds les plus mobiles en l'occurrence le cuivre, le zinc et le nickel ont également été retrouvés dans les percolâts mais leurs teneurs restaient bien en dessous des seuils recommandés pour l'eau potable préconisé par l'Organisation Mondiale de la Santé , c'est-à-dire, 1mg Cu/L, 5mg Zn/L et 0.02 mg Ni/L. Les résultats de quenching de fluorescence de la matière organique dissoute de la vinasse et de ses fractions (issues de la dialyse) avec le cuivre ont confirmé une bonne complexation entre cette matière organique dissoute et le cuivre. La cendre de bagasse n'avait pas engendré une présence plus prononcée des métaux lourds et des micropolluants organiques dans les eaux drainant à un mètre de profondeur des lysimètres. La seule différence remarquée entre la vinasse et la cendre de bagasse, était une capacité accrue de cette dernière à mobiliser le nitrate dans le sol. Ainsi suite à l'apport de 100 T/ha de cendre de bagasse, la concentration du nitrate dans les percolâts avait durant la période de novembre 2005 à février 2008 dépassé en de nombreuses occasions à Belle Rive et Réduit respectivement, le seuil de 10 mg N-NO3- /L recommandé pour l'eau potable par l'Organisation Mondiale de la Santé. En conclusion, cette étude a donné des résultats forts intéressants et valables qui indiquent que si l'épandage des fortes doses de vinasse peut être accepté, celle de la cendre de charbon est à éviter puisqu'elle n'est pas sans conséquence nuisible pour les sols ou les cultures et même les eaux souterraines. En effet, les fortes doses de cendre de charbon dans les champs de canne à l'île Maurice, conduiraient à une baisse de production et à une pollution plus accentuée de la nappe souterraine par le nitrate

碩士
國立屏東科技大學
環境工程與科學系所
97
In Taiwan, drinking water is popularized up to 90.7% but in Pingtung County the popularization rate for drinking water is only 45.13%, which is the lowest one in Taiwan. In Pingtung area, groundwater is the most important water resources whether for irrigation, aquaculture, life, and industrial purpose are used groundwater. The water consumption from groundwater is 70.5% and from surface water is 24.3%. Therefore, once people living in Pingtung area use groundwater as drinking water the long-term consumption of groundwater containing heavy metals, leading to heavy metals accumulated in the body that is a concern for health risks. In this study, the data for health risk assessment was taken from EPA National Environmental Information Network (the groundwater monitor data) ranging from 2003 to 2008. The groundwater data has periodically measured the concentrations of heavy metals. The concentrations of arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), zinc (Zn), and manganese (Mn) in groundwater were used to asses health risk in the study. The health risk assessment was carried out by tier method. Tier one the maximum concentrations of heavy metals were used to compute heath risk. In tier two the concentrations of heavy metal was taken mean 95% upper confidence limits (using Bayesian statistical method). In tier three the concentrations of heavy metals were used probabilistic distributions to calculate health risk with Monte Carlo simulation. The results show that the concentrations of heavy metals in groundwater met the current regulation standards in every township in Pingtung County from 2003 to 2008. In addition, most heavy metal concentrations in coastal areas are higher than the concentration in inland areas. The concentrations of arsenic, cadmium, and manganese showed significantly different between the two areas. The results of health risk assessment showed oral ingestion was most important exposure pathway both carcinogenic risk and non-carcinogenic risk. The skin exposure pathway had a minor contribution. The arsenic and manganese contributed the highest proportion of risk. Regarding carcinogenic risk, the results calculation in all scenarios were greater than 10-6 but a few townships such as Kanding Township, and Woodside Township the carcinogenic risk were greater than 10-4. Regarding non-carcinogenic risk, the results show a few townships were greater than 5 in the results from tier 1 and tier 3 calculations. Nevertheless, there were 38.1% of township was greater than 1 with tier calculation but it need notice that 61.9% of the area the risk less than 1 with tier two calculation. Therefore, in the relatively high risk area the point of use to remove heavy metals in groundwater was recommended to reduce health risk using drinking water.

碩士
國立成功大學
環境醫學研究所
87
Abstract The finding in literature that the concentrations of dissolved organic carbons (DOCs) affect the mobility of heavy metals in aqueous milieu motivate one of the purposes in this study : the effect of DOCs on the relationship between the concentrations of leachate and groundwater. This study also aimed to investigate whether the duration after waste deposit affects the heavy metals in the groundwater nearby a sanitary landfill. Another interest of this study is to determine whether the heavy metal concentrations of groundwater will be affected by the location site of groundwater well corresponding to the up/downstream in the underground stream. In this study, we also tried to find out whether the sea tide affects the heavy metal concentrations of groundwater. Using composite sampling, groundwater samples were collected in August, September, January, and June. Heavy metals were analyzed by ICP-MS/GFAAS. It was found that 1). Significant association were found between leachate and groundwater for some heavy metals. After adjusting DOCs, the associations became more significant for some heavy metals. 2). The variation of heavy metal distributions for the samples collected in the zero-stage dump site were found to be much less than those in the second-stage dump site. 3). Zinc and copper concentrations in the samples located in the lower underground stream were found to be higher than those from the upper ones. Whereas the lead, chromium, and arsenic distribution showed the opposite trends. 4). The differences of heavy metals could be larger than 10 folds among the groundwater samples collected from the identical well site at different time within a day. This discrepancy is not able to be justified by sea tide. This study suggests further studies on the more clear-cut duration landfill, samples collected from the farmost up- and downstream of underground stream, and the collaboration with the experts in hydrology and oceanics, to elaborate the duration effect, up/downstream effect, and tidal effect, respectively. This study also suggests that 1). the re-examination of the design of leachate collection system and continuous monitoring on the groundwater to assure the pollution generated from the sanitary landfill has been fully controlled; 2). conducting long-term health surveillance on the waste collectors and operators; 3). Composite sampling will be more representative and accurate compared with the single or grab sampling in terms of environmental monitoring on water samples.

碩士
朝陽科技大學
環境工程與管理系
106
Currently, heavy metal contamination of groundwater is dominated by hexavalent chromium, a highly toxic and mobility. Hexavalent chromium can be reduced to trivalent chromium, which is easily suspended with less mobility, and conducive to sedimentation, such as chromium hydroxide. Trivalent chromium is an essential element of the human body, it is less toxic than hexavalent chromium. Many hexavalent chromium polluted sites use chemical reduction method for remediation. However, the stability of sediment produced by chemical reduction was questioned, the reason is the physical conditions of groundwater are restored to the past condition. Heavy metals may be released by iron-manganese oxide and acidic groundwater. That is the chemical precipitation in question. Calcium polysulfide has been applied in recent years to treat chromite ore processing residue in other countries, that confirmed the ability to reduce hexavalent chromium. In addition, multiple hexavalent chromium contaminated sites have also been tried with calcium polysulfide, it also shows significant effect on the reduction and stabilization of hexavalent chromium. This study used deionized water, groundwater and contaminated water samples to prepare hexavalent chromium solution. Batch tests were conducted using commercially available calcium polysulfide and lab-prepared calcium polysulfides. Quartz sand, sand and clay for column test. The result shows calcium polysulfide reduction of hexavalent chromium quite quickly. Low pH conditions favor the reduction of hexavalent chromium by calcium polysulfide. Dissolved oxygen does not affect the effect of calcium polysulfide reduction of hexavalent chromium. Lab-prepared calcium polysulfide reduction of hexavalent chromium better than the commercially available calcium polysulfide. The hexavalent chromium removal rate of commercially available calcium polysulfide is as hight as 95 % when the molar ratio of applied dose is 18:1. The hexavalent chromium removal rate of lab-prepared boiled for 60 min calcium polysulfide is as hight as 100 % when the molar ratio of applied dose is 9:1. Column test results show that the concentrations of total chromium dissolved in quartz sand, sand and clay within 12 weeks were lower than the second type of water control standards.

Thesis (MTech. degree in Environmental management.)-Tshwane University of Technology, 2008.
Aims to generate information on the quality of water from boreholes and the Steelpoort river in order to ascertain the level of pollution within the vicinity of Vantech mine. The information is envisaged to help a better water management within the area. The following objectives were pursued: to measure water quality parameters ; to investigate the extent of the pollution plume movement ; to study the composition and geological factors in the area in relation to mobility of groundwater and to determine the impacts of Geo hydrological characteristics.

碩士
朝陽科技大學
環境工程與管理系
107
Remediation of groundwater contaminated by heavy metals has become an environmental issue that needs to be resolved in recent years. The extraction process is currently the most important treatment. However, when the amount of water pumped out is large, the amount of remediation is relatively increased. If the treated water is not re-injected, it will cause waste of water resources. Therefore, it is a convenient and more economical remediation technology to use the local treatment with less impact on the environment with lower cost. Calcium polysulfide is a strong oxidant. It can reduce hexavalent chromium to trivalent chromium and used in the treatment of chromite ore residue and hexavalent chromium contaminated soil and wastewater. Calcium polysulfide reduces hexavalent chromium and shows significant reduction effect on hexavalent chromium. Therefore, this study used calcium polysulfide to reduce and stabilize heavy metals and explore calcium sulphide to hexavalent chromium, copper, zinc, nickel, lead and cadmium. The removal efficiency of heavy metals confirm the types of heavy metals that are suitable for processing calcium polysulfide and establishes optimal operating conditions. In this study, firstly, the removal efficiency of lead and copper aqueous solutions in different reaction rates of different polysulfide calcium was studied. The analysis results showed that, with an increase in reaction time, the removal efficiency also increases but the calcium polysulfide has a rapid reduction and stability effect, though the effect is not much different. Calcium polysulfide has the effect of rapid reduction and removal of chromium and lead, but also has the removal effect on nickel, zinc, cadmium and copper, but the excessive dose will form a complex polysulfide and increases in the concentration rate. Therefore, in the application of groundwater pollution remediation, it is difficult to control the exact dose.

碩士
國立中山大學
環境工程研究所
102
In Taiwan, most of the listed polluted sites by Taiwan Environmental Protection Administration are contaminated by heavy metals and the polluted media are mainly soils. In this study, the design factors and operational parameters for the remedial systems for a heavy-metal polluted groundwater site were investigated. At this site, the soils also contained low levels of Zn and Ni (lower than the soil standards). However, groundwater contained high levels of Ni, Zn, and Cr. In this study, groundwater containment and soil stabilization technologies were applied for site remediation. The site soils were mainly silt and sandy silt. Clay layer was located around 11 m below the land surface. The hydrologic conductivity was around 10-3 cm/s, which indicating that the site soil had good permeability. Preliminary test results showed that no heavy metal dissolution occurred when the soil pH was adjusted to 5.5. Investigation results showed that the site containment could effectively minimize the plume migration and reduce the impact of contaminants on site environment. Groundwater extraction could also reduce the heavy metal concentrations in groundwater. Soil stabilization could result in the increase in soil pH and achieve the soil remediation objective. X-ray fluorescence was used for on-site soil analysis to evaluate the remedial effectiveness.

碩士
嘉南藥理大學
觀光事業管理系
104
Taiwan locates at the boundary of Eurasian Plate, and has rich hot-spring resources. The utilization of hot spring can be not merely hot spring bathing. As the national awareness of leisure and health preservation has been prompted, hot spring has been developed to a widely diversified fields, including cosmetics, treatments, health preservation, agriculture, food products, aquaculture and even hot spring housing. In hot-spring areas, the hot spring may raise up as it does while it also can be obtained by drilling wells. Even in non-hot-spring areas, hot spring may be obtained through drilling wells. The control management of hot spring water quality thus appears to be critical. The research has gathered the heavy-metal data of hot springs in Northern Taiwan and the data of ground-water heavy metals from EPA. Z-test is applied to compare the values of average concentration rate of Cd, Cr, Pb, Zn, Cu, Hg, Ni and As. Due to the fact that Cd, Cr and Hg are not found in the hot spring nor in the ground water, these three elements are not taken for further comparison. The result shows the concentration rates of As, Pb, Zn and Ni in hot spring are significantly related to their rates in ground water. Meanwhile, the concentration rate of Cu in hot spring has no significant difference. As a result, it is advised to control hot spring water discharge in order to minimize the risk of heavy-metal pollution from hot spring to surface water.

碩士
國立交通大學
環境工程系所
107
In recent years, the groundwater pollution was more and more serious. Actually, the Fe(III) and As(V) was the common heavy metal ions in ground water. Simple, inexpensive and rapid sensing systems are highly essential for a myriad of uses. Intrinsic properties of emerging paper-based analytical devices have been demonstrated to have a considerable potential to fulfill such demand. This work reports an easy-to-use, low cost, and disposable paper-based sensor in which the functionalized graphene quantum dots (GQDs) embedded cellulose matrix acts as a fluorescence probe for selective and sensitive determination of Fe(III) and As(V). After functionalization, the 3,4-dihydroxyaniline (DHA-GQDs) and poly dimethyl diallyl ammonium chloride (PDADMAC-GQDs) were used for detecting Fe(III) and As(V), respectively. The cellulose of fluorescent paper was extracted from rice straw through TEMPO oxidation. The fluorescent paper was applied to detect Fe(III) and As(V) in ground water successfully. It opens a new avenue for simple and fast screening of HMIs and offers numerous possibilities for versatile applications.

M. Tech.
Gold (Au) mining in South Africa resulted in vast volumes of hazardous waste being generated. Poor management of most of the tailings dams has resulted in the release of acid mine drainage, which caused stream water and soil contamination with their run-offs. The consequence of mine closure has not only been observed in large-scale land degradation, but also in widespread pollution of surface water and groundwater in the Wonderfonteinspruit Catchment Area (WCA). Thus, clean-up methods must be developed in order to remove heavy metals from contaminated water bodies in this area. The efficacy of algae, zeolite and zeolite functionalized with humic acid in reducing the concentration of the heavy metals iron (Fe3+), zinc (Zn2+), manganese (Mn2+) and nickel (Ni2+) to acceptable levels in WCA was investigated in this study. It is also envisaged that the heavy metals to be removed from contaminated water can be useful in various industries. A sampling exercise was undertaken with the aim of identifying the heavy metals that contaminate the water in the catchment, as well as identify the priority heavy metals for laboratory sorption tests. Batch experiments were conducted to study the adsorption behavior of natural zeolite clinoptilolite and algae Desmodesmus sp. with respect to Fe3+, Mn2+, Ni2+, and Zn2+. The data was analysed using the Langmuir and Freundlich isotherms. Two kinetic models namely, pseudo-first order and pseudo second order were also tested to fit the data. It was found that the concentration of Fe3+, Mn2+, Ni2+ and Zn2+ was 115 mg/L, 121 mg/L, 26.5 mg/L and 6.9 mg/L from the sampled water bodies in the WCA, respectively. The Langmuir isotherm was found to correlate the adsorption of Fe3+, Mn2+, Ni2+, and Zn2+ better, with the adsorption capacity of 11.9 mg/g, 1.2 mg/g, 1.3 mg/g, and 14.7 mg/g, for the functionalized zeolite (FZ), respectively. The algae system gave adsorption capacities of 1.523 mg/g, 144 mg/g and 71.94 mg/g for Fe3+, Mn2+ and Ni2+; respectively. Pseudo second-order equation was found to be the best fit for the adsorption of heavy metals by unfunctionalized zeolite (UFZ) and the algae system. Zeolite functionalization with humic acid increased its uptake ability. The best results for kinetic study was obtained in concentration 120 ppm for Fe3+ and Mn2+, whilst for Ni2+ was at 20 mg/L , which is about the same concentrations found in contaminated water in the WCA (Fe3+ 115 mg/L, Mn2+121 mg/L and Ni2+ 26.5 mg/L).