Αντικείμενο της παρούσας εργασίας είναι ο κίνδυνος ρύπανσης των αντλητικών γεωτρήσεων της ΔΕΥΑ Πάτρας από ρύπους που μεταφέρονται μέσα στο υδροφόρο στρώμα, τόσο μέσω του νερού που εμπλουτίζει τον υδροφορέα, όσο και από τοπικές ρυπάνσεις που προέρχονται από ανθρώπινες δραστηριότητες. Σημειώνεται ότι ο υδροφορέας του Γλαύκου ποταμού είναι ένας σημαντικός ταμιευτήρας γλυκού νερού για την πόλη των Πατρών. Εξετάστηκε η εξάπλωση ρυπάνσεων που μπορούν να προέρχονται (i) από τον ποταμό Γλαύκο, (ii) από την περιοχή των χειμάρρων Διακονιάρη–Ελεκίστρας, (iii) από την περιοχή Σαραβαλίου–Κρήνης, όπου ο υδροφορέας του Γλαύκου εμπλουτίζεται πλευρικά με σημαντικές ποσότητες νερού που προέρχονται από τους ανάντη καρστικούς σχηματισμούς, (iv) από το νερό της βροχής που κατεισδύει στη μη αστικοποιημένη περιοχή του υδροφορέα και (v) από σημειακές ρυπάνσεις που μπορεί να προκύψουν σε περιοχές με έντονες ανθρωπογενείς δραστηριότητες. Μια τέτοια περιοχή είναι η περιοχή της δημοτικής Λαχαναγοράς. Η διερεύνηση έγινε με το αριθμητικό μοντέλο MT3DMS (Zheng and Wang, 1999). Οι μηχανισμοί μεταφοράς που ελήφθησαν υπόψη είναι η μεταγωγή και η υδροδυναμική διασπορά. Θεωρήθηκε ότι οι ρύποι διαλύονται στο νερό χωρίς να επηρεάζουν την πυκνότητα και το ιξώδες του. Η διείσδυση του θαλασσινού νερού στην παράκτια ζώνη, η οποία επηρεάζει την ροή του γλυκού νερού προς τη θάλασσα, ελήφθη προσεγγιστικά υπόψη (βλέπε Κεφάλαιο 4). Τα υδραυλικά χαρακτηριστικά καθώς επίσης και τα μεγέθη του υδρολογικού ισοζυγίου του υδροφορέα ελήφθησαν από την διδακτορική διατριβή του Ζιώγα (2013). / In this Master’s Thesis, the numerical simulation of groundwater contaminant transport in the coastal aquifer of Glafkos river is studied. The study region is located southwest of the city of Patras in Greece.

Fully-dynamic, continuous fugacity-based fate and transport models have been developed to examine all natural processes and interactions in the aquatic water systems. Within a body of surface water such as a lake or a river, a dynamic interaction among different media takes place. Chemical compounds are continuously dissolving, adsorbing into solid particles, attaching to suspended particles, resuspending, reacting, diffusing, and advecting. As the inclusion of all these interactions into a model is complex, the use of fugacity concept instead of concentration, renders the modeling task relatively easy. Fugacity, which is described as the escaping tendency of a chemical from a medium, is continuous among different phases, thus easier to follow the movement of the chemical. The first model has been developed to be used as an emergency response model by decision makers, which models the fate and transport of any contaminant in a lake. Due to uncertainties involved in the analysis, Monte Carlo simulations are performed. The fate of three representative contaminants; polychlorinated biphenyls (PCBs), atrazine, and benzene in air, water, and sediment compartments are examined. The second model developed is a continuous, dynamic river fugacity-based water quality model. In order to develop a continuous model, the hydrodynamics of the river system is solved first. Water depth and velocity at each point along the river are used in the advection-dispersion equation to determine the fate and transport of a contaminant. Interactions between different phases are also incorporated into the advection-dispersion equation which is solved numerically and coupled with a mass balance equation derived for the same contaminant in the sediments. The third model is a multispecies contaminant fate and transport model which can be used for the fate of a single contaminant and its daughter products. Trichloroethylene (TCE) and its daughter products, dichloroethylene (DCE) and vinyl chloride (VC), are used as representative of multispecies contaminants. The fate and transport of TCE and its daughter products has been analyzed first in a lake environment, and then in a river environment with the addition of a biofilm compartment where all biotransformations take place.

É crescente a demanda por materiais que atendam as exigências para construção de barreiras selantes (liners) em obras para disposição de resíduos. A utilização de solos tropicais para esta finalidade só não é maior por falta de conhecimento sobre muitas de suas características técnicas, principalmente a migração de contaminantes. Tentativas de melhoria das qualidades de solos supostamente inadequados também são importantes. Esta tese apresenta estudos sobre a migração dos íons \'CD POT.2+\', \'K POT.+\', \'CL POT.1-\' e \'F POT.-\' em latossolos residuais das formações Botucatu e Serra Geral e três diferentes misturas destes solos, com ênfase nos processos de sorção e difusão molecular. O potencial de retenção dos íons é avaliado através da construção de 33 isotermas de sorção resultantes de ensaios de equilíbrio em lote. Seus parâmetros são obtidos da adequação dos modelos linear, Freundlich e Langmuir as isotermas. O potencial de transporte dos íons é avaliado através de ensaios de difusão em colunas estanques, onde curvas teóricas produzidas no programa POLLUTE são ajustadas aos dados de concentração para a estimativa dos parâmetros de difusão. Os resultados dos estudos de retenção mostram que o \'CL POT.-\' experimenta sorção sob certas condições, o \'K POT.+\' e \'F POT.-\' possuem taxas semelhantes de retenção, e que a sorção do \'CD POT.2+\' se mostrou altamente dependente da composição da solução contaminante. Os ensaios de difusão resultaram em vários valores para o coeficiente de difusão efetiva (D*), mostrando que o fluxo difusivo dos íons diminui para solos mais argilosos. / There is a growing demand for materials that can be used in lining systems for waste disposal facilities. The use of tropical soils for this purpose is restricted due to the lack of technical knowledge about this type of material. Attempts to improve the quality of supposed unsuitable soils play also an important role. This thesis presents studies concerning the migration of the ions \'CD POT.2+\', \'K POT.+\', \'CL POT.-\' and \'F POT.-\' in latosoils from the Botucatu and Serra Geral formations and three different mixtures of these soils, with emphasis on sorption and molecular diffusion. Batch equilibrium tests were conduced to examine the retention capacity of the soils, and the sorption parameters are estimated by fitting the linear, Freundlich and Langmuir models to the experimental isotherm plots. The potential for these soils to transport ions is evaluated by diffusion tests, where theoretical curves produced in the POLLUTE code are used to estimate the effective diffusion coefficients (D*). The results show that the \'CL POT.-\' is sorbed under specific conditions and, therefore, it can not always be used as a conservative ion (i.e. nonreactive ion), \'K POT.+\' and \'F POT.-\' are sorbed in similar amounts, and that the \'CD POT.2+\' sorption is highly dependent on the contaminant solution composition. Several D* values are reported, showing that the diffusion rates are decreased for soils with more clay.

Certain types of waste, e.g. bottom ash originating from municipal solid waste incineration (MSWI bottom ash) can be used as road construction materials. A potential problem is the possibility of substances leaching out of the road and spreading in the surrounding groundwater. The aim of this master’s thesis is to conclude whether hydrogeological type settings can be employed to, based on local conditions, provide an estimate of the probable spreading of these substances in the surrounding groundwater, and whether certain types of soils can be identified as being less suitable for the localization of a MSWI bottom ash road. A hydrogeological type setting is defined as a mappable unit with similar hydrogeological properties. An advantage of this approach would be that mainly existing maps and surveys could form the basis for the assessment. The work has been performed by placing a hypothetical road construction in different hydrogeological type settings. The expected patterns of spreading has then been evaluated using theoretical reasoning and analytical and numerical models. The method can be used. In the report various type settings are defined. In several cases further information will be required to render possible a more exact estimate of the spreading. By locating the road on less permeable soils to reduce the local spreading of substances in groundwater, a greater proportion of the water will be drained as surface water. Thus it becomes important to take into account surface water transport aswell. In the report a procedure to estimate the maximum concentrations in groundwater at locations situated downstream the road is presented. This estimate could be used as basis for a more balanced valuation of appropriateness, e.g. by relating the estimated concentrations to background values. / Vissa typer av avfall, exempelvis slaggrus (sorterad bottenaska från avfallsförbränning), kan användas som vägbyggnadsmaterial. Ett potentiellt problem är möjligheten att ämnen lakas ut ur vägen och sprids i omgivande grundvatten. Syftet med detta examensarbete är att avgöra om hydrogeologiska typmiljöer kan användas för att, utifrån omgivningens förutsättningar, ge en bild av hur den vidare spridningen av dessa ämnen i omgivande grundvatten sannolikt ser ut, och om vissa typer av mark kan pekas ut som mindre lämpade för lokalisering av en slaggrusväg. En hydrogeologisk typmiljö definieras som ett område möjligt att avgränsa med avseende på karakteristiska hydrogeologiska förhållanden. En fördel med angreppssättet skulle vara att underlagsmaterialet till bedömningen då kan utgöras av i huvudsak befintligt kartmaterial. Studien har utförts genom att en hypotetisk vägkonstruktion placerats in i olika hydrogeologiska typmiljöer. De troliga spridningsscenarierna har sedan utvärderats genom teoretiska resonemang, samt genom användande av analytiska och numeriska modeller. Metodiken går att använda och i rapporten definieras olika typmiljöer. I flera fall kommer platsspecifik kunskap behöva inhämtas för en närmare beskrivning av spridningsbilden. Genom placering av vägen på tätare mark för att minska lokal spridning av ämnen i grundvatten kommer en större andel av vattnet att avledas som ytvatten. Därmed blir det viktigt att även inhämta kunskap om transport med ytvatten. I rapporten presenteras också en metod för uppskattning av maximala halter i grundvatten nedströms en väg. Denna metod kan användas som underlag för en mer nyanserad värdering av lämplighet, genom att de uppskattade halterna relateras till bakgrundsvärden eller lämpliga riktvärden.

The enormous rate of increase in waste generation across the world is a serious threat to the future generation, if not handled properly, due to the creation of health hazards and global warming. This was awakened many engineers and researchers to find an appropriate solution for efficient management of waste. The land filling of the waste is the most widely adopted method for its disposal, whose efficiency mainly depends on the engineered barrier system in place. Though possessing many limitations, clay liner solely or along with Geo-membrane is often used to avoid ground and surface water contamination. The thickness of the liner of a given breakthrough time depends on the transport rates of the selected contaminants. To estimate the transport rate of any given contaminant, it is necessary to understand the different migration processes of contaminants through the liner material. It was observed from the literature that, the transport rate of contaminants mainly depends on Dispersion coefficient (D) and Distribution coefficient (K) which are the main contaminant transport parameters. The amount of contaminant transport through the liner system for a desired time period is thus estimated from these contaminant transport parameters using the Advection-Dispersion Equation (ADE). The unregulated open dumps are another cause of serious environmental problem, where the contaminants are free to migrate in any direction through the underground soil. The percolation rate and the accumulation of leachate increase during the rainy season, which picks up more contaminants from the waste and thus the threat of the leachate increases. The leachate normally migrates in vertical and lateral directions, causing contamination of ground and surface water resources, and hence, there is a need to estimate the transport rates of contaminants in the porous media. These transport rates are not only useful for designing barrier systems, but also useful to find a suitable remediation technique for the removal of contaminants from a contaminated site. Thus, determination of transport rate is very important in effective waste management systems. Most of the researchers have obtained the contaminant transport parameters through the column tests to simulate one dimensional flow. Often, it is a lengthy process and there is a need to find an easy and effective method of determining these parameters which can reduce the time and effort. Generally, the metallic contaminants such as Cadmium (Cd), Copper (Cu), Lead (Pb), Mercury (Hg), Nickel (Ni) and Zinc (Zn) which are most hazardous are considered for the contaminant migration studies. In the present study, the transport rates of two heavy metals Copper and Zinc through locally available Black Cotton soil and Red soil were studied. Column experiments were conducted to simulate the field conditions under two types of test conditions i.e., Constant and Decreasing source concentrations. For Black Cotton soil as the hydraulic conductivity was very less and was taking a long time for achieving complete breakthrough, the soil sectioning method was used to get the depth versus concentration. The soil sectioning method involves the determination of pore water concentration of any given contaminant in different sections of the soil column. The depth versus concentration profile can serve as the same purpose as that of complete column test after breakthrough. The column experiments can be done only up to a relative concentration (C/C0) of about 0.2 instead of 0.8 or more. The soil samples were compacted to different densities to know the effect of density on transport parameters. The Black Cotton Soil samples were compacted to 0.76-0.97 times of maximum dry density and Red Soil samples were compacted to 0.81-0.98 times of maximum dry density. The samples were compacted to lesser densities to reduce the experimentation time. The transport parameters for field densities can be determined by setting „Forecast Trend Lines‟ to the density versus dispersion coefficient and density versus distribution coefficient plots. The contaminant transport was modeled by various methods i.e., Analytical, Semi-analytical, Explicit Finite Difference and Implicit Finite Difference methods. These models can be extended to predict the contaminant migration through soil liners constructed with similar soils. During the lifetime of a landfill, it may be subjected to both constant and decreasing source concentration conditions and thus the contaminant transport parameters determined by both constant and decreasing tests will be useful to estimate the optimum thickness of soil liner. The disposal of waste solutions and sludges by industries has led to problems with the contamination of both soil and groundwater. Much research work has not been carried out in the past for the remediation of contaminated soils in India. Thus an attempt has been made to study in detail the different remediation techniques on various contaminated soils. Three heavy metal contaminated soils were studied with two remediation techniques i.e., Soil washing and immobilization. As a case study, Zinc contaminated soil was collected from Hindustan Zinc Limited located near Udaipur in Rajasthan State, India and column leach tests were conducted on this soil with different leaching solutions to study the efficiency of the soil washing technique. The leaching solutions used for removing zinc from this soil were 0.1N HCl, 0.1N EDTA, 0.1N HCl+0.1N EDTA and 0.1N FeCl3. It was found that 0.1N FeCl3 was more efficient to remove zinc from this soil. The removal efficiency was also high with 0.1N HCl+0.1N EDTA solution. The transport rates were determined by matching the theoretical elution curves with experimental elution curves. The contaminant transport for column leach tests was modeled using analytical solution based on the Leaching Mass Ratio approach. These transport rates are useful to estimate the rate of treatment as well as the amount of flushing solution required to remove Zinc knowing the area of contamination and in-situ soil conditions. One of the potential sources of soil and ground water contamination with toxic metal ions is Effluent Treatment Plant sludge (ETP Sludge). The efficiency of soil washing technique was also studied on ETP Sludge using five leaching solutions i.e., distilled water, 0.1N HCl, 0.1N EDTA, 0.1N HCl+0.1N EDTA and 0.1N FeCl3. ETP sludge was collected at a filter press, KIADB industrial area, Doddaballapur, Bangalore. The removal efficiencies of these leaching solutions for removal of different metal ions (Copper, Zinc, Iron, Nickel, Cadmium, Lead and Chromium) were studied. The highest removal efficiencies were observed with 0.1N FeCl3 and 0.1N HCl+0.1N EDTA. The transport rates of different metals were determined which will be useful to estimate the quantity of leaching solution required in the field to remediate this sludge using soil washing technique. Even though soil washing technique is more effective than immobilization, for less permeable soil with more clay content, it is not a cost effective method. In such cases immobilization technique can be used to remediate the contaminated soil. The immobilized metals will not migrate through soil to groundwater and will not give adverse environmental hazards in their treated state. In the present study, immobilization technique was studied on two materials, (i) contaminated soil from open dump and (ii) ETP Sludge. The contaminated soil was collected from an open dump located at the Bingipura dumping yard, Bangalore and was tested for the presence of heavy metal ions. The efficiency of treatment to immobilize the metals was studied with different additives. The chemical agents with which can decrease the solubility product will be effective to immobilize the metal ions. The stabilizing agents used for treating these materials were lime water, NaOH and cement. These stabilizing agents were selected after preliminary batch tests. Since most of the heavy metals in soils become less mobile with increase in pH, the lime water / NaOH was added to the soil/sludge to adjust the pH of the mixture to 7.0, 8.5 and 10.0. The cement: soil ratios used were, 1:100 (pH=6. 8), 1:50 (pH=8. 1) and 1:25 (pH=9. 8) by weight. Leaching tests were conducted on the amended soils to know the long term efficiencies of the chemical agents for immobilizing the metal ions. The work carried out in this thesis is presented in different chapters as given below: For the design of the liner system, it is necessary to know the different contaminant transport processes, the determination of their rates and modeling. For remediation of contaminated soil, it is required to find the suitable remediation technique based on the amount and type of pollutants, the type of soil and other geological conditions. The detailed information about sources of heavy metals, effects of heavy metal contamination on health and the environment, contaminant transport processes, methods of determining transport rates, and different modeling techniques for contaminant transport are explained in Chapter 1. The Background information along with the scope and objectives of this study are presented in this chapter. The extensive review of literature related to column experiments, various solutions to Advection-Dispersion Equation, and different remediation techniques to treat the contaminated soil, is also presented in this chapter. Chapter 2 gives detailed information about various materials and methods used in this study. The characteristics of soils used in the present study and preparation of different chemical solutions were explained. The experimental procedures of batch tests, column tests and soil sectioning to determine the contaminant transport parameters were given in detail. The experimental procedures that are required for assessing the efficiency of soil washing technique i.e., Batch leach tests and column leach tests were also explained. The laboratory assessment of immobilization efficiency through leaching test was explained briefly. The analytical and numerical solutions used for this study were discussed in detail. This chapter also includes a method of prediction of breakthrough curves from the incomplete column test data. The contaminant transport parameters of metal ion Copper in two locally available soils i.e., Black cotton soil and Red soil were determined by various techniques i.e., Analytical (using MATLAB v7 software), semi-analytical (using POLLUTE v7 software), Explicit Finite Difference Method with two software tools (MATLAB v7 and M.S.EXCEL 2010), Implicit Finite Difference method with three schemes (BTCS, UPWIND & CRANK NICOLSON) using two software tools (MATLAB v7 and M.S.EXCEL 2010). Modifications were done in the spreadsheet solution of non-reactive solute available from the literature to incorporate the retardation factor as the solutes used in this study are reactive in nature. These results are presented in Chapter 3. The contaminant transport parameters determined for different test conditions (constant and variable source concentrations) and for different densities of soil are reported in this chapter. Determination of transport rates corresponding to maximum dry density using trend lines and preparation of design charts to estimate the thickness of the liner are also discussed in this chapter. The contaminant transport parameters were also determined for metal ion Zinc in the same soils with the same techniques as that of Copper and the migration rates were compared for both the ions. These models and comparative results are presented Chapter 4. It was observed that with increase in density, the dispersion coefficient decreases and Distribution coefficient increases. It was also found that the dispersion coefficient of Black Cotton Soil was lower than that of Red Soil whereas the distribution coefficient of Black Cotton soil is much higher than that of Red Soil. Further, it was observed that the dispersion coefficient of Copper was less than that of Zinc whereas the distribution coefficient of Copper was higher than Zinc. The design of liner thickness, based on transport rates of Zinc is briefly discussed in this chapter. A case study has been explained for the remediation of Zinc contaminated sandy soil using soil washing technique. The undisturbed soil samples collected from four locations of waste disposal site of Hindustan Zinc Limited located near Udaipur in Rajasthan State of Western India were assessed to find the suitable leaching solution and number of pore volumes for the effective removal of Zinc from this soil. The chelates/ solvents used for this soil were 0.1N HCl, 0.1N EDTA, 0.1N HCl+0.1N EDTA and 0.1N FeCl3. The contaminant transport parameters were also determined from the column leach tests based on the Leaching Mass Ratio approach and the results are presented in Chapter 5. From the experimental study it was observed that 0.1N FeCl3 and 0.1N HCl+0.1N EDTA are the most suitable leaching solutions to treat this soil. The Chapter 6 contains the sludge analysis of an industrial ETP sludge, column leach test results of this sludge with different leaching solutions, removal efficiencies of different solutions used and the transport rates of different contaminants. The leaching solutions used for this sludge were distilled water, 0.1N HCl, 0.1N EDTA, 0.1N HCl+0.1N EDTA and 0.1N FeCl3. It was observed that 0.1N FeCl3 and 0.1N HCl+0.1N EDTA are the most suitable leaching solutions to treat this sludge. Other solutions have also removed the contaminants by more than 50%, but the number of pore volumes required to leach out the contaminants was high. The order of removal efficiencies of different solutions is presented below: 0.1N FeCl3 > 0.1N HCl + 0.1N EDTA > 0.1N EDTA > 0.1N HCl > distilled water. The transport rates of different contaminants (Cu, Zn, Cd, Fe, Ni, Pb and Cr) were determined using analytical solution and are presented in this chapter. These transport rates are useful to estimate the quantity of leaching solution required in the field to remediate the sludge using soil washing technique. A contaminated soil collected from an open dump site within Bangalore city and ETP Sludge were analyzed to know the efficiency of immobilization/ solidification technique of remediation using three chemical agents lime, NaOH and cement. The soil samples were mixed with different proportions of these chemicals to adjust the pH of the mixtures to 7.0, 8.5 and 10.0. Leaching tests were conducted on the modified soils to know the long term efficiency of these chemical agents to immobilize the contaminants and these results are discussed in Chapter7. The results showed that highest immobilization efficiencies can be achieved with lime for this contaminated soil and cement is the most suitable chemical agent to treat this sludge. The immobilization efficiencies of different stabilizing agents for various metals were studied and the results analyzed. The Chapter 8 includes the major observations and conclusions of the present research work which will be useful for Geotechnical and Geo-environmental engineers to estimate the transport rates of contaminants, to design the soil liners, to assess the efficiency of soil washing technique to remediate the contaminated soil, to estimate the quantity of leaching solution required in the field for soil washing and to find the suitable chemical agent for remediating the contaminated soil by immobilization technique.

[pt] A contaminação do meio ambiente de subsuperfície com resíduos perigosos e tóxicos tem se tornado um dos maiores problemas ambientais em vários países, com muitos locais apresentando contaminação da água subterrânea. A dissertação visa a caracterização de propriedades de transporte em solos residuais do estado do Rio de Janeiro; em especial será focalizado o comportamento e a mobilidade neste solo de metais pesados como o cádmio, zinco, cromo e chumbo. O conhecimento do comportamento dos metais no solo é importante para a previsão de acidentes ambientais e para a avaliação de possíveis soluções. Mudanças no ambiente, como variação do pH, podem interferir no comportamento do metal, desta forma o conhecimento das condições locais é importante para previsão do comportamento do contaminante. Foram realizados ensaios de batelada e de coluna com diferentes metais, para entender como se comportam nos solos residuais caracterizados. Para complementar o estudo uma modelagem geoquímica foi feita a partir dos dados experimentais com o programa computacional PHREEQC. / [en] The contamination of the underground environment by hazardous and toxic wastes has become one of the main environment problems in several countries where many sites present groundwater infection. The project purpose is the characterization of the transport properties in residual soils of the Rio de Janeiro state. Mainly it will be focused the behaviour and the mobility of heavy metals, for example, the cadmium, the zinc, the chromium and the lead in this kind of soil. To know the behaviour of the metals in the soil is important for the prevision of environmental accidents and for the evaluation of possible solutions. Changes in the environment, as the pH variation, may interfere in the metal conduct thus the knowledge of the local conditions is essential for the prevision of the contamination procedure. Batch and column tests were made using different metals in order to understand how they act in the characterized residual soils. To complement the studies a geochemical modeling was made using the experimental data with the compute program, PHREEQC.

No description available.

Drinking water contamination is a big concern in Sweden and is commonly traced back to being waste from former manufacturing industrial sites. Pollutants in the topsoil can be remediated by several techniques, such as decontamination or excavation but the toxins already enclosed in the bedrock cannot be treated the same and is harder to track possible contaminant pathways. To gain knowledge of modelling fluid flow and solute transport in the bedrock is therefore highly crucial to detect any safety risks. Not only for drinking water safety but also to understand possible reservoir storage or to store disposals from radioactive waste.  For this study, high levels of chlorinated solvents have been measured at a former industrial plant manufacturing electronic products, where the prominent chemicals are PCE and its degradation products. The soil will be remediated from the site, but the remaining question is if the contaminants can be further transported in the bedrock fractures to a drinking water source for the municipality. The lake is located approximately 4km from the site and will take too much time and computational effort to run the model. Instead, this study will focus on a small-scale model estimating a suitable distance from the source where additional boreholes can be placed. The model will have a size of 455 x 436 x 38m and the study will be divided into three main tasks; improve understanding of the fracture geometry by statistical analyses of the measured fractures in the study area, build and run a groundwater flow model representing the study area, investigate possible pathways of contaminant transport in the fracture networks and analyze the impact of geological features.  The methodology is divided into several parts. First, statistical analyses of the fractures will be done using the software FracMan version 8.0, which will act as a foundation of the DFN model. Next part includes calibration of the model and generation of fracture network based on the statistical analysis. The last part includes flow and transport simulations using the application Pflotran within FracMan version 8.1.  The results shows that large fracture zones affect the flow to a great extent and therefore also control the transport of contaminants in the bedrock. Because of uncertainties regarding size of the zones, additional boreholes should be placed upon their respective orientations close to the already existing boreholes to investigate their characteristics. It is also necessary to place additional boreholes randomly within the study model to detect other fracture zones and possible dominant fracture sets. The additional boreholes should be deeper than the existing ones to detect possible fracture networks further down in the bedrock. Contaminant pathways are hard to establish because of the deterministic zones that determines the flow. The scenario where no zones were included, two dominant pathways are visible, one on the upper part and one in the lower part of the model. The scenario where zones were included, one dominant pathway is visible, following the large fracture zone reaching from one borehole towards the outlet boundary. In conclusion, these results highlight the importance of doing more measurements to strengthen the basis for evaluation of pollutant transport to the nearby lake. Because of the risk of poisoning the drinking water, it is extremely important to be able to make a realistic model for contaminant transport. Since the results of flow simulations differs between different input transmissivities, next step should be to do hydraulic tests in the already existing boreholes to establish the local transmissivity for the fractures. After that, additional boreholes in the field, both on top of the measured zones close to the existing boreholes as well as boreholes randomly throughout the study area should be placed. / Rent dricksvatten är en angelägenhet för alla i Sverige och för att säkerhetsställa rent dricksvatten krävs förebyggande åtgärder som kan förhindra att föroreningar tar sig till dricksvattenkällor. Dessa åtgärder kan bland annat innehålla mätningar för att spåra föroreningens ursprung och transportvägar. Ursprungen kan oftast kopplas till avfall från gamla tillverkningsindustrier. Föroreningar som spåras till matjorden kan åtgärdas genom sanering eller schaktning medan föroreningar som tagit sig ner i berggrunden inte kan behandlas på samma sätt. Föroreningars transport genom sprickor är svåra att spåra och lokalisera på grund av oförutsägbara förhållanden med olika bergarter, kvalitéer, sprickstorlek etcetera. På grund av detta är det viktigt att kunna modellera flöden och transport av lösa ämnen för att förhindra hälso-och säkerhetsrisker. Modellering av spricksystem är även viktigt för att undersöka framtidens energiextraktion från geotermisk aktivitet, eller att kunna lagra avfall från radioaktiva ämnen.  Denna studie görs då det har mätts upp höga nivåer av klorerade lösningsmedel från en gammal fabrik som tillverkat elektronikprodukter, främst kemikalierna PCE och dess nedbrytningsprodukter. Mätningar har gjorts på platsen i form av tre borrningar och bergkartering. Föroreningar i jordmånen kommer att åtgärdas men den kvarstående funderingen är om de föroreningarna som redan tagit sig ner i berggrunden, kan transporteras genom spricknätverket fram till en sjö som kommunen använder som dricksvattenkälla. Sjön är lokaliserad ungefär fyra kilometer från den gamla anläggningen och på grund av den långa distansen kommer det krävas mycket lagring och beräkningskraft av den använda datorn. För att undvika detta, kommer denna studie i stället fokusera på en småskalig modell med den ungefärliga storleken 455 x 436 x 38m där syftet är att uppskatta var nya borrningar kan göras för att få fram mer information angående potentiella föroreningar och dess flyktvägar. Denna studie kommer vara uppdelad i tre huvudsakliga syften; göra statistiska analyser av data som samlats in från fält, bygga upp och köra en grundvattenmodell som representerar studieområdet, undersöka potentiella vägar för transport av föroreningar i spricksystemet samt analysera dess påverkan av geologiska egenskaper.  För denna studie har metoden delats upp i flera steg. Det första steget innehåller statistiska analyser av sprickorna i området som kommer utgöra grundinformationen för spricknätverket. Detta görs i programmet FracMan version 8.0. Nästa del innehåller kalibrering av modellen samt flödes- och transportsimuleringar genom applikationen Pflotran som är installerat i FracMan version 8.1.  Resultatet av flödes- och transportsimuleringarna visar att stora sprickzoner påverkar flödet i stor utsträckning och kontrollerar därför transporten av föroreningar. Storleken av sprickzonerna är svåra att bedöma då det inte finns någon mer information än det som mätts i borrhålet, där den minsta storleken är av borrhålets radie. På grund av detta lades zonerna in deterministiskt med en radie lika stor som modellen. Detta medför att resultaten över transporteringsvägar är högst bestämmande av zonerna där zonen som går mot utflödesgränsen agerar som en motorväg för föroreningar medan zonen som går mot en gräns utan utflöde agerar likt en sjö, vilket gör att partiklarna som hamnar i zonen stannar där och kan inte ta sig därifrån och fortsätta transporten. På grund av denna osäkerhet kring storleken för zonerna bör det placeras ytligare borrhål längs med orienteringen av sprickorna max 10 meter från de existerande borrhålen för att se om zonerna fortsätter eller blivit avkapade. Eftersom inga hydrauliska tester gjorts i borrhålen är det ett viktigt nästa steg för att bestämma rätt transmissivitet i sprickorna. Det är möjligt att det finns fler zoner inom området som kan bestämma flödesvägar, därför är det också viktigt att placera ut fler borrhål slumpmässigt inom området för att upptäcka fler zoner eller andra dominerande sprickorienteringar än de som hittills mätts. Alla nya borrhål bör även gå djupare än de som redan finns för att kunna upptäcka andra eventuella spricknätverk djupare ner i berggrunden. På grund av risken att kontaminera dricksvattnet är det otroligt viktigt att kunna göra en realistisk modell som representerar transporten av föroreningar. Fortsatt arbete bör därför prioritera hydrauliska tester för att bestämma transmissiviteten i spricknätverket, därefter utföra fler och djupare borrhål i området för att undersöka andra potentiella deformationer.

The continuous demand on new residential and economic areas of the modern society has to face up with problems posed by polluted sites related to former industrial activities, typically located in suburbs areas. These sites, known as brownfields, are often located nearby navigable rivers to facilitate transport operations of industrial manufacturing, which increase their potential environmental threat due to the possible migration of pollutants in groundwater to surface water bodies through groundwater discharge. In this context, the objective of this research, performed in the scope of the FP6-IP AquaTerra project, was to contribute to a better assessment of the risk of groundwater contaminant dispersion for a brownfield located next to the Meuse River (Belgium), in a context where strong groundwater - surface water interactions prevail. The brownfield of interest corresponds to the site of the former coke factory of Flémalle. Resulting from industrial activities, soil and groundwater located in the alluvial aquifer are heavily contaminated with various types of organic (BTEX, PAHs, mineral oils...) and inorganic (As, Zn, Cd...) pollutants. To do so, detailed characterisation campaign was performed, consisting of, on the one hand, classical field experiments such as pumping tests, injection tests and tracer experiments; on the other hand, advanced and original field experiments such as detailed monitoring of groundwater - surface water interaction and dynamics, and the development and application of an innovative tracer technique, the Finite Volume Point Dilution Method (FVPDM), used to quantify and monitor groundwater fluxes. Monitoring and field works data was subsequently used to develop and calibrate a groundwater flow model using the finite difference code MODFLOW, with an automatic parameter estimation approach based on an original combined regional scale (zonation) and local scale (pilot points) approach. A transport model was also developed using MT3DMS and calibrated using tracer experiments performed in the brownfield. This groundwater flow and transport model was used to better quantify the dynamics of groundwater - surface water interactions and to model various scenarios of contaminant dispersion through the aquifer - river system. For these scenarios, benzene was considered because it is one of the main pollutants encountered in the site, its large solubility and mobility in groundwater and its acute toxicity. These scenarios were established considering various groundwater flow conditions (steady state vs. transient) and various hydrodispersive processes possibly affecting the mobility of benzene in groundwater, namely advection, hydrodynamic dispersion, sorption - desorption and, as evidenced by the research results of the University of Neuchâtel (Switzerland), benzene degradation under sulphate reducing conditions. These simulations indicate that benzene attenuation is mainly controlled by ongoing benzene degradation processes, aquifer heterogeneity and river stage fluctuations. Based on this analysis, the risk of benzene dispersion is low, and monitored natural attenuation (MNA) is a valuable option with (1) monitoring benzene at control planes downstream from the sources; (2) further investigation on risk of sulphate depletion in the alluvial aquifer; and (3) further investigation on mobilisation/immobilisation of heavy metals related to dynamics of organic pollutant plumes.

The main objective of this study is to develop a modeling methodology that facilitates incorporating the plant pathway into environmental contamination models recognizing the fact that plants are dynamic entities that regulate their life cycle according to natural and anthropogenic environmental conditions. A modeling framework that incorporates the plant pathway into an integrated water flow and contaminant transport model in terrestrial systems is developed. The modeling framework is aimed to provide a tool to analyze the plant pathway of exposure to contaminants. The model developed using this framework describes the temporal and spatial variation of the contaminant concentration within the plant as it is interacting with the soil and the atmosphere. The first part of the study focuses on the integration of the dynamics of water and contaminant distribution and plant related processes within the vadose zone. A soil-plant system model is developed by coupling soil-water flow, contaminant transport, plant life-cycle, and plant pathway models. The outcome unifies single media continuous models with multimedia compartmental models in a flexible framework. The coupling of the models was established at multiple interfaces and at different levels of solution steps (i.e. model development phase vs. numerical solution phase). In the second part of the study, the soil-plant system model is extended to cover large spatial areas by describing the environmental system as a collection of soil-plant systems connected through overland flow and transport processes on the ground surface and through lateral interactions in the subsurface. An overland flow model is integrated with the previously coupled model of unsaturated zone soil-water flow and plant life-cycle by solving the flow model equations simultaneously within a single global matrix structure. An overland / subsurface interaction algorithm is developed to handle the ground surface conditions. The simultaneous solution, single-matrix approach is also adopted when integrating the overland transport model with the previously coupled models of vadose zone transport and plant pathway. The model developed is applied to various environmental contamination scenarios where the effect of the presence of plants on the contaminant migration within environmental systems is investigated.