The basal Pennsylvanian Caseyville Formation of south-central Kentucky includes an extensive network of paleochannels, which unconformably overlie various Mississippian (Chesterian Series) rocks. Questions have been raised about the extent and orientation of paleochannels and the systemic boundary in the region. The problematical systemic boundary is quite significant in cases where marker beds are lacking or where sandstone facies of Pennsylvanian age are juxtaposed on lithologically similar Mississippian-age strata. Discerning the systemic boundary may also be complicated by facies changes in Chesterian strata. This study employs various data to investigate the Mississippian-Pennsylvanian systemic boundary such as well logs, outcrops, and subsurface-to-outcrop cross-sections. The subsurface and outcrop investigation was aided by use of the Kentucky Geological Survey's newly available Digitally Vectorized Geological Quadrangles (DVGQs) and the Indiana Geological Survey's Stratigraphic Column Generator. Several trunk and tributary systems were identified in this study covering about 20 miles of channels. Fluvial systems have a maximum incisement of 370 feet. Results of this study provide a better understanding of the sub-Pennsylvanian topography that evidently is dependent on lithologic variation of Upper Mississippian strata. Integration of DVGQs with Geographic Information Systems (GIS) provides a new avenue that researchers can use to identify Pennsylvanian paleochannel systems that have proven to be economically important in the Illinois Basin region.

ABSTRACT This study focuses on the dissolution and near-source attenuation of oxygenated gasoline hydrocarbons in groundwater from two gasoline residual sources: one containing gasoline with 9.8% methyl tert butyl alcohol (MTBE) and 0.2% tert-butyl alcohol (TBA) (GMT source) and the other containing gasoline with 10% ethanol (E10 source). The sources were injected into a shallow sand aquifer, leaving a residual plume to dissolve under natural gradient conditions. The MTBE plume (from the GMT source) and the ethanol plume (from the E10 source) were compared with predictions by the BIONAPL numerical model assuming ideal source dissolution and no biodegradation of the oxygenates or aromatic hydrocarbons. While the complete mass of injected MTBE appeared to pass row 2, little MTBE was found further downgradient. This mass loss was considered to be an artifact of the monitoring system and of possible biodegradation. The ethanol mass flux was better captured in the E10 gate. Essentially all the ethanol from the E10 source also passed row 2, but, the ethanol mass flux decreased somewhat from row 2 to row 4. The better mass recovery may reflect that the ethanol plume remained more in the center of the monitoring network as compared to the MTBE plume some of which may have bypassed the monitoring fence. MTBE, TBA, and ethanol in the model were assumed to dissolve at equilibrium. The MTBE and TBA concentration breakthrough curves are generally consistent with equilibrium dissolution. However, the mass flux values suggest non ideal dissolution. The ethanol concentration breakthrough curves and mass flux are consistent with equilibrium dissolution. Also, the observed concentrations were often higher than predicted at later times. These features could be due to non-equilibrium (kinetically-limited) dissolution However, non-ideal source conditions may have arisen due to most of the oxygenates being dissolved into the water injected along with the gasolines thus distributing the residual gasoline in a non-uniform manner. The concentrations of aromatics are higher than expected from the BIONAPL model and are consistent with tailing expected with non-equilibrium dissolution. However, the probable complexity of the source concentration distribution likely account for much of the concentrations variability. There were insufficient electron acceptors to support complete mineralization of either the oxygenates or the BTX-TMB compounds. Although, evidence of weak MTBE biodegradation was found, the major mass loss seemed to be related to the uncertainties in the monitoring network. Some ethanol mass loss could be attributed to fermentation to organic acids (which were not sought in the field experiment). The persistence of BTX-TMB through the gates seemed to be slightly greater in the presence of ethanol. The field study was also used to test the Ratio Mass Estimation (RME) method of estimating the initial NAPL mass in the source from downgradient contaminant concentrations. The method was found reasonably reliable if the downgradient concentrations were collected close to the source where biodegradation was minor.

Although iron-based permeable reactive barriers are gaining importance in the treatment of groundwater contaminants, there have been field observations indicating that sulphide may affect the degradation rates of certain chlorinated ethenes. Previous observations suggest that sulphide has little effect on TCE degradation rates but can cause a significant decline in the rate of degradation of cis-DCE. This study was conducted to systematically test the effects of S2- on TCE, cis-DCE, trans-DCE, 1,1-DCE and VC. Two different concentrations of sulphide (5 and 50 mg/L) were used in the column experiments. The results showed that the rate of TCE degradation was only slightly reduce in the presence of sulphide, while there was substantial reduction in the rates of degradation of cis-DCE, 1,1-DCE and VC. Trans-DCE was affected by sulphide, however, not as severely as cis-DCE, 1,1-DCE and VC. Raman Spectra showed the presence of a small amount of sulphide precipitates, and corrosion potential measurements showed that sulphide shifted the corrosion potential of the iron to less negative values by approximately 70 mV, suggesting that the change in corrosion potential was not responsible for the preferential degradation of TCE relative cis-DCE and VC. The dominant pathway for TCE degradation is β-elimination, while that for cis-DCE and VC is generally considered to be hydrogenolysis, though there is also evidence in the literature indicating that cis-DCE and VC can also degrade by catalytic hydrogenation. The results indicate that sulphide does not inhibit β-elimination but severely limits the hydrogenolysis/catalytic hydrogenation pathway. The fact that sulphide inhibited the conversion of ethene to ethane, a known catalytic reaction, indicated that sulphide is acting as a catalyst poison. It is therefore concluded that the primary mechanism for the transformation of cis-DCE to VC and for VC to ethene is catalytic hydrogenation, and that sulphide inhibits these transformations through its role as a catalyst poison.

The 1946 M7.3 Ancash earthquake triggered a large number of landslides in an epicentral area along the continental divide in the Andes of Peru. Reconnaissance reports by Silgado (1947, 1951), Heim (1949) and Rüegg (1950) published shortly after the earthquake describe some of the landslides, but lack any detailed documentation. A review of literature, field traverses, aerial photograph interpretation and GIS mapping, identified 45 landslides inferred to have been triggered by the event. The cumulative volume-frequency plot shows a strong power law relation, similar in form to that derived for landslides triggered by the 1994 Northridge earthquake (Harp and Jibson, 1995). Data for the Ancash earthquake plots near the regression line calculated by Keefer (1994), and modified by Malamud et al. (2004), for earthquake moment magnitude vs. total volume moved by landslides during the earthquake. A denudation (average surface lowering) of 76 mm and a denudation rate of 0.00585 mm/yr was estimated for the area over which the earthquake-triggered landslides occurred. Rock avalanches constituted 83% of the landslides which involved Cretaceous limestones interbedded with shales. Rock slope failures were common on slopes with a southwest aspect, an orientation corresponding to the regional dip direction of major planar structures in the epicentral area. In valleys oriented transverse to the NW-SE structural trend of the epicentral area, south-westerly dipping bedding planes combined with orthogonal joint sets to form numerous wedge failures. Three rock avalanches were analysed using conventional wedge failure criteria. Two of the rock avalanches which did not satisfy conventional criteria were utilized to develop a new criteria, i.e. stepped wedge criteria. Stepped wedge failure involves wedge movement along a stepped line of intersection formed by a nearly-vertical discontinuity, striking roughly parallel to the slope, and the conventional line of intersection formed by the bedding and orthogonal joint set. The nearly-vertical discontinuity forms the essential backscarp needed to facilitate stepped wedge failure. Additional characteristics of stepped wedge failure were also distinguished based on the wedge failures studied in the epicentral area of the 1946 Ancash earthquake.

Oxygen has been shown to be an effective addition of enhancing the bioremediation of petroleum hydrocarbon contamination in porous media; however, the ability to effectively deliver oxygen to petroleum hydrocarbon contaminated groundwater has proven difficult. A field and numerical modelling study was completed at a former gas station in southern Ontario, to assess the delivery of oxygen into groundwater in a fractured limestone aquifer that had been contaminated with petroleum hydrocarbons. A field investigation was completed to characterize the bedrock aquifer and the groundwater flow system. Several hydraulically active fracture zones were identified and characterized. To evaluate how dissolved oxygen would behave in this type of groundwater environment, an injection test was completed using iTi’s gPro® oxygen injection technology. About 1000 L of water containing dissolved oxygen at ~ 30 mg/L and a bromide tracer was injected over ~ 90 minutes and monitored for ~ 10 days in the injection well and in a multilevel monitoring well located 3 metres down-gradient. The oxygen concentration rose rapidly within the injection well and at two of the down-gradient monitor intervals which were aligned with the injection well via major fractures. Concentration tailing persisted in the injection well for several days following injection. The effects of biodegradation were not assessed as part of this investigation. A three-dimensional numerical model for groundwater flow and advective-dispersive transport within a discretely-fractured porous medium was calibrated to the field conditions. The simulated injection test demonstrated that oxygen rapidly filled the porous matrix surrounding the injection well and filled the local intersecting fractures. Following injection, the oxygenated groundwater in the local fractures was rapidly flushed by the natural groundwater flow, with oxygen arrivals appearing as sharp pulses in the fracture-associated breakthrough curves in the monitor well. Back diffusion of oxygen from the porous matrix into the injection well was accurately reproduced by the model. Media properties (fracture apertures, hydraulic gradient and hydraulic conductivity) were varied to assess the sensitivity of the model and to evaluate the effectiveness of the remediation technology under different conditions. The sensitivity runs demonstrated that the distribution of oxygen within the system could be significantly different with varying degrees of advective transport within the fractures and diffusion into the rock matrix which depends on the physical properties and hydrogeological conditions. Predictive simulations were then run with two different injection scenarios: a continuous injection for 1 week and a cyclic injection scenario (injection every 2 days). The same mass of oxygen was delivered in each simulation (~3 kg). The results demonstrated that the delivery of oxygen into the system (continuous or cyclic) could affect the advective transport of oxygen through the fractures and the diffusion of oxygen into the matrix. The continuous injection resulted in a maximum zone of influence (down-gradient and in the transverse direction) while maintaining high levels of oxygen within the matrix. On the other hand the cycle injection provided a more continuous supply of oxygen over time to the system. The zone of influence was reduced but diffusion into the matrix along the fractures increased, creating a more uniform zone of increased oxygen concentrations around the injection well and along the fractures. This study demonstrated that oxygen could effectively be delivered to a fractured bedrock system at levels potentially sufficient to enhance aerobic biodegradation. Additional areas requiring investigation include the behavior of oxygen during hydrocarbon biodegradation through field and modelling studies. Full scale implementation of the technology should then be considered to provide additional information with respect to the applicability of the technology to real world environments.

Best or beneficial management practices (BMPs) are often relied upon as a mitigation strategy for nitrate contamination throughout Canada. At a regional scale, reducing the quantity of nutrients applied to agricultural land is one BMP approach that has been implemented internationally. While these BMP strategies have been proven to successfully reduce the environmental impact of agriculture on water systems, the time interval between BMP implementation and a noticeable improvement in groundwater quality can be quite extensive. This lag time has been observed at the agriculturally impacted Thornton Well Field in Oxford County. Despite seven years of significant reductions in fertilizer application within the capture zone of this municipal well field, declining nitrate concentrations have yet to be observed in the production water wells. In order to accelerate nitrate reductions at the Thornton Well Field, an integrated approach, combining BMPs with a stimulated in situ denitrification strategy, was implemented. This research focused on the use of a cross-injection scheme to stimulate in situ denitrification within the production aquifer units, up-gradient of the Thornton Well Field. Briefly, this strategy involves injecting a carbon source and electron donor into a high flux aquifer zone using an injection and extraction system positioned perpendicular to the regional flow field. Through altering the geochemical conditions, the injections stimulate indigenous bacteria to reduce harmful nitrate to innocuous dinitrogen gas. The main objectives of this research included: characterizing the hydrogeologic and geochemical properties of the target aquifer; pilot scale testing of the proposed in situ denitrification system; and suggesting an approach for up-scaling to a full-scale treatment scheme capable of remediating the elevated nitrate concentrations at the Thornton Well Field. Core logging, electrical resistivity studies, several methods of hydraulic characterization, tracer testing, and three-dimensional groundwater modelling were used to quantify the physical properties of the target aquifer and to develop a hydrogeologic conceptual model of the site. The aquifer unit was found to be unconfined in the experiment vicinity, consisting of a complex system of six main hydrostratigraphic layers of sand and gravel featuring variable hydraulic conductivity (K) values. Despite the hydrogeologic complexity, the geochemical properties of the aquifer were relatively uniform with depth. Anion, cation, alkalinity, pH, dissolved oxygen, and nitrous oxide data all contributed to this conjecture. Of particular interest, however, were the elevated dissolved oxygen concentrations, which rivalled atmospheric saturation throughout the entire aquifer sequence. The background physical and chemical characterization identified two main challenges that would potentially influence the performance of the in situ denitrification process: stimulating uniform denitrification in the fast flowing, complex aquifer system and overcoming the elevated oxygen concentrations to achieve the necessary anaerobic conditions. Following the initial site characterization phase, several preliminary cross-injection experiments were designed and performed. These experiments featured an injection-extraction circulation cycle which spanned five metres and was operated normal to groundwater flow. Acetate was selected as the electron donor and carbon substrate. The first test involved a single acetate injection followed by an extensive period of groundwater sampling. Unfortunately, this initial test provided no indication of stimulated in situ denitrification. All anion, cation, and nitrous oxide concentration and isotope data collected during and following this injection remained within the range of background estimates. Following the first injection experiment, a subsequent test involving multiple, repetitive acetate injections was implemented to overcome the highly aerobic nature of the aquifer and support the growth and reproduction of denitrifying bacterial populations. The second injection phase included 19 individual injections that were operated at intervals of every day to every other day over a total period of 26 days. These injections successfully lowered the dissolved oxygen concentrations within the target aquifer to an average range of 0 to 4 mg/L. The least conductive layers featured the lowest oxygen concentrations, while the higher K layers maintained elevated oxygen concentrations. The nitrite, nitrate, and enriched NO3-15N and NO3-18O isotope data suggested a high degree of stimulated denitrification in the least conductive layers and a limited degree in the high-K layers. The lower-K units corresponding to multi-level well ports ML7-2, ML7-5, and ML7-6 achieved a 46 percent reduction in nitrate, while the layer represented by ML7-1 attained a 100 percent reduction in nitrate. Alternatively, due to the constant influx of dissolved oxygen and limited residence times, very little denitrification was observed in the fast flowing layers corresponding to ports ML7-3, ML7-4, and ML7-7. Overall, a percent reduction, in terms of nitrate mass crossing the 5-m wide treatment lens, of only eleven percent was calculated. These results clearly demonstrate that the K-profile had a significant impact on stimulating in situ bioremediation. Two major system challenges were observed, including an inability to successfully stimulate denitrification within the highly permeable layers and the generation of harmful nitrite at nearly all aquifer depths. Based on these significant challenges, it was concluded that additional experimentation is required before this remediation technique can be expanded to a full-scale in situ treatment scheme. The most significant recommendation requested the development and execution of a third injection phase, consisting of multiple, consecutive substrate injections designed to systematically test various pulsing intervals, injection concentrations, and electron donors. Despite the current limitations, this approach has great potential. It is believed that with additional research, the in situ stimulation of denitrification could be used to successfully reduce the elevated nitrate concentrations at the Thornton Well Field.

Användningen av avloppsslam från kommunala avloppsreningsverk som ett alternativt gödningsmedel ökar i det svenska jordbruket. Ett problem med slam som gödningsmedel är dock att de metaller och oönskade ämnen som finns i avloppsvattnet också tillförs åkermarken via slammet, och slutligen, genom ackumulering i mark och grödor, kan ge effekter på miljön och människors hälsa. För att möjliggöra användning av avloppsslam som växtnäring finns certifieringssystemet REVAQ. Målet med REVAQ är att genom systematiskt uppströmsarbete vid reningsverken förbättra slammet. Detta, genom att minska metaller och oönskade ämnen i inkommande avloppsvatten till den nivå där halterna i slammet inte påverkar markorganismer och gröda, negativt. Kalmar Vatten AB är certifierat enligt REVAQ och samtliga metallhalter i deras avloppsslam, avsett för slam som växtnäring, har en godkänd halt. Emellertid har halterna av koppar och kadmium varit något förhöjda. Med anledning av detta har det, som en del av uppströmsarbetet enligt REVAQ, i denna studie undersökts om något område i Kalmar kommun bidrar med ett större tillskott av dessa metaller i avloppsvattnet och det har spekulerats i vad detta i så fall kan bero på. För att svara på detta har provtagningar gjorts i pumpstationer som utgör knutpunkter inom större avrinningsområden för kommunens spillvattennät. Resultaten visar att kommunen har områden som är av betydelse för koppar- och kadmiumtillförseln till reningsverket, både när mängderna sätts i relation till antalet anslutna personer på avloppsnätet och vad gäller mängder/koncentrationer som kan påverka halter i slammet. Orsakerna till mängder från dessa områden beror möjligen på hur områdena ser ut och är uppbyggda. Vidare provtagningar, uppströms de presenterade områdena, är nödvändiga för att fastställa de källor som behöver åtgärdas för att slutligen minska koppar- och kadmiumhalterna i slammet.

Future climate change and variability is one of the top priorities for most countries and regions in the world. Unpredictability and uncertainty regarding future climate is making adaptation forecasts and mitigation of climate change on societies a real challenge for both climate scientists and policy makers. The climate system is not a static entity. On the contrary, changes are part of the mechanism. The impact of human activities, however, has accelerated processes inducing the need for rapid adaptation and mitigation strategies. This thesis focuses on understanding how hydrology and climate influence vulnerability and adaptation of rural Tanzania. This is done by looking at social, climatic and biophysical factors of two villages located in western Tanzania. Analysis of local climate and hydrology factors showed that precipitation and evapotranspiration amounts were about thesame, resulting in small margins for error for successful small scale agriculture. Investigation of various strategies used by farmers as a response to present climate variability are insufficient, and raise concerns about the potential hazard of future climate change. Most of the strategies rely on socio-ecological services from the surrounding environment, and therefore would face dire consequences as a result of future climate change. A wider understanding of successful current adaptation and resilience strategiesand their systematic application would increase the ability of farmers to meet the challenges of future climate volatility.

Calcareous fens constitute a specific habitat which is uncommon in Europe and protected by the EU habitat directive due to its importance to several threatened species. Hagebyhöga in Östergötland is a calcareous fen habitat included in the Natura 2000 Networking Programme. Adjacent to the existing fen, a degraded fen area is situated. The area has been used for agriculture for several years but is now going to be restored to its former state by the county administrative board of Östergötland. When working with restoration of degraded fen areas it is important to aquire knowledge about the chemical soil conditions. Plant growth limited by phosphorus and low fertility are characteristic conditions for calcareous fens, whilst arable land usually is highly fertile and limited by nitrogen. The purpose of this study is to bring forth useful knowledge for restoring the degraded calcareous fen of Hagebyhöga. Phytometric assessments have been conducted on samples from the ground that is going to be restored, to investigate which element limits growth, and whether the fertility is comparable to that in the fen allready present. The results will be used when deciding whether the top soil layer needs to be removed, and if that is the case, how much of the soil needs to be removed to recreate the fen environment. The samples were collected from two areas (A and B) with different moisture content in the arable ground and three depths from each area (0-10 cm, 10-30 cm and 30-40 cm). As reference, a sample from the top soil layer of the existing fen was used. The results from the phytometric assessment reveals all samples from area A and the sample from area B, 30-40 cm to have plant growth limited by phosphorus. The results also reveals the fertility in all samples except for area A, 30-40 cm to be significantly higher than the fertility of the existing fen. Both conditions, low fertility and plant growth limited by phosphorus, are present in the sample from area A, 30-40 cm.

The Mariana convergent plate margin is a non- accretionary subduction system in the western Pacific Ocean. Subduction of the Pacific plate causes dissolution of carbonate minerals releasing inorganic carbon, and causes dehydration of hydrous minerals in the subducted slab, generating hydrous fluids. The hydrous fluids infiltrate the overriding plate and induce serpentinization of mantle peridotite. Serpentinized material is transported by the rising fluids, which are channeled along fractures and faults in the forearc region, consequently erupting at the seafloor forming serpentine seamounts. Manganese (IV) oxides that commonly occur in fractures near convergent plate margins are naturally occurring oxidants for chromite ((Al,Mg,Fe)Cr2O4), which is an accessory mineral in mantle peridotite. Chromite is known to be an efficient catalyst in Fischer- Tropsch type (FTT) reactions where molecular hydrogen produced by serpentinization reacts with dissolved inorganic carbon, producing organic hydrocarbons.   Samples were collected from two serpentine seamounts in the Mariana forearc during Ocean Drilling Program, Leg 125 and Leg 195. The aim of this study is to relate organic content in fluid inclusions to minerals that are known to be efficient catalysts in FTT- reactions. The results show that chromites have been altered, with hematite (Fe2O3) precipitated at the margins of the chromites. This is inferred to be caused by an oxidation reaction where manganese (IV) oxides acted as oxidants, oxidizing Fe (II) in chromites to Fe (III) which precipitated as hematite. No fluid inclusions were found in the samples. However, elemental carbon was detected in fractures of the chromites, suggesting that FTT- reactions has occurred where chromite probably acted as a catalyst / I västra Stilla havet ligger Marianergraven som är en del av en konvergerande plattgräns. Det är ett subduktionssystem där sediment saknas på den överliggande oceanskorpan. Subduktionen av stillhavsplattan leder till att karbonatrika mineral löses upp och frigör oorganiskt kol. Dehydrering av hydrerade mineral i den subducerande plattan genererar vattenhaltiga fluider, när dessa fluider infiltrerar den överliggande plattan orsakar de serpentinisering av mantelperidotit. Det serpentiniserade material som bildats, transporteras av fluiderna längs sprickor och förkastningar i området kring den vulkaniska öbågen. När fluiderna och det serpentiniserade materialet erupterar vid havsbotten bildas vulkanliknande djuphavsberg. Mangan (IV) oxider som förekommer i sprickor är naturliga oxidationsmedel för kromit ((Al,Mg,Fe)Cr2O4), som är ett accessoriskt mineral i mantelperidotit. Kromit är ett mineral som är en effektiv katalysator i Fischer- Tropsch (FTT) reaktioner, en reaktion där molekylärt väte, som är en produkt från serpentinisering, reagerar med frigjort oorganiskt kol och bildar organiska kolväten.   Prover togs på två av Marianergravens djuphavsberg under Ocean Drilling Program, Leg 125 och Leg 195. Syftet med denna studie var att relatera organiskt innehåll i vätskeinneslutningar till mineral som är kända katalysatorer i FTT- reaktioner. Resultaten visade att kromiterna är omvandlade med hematite (Fe2O3) utfällt på kanten av kromiterna. Detta antas därmed vara en redoxreaktion där mangan (IV) oxider agerat som oxidationsmedel. Fe (II) i kromiterna oxiderade till Fe (III) och fälldes ut som hematite. Inga vätskeinneslutningar hittades i proverna, men elementärt kol hittades i sprickor i kromiterna. Förekomsten av kol antyder att Fischer- Tropsch- reaktioner har skett med kromiterna agerandes som katalysatorer.