Dissertations / Theses on the topic 'Lithologic sources of arsenic'

Analytical techniques were developed for the detection of inorganic arsenic (As(III) and As(V)), monomethylarsenic (MMA) and dimethylarsenic (DMA) in water, pore waters, suspended particles and bed sediments of the Humber Estuary, Thames Estuary and the southern North Sea. Dissolved inorganic As in the Humber Estuary showed removal in the mouth of the estuary in association with an Fe-rich outfall. Intertidal sediments and suspended particles had elevated inorganic As concentrations in the vicinity of the As-rich outfall located in the low salinity zone. Particulate As had a distinct concentration gradient away from the estuary mouth, indicating the transport of As out of the estuary. The presence of MMA and DMA in the water column was attributed to the methylation of inorganic As by marine phytoplankton and was not detected when the seawater temperatures were below about 10° C DMA concentrations were higher than MMA. The Humber and the Thames Estuaries both had sources of inorganic As, but As methylation within the estuaries was not significant. MMA and DMA in the estuarine plumes and the North Sea showed strong seasonality, with concentrations below detection in winter, and maximum concentrations in late summer when the methylated As was 21% of the total As in the Humber and Thames Plumes. The concentrations of MMA and DMA in the early autumn (32% of the total dissolved As) were highest off the Dutch coast where the water temperatures were up to 18° C. There were no significant correlations between the methylated As and inorganic As, temperature, chlorophyll a nor phosphate. A water sample from a developing spring bloom was incubated and showed the removal of inorganic As at a rate of 0.04ugAs/l/day, but there was no subsequent increase in the dissolved organic species, indicating a delay interval between peak primary productivity and the release of MMA and DMA. Inorganic As was detected in the porewaters of the Humber and Thames Plumes. In late summer, MMA and DMA were found at equivalent concentrations in all the Humber Plume porewaters. Flux calculations indicated that the diffusion of inorganic As, MMA and DMA from the sediments into the water column was insignificant, largely as a result of low sediment porosity. However, a resuspension event caused a detectable increase in inorganic As at the bottom of the water column. The importance of this work to the development of the 3-D hydrodynamic model of the North Sea is discussed.

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

The Swedish mining industry has changed from the historical situation with several smaller mines to the present situation with a few, bigger mines. This results in presence of abandoned mines around Sweden. Remediation of mines is regulated by legislation and the present demands are considerably higher than it was some decades ago.  The Storliden mine was a Zink- and Coppermine active between 2001-2008. Storliden is located in Malå municipality, Västerbotten county, and is included in the Skellefte district, known for its sulfide mineralizations.  The ore was broken underground with a technique called cut and fill mining. It was estimated that the ore was to be consumed in 2007, but due to rising ore prices, the mine was operated until 2008. Remediation was done through backfilling the mine with waste rock from Storliden and Boliden’s mines Renström, Kedträsk, and Kankberg. Also, tailings, concrete, and sludge from the sedimentation basins were backfilled. Today, the mine is filled with water.  High Arsenic concentrations in water is a serious health issue in parts of the world. Bangladesh is perhaps the most common example where Arsenic in groundwater has caused health problems for millions of people. In Sweden, the Skellefte field is known for its elevated Arsenic concentrations in the bedrock, related to sulfide mineralizations. Studies confirm a correlation between Arsenic-bearing bedrock and elevated concentrations in water.  This thesis work has been conducted together with the consultant company Golder Associates (Golder) in Luleå. Golder has performed environmental investigations in the Storliden area during the period 2018-2020. Installation and sampling of groundwater wells were included in this investigation. High concentrations of Arsenic was found in some of the groundwater wells. This thesis aims to review potential sources of Arsenic and their potential significance. The purposes are to be fulfilled by evaluating and interpreting the results from the sampling, Piper diagrams, ratios, and modeling in the program PHREEQC.  The results indicate that the presence of Arsenopyrite in the bedrock is the most likely source of the elevated concentrations of Arsenic in deep groundwater. Oxidation of Arsenopyrite is likely caused by mainly dissolved oxygen in groundwater. Further, the water quality differs from different depths, indicating that deep groundwater and water flow from the mine via the ramp do not have any immediate connection. It is likely that remains of tailings on the industrial area cause low pH and leaching of metals locally.  High concentrations of Arsenic can occur very locally, highlighting the importance of conducting sampling of groundwater used as drinking water in areas where sulfide mineralizations are confirmed or suspected. Further, a relation between the time that water is in contact with the bedrock/mineralization and the concentration of Arsenic is stated. Higher concentration HCO3- tends to correlate with elevated Arsenic concentration.
Sveriges gruvindustri har förändrats i snabb takt, från ett flertal mindre gruvor till dagens läge med ett mindre antal större gruvor. Detta resulterar i förekomst av nedlagda gruvor runt om i Sverige. Efterbehandling av gruvor regleras genom lagstiftning, och kraven idag är betydligt högre än för bara något decennium sedan.   Storlidengruvan var en zink- och koppargruva verksam mellan 2001–2008. Storliden ligger i Malå kommun och området ingår i Skelleftefältet, känt för sina sulfidmineraliseringar. Malmen bröts i en underjordsgruva med så kallad igensättningsbrytning, dvs. tomrum har succesivt fyllts ut med material under driften. Malmen beräknades vara förbrukad 2007, men när malmpriset ökade kunde gruvan leva vidare till 2008. Efterbehandlingen innebar att fylla igen gruvan med gråberg från Storliden men också gråberg från Bolidens gruvor Renström, Kedträsk och Kankberg. Dessutom användes anrikningssand, cement och slam från sedimentationsbassängerna för att fylla igen gruvan. Länshållning av gruvan upphörde och idag är gruvan vattenfylld. Höga arsenikhalter i vatten är ett hälsoproblem i delar av världen. Det kanske vanligaste exemplet är Bangladesh, där arsenik i grundvatten har orsakat hälsoproblem för miljontals människor. I Sverige är Skelleftefältet utmärkande för den höga arsenikhalten i berggrunden. Naturlig arsenikhalt i borrade brunnar har undersökts i flera studier som visar ett samband mellan arsenikhaltig berggrund och förhöjda halter i vatten.  Examensarbetet har utförts tillsammans med konsultföretaget Golder Associates i Luleå. Golder har fått i uppdrag att utföra miljötekniska undersökningar i Storlidenområdet, bland annat ingick installation och provtagning av grundvattenrör. Denna provtagning skedde under perioden 2018–2020. I några av grundvattenrören påträffades förhöjda halter av arsenik. Detta examensarbete syftar till att utreda förekomsten av Arsenik i grundvattnet, undersöka vilka källor som kan vara orsaken till arsenikhalterna samt källornas förväntade betydelse. Detta har gjorts genom att utvärdera och tolka resultaten från provtagningarna samt användningen av Piper-diagram, geokemiska kvoter och geokemisk modellering i programmet PHREEQC. Resultaten indikerar att förekomst av arsenikkis som mineralisering i berggrunden är den mest troliga källan till de förhöjda halterna av arsenik i djupt grundvatten. Oxidationen av arsenikkis sker troligtvis främst av löst syre i grundvattnet. Vidare skiljer sig vattenkvalitén åt från olika djup och delar av området som provtagits, dvs. det verkar inte finnas någon omedelbar koppling mellan djupt grundvatten och vatten som kommer via rampen som leder till gruvan. Det är troligt att rester av anrikningssand på industriområdet orsakar lågt pH och metallutlakning lokalt.  Höga arsenikhalter kan förekomma lokalt, vilket understryker vikten av att utföra provtagning av grundvatten som används för dricksvatten i områden där misstänkt eller konstaterade sulfidmineraliseringar förekommer, eftersom arsenik annars kan vara en mycket skadlig ”diffus” förorening. Vidare konstateras också samband mellan den tid som vatten är i kontakt med mineralisering och arsenikhalt. Högre halt HCO3- tenderar att korrelera med förhöjd arsenikhalt

Thesis: M. Eng., Massachusetts Institute of Technology, Department of Civil and Environmental Engineering, 2018.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 58-61).
Lead and arsenic in drinking water are a health risk to communities throughout the world; lead can be a problem in houses with old piping systems with either lead piping or 50/50 lead solder, and groundwater in Maine contains high arsenic concentrations. This study sought to determine the prevalence and sources of arsenic and lead in the drinking water of Eastport, Perry, and Pleasant Point, Maine. Citizens of these towns submitted water samples from their homes, and arsenic and lead were measured in these samples. Each citizen submitted two samples: one where water stood in the pipes for a minimum of six hours, and another where the tap was flushed for 2+ minutes before sample collection. The primary water sources in the region were municipal water, from the Passamaquoddy Water District (PWD), and well water from private wells. Water samples were also collected from the source waters of the municipal water system, the Passamaquoddy Water District, and immediately following water treatment to determine sources of lead in the municipal system. Lead concentrations were found to be below the Environment Protection Agency (EPA) action level of 15ppb throughout the municipal system, and less than 1% of PWD samples exceeded the action level for lead in the standing samples. Overall, including houses with wells, 2% of houses exceeded the EPA action level in standing samples, and these houses are inferred to contain high lead levels in their piping. Arsenic levels in well water samples were found to exceed the EPA Guideline of 10[mu]g/L in 15% of samples, and did not depend on bedrock type, pH, or well depth, suggesting that bedrock heterogeneity and fracture geometry plays a large role in arsenic concentrations in this region.
by Abby Harvey.
M. Eng.

Arsenic contamination of circum-Himalayan groundwater is leading to one of the greatest humanitarian disasters of modern times, poisoning at least 70 million people who are mostly poor and rural. The groundwater is hosted in Holocene aquifers consisting of Himalayan sediments deposited by the great Asian rivers in deltaic environments. Arsenic is released when organic material (OM) reacts with the iron-oxide minerals co-deposited in the sediments onto which arsenic is adsorbed. The source of OM is one of the most important questions facing researchers and policy makers. There are generally accepted to be three potential sources of OM: 1) sedimentary bound OM (SOM) co-deposited with sediments; 2) thermally mature petroleum upwelled from reservoirs below the aquifers; 3) dissolved organic carbon (DOC) some of which might be drawn in to the aquifer through modern pumping and irrigation. In this thesis the nature of organic material in the aquifer is researched and the processes and timescales which lead to arsenic release are studied. Here evidence for a new conceptual model of arsenic release is presented. Isotopic tracing combined with a new geochemical model and organic geochemical techniques, shows that OM driving arsenic release pre-dates agriculture in the region and was from natural grasslands in the early Holocene. The geochemical model utilises strontium isotopes to correct the radiocarbon age of dissolved inorganic carbon (DIC) to find only the age and isotopic signature of DIC from oxidation of organic material. This shows that DIC from oxidation of OM was from the early Holocene and had an isotopic signature consistent with the early Holocene SOM in this region. A study of the sediments in the region built upon a geomorphological history shows that the most oxidised SOM is from early Holocene sediments. Thus both techniques separately indicate that pre-agricultural organic material drove arsenic release. This conceptual model however reveals the "arsenic sand paradox", because whilst release is from early Holocene clays, today highest concentrations of arsenic are in younger sands. Explaining this paradox is the most important next step leading on from this research.

Arsenic (As) and nitrate (NO3) are common contaminants in groundwater that are introduced through a variety of natural and anthropogenic sources. In this study we investigated the sources and distribution of As and NO3 in Goshen Valley, Utah, USA. Goshen Valley is a semi-arid alluvial basin that is impacted by geothermal waters, agriculture, urban development, and legacy mining. In this study we sampled surface water, springs, and wells to analyze concentrations of major ions, trace elements (As, B, Ba, Ca, Fe, K, Li, Mg, Mn, Mo, Pb, Si, Sr, Zn), and stable isotopes in water (δ18O and δD). A subset of samples were also analyzed for 87Sr/86Sr, δ34S, and tritium (3H). Major ion concentrations showed high spatial variability ranging from freshwater to brines, with the highest concentrations found in springs discharging from playa sediments. Likewise, the highest trace element concentrations, including As, were found in the playa-impacted springs. Elevated NO3 concentrations were found in springs and wells in agricultural areas of the valley. δ18O and δD values range from -0.90238 to -17.6 and -37.0891 to -134.5 respectively and represent that the valley contains old groundwater, evaporative surface water, and mixed water signatures in multiple wells. Tritium values range from 0.5 to 7.8 and further show the diversity of water in the valley by indicating old, young, and mixtures of old and young waters. Variations in 87Sr/86Sr were used to evaluate flowpaths of waters with elevated As. 87Sr/86Sr ratios suggest that the groundwater has interacted with a mixture of lithologic units including Tertiary volcanics, Paleozoic carbonates, and Quaternary alluvial/lacustrine fill. Correlations with As and playa affected springs indicate playa sediments as a major As source. The As found in wells has no apparent elemental correlations or spatial patterns and is likely due to the naturally occurring As in the valley alluvium and carbonate units. NO3 in the valley is concentrated in agricultural areas and is likely due to fertilizers, livestock, and alfalfa crops. Of all the potential contaminant sources, the data suggests that the major source of As is the saline playa soils and the major source of NO3 is agricultural activities in the valley.

Cette étude est associée à une problématique industrielle visant à acquérir des connaissances fondamentales sur le fonctionnement de nouvelles technologies de post-traitement des fumées provenant de fours industriels et en particulier leur résistance face aux phénomènes de la désactivation. Aujourd’hui, la technologie catalytique est la plus efficace pour réduire les émissions d’oxydes d’azote (NOx). L’empoissonnement de catalyseurs V2O5-WO3/TiO2 par le potassium et l’arsenic issus de fours à combustion alimentés par des sources biomasses et des fours verriers ont été étudiés. L’empoisonnement a été simulé par imprégnation de potassium et d’arsenic pour différents rapports K/V et As/V correspondant à différents temps de fonctionnement de l’installation. L’étude cinétique a permis d’établir des relations structure-activité pertinentes permettant a priori d’établir un modèle prédictif permettant de prévoir une perte de performances d’un catalyseur SCR pour des rapports proches de 3. Dans ces conditions la sélectivité du catalyseur est fortement dégradée au profit d’une réaction secondaire non désirée : l’oxydation de l’ammoniac en NO
The aim of this study is in connection to industrial problem which consists in implementing the best available technologies for the purification of fumes from industrial furnaces and particularly to check their lifetime due to deactivation phenomena. Nowadays, the catalytic technology is highly efficient to treat tail gas before rejection in the atmosphere. V2O5-WO3/TiO2 is recognized as benchmark catalyst and has been investigated in this study for the abatement of NOx. Poisoning effects induced by potassium and arsenic due to the use of biomass sources as fuel and more specifically in the fabrication process of glass were investigated.Potassium and arsenic poisoning have been simulated taking different K/V and As/V ratios corresponding to various time exposures of the catalysts in typical running conditions. The kinetic study allows the establishment of structure-reactivity relationships which can a priori predict the deactivation corresponding to a quasi-complete degradation of the catalysts for atomic ratios reaching 3. In these conditions, it was found that the selectivity is strongly altered mainly due the occurrence of undesired reactions: the ammonia oxidation to NO

Access to safe drinking water is a challenge for rural communities in many developing countries. Drinking contaminated water endangers human health and impairs social and economic development. Arsenic (As) is a metalloid widely distributed into the environment and is highly toxic in its trivalent inorganic form. The natural occurrence of As in groundwater used for drinking has been associated to the insurgence of skin disorders and respiratory diseases in many parts of the world. Arsenic is frequently found in the form of sulphide in gold deposits. Human exposure to As via drinking water has resulted from gold mining activities in some instances in USA, Asia, South America and Africa. The problem of As in drinking water has been brought to attention in Tanzania only few years ago and further investigation are therefore needed to enable an early detection of harmful exposures. This study aims to assess occurrence, source and mobilization mechanisms of As in some drinking water sources within the Lake Victoria Basin, in Northern Tanzania. Rural communities living in areas known for artisanal and large-scale gold mining activities were the target of the present study. Fifty-four water samples were collected from a variety of drinking water sources (spring, borehole, river and shallow well) in Mara and Geita region during October 2016. pH, electrical conductivity (EC), Redox potential (Eh) and As were measured in situ. Major ions, dissolved organic carbon (DOC) and trace elements, including As, were analysed in the sampled water at KTH-Royal Institute of Technology, in Sweden. 53% of the sampled water do not comply with the WHO recommended limit of 10 μg/L, representing a serious health risk for some rural communities within the Lake Victoria Basin. The spatial distribution of As in the area under investigation is highly heterogeneous and it is mainly influenced by local geology and proximity to the mining sites (approx. < 5 km). Lower As levels in boreholes than in rivers and shallow wells indicates contamination of surface drainage by mining activities and suggest that deep groundwater ( > 40 m) generally represent a source of safer drinking water. The field-measured Redox potential indicates oxidising conditions, suggesting that oxidation-dissolution of arsenic sulphide minerals is a major mechanism of arsenic mobilization in groundwater. However, this study reveals that several geochemical processes control fate and mobility of As, once it has been released into the aquatic environment. Large discrepancies between field and laboratory measurements of As indicates a strong partition of the metalloid into the particulate fraction. As revealed by the geochemical modelling, co-precipitation with iron /aluminium hydroxides and adsorption on clay minerals are presumed to be the major sinks for dissolved As. Moreover, a good match between peaks in As and dissolved organic carbon concentrations suggests that complexation by humic acids is responsible for enhanced As mobility. Overall, the present study has led to a better understanding of the problem of arsenic in proximity of gold mining areas in Tanzania and it calls for the development of affordable and sustainable solutions which would provide safe drinking water to the affected population.
Tillgången till rent, säkert vatten är en utmaning på landsbygdssamhällen i många utvecklingsländer. Åtgång på förorenat vatten riskerar människors hälsa och skadar social och ekonomisk utveckling. Naturlig förekomst av arsenik (As) i grundvatten är ett globalt miljöproblem, vilket utgör en allvarlig risk för människors hälsa på grund av metalloidens höga toxicitet. Med tanke på att arsenic sulfids mineraler är en viktigt del av guld insättning, har guldgruva aktiviteter anvisas som en orsak till att föroreningar av dränering och grundvatten i flera länder. Problemet med As i dricksvatten har uppmärksammats i Tanzania för några år sedan och det krävs ytterligare undersökning för att möjliggöra tidig upptäckt av skadliga exponeringar. Denna studie syftar till att bedöma förekomsten, källan och mobiliseringsmekanismerna för arsenik i vissa dricksvattenkällor i Lake Victoria Basin, i norra Tanzania. Landsbygdssamhällen som är kända för hantverksmässiga och storskaliga guldgruva arbeten var målet för den nuvarande studien. Femtiofyra vattenprover samlades från källvatten, borehålsvatten, floder och grundbrunn i Mara och Geita-regionen under oktober 2016. pH, redoxpotential (Eh), temperatur och elektrisk konduktivitet (EC) mättes i fält. Vattenprovernas koncentration av an- och katjoner, spårämnen (bl.a. arsenik), As(III) samt löst organiskt kol (DOC) analyserades i Sverige på Kungliga Tekniska Högskolan (KTH). Femtiotre procent av det provtagna vattnet överensstämmer inte med WHO:s rekommenderade gräns på 10 μg / l, vilket utgör en allvarlig hälsorisk fö vissa landsbygdssamhälen i Victoria-sjö. Den geografiska fördelningen av As i det undersökta området är högst heterogen och påverkas huvudsakligen av lokal geologi och närhet till gruvplatserna (ca <5km). Lägre As-nivår i borehål än i floder och grunda brunnar visar att föroreningar av dränering pågrund av gruvverksamhet och föeslår att djupt grundvatten (> 40m) i allmähet utgör en källa till säkrare dricksvatten. Däremot, visar denna studie att flera geokemiska processer kontrollerar förutbestämmelse och röligheten för As, nä det har blivit frisläppts ut i vattenmiljö. Stora skillnader mellan fält- och labbmäningar av As indikerar en stark partition av metalloid i partikelfraktionen. Som avslöjas av geokemisk modellering antas, samutfällning med järn / aluminiumhydroxider och adsorption på lermineraler vara de huvudsakliga sänkorna fö upplöst As. Dessutom antyder en bra matchning mellan toppar i As och upplösta organiska kolkoncentrationer att komplexbildning med humana och fulviska syror är ansvarig för föbättrad rölighet.

Barkley Sound and Alberni Inlet, located on the west coast of Vancouver Island, British Columbia, are home to economically important oyster farms. The headwaters of Alberni Inlet are proximal to the city of Port Alberni, where industrial activities (e.g., paper mills, recycling plants) release significant quantities of heavy metals into Alberni Inlet annually. The distribution of As, Cd, and Pb and Pb isotopic composition of Pb were studied in surface and cored sediments collected downstream from the paper mill using quadrupole and multi collector inductively coupled plasma mass spectroscopy (Q-ICP-MS, MC-ICP-MS). Surface and core sediment concentrations of As, Cd and Pb generally decrease downstream from Port Alberni, with the exception of a Pb spike observed in Barkley Sound. Alberni Inlet and Barkley Sound display ranges of 3.8-24 and 3.5-21.6 ppm for As, from 0.03-0.87 and 0.2-1.1 ppm for Cd, and 4.1-18 and 2.9-24.2 ppm for Pb, respectively. Scavenging of dissolved metals is observed at the distance of 10-25 km downstream from Port Alberni. Based on comparison to Sediment Quality Guidelines, the environmental impact of trace metals in the sediment on bottom dwelling organism is low. Major elements compositions determined using Aluminum as an elemental normalizer indicated that the sediment corresponds to a source predominantly from Vancouver Island bedrock. The isotopic composition for surface sediment ranges from 1.17020 to 1.21602 for ²⁰⁶Pb/²⁰⁷Pb, and 2.0397 to 2.0835 for ²⁰⁸Pb/²⁰⁶Pb. In core samples, the range is from 1.16571 to 1.19109 for ²⁰⁶Pb/²⁰⁷Pb and 2.06883 to 2.08533 for ²⁰⁸Pb/²⁰⁶Pb. Lead isotope fingerprinting indicates that sediments derived from Vancouver Island were contaminated with trace metals by a source displaying the Pb isotopic signature of the Sullivan Ore, the primary anthropogenic Pb source for British Columbia. This is consistent with paper mill effluent from Port Alberni. Sediments from the lower inlet and Barkley Sound also show a contribution from Chinese loess. Other human activities are most likely responsible for the spike in Pb concentrations in Barkley Sound. This study demonstrates that the combination of trace metal analysis and high precision Pb isotopic data are effective tools for monitoring anthropogenic input into the environment.

Grain assemblages in organic-rich mudrocks of the Eagle Ford Formation of South Texas are assessed to determine the relative contributions of intra- and extrabasinal sediment sources, with the ultimate goal of producing data of relevance to prediction of diagenetic pathways. Integrated light microscopy, BSE imaging, and X-ray mapping reveal a mixed grain assemblage of calcareous allochems, biosiliceous grains (radiolaria), quartz, feldspar, lithics, and clay minerals. Dominant fossils are pelagic and benthic foraminifers and thin-walled and prismatic mollusks; echinoderms, calcispheres, and oysters are present. Early-formed authigenic minerals, including calcite, kaolinite, dolomite, albite, pyrite, quartz, and Ca-phosphate, some reworked, add to the overall lithologic heterogeneity. Point counting of images produced using energy-dispersive X-ray mapping in the SEM provides observations at a scale appropriate to classifying the mudrocks based on the composition of the grain assemblage, although grains and other crystals of clay-size cannot be fully characterized even with the SEM. Each sample is plotted on a triangle, whose vertices correspond to terrigenous and volcanic grains (extrabasinal components), calcareous allochems, and biosiliceous grains. As a subequal mix of grains of intrabasinal and extrabasinal origins the detrital grain assemblage of the Eagle Ford, presents a formidable challenge to the task of lithologic classification of this unit, as neither conventional limestone nor sandstone classifications can be readily applied. The abundant marine skeletal debris in the Eagle Ford is accompanied by abundant calcite cementation and the dissolution and replacement of biosiliceous debris is accompanied by authigenic quartz, suggesting that mudrock grain classification has potential for yielding diagenetic predictions.
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博士
國立臺灣大學
生物環境系統工程學研究所
107
In this study, on the basis of physicochemical characteristics of groundwater and the nitrogen and oxygen isotope composition of NO3−, it was inferred that the main sources of NO3− in the proximal fan of the Choushui River alluvial fan are likely to be ammonium fertilizers, manure, and septic waste; that in the mid-fan and the distal fan, the possible sources are nitrate fertilizers and marine nitrate. In the proximal fan, the oxidative state obviously promotes microbial nitrification. High DO concentrations and relatively low values of δ18ONO3 in the deeper aquifer of the proximal fan may be attributed to unconfined granular nature and groundwater pumping by agricultural activities. In the mid-fan, NO3− assimilation is the dominant response to NO3− attenuation, and denitrification is insignificant; however, high concentrations of As, NH4+ and Fe and depletion of δ15NNO3 imply the occurrence of feammox process. By contrast, denitrification evidently occurs in the distal fan, through assimilation, mineralization, and dissimilatory NO3− reduction to NH4+, resulting in depletion of NO3− and increase in NH4+ in groundwater. Feammox in the mid-fan and denitrification in the distal fan may be the main processes leading to the release of As from As-bearing Fe oxyhydroxides into groundwater. The simulation result of nitrification shows that the nitrification and/or feammox mostly occur in the proximal fan and mid-fan, whereas they slightly occur in the distal fan. The concentrations of NO3− and NH4+ in the proximal fan evidently support the occurrence of NH4+ nitrification. The spatial concentration distribution of NO3− from the proximal fan to the distal fan indicates the gradual occurrence of NO3− denitrification and/or DNRA from upstream to downstream of the Choushui River alluvial fan. The mid-fan and the distal fan were assessed on the basis of the local DO and ORP values to be in relatively more reductive conditions, driving the occurrence of denitrification and/or DNRA. In the proximal fan, As3+ decreased and As5+ increased, and this valence transformation of As species and As concentration difference seem comprehensible. In the mid-fan and the distal fan, the reductive state was observed base on the DO and ORP data of the groundwater, and the circumstance of reduction from As5+ to As3+ was obvious. The discrepancy of δ15N in NO3− in groundwater was simulated on the basis of the influence of the reaction of NO3− denitrification. The values of δ15NNO3 increased in the groundwater of the mid-fan and the distal fan; in theory, the denitrification increases δ15N values of the residual NO3−. The 1-D transport simulation result suggested that NO3− assimilation occur from the mid-fan of the Choushui River Alluvial Fan to the distal fan, whereas NH4+ nitrification is observed at the beginning of the proximal fan. The concentration of As5+ increased at the beginning of the mid-fan, which may be caused by the reductive dissolution of As-bearing Fe oxyhydroxides and the desorption of adsorbed As. The concentration of As3+ increased obviously at the beginning of the distal fan, which may be related to the transformation of As5+ to As3+ in the reductive environment, and the continuous desorption of As from Fe oxyhydroxides simultaneously. Both the concentrations of Fe3+ and Fe2+ increased at the end of proximal, causing by the reductive dissolution of Fe oxyhydroxides. The transformation of Fe3+ to Fe2+ occurred soon when the groundwater reached the mid-fan. The increase in Fe2+ is not only related to the reductive environment, but also attributed to the reaction of feammox, which Fe oxyhydroxides react with NH4+ and produce Fe2+ in the groundwater.

Anthropogenic and geogenic sources of arsenic (As) have been identified in mining-impacted soils from the Giant mine (1948-1999), NT and the North Brookfield mine (1886-1906), NS. Both used roasting to extract gold from the arsenopyrite ore, decomposing it to As-bearing iron oxides (roaster oxides or RO) containing As, and releasing As3+-bearing arsenic trioxide (As2O3). Arsenic trioxide is considered highly soluble with the dissolved As3+ species being more mobile and toxic than other oxidation states. Soil profiles from the Giant mine show elevated As and antimony (Sb) at the surface (As=140-3300ppm) and decreasing concentrations with depth (As=22-600ppm). Surface soils contain anthropogenically-derived As2O3 identified using synchrotron methods (µXRD, µXANES) and environmental SEM. The persistence of As2O3 is attributed to Sb in As2O3 grains, dry climate and high organics in the soils. Anthropogenically-derived RO of maghemite (containing both As3+ and As5+) and natural arsenopyrite were observed. Sequential selective extractions (SSE) from surface soils show between 20% and 75% of As extracted in the crystalline iron-oxide phase is attributed to As2O3 and RO, while at depth As is bound by organics in the weaker leaches. North Brookfield mine soils show lower total As (2ppm to 45ppm) except near the roaster (4300ppm). No As2O3 was identified, probably due to the smaller scale and age of the mine, lower organic content and the lack of Sb. As-bearing phases include RO of hematite (As5+), As-rich rims on titanium-oxides, and As associated with clays and goethite. Adjacent to the roaster, SSE show As was also in the amorphous iron-oxide phase, also shown by As in arsenopyrite weathering rims. There are many differences between the North Brookfield and Giant mine soils including roasting techniques which produced different RO mineralogy, the scale of mining, climate, soil type, and the presence of As2O3. Currently, the Giant property is not publically accessible but may become so in the future while the North Brookfield property is accessible. Understanding the form and distribution of As phases is critical because of the potential risk to human and ecosystem health associated with ingestion of soil particles and their control on the total dissolved As in surface and groundwater.
Thesis (Master, Geological Sciences & Geological Engineering) -- Queen's University, 2008-09-29 17:21:50.73

碩士
國立臺灣大學
生物環境系統工程學研究所
96
In Guandu Plain, 128 hectares of paddy soils with the high arsenic content, exceeding soil pollution control standards (over 60 mg kg-1), were determined due to the irrigation with the water mixed hot spring with arsenic in the early periods. The isotopic compositions of lead exhibits wide variations in natural and anthropogenic materials that often can be used as a diagnostic“signature.”Lead isotopic compositions, analyzed on multi-collector inductively coupled plasma mass spectroscopy was used to distinguish pollution sources. The results of cluster analysis clearly indicate that the paddy soils of Guandu Plain have been primarily influenced by the parent rock of Tatun Volcano Group because those were located within the basin of Huang Gang Creek and the soil of the polluted extremely polluted lead was from the long-term irrigated with the water mixed hot spring in the Thermal Valley. Furthermore, the anthropogenic pollution was also verified in the paddy soils with the exceptional lead content. The results suggest that lead isotope ratios can be used effectively to constrain the sources of lead in Guandu Plain, especially for natural versus anthropogenic influence can be identified.

碩士
臺灣大學
職業醫學與工業衛生研究所
96
Abstract Pregnant women and fetuses are susceptible to environmental hazards. If women are exposed to heavy metals during pregnancy, their fetuses’ growth development could be adversely affected. Therefore, the aims of the present study were to find the relationship of arsenic, cadmium, manganese, mercury, and lead concentrations among maternal blood, cord blood and placenta, and to explore the potential environmental exposure sources of these five metals. Study subjects included 480 mother and infant pairs collected from three different level hospitals in Taipei area. Questionnaires were administered to get study subjects’ environmental exposure history before and during pregnancy. Biological samples, including maternal blood, cord blood, and placenta, were collected at delivery. Then ICP-MS was applied to analyze arsenic, cadmium, manganese, mercury and lead contents in maternal blood, cord blood, and placenta samples. Metal concentrations in maternal blood, cord blood, and placenta samples were as follows (GM (GSD)): 4.47 μg/L (1.66), 3.72 μg/L (1.55), 22.91 ng/g (1.62) for arsenic, 1.15 μg/L (2.04), 0.23 μg/L (3.55), 63.10 ng/g (1.48) for cadmium, 20.89 μg/L (1.62), 46.77 μg/L (1.38), 549.54 ng/g (1.23) for manganese, 5.25 μg/L (2.69), 11.48 μg/L (1.86), 213.80 ng/g (1.62) for mercury, and 14.13 μg/L (2.24), 11.48 μg/L (2.00), 66.07 ng/g (1.70) for lead, respectively. The correlations among the concentrations of the study metals were examined by Pearson’s correlation. It appeared that arsenic and lead concentrations, respectively, in maternal blood, cord blood, and placenta were significantly and positively correlated. Manganese and mercury concentrations, respectively, in cord blood and placenta were also significantly positively correlated, as well as the mercury concentrations in maternal blood and cord blood. A significant correlation of cadmium concentration was only shown between maternal blood and placenta samples. Because it was prohibited to use leaded gasoline, cord blood lead concentration was continuously decreasing. From 2002 to 2004, cord blood lead concentration was decreased by about 10 μg/L. Although maternal and cord blood mercury concentrations also decreased by 50% during the past years, they were still significantly higher than those of western countries. Multiple stepwise regression models were used to explore the factors affecting the maternal blood, cord blood and placental arsenic, cadmium, manganese, mercury, and lead concentrations. Results showed that study area was the major factor of maternal blood arsenic and mercury concentrations, and also affected maternal blood manganese and lead and cord blood cadmium and placental manganese and lead concentrations. Cord blood arsenic, manganese, mercury and lead and placental arsenic, cadmium and mercury concentrations were affected by those concentrations of maternal blood. In cord blood and placental lead concentrations, maternal blood lead concentration and study area had about the same influence of cord blood and placental lead concentrations. Cord blood lead concentration was getting close to the developed countries. However, mercury concentrations in maternal and cord blood were still high. To find out the exposure mechanism, a follow-up study may be needed to investigate the possible mercury exposure sources for the pregnant women in the future.

碩士
高雄醫學大學
職業安全衛生研究所碩士班
92
The arsenic compounds were a ubiquitous element found in various sectors such as industry manufacturing process and related applications, however risk of health effects of arsenic compounds were an existing problem hard to ignore. There were many possible routes of arsenic exposure, the frequently mentioned were inhalation and ingestion. Different route of exposure can derive to different pattern of arsenic metabolism, while industrial exposure and environmental exposure from drinking water were anticipated with different results and safety. This research collected spot urine from people exposed through industrial and drinking water sources. The urine samples were analyzed with HPLC and HG-AAS for arsenic species, which were metabolized from exposed body into urine. Both stratified analysis and statistical methods were applied to differentiate arsenic metabolism patterns between people from industrial and drinking water exposures. The data have shown that the total amount of urinary arsenic metabolism on arsenite (As3+) were larger than arsenate(As5+) in industrial exposures while a reverse observation was made in drinking water exposures. A larger amount of dimethylarsinics acid(DMA) was found in both exposure sources than that of monomethylarsinics acid(MMA). For the metabolism pattern of arsenic species, the percentage of inorganic arsenic, the percentage of MMA, and the ratio of MMA to DMA, drinking-water exposure was larger than industrial exposure. However, the percentage of DMA was larger in industrial exposure than that of drinking-water exposure. The study has found that different routes of arsenic exposure resulted in different pattern of urinary arsenic metabolism patterns while the biohazard markers of inorganic arsenic were found to be different, which gives implications for different risk of adverse effects in the future. The previous studies on risk analysis of inorganic arsenic exposure were rarely taking metabolism patterns into accounts. The findings in this thesis deserve for further consideration in policy making of industrial safety and health. ability, so this research to establish the standard for industrial safety and health in further.

The Bolivian Altiplano (BA) is a high plateau located in the western part of the country at an altitude of 3,600 to 3,900 meters above sea level and is bordered by the Eastern and Western Cordillera. Within the BA there is a large endorheic hydrologic system linking the Titicaca Lake in the north the Desaguadero River, lakes Uru-Uru and Poopó in the central part; and the Lacajahuira River and Coipasa and Uyuni salt pans in the south. Several mineralized areas, especially in the Eastern Cordillera, have been intensively exploited for centuries for the extraction of silver, gold, and tin from polymetallic sulfide ore deposits. Presently many urban centers are also contributing for an extensive contamination in localized areas; especially the Poopó Lake and some rivers are affected by high loads of wastewater and solid waste, in addition to the release of heavy metals and arsenic (As) due to acid mine drainage. The presence of As in the BA was known to be related to mining only, but recent studies revealed that As of geogenic origin also contributing to the elevated concentration of As in surface and groundwater. The Poopó Lake basin is characterized by a semiarid climate. Geologic formations predominantly are of volcanic origin and groundwater flow is sluggish in nature. These environmental settings have generated substantially elevated concen- trations of geogenic As and other trace elements in surface and groundwater. Both surface and groundwater used for drinking water have high concentrations of As that by far exceed the World Health Organization (WHO) guideline. The overall objective of the present study has been focused on the determination of the sources and principal mechanisms for mobilization of geogenic As into surface and groundwater of the Poopó Lake basin area. More specifically, this study has determined the spatial distribution and the extent of As contamination in surface and groundwater; chemical composition of surface and groundwater, rock and sediment; major geochemical mechanisms for As mobilization from solid phase to aqueous phases. This study also made an assessment of drinking water quality in rural areas within the Poopó Lake basin. Arsenic concentration exceeded the WHO guideline and national regulations for drinking water of 10 µg/L in 85% of the samples collected from the area around the Poopó Lake (n=27) and 90% of the samples from the southern part of the lake basin (n=42). Groundwater samples collected from drinking water wells had As concentrations up to 623 µg/L, while samples collected from piezometers had even higher up to 3,497 µg/L. Highest concentration in river water samples was observed 117 µg/L. Alkaline nature of water (median pH 8.3 for groundwater and 9.0 for surface water), predominance of Na-Cl-HCO3 water type and elevated Eh reflecting oxidized character has been revealed by As(V) as the major species in As speciation. Different rock types were analyzed for their As content and the highest concentration of 27 mg/kg was found in a coral limestone sample. In evaporate it was 13 mg and 11 mg As/kg was measured in calcareous sandstone. Elevated concentration of As was also observed in sediment cores collected from two drilling sites; 51 mg/kg in Condo K and 36 mg/kg in Quillacas. Physical and chemical weathering of volcanic rocks, limestone, carbonates and plagioclase minerals enhance the supply of Na+ and HCO3- into solution and as a consequence pH and alkalinity increase, which in turn, favor As desorption from solid mineral surfaces (especially Fe(III) oxyhydr- oxides) and therefore dissolved As in water is increased.

QC 20150529