Dissertations / Theses on the topic 'Trace element contents'

Des xénolites de péridotite provenant de deux localités du sud du Massif Central Français (Allègre et Mont Coupet), émis avec des modes éruptifs différents, ont été étudiés pour définir l’évolution du manteau sous continental et pour étudier le comportement de Li et H lors des réactions fluides roches lors de leur remonté vers la surface. Un ensemble de 6 xénolites représentatifs a été sélectionné pour chaque localité. La description pétrologique et minéralogique de chaque échantillon a été associée à la mesure des compositions chimiques en éléments majeur (par microsonde électronique) et trace (par LA-ICP-MS) des principales phases minéralogiques (Olivine, Pyroxène, Amphibole). La teneur et la composition isotopique du Li ont été mesurées par microsonde ionique (SIMS), et les teneurs en eau par spectroscopie infrarouge à transformée de Fourrier (FTIR) et SIMS dans les pyroxènes et les olivines. Pour les xénolites d’Allègre, les anomalies négatives en HFSE et les rapports LREE/HREE élevés reflètent un métasomatisme lié à des liquides carbonatitiques, succédant à un processus de fusion partielle du manteau lithosphérique. Pour les échantillons du Mont Coupet, Les anomalies négatives en Ti et Nb des Cpx de tous les échantillons et les anomalies négatives de Zr et Hf pour deux échantillons plus fortement métasomatisés (MC38 et MC34) soulignent également un métasomatisme carbonatitique. Les amphiboles des échantillons MC36 et MC53, dont l'origine doit être associée à des fluides de subduction, sont à l’équilibre avec les Cpx coexistant, ce qui indique que le fluide qui a permis leur formation n’a pas enrichi les Cpx en LREE ou LILE. La composition isotopique de des xénolites d’Allègre montre qu’ils ont été affectés par un métasomatisme en au moins deux étapes par des fluides différents. Les teneurs très élevées en Li des Cpx (jusqu'à 50 ppm) et l’enrichissement même modéré des bordures des olivines sont attribués à un apport de Li par diffusion depuis le magma hôte. Par contre, les compositions isotopiques pauvres en 7Li préservées au coeur des Ol (δ7Li jusqu’à -25‰) suggèrent l’existence d’un autre évènement métasomatique ayant affecté les péridotites avant leur remonté vers la surface. En revanche, les minéraux des xénolites de Mont Coupet ont des concentrations en Li similaires à celles du manteau, avec une répartition à l’équilibre entre les minéraux. Cependant les valeurs de δ7Li négatives observées pour les Cpx et Opx de certains échantillons suggèrent une interaction avec un fluide en quantité limitée et une composition isotopique négative. La préservation du fractionnement isotopique du Li entre les pyroxènes et olivines indique que cette interaction a du avoir lieu peu de temps avant l'entrainement des xénolites vers la surface. Les fluides métasomatiques à l’origine des valeurs de δ7Li négatives observées à Allègre et à Mont Coupet sont liés à un environnement de subduction, probablement lié à l'orogenèse varisque dans le cadre régional du FMC. Les teneurs en eau mesurées dans les xénolites d’Allègre vont de 10,6 à 12,4 ppm, des valeurs beaucoup plus faible que celle du manteau source des MORB. Ceci s’explique par une perte d’eau associée au dégazage du magma lors du refroidissement du lac de lave. L’absence de variation cœur-bord montre une distribution de l’eau à l’équilibre entre les xénolites et la lave hôte. A l’inverse, les xénolites du Mont Coupet ont pu conservé leur teneur en eau acquise en profondeur, contrôlée par les processus de fusion partielle qui ont affecté les péridotites. Cependant, l'échantillon MC34, affecté par le métasomatisme carbonatitique, a la plus haute teneur en eau parmi ces xénolites. Inversement, les échantillons MC36 et MC53 qui contiennent des amphiboles, n’ont pas des teneurs en eau élevées, suggérant que l'agent métasomatique responsable de la formation des amphiboles n'a pas enrichi en eau les autres phases de la péridotite
Peridotite xenoliths sampled from two volcanoes erupting in different modes in two localities, Allègre and Mont Coupet, in the southern domain of the French Massif Central (FMC), have been investigated to constrain the evolution of the sub-continental lithospheric mantle beneath the FMC and the behaviors of Li and H during melt-rock reactions. To answer these questions, a set of 6 representative xenoliths was selected for each locality, and described for their mineralogy and petrography. In-situ measurements were then performed for major and trace elements in Ol, Cpx and Amp when existing, via EPMA and LA-ICP-MS respectively, for Li concentrations and isotopic compositions in pyroxenes and Ol (via SIMS), and water concentrations in minerals (via FTIR and SIMS). Negative HFSE anomalies and markedly high LREE/HREE ratios reflect a carbonatite-related metasomatism following an earlier partial melting process in the lithospheric mantle under Allègre. The Ti and Nb negative anomalies in Cpx from all the Mont Coupet samples and Zr-Hf negative anomalies in Cpx from two most strongly metasomatized samples MC38 and MC34 also point to a carbonatite-related mantle metasomatism. Amp in samples MC36 and MC53, whose origin should be associated with fluids from the subducting slab, have equilibrated most of the trace element composition with coexisting Cpx and the modal metasomatism responsible for the Amp genesis haven’t refertilized Cpx in LREE and LILE. Lithium isotope systematics indicates that Allègre xenoliths were overprinted by (at least) a two-stage metasomatism by melts of different origins. Exceptionally high Li concentrations in Cpx (up to 50 ppm by weight) and slightly increased Li contents at Ol rims are ascribed to a diffusive Li uptake from infiltrating melts derived from the host magma. On the other hand, extremely light Li isotopic compositions preserved in Ol cores (with δ7Li as low as -25‰) suggest another metasomatic event prior to xenolith entrainment by the host magma. In contrast, xenoliths from Mont Coupet have Li concentrations in constituent minerals similar to the normal mantle, and display nearly equilibrated inter-mineral Li partitioning and homogeneous intragranular Li distribution in every phase. The negative δ7Li values of Cpx and Opx in some samples were brought by the exchange with a small-volume melt with Li concentration similar to the normal mantle and light Li isotopic compositions. The preservation of inter-mineral large Li isotopic fractionation currently observed in these samples indicates that the percolation of the melt should occur shortly prior to the entrainment of Mont Coupet peridotite xenoliths by the host magmas. The metasomatic agents, accounting for negative δ7Li values in Ol cores in Allègre xenoliths and in Cpx and Opx in some Mont Coupet xenoliths, are related to a subduction environment. In the regional framework of the FMC, the subduction event most likely occurred during the Variscan orogeny. Water content in Allègre xenoliths ranges from 10.6 to 12.4 ppm in weight, much lower than the water content in the MORB source mantle. It implies that water were lost during the degassing of the host magma during slow cooling of the lava lake. No core-rim variations from profile analysis suggest that xenoliths have achieved water diffusive equilibrium with the host magmas. Peridotite xenoliths from Mont Coupet have retained their original water content from the mantle depths. Partial melting has controlled the water content in most samples from Mont Coupet. However, the subsequent carbonatite-related metasomatism has affected the sample MC34, which had the highest water content among the Mont Coupet xenoliths. And the aqueous agent responsible for presence of Amp in samples MC36 and MC53 has not lead to the considerable increase of water content

Soil quality guidelines are currently based on total trace metal loads. There is a need to define indices of bioavailability to allow reasonable predictions for plant metal uptake and toxicity in soils. Trace metal toxicities to plants often correlate best with free metal ion activities. The first objective was to develop a plant bioassay that is sensitive to trace metals at concentrations realistic for soils. The root elongation of lettuce Lactuca sativa 'Buttercrunch' was used as toxicological endpoint. This endpoint was sensitive and reproducible to environmentally relevant concentrations of Cd, Cu, Ni, Pb and Zn. The second objective was to test whether free metal ion activities are constant predictors of metal toxicities in synthetic solutions and in soil extracts that differ in their concentrations of cations and ligands. The root elongation assay was used to test this hypothesis. In synthetic solutions, the rhizotoxicity of Cd, Cu, Ni, Pb and Zn decreased with increasing Ca and H concentrations. This could not be explained with the effect of higher cationic concentrations on root growth or on solution speciation. It was concluded that Ca and H inhibited the rhizotoxicity of all metals tested. The rhizotoxicity of Cu and Cd was further examined in soil extracts. Both metals became less rhizotoxic at higher H and dissolved organic matter concentrations. The rhizotoxicity endpoints from the experiments in synthetic solution were used to develop parameters for a Biotic Ligand Model (BLM) for Cd, Cu, Ni, Pb and Zn. The BLM accounts for solution speciation and interprets cationic inhibition of rhizotoxicity as competition of metals with Ca and H for potential sites of rhizotoxicity. The BLM predicted metal rhizotoxicity better than the free metal ion activity in synthetic solutions and in soil extracts. Different models were tested against literature rhizotoxicity data for metals at different Ca and H concentrations. Predictions for metal rhizotoxicity given by BLM, Gouy-Chapman-Stern model and Freundlich equation model were compared with predictions based on free metal ion activities in solution. The BLM predicted rhizotoxicity most accurately. The BLM seems promising for predictions of metal toxicity and metal bioavailability in soils to support site-specific environmental risk assessments.

Trace elements added to the soil by human activities could contaminate it and occasionally cause a threat to environmental and human health. The toxicity and mobility of a trace element are affected by the element's solubility, which in turn is influenced by the soil properties. When mobile, trace elements can be leached out of the soil. If leaching occurs at a faster rate than atmospheric deposition, element concentrations in the soil will decrease by natural attenuation.
We analyzed soil properties in 40 soils and their soil solutions to obtain a set of equations with the most significant predictors of As, Cd, Co, Cu, Mo, Ni, Pb and Zn in solution. The total element concentration and the pH were the best predicting variables of the amount of element in solution for all trace elements analyzed, while organic carbon and Al or Mn oxides also influenced the solubility of some trace elements. Using the equations predicting elemental solubility, we wrote a model for natural attenuation in the computer program Stella that considers atmospheric deposition as the input for trace elements and leaching as the output. Simulations were carried out for the 40 soils during 1,000 years with steady deposition inputs.
At current atmospheric deposition rates and the neutral to alkaline pH of these soils, attenuation occurred in most soils for Mo. For As, Cd, Co, Cu and Ni it occurred only in soils with abundant total element concentrations or an acidic pH. Minor retention occurred with Pb and Zn. Only Cd and Cu were of concern in leaching waters. The developed model can serve as a decision making tool in the selection of natural attenuation as a remediation strategy.

The Fäboliden gold deposit is an ore body in northern Sweden’s Bothnian Basin and has been the subject of studies and test mining since the early 2000s when the Gold Line, an area of anomalously high-Au glacial till in Northern Sweden, became a center of economic interest. The deposit is a hypozonal orogenic gold deposit that displays many characteristic features of ore bodies of this type, including the presence of compound sulfide grains composed of a core of löllingite surrounded by a rim of arsenopyrite, and an abundance of pyrrhotite throughout the deposit and surrounding alteration zone. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was used to first map the distribution of trace elements in several of the arsenpyrite-löllingite grains, then to perform spot analyses of pyrrhotite grains in samples from across the distal and proximal alteration zones of the deposit. The maps of the trace elements in the compound löllingite-arsenopyrite grains show that: As and Au are found in greater abundance in the löllingite than in the arsenopyrite; Cu, Fe, S, and Ti are found in greater abundance in the arsenopyrite than in the löllingite; and Ag, Au, Bi, La, Mn, Pb, Sr, Ti and Tl are found in zones of secondary enrichment along fractures within the grains. Uranium and V may also be enriched along fractures, although this isn’t clear on all of the maps. Gold is an element of particular interest, because its distribution throughout the sulfide phases can be used to constrain the mechanism and relative timing of mineralization within the deposit. The presence of invisible gold within the löllingite, but not within the arsenopyrite, shows that gold is not incorporated into arsenopyrite at high temperatures and will instead be concentrated in the löllingite core of the composite grain and at the margin between the two sulfide phases as the löllingite is altered to arsenopyrite. Previous research on the Fäboliden gold deposit, including geothermometric analysis of vein-hosted graphite within fluid inclusions and garnet-biotite geothermometry as well as structural evidence provided by regional deformation, indicate that mineralization occurred post-peak metamorphism. The textures seen are therefore not conclusive of mineralization occurring syn- or pre-peak metamorphism, as has previously been proposed based on research of orogenic gold deposits in Western Australia. The spot analysis of pyrrhotite samples from across the deposit shows a distinct decrease in Ni and Co content in the proximal alteration zone, suggesting uptake of these elements by other minerals such as the löllingite and arsenopyrite. Multiple analyses performed on single grains show local variation, but are insufficient to establish the presence or determine the character of growth zonation within pyrrhotite.

Chapter 1 of this thesis is a general review of published work o_ the origins and distribution of Cd, Cu, Fe, Mn and Zn in soils and their uptake and functions in plants. Chapter 2 is a synopsis of the geological history of the Fayoum of relevance to the origins of sediments at the study sties. Previous fractionation procedures, and a proposed modification to improve the determination of carbonate-bound elements are discussed in Chapter 3, while other analytical procedures are described in Chapter 4. Results of general soil analyses, of the fractionation analyses and useful correlation matrices, are tabulated together (for convenience in Chapter 5) and are discussed in detail in the following chapter. Texture was a crucial factor, finer-textured soils generally having lower pH and higher organic matter contents, although the latter were generally greater closer to the surface. Clay and silt contents were highly correlated, probably reflecting water sorting in the Fayoum, which aided the texture/drainage effect. Drainage (i.e. texture) was apparently very important in the fractionation chemistry of elements influenced by redox-reactions, i.e. Fe and Mn, and elements for which distribution depended upon Fe and Mn oxides (e.g., Zn) to a significant extent. Clay was especially important to the concentration of crystalline and amorphous iron oxides. Cd and Cu showed marked surface accumulation, especially in the exchangeable fractions, for many profiles, probably through pollution. The Cu content of organic matter was strikingly uniform at the Fayoum. Amorphous and crystalline Fe oxides seem to be especially important in the distribution of Zn. Clay Cd, Fe and Zn and, to a lesser extent, Cu and Mn contents were relatively constant, suggesting uniform origins. Chapter 7 describes a pot experiment on the soils using barley as a test crop, aimed at relating uptake to the fractionation results. Interpretation was complicated by a dominant effect of soil salinity. Chapter 8 suggests future related research.

Soil samples from 118 sites on 71 geologic units in southwest Oregon were collected and analyzed to determine the background concentrations of metals in soils of the region. Sites were chosen in areas that were relatively undisturbed by human activities. The U.S. Environmental Protection Agency approved total-recoverable method was used to recover metals from samples for analysis. The twenty six metals analyzed were: Ag, AI, As, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, La, Li, Mg, Mn, Mo, Na, Ni, Pb, Sb, Se, Tl, V and Zn. The Klamath Mountains followed by the Coast Range contain the highest soil concentrations of AI, Ca, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Ni, V and Zn. Soils of the Coastal Plain and High Lava Plains contain the lowest concentrations of these metals. Unusually high soil As concentrations are found at two sites in the Klamath Mountains. All Be and Cd values above laboratory's reporting limits are also from the Klamath Mountains and Coast Range. Concentrations of soil Ba and La are fairly uniform throughout the region. Soil Pb levels are generally low with a few exceptions in the Klamath Mountains, Coast and Cascade Ranges. The region west of the Cascade Range has higher soil Hg contents than in the east. Soil metal concentrations are generally much higher in the region west of the Cascade Range, excluding the Coastal Plain, than in the east with the exception ofNa, because of more ultramafic rocks and a wetter climate. Soil metal concentrations are directly related to soil development with the highest concentrations being found in well developed Alfisols and Ultisols and the lowest concentrations in poorly developed Entisols. Most metals have similar averages and ranges of concentration compared to the rest of the United States (U.S.). Metals with high values compared to the rest of the U.S. are Cr, Co, Cu, Mn and Ni. In general, AI, Co, Cr, Cu, Fe, La, Li, Mg, Na, Ni, and V are concentrated in the B horizon while Ba, Ca, Hg, K, Mn, Pb and Zn are concentrated in the A horizon.

El metabolisme monocarbonat i els elements traça essencials afecten al desenvolupament i resultat de l'embaràs. Es desconeixen els efectes de diversos polimorfismes del metabolisme monocarbonat (MTHFR c.665C>T, BHMT c.716G>A, SLC19A1 c.80G>A i MTRR c.66A>G) durant l'embaràs i la seva possible modulació segons l'estat en folat; i quins factors estan associats amb les concentracions d'elements traça (zinc, coure, seleni i ferro) en la placenta. Aquests aspectes dels esmentats polimorfismes i elements traça s’han estudiat en 617 embarassos del Reus-Tarragona Birth Cohort i 218 placentes. Amb alt estat en folat eritrocitàri a ≤12 setmanes gestacionals (SG), i en folat plasmàtic des de les 15SG, l’MTHFR c.665C>T no va haver tenir cap efecte sobre l'homocisteïna plasmàtica. Els genotips variants de BHMT c.716 tenien menor concentració de dimetilglicina des de la meitat de l'embaràs, i a principis de l'embaràs si l'estat en folat plasmàtic era alt. Homozigots variants de MTRR c.66 van tenir major concentració d'homocisteïna plasmàtica a principis de l'embaràs, però això no es veia en els tercils extrems de folat plasmàtic. Les concentracions en placenta de zinc, coure i seleni estaven positivament correlacionades entre si, i negativament associades al pes al néixer. Les fumadores durant l'embaràs van tenir majors concentracions de coure i seleni. La ingesta d'aquests elements traça de la dieta i/o suplements no es va associar amb les seves concentracions en placenta. Les concentracions plasmàtiques de cobalamina a ≤12SG i d'homocisteïna al part es van associar negativa i positivament, respectivament, amb les de coure en la placenta. L'al•lel normal de MTHFR c.665 del neonat i la concentració de coure en la placenta es van associar positivament amb el creixement intrauterí restringit. Els polimorfismes i la seva modulació segons l'estat en folat, i elements traça en placenta estudiats estan associats amb canvis en el metabolisme i resultat de l'embaràs.
El metabolismo monocarbonado y los elementos traza esenciales afectan al desarrollo y resultado del embarazo. Se desconocen los efectos de varios polimorfismos del metabolismo monocarbonado (MTHFR c.665C>T, BHMT c.716G>A, SLC19A1 c.80G>A y MTRR c.66A>G) en el embarazo y su posible modulación según el estado en folato; y qué factores están asociados con las concentraciones de elementos traza (zinc, cobre, selenio y hierro) en la placenta. Se estudiaron estos aspectos de dichos polimorfismos y elementos traza en 617 embarazos del Reus-Tarragona Birth Cohort y 218 placentas. Con alto estado en folato eritrocitario a ≤12 semanas gestacionales (SG), y en folato plasmático desde las 15SG no se observó el efecto de MTHFR c.665C>T en la homocisteína plasmática. Genotipos variantes de BHMT c.716 tuvieron menor concentración de dimetilglicina desde la mitad del embarazo, y esto ocurrió también a principios del embarazo si el estado en folato plasmático era alto. Homozigotos variantes de MTRR c.66 tuvieron mayor concentración de homocisteína plasmática a principios del embarazo, pero esto no ocurría en los terciles extremos de folato plasmático. Las concentraciones en placenta de zinc, cobre y selenio estaban positivamente correlacionadas entre sí, y negativamente asociadas al peso al nacer. Fumadoras durante el embarazo tuvieron mayores concentraciones de cobre y selenio. La ingesta de estos elementos traza de la dieta y/o suplementos no se asoció con sus concentraciones en placenta. Las concentraciones plasmáticas de cobalamina a ≤12SG y de homocisteína en el parto se asociaron negativa y positivamente, respectivamente, con las de cobre en la placenta. El alelo normal de MTHFR c.665 del neonato y la concentración de cobre en la placenta se asociaron positivamente con el crecimiento intrauterino restringido. Los polimorfismos y su modulación según el estado en folato, y elementos traza en placenta estudiados están asociados con cambios en el metabolismo y resultado del embarazo.
One carbon metabolism and essential trace elements affect foetal development and pregnancy outcome. The effects of several highly prevalent one carbon metabolism polymorphisms (MTHFR c.665C>T, BHMT c.716G>A, SLC19A1 c.80G>A and MTRR c.66A>G) in pregnancy and their possible modulation by folate status, and which factors are associated with the placenta trace element concentrations (zinc, copper, selenium and iron), are unknown. These aspects of the aforementioned polymorphisms and trace elements were studied in 617 pregnancies of the Reus-Tarragona Birth Cohort and 218 placentas. With high erythrocyte folate status at ≤12 gestational weeks (GW) and with high plasma folate status from 15GW on, the homocysteine-enhancing effect of MTHFR c.665C>T was not observed. Lower plasma dimethylglycine in BHMT c.716 variant genotypes was found at mid-late pregnancy, and this was also true for early pregnancy if plasma folate status was high. MTRR c.66 variant homozygotes had higher plasma homocysteine concentration at early pregnancy, and after plasma folate status stratification this was not observed in the extreme tertiles. Placenta concentrations of zinc, copper and selenium were positively correlated, and negatively associated with birth weight. Smoking during pregnancy was associated with higher copper and selenium concentrations. Intake of these trace elements from food and/or supplements was not associated with their concentrations in placenta. Plasma cobalamin at ≤12GW and homocysteine at labour were negatively and positively, respectively, associated with placenta copper concentrations. MTHFR c.665 normal allele in the neonate and placenta copper concentration were positively associated with intrauterine growth restriction. These studied polymorphisms and their modulation by folate status, and the placenta trace elements, are associated with metabolic changes and pregnancy outcome.

Innovative means and methods were tested to develop an economical, pragmatic and environmentally sustainable soil remediation process for heavy metal contaminated soils. An unsaturated-flow soil washing procedure was devised to dissolve the soil-bound toxic heavy metals; the latter were extracted by a chemical washing solution that percolated through the soil matrix. Subsequently, the leached toxic heavy metals were selectively concentrated, by a chemical precipitation process, into a solid waste. Thereby, a fraction of the spent ethylenediaminetetraacetic acid (EDTA), within the washing and rinsing leachate, was theoretically regenerated and recycle-ready.
The unsaturated-flow washing procedure was perfected by applying different treatments to a soil from a secure landfill. This soil was contaminated with Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, S and Zn. The major contaminants were Fe, Pb, Zn, S, Cu and Mn, making up 25, 1.9, 1.0, 0.4, 0.4 and 0.2%wt of the soil. The extraction responses of the contaminants and those of Al, Ca, Mg and P were established for citric acid (0.5 M) and different molarities of diammonium EDTA ((NH4)2EDTA). The DOW Chemical Company supplied the (NH4)2EDTA (i.e. VERSENE), a 1.37M industrial cleaner, which roughly costs $1.85kg-1 in bulk. The affordability of VERSENE was a pre-condition for hoping to satisfy the economical feasibility of remediating trace metal contaminated soils.
Ultimately, the developed unsaturated-flow washing procedure was tested in a pilot-scale experiment, for its ability to remediate a soil from an abandoned car battery recycling facility. The latter soil was severely contaminated with Pb (3.9%wt). Drip irrigation was used to apply (NH4) 2EDTA and water-rinsing solutions to the surface of soil heaps that rested atop an impermeable barrier, which permitted the retrieval of the leachate. A cumulative EDTA input to the soil of 10.6% wt extracted 49.4% of the total Pb content of the soil. Alternatively, readily biodegradable citric acid barely extracted 2.2% of the total Pb content of the soil, for a cumulative input of 18.1% weight of soil. Different treatments were tested for their effectiveness in concentrating the leached toxic heavy metals into a solid waste. The Pb was best precipitated with Na2S alone, as it provided the most concentrated solid toxic waste.
The environmental sustainability of remediating trace metal contaminated soils was thoroughly examined, as per the amounts of chemical entrants and toxic waste by-products, and per the post-treatment leaching of toxic levels of the remaining and potentially toxic trace metals. (Abstract shortened by UMI.)

An investigation of heavy metal concentrations in sediments from Coxs River catchment, a tributary of the Hawkesbury-Nepean River system, has been undertaken. A number of digestion methods were assessed for the determination of Pb, Cu, Cd, Zn, Ni, Mn, Fe, Co and Cr in reference materials by flame AAS. The method that produced the best recovery is reverse aqua regia, HNO3-HC1 with ultrasonification followed by heating on a hotplate. Based on analysis of sediments from 133 sites, background concentrations were established. Elevated heavy metal concentrations were recorded in some samples. The three most polluted areas were investigated for heavy metal associations and distributions. Metal bioavailability was assessed from sediment samples by using selective extraction techniques. The association of heavy metals with different solid phases was assessed by a sequential extraction technique involving a series of extraction reagents. Pd, Cu, Fe and Cr were mainly associated with Fe/Mn oxides and organic matter plus sulphide phases. While Cd, Zn, Ni and Co which behave similarly were extracted from each step, the largest percentages of these metals were found in Fe/Mn oxides and organic matter phases. Mn was different to other metals, in that it predominantly associated with the ion exchangeable form.
Master of Science (Hons)

Maternal smoking during pregnancy is known to result in an increased incidence of intra-uterine growth retardation. This in part may be due to deleterious effects on the placenta, which is the conduit between the mother and fetus. This study was designed to investigate the effect of maternal smoking on placental function: morphometry, oxygen diffusive capacity, trace element content (zinc and cadmium), microvillous border membrane (MVBM) vesicle zinc and alanine uptake, and placental enzyme activity. The magnitude of maternal smoking and confounding factors were determined twice by questionnaire during pregnancy and confirmed by plasma cotinine; a total of 105 placentae were collected. Morphological changes in membrane thickness, and chrionic villi composition were observed with maternal smoking, however these changes were not great enough to affect the placental oxygen diffusive conductance. Placental cadmium content increased with maternal smoking and also correlated with placental zinc content. There was no correlation for cadmium or zinc with placental metallothionein. MVBM vesicle uptake of zinc exhibited no differences between smoking and non-smoking groups. Similarly, MVBM vesicle sodium-independent alanine uptake exhibited no difference, however sodium-dependent alanine uptake was greater in the smoking group. Placental cytochrome P450 ethoxyresorufin-O-deethylase activity was greater in the smoking group placentae compared to the non-smoking group, however quinone reductase activity was unaffected by maternal smoking. The overall findings of this study extend knowledge regarding the impact of maternal smoking on placental function and support current clinical advice for pregnant mothers to stop smoking during pregnancy.

The Sr/Ca ratios in calcium carbonate fossils are used by the paleooceanographic community to infer past environmental conditions, such as sea surface temperature and ocean chemistry. The processes of biogenic calcification that produce these chemical signatures are complex and not fully understood, however, and vital effects are known to affect the trace element composition of the CaCO3 biomineral products. The recent discovery that calcifying organisms produce amorphous calcium carbonate (ACC) as an intermediate phase during the crystallization process calls into question whether this pathway to mineral formation affects trace element distributions in the final product. This non-classical mineralization process raises the question of whether the Sr/Ca ratios of the final products are dependent upon temperature. That is, what is the temperature dependence of Sr/Ca ratios in calcite produced via ACC compared to the measurements obtained from calcite grown by the classical process in laboratory experiments and from biogenic settings.

The goal of this study is to determine the effects of solution chemistry and temperature on the Sr composition of ACC and resultant crystalline CaCO3. Two types of experiments were designed: First, experiments were conducted to synthesize inorganic ACC in a batch reactor for a suite of selected chemical compositions and allowing this intermediate phase to transform into calcite in the reactant solution. In a second series of experiments, ACC was precipitated by a flow-through method to compare results to the batch reactor experiments. The experimental design focused on determining the Sr/Ca ratio and Sr distribution coefficients (KD, Sr) of the amorphous and final crystalline products. Mg/Ca ratios of 5/1 were found to suppress Sr uptake into ACC by a factor of 25% when the initial Sr solution had concentration of one millimolar. ICP-AES data collected across the 18" to 30"C range showed that the Sr/Ca ratio in both ACC and the resultant calcite was independent of temperature. Upon transformation, the Sr/Ca ratios of both the ACC and calcite product were found to be similar, showing that Sr/Ca ratios were independent of the transformation process. Analysis of the data determined KD, Sr values of 0.564(±0.006) for ACC and 0.466(±0.009) for the resultant calcite in the 18-30"C temperature range.

The findings show that the Sr/Ca ratios of ACC and the transformed calcite are independent of temperature. However, the corresponding KD, Sr values exceed those reported for calcite grown by classical processes by an order of magnitude. The findings for the inorganic calcite yield KD, Sr values up to four times higher than those found in biogenic calcites. Because the findings of this study show that Sr/Ca is independent of temperature, this study calls into question whether previously reported Sr/Ca measurements in biogenic calcites should be revisited. It is plausible that biological factors have a significant influence on trace element incorporation into biogenic calcite. Vital effects, such as the influence of macromolecules during the ion uptake process, may regulate the apparent Sr/Ca versus temperature trends observed in marine paleontology. Higher KD, Sr values in marine calcifiers may indicate that organisms use the non-classical mineralization pathway in whole or in part. Future studies of trace element incorporation in calcifying species should consider the pathway to mineralization in tandem with interpretations of environmental controls on distribution coefficients.

Master of Science

Orientadores: Telma Teixeira Franco, Gustavo Paim Valença
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica
Made available in DSpace on 2018-08-15T16:00:27Z (GMT). No. of bitstreams: 1 Ayres_BiancaMairaTeixeira_M.pdf: 702836 bytes, checksum: 9d7d2a539cf470dfe7892bf64c17518d (MD5) Previous issue date: 2010
Resumo: O presente trabalho estudou as melhores condições para a produção de monoacrilato de frutose a partir da esterificação de ácido acrílico com D-frutose catalisada pela lípase comercial de Cândida antárctica (Novozyme 435). O interesse na produção deste éster se dá devido à promissora propriedade absorvente de água do polímero a ser produzido, com diferentes aplicações possíveis. Esterificações enzimáticas são reações de equilíbrio cujo subproduto é a água. A presença desta tem de ser controlada para possibilitar atividade enzimática e evitar a hidrólise dos ésteres. A adição de peneira molecular 3 Á ao sistema foi investigada para remoção da água produzida e favorecimento do deslocamento do equilíbrio para síntese dos ésteres. A produção exclusiva de monoéster foi observada quando a razão molar frutose:ácido acrílico de 1:3, 55 °C, agitação de 200 rpm e 20 mg mL-1 de lípase foram empregadas. Quando a razão molar foi aumentada para 1:5 a conversão de frutose aumentou, mas o equilíbrio foi deslocado para a produção de di- e triéster de frutose. A adição de 3 g de peneira molecular em 25 mL de sistema reacional resultou na produção de 49.5 mM de monoacrilato de frutose com 84 % de conversão da frutose inicial e 41 % da conversão de ácido acrílico após 24 h de reação. Devido à inexistência de padrões de acrilatos de frutose no mercado, um método para quantificação destes por fatores de resposta de CLAE foi desenvolvido baseado nos dados cinéticos da reação
Abstract: The optimal conditions for the enzymatic production of fructose acrylates were studied. Fructose to acrylic acid molar ratio, the amount of immobilized lipase Candida antarctica and the influence of molecular sieve in the reaction media were studied. The results of these variables in converting sugar were monitored. Enzymatic esterifications are equilibrium reactions whose subproduct is water. The presence of this must be controlled to allow enzymatic activity of the lipase and to avoid hydrolysis of esters. The addition of molecular sieve 3 A to the system was investigated to remove of produced water and to shift the equilibrium to the synthesis of ester. The exclusive production of monoester was observed when the molar ratio of fructose: acrylic acid of 1:3, 55 °C, 200 rpm and 20 mg ml-1 of immobilized lipase was employed. When the molar ratio is increased the conversion of fructose increases, but the equilibrium was shifted to the production of di- and triester. The addition of 3 g of molecular sieve resulted in the production of 49.5 mM of fructose monoacrylates, 84 % conversion of the initial fructose and 41 % conversion of acrylic acid after 24 hours of reaction. Since sugar acrylates are not available, it were obtained the concentrations of esters from the determination of response factors of each ester by HPLC-RI based on linear regression
Mestrado
Desenvolvimento de Processos Químicos
Mestre em Engenharia Química

The adsorption behaviour of trace metals in soil may provide us with a way to more accurately predict and assess the toxicity of metals in the environment. This thesis reports efforts to apply surface complexation modeling to agricultural and forest soil and to relate model parameters to common soil properties. This study considered Ca, Cd, Cu, Pb and Zn but the methods here could be applied to other metals. In Chapter 2, the surface charge and adsorption behaviour of a set of Ap horizons was characterised using back-titration and batch adsorption techniques. With the objective of simplifying the application of the NICCA model to surface charge and cation adsorption in whole soils the parameters of the NICCA model were related to soil properties (Chapter 3). Four of the six surface charge parameters could be predicted from soil properties and this enabled me to reasonably predict the surface charge of a second group of soils from soil properties. These results suggest that it is possible to make reasonable predictions about the surface charge and adsorption behaviour of a given type of soil using some easily measurable soil properties and a set of generic NICCA adsorption parameters for that soil type. In Chapter 4 this idea is applied to the determination of lime requirement for the agricultural soils.

The research used dendro-chemical analysis of ash tree rings and current year leaf litter to track Cd, Pb, Zn, Cu, Mn, Cr, and Sn spread and cycling from a closed garbage dump-toxic waste site. This technique allowed for determination of areal extent, contaminant levels and time period of initial contaminant contact. Only Zn, Sn, and Cu were found in elevated quantities in the xylem wood and Pb in the leaf litter. Elemental concentrations of Pb, Sn and Cd in xylem wood and leaves of ash were positively correlated. Tin was the only element to demonstrate a clear initial contact period and elemental accumulation with age. Significant levels of Cu accumulated in the heartwood while Zn revealed significant but inconsistent accumulated patterns. Expected attenuation zones associated with municipal solid waste landfill leachate dispersion were not found; thus the pathway for contaminant dispersion was likely through groundwater flow.
An elemental index was developed to facilitate the use of dendro-chemical analysis in periods of suppressed tree growth resulting from environmental pollution.

The emission of trace metals (TMs) into boreal forest regions of the northern hemisphere is an important environmental issue due to their potential detrimental impacts on these sensitive ecosystems. One of the foremost factors controlling metal cycling is the chemistry of the overlying organic forest floor of the forest soil. In this thesis we examine the chemistry of forest floor horizons of podzolic soils. Our goal is to improve our ability to predict the partitioning of metals between the soil solid and solution phases.
We developed a standard protocol to produce solutions that resemble lysimeter solutions from podzolic soils using air-dried samples. We hypothesized that the stabilization point of the electrical conductivity (EC) of the soil solution is indicative of the point in which soluble salts and organic material precipitated during sampling and storage are removed from the soil particle surfaces. Solutions produced by leaching the soils, once the EC of wash solutions had stabilized, were comparable to lysimeter solutions from the area where samples were collected with respect to the concentrations of divalent cations, pH, EC and dissolved organic carbon (DOC). The applicability of this procedure to trace metal partitioning in forest floors was explored. Laboratory extractions produced partition coefficients (log Kd) similar to observed lysimeter solutions ranging from 3.4 to 3.9 for Cd, 3.4 to 3.9 for Cu, 3.4 to 4.1 for Ni, 4.1 to 5.2 for Pb and 3.2 to 3.5 for Zn. According to a semi-mechanistic regression model based on observed lysimeter concentrations, the metal concentrations in solution were appropriate relative to known factors that influence metal partitioning in soils: pH, the concentrations of total metals and DOC.
While chemical characteristics of soils have been consistently observed to play important roles in the partitioning and toxicity of metals we wished to place the importance of the chemical characteristics of soil on mobility and toxicity in context. We interpreted field data that had been collected from transects established with distance from two point source emitters in Rouyn PQ, and Sudbury ON. Canada find developed equations that predict dissolved metal concentrations from total metal concentrations, soil pH, soil organic matter (SOM), and DOC contents. We integrated these equations into a simple box model that calculates changes in the concentration of metals in the organic and upper mineral horizons and includes a loop for vegetative return of metals to the forest floor.

Bibliography: leaves 213-245. Genetic control of tolerance to boron was investigated between a moderately tolerant variety, Halberd, a tolerant line G61450 and the moderately sensitive varieties Schomburgk and Condor.

Also aged bottles are safer to use than new bottles because their chemical leaching was found to be lower than that of new bottles. This study recommends the reassessment of the absence of international guidelines for acetaldehyde in water and foods. The study also recommends that the amount of acetaldehyde that can be added to soft drinks as flavouring agent should be below the specific migration limit (SML) for migration of acetaldehyde from PET bottle into bottle contents. This is essential since the SML was designed to ensure that exposure to acetaldehyde, as a result of intake of bottled water and soft drinks in PET bottles, is below the tolerable daily intake (TDI) for acetaldehyde. As antimony was reported to go beyond the safe limits in some Nigerian bottled water and soft drinks after 11 months of storage this study discourages the use of bottle contents stored for a very long time.

碩士
輔仁大學
營養科學系
96
Regarding the quantity of minerals and trance element contents in a diet is unable to be comprehensive during to insufficient of food nutrient data base and limited of the calculation tools in Taiwan. Dietitians could focus mostly on the aspects of calorie, carbohydrate, protein and fat requests in a diet plan or nutrition education for sickness. In general the mineral and trace element contents of foods depend largely on the mineral contents of the water source and soil where those foods grow. Since the hospital diet belongs to the quantitative food preparation, bleeching usually is the first step of cooking, especially for the green vegetables. However, minerals are lost from the draining. Therefore, if there is sufficient amount of minerals in the hospital diets need to be concerned. In addition, whether there is a need to give mineral supplements to the patents in the long-term medical care facility in avoiding long-term deficiency of minerals. In this study, normal diets and therapeutic diets of in –patient were examined from a medical center in central Taiwan. Calcium, magnesium, iron, zinc and copper of samples of above diet were analyzed by using of Inductively Coupled Plasma Mass Spectrum ( ICPMS ) analyzer, Inductively Coupled Plasma Optical Emission Spectrophotometer ( ICPOES ) and/or the Atomic Absorption Spectrophotometry ( AAS ). Result reveals that calcium and magnesium contents in all diets are unable to meet RDIs of the nutrients. Iron contents of all diets can meet DRI for adult males (10 mg/day). Except the parturient diet, other diet are unable meet the DRIs for Zinc. With the exception of the vegetarian diet, which showed a serious deficiency in selenium levels, all other diet were able to provide sufficient levels of copper, selenium manganese chromium, molybdenum, and other trance elements, to meet the DRIs. There are discrepancy between the calculated values and actually measured the values of Mg, Zn in the diets. Therefore, the integration of this study’s results suggests that there is a need to add more calcium-rich magnesium-rich and iron-rich foods in the parturient diet, and calcium, iron, magnesium zinc foods and/or nutrient supplement in all other diets when a dietitian plans and design these diets.

碩士
國立中央大學
應用地質研究所
89
The distribution of sulfur and trace element in coal is controlled by the depositional environment of peat. Four high volatile bituminous coal samples were collected from the Shihti Formation, northern Taiwan. Their sulfur and trace element contents were analyzed according to ASTM procedures. The analytic results indicate a reductive, littoral to brackish environment. The high pyrite contents can lead to the enrichment of B, As, Tl, with enrichment factors reaching 100. The depositional environment of Lifeng, Yufeng, and Anshuen mines were concluded as a lagoon or swamp, whereas the Wukeng mine was believed to be a delta.

碩士
國立屏東科技大學
環境工程與科學系所
99
Serpentinitic soils from ultramafic parent rocks are characterized by low availability of N, P, K, and Ca/Mg and extremely high contents of heavy metals like Cr, Co, and Ni. These metal levels in the serpentinitic soils can be much higher than the soil pollution control standards (SPCS) of Taiwan. Additionally, low contents of Si and Ca causes to poor growth of general plants. The heavy metals in the serpentinitic soils are not anthropogenic, but they have potential risk to ecosystem and human health. Therefore, this study selected an abandoned site of serpentine at Wang-Ron, Hualiean to collect 7 species of plant and the corresponding soils in the root zone. The plants include Crotalaria zanzibirica, Miscanthus floridulus, Leucaena leucocephala, Bidens pilosa, Dolichos lobatus Willd., Melilotus indicus and Conyza Canadensis. The purposes are to explore element contents in the soils and plants, to fractionate heavy metals by sequential extraction and single extraction, to understand the plant uptake of the elements and their compartmentation in different plant tissues, and evaluate the phyto-availability. The experimental results indicated that the Ca/Mg ratio was lower than 1.0 in most cases of soils and reflected the typical characteristics of serpentinitic soils. The concentrations of Cr and Ni ranged from 59 to 723 mg/kg and from 691 to 1220 mg/kg respectively, which greatly exceeded the SPCS. Regarding solid fractionation of Cr and Ni, the dominant phases of Cr and Ni are the residual forms which are fixed in the mineral framework. The DTPA- and HCl-extractable amounts of Ni was higher than that of Cr, which difference in trend betwee elements is the same to that by sequential extraction. Therefore, Cr is hard to be absorbed by the plants. The heavy metal contents in the studied plants were higher than those in the other plants. The concentrations of Mn, Cr, and Ni in the plant ranged from 10.4 to 69.4 mg/kg, from 6.08 to 36.9 mg/kg, and from 8.52 to 51.4 mg/kg. In addition, most Mn and Cr in the plant accumulated in the root, while Ni was in the leaves. This study elucidates that the plant may be potential accumulators of Ni, because the transfer factor (TF, leaf/root) of Ni is higher than 1.0, particullarly for Crotalaria zanzibirica with TF 2.27.

碩士
國立臺灣海洋大學
海洋環境資訊系
102
The concentrations of trace elements in eggs of five crustacean (Portunus trituberculatus、Thalamita crenata、Charybdis feriatus、Parapenaeus fissuroides、Bathysquilla crassispinosa) and four fishes (Mugil cephalus、Miichthys miiuy、Cypselurus poecilopterus、Ephippus orbis) were determined in the present study. The eggs of these analyzed organisms were digested by strong acid at the water bath and the contents of trace elements were analyzed by the ICP-MS. The analyzed results showed that the concentrations of the trace elements ranged within 0.000027-374.1 mg/kg. The concentration sequence of the analyzed trace elements were as follow: Al > Zn > Fe > Cu > As > Sr > Se > Mn > Rb > Cr > Ni > Pb > V > Li > Ba > Ga > Co > Cd > Hg > Cs > Ag > Bi > Ge > Be > Tl > U >In. However, the sequence of Zn、Fe、Mn and Cr will differ from the different crustacean. Similar result was also found in the fish eggs. While, the concentration differences of Ni, Cr, Rb and Mn in the crustacean were extremely significant, especially Mn could reach million fold. In addition, the concentration difference of Fe in Portunidae was also significant and could reach 100 folds. The bio-concentration factors (concentration in eggs dividing the concentration in seawater) of these analyzed eggs ranged within 10-3 - 107. Lead has the highest bio-concentration factor, and Li and Sr have the lowest bio-concentration factor. The bio-concentration factor of crustacean eggs was generally higher than that of fish eggs.

by Leung Ho-yin.
Thesis (M.Phil.)--Chinese University of Hong Kong, 1998.
Includes bibliographical references.
Abstract also in Chinese.
Acknowledgement --- p.i
Abstract --- p.ii
Table of Contents --- p.iv
List of Tables and Figures --- p.v
Chapter Chapter 1 --- Introduction --- p.1
Chapter Chapter 2 --- Methodology --- p.12
Chapter Chapter 3 --- Experimental --- p.17
Chapter 3.1 --- Sample Collection --- p.17
Chapter 3.2 --- Preliminary Sample Treatment --- p.18
Chapter 3.3 --- Dissolution Test Apparatus --- p.18
Chapter 3.4 --- Reagents --- p.20
Chapter 3.5 --- ICP Experimental Conditions --- p.21
Chapter Chapter 4 --- Determination of Total Contents in Chinese Mineral Drugs --- p.28
Chapter 4.1 --- Procedure --- p.28
Chapter 4.2 --- Results --- p.39
Chapter Chapter 5 --- Determination of the Effective Contents --- p.51
Chapter 5.1 --- General Procedure --- p.51
Chapter 5.2 --- Results --- p.52
Chapter Chapter 6 --- Recovery Test for Dissolution --- p.77
Chapter 6.1 --- General Procedure --- p.77
Chapter 6.2 --- Results --- p.78
Chapter Chapter 7 --- Discussion --- p.80
Chapter 7.1 --- The Presence of Toxic Elements in many CMD --- p.80
Chapter 7.2 --- Mass of Samples Added in the Dissolution --- p.80
Chapter 7.3 --- Height of the Dissolution Paddle of the Dissolution --- p.81
Chapter 7.4 --- Particle Sizes of the Sample in the Dissolution --- p.83
Chapter 7.5 --- The Total and the Effective Contents --- p.83
Chapter 7.6 --- Discussion for each CMD --- p.84
Chapter 7.7 --- Conclusion --- p.103
Appendix English 一 Chinese table of CMD --- p.108

碩士
國立嘉義大學
食品科學系碩士班
92
Herbal medicine has been used for thousands of years as diseases curing agents for Chinese people. Nowadays, Chinese herbal medicine serves more diverse purposes, such as health foods for promoting health status for the general public. Traditionally, herbal ingredients are soaked in water and subsequently decocted for hours to reach consumable form. During the decocting process, many chemical and physical changes occur simultaneously. In addition, the container used to decoct might have profound effects on the effectiveness of herbal medicine. The purpose of this research is to detect the trace elements concentrations, after decocting herbal medicine with containers of different materials. In our research, two generally used prescriptions, Shy-Wuh-Tang and Hwang-Lian-Jiee-Dwu-Tang, were chosen; and five types of containers made of stainless steel, pottery, casserole, enamel, and glass, were used. The herbal medicine materials were soaked in de-ionized distilled water for thirty minutes before heated to boiling. Then, the content was boiled with mild heat for another thirty minutes. The decanted aqueous layer was centrifuged and filtered to obtain pulp-free herbal infusion that was stored in pre-cleaned PE bottle and used in the following analysis. In the preliminary study, the optimal microwave digestion conditions for herbal infusion were obtained as following-- infusion: nitric acid ratio= 4: 3 (v/v), and microwave energy level -- 800W for 15 min. The contents of copper, iron, manganese, and chromium in herbal infusion were determined with graphite atomic absorption spectrometer (GAAS). ICP-MS was also applied to quantify the trace element (including copper, iron, manganese, chromium, zinc, cadmium, lead, arsenic, selenium and germanium) concentrations. As for Hwang-Lian-Jiee-Dwu-Tang, infusion obtained from stainless pot contained less copper and more chromium than those prepared with other types of pots. No significant differences of trace elements were detected among Hwang-Lian-Jiee-Dwu-Tang infusions prepared with all five types of containers. However, amounts of the trace element contents in the Hwang-Lian-Jiee-Dwu-Tang infusions were mangnases (8.04~10.36 µg/g) > iron (2.76~4.19 µg/g) > copper (0.46~0.67 µg/g) > chromium (0.04~0.14 µg/g). For Shy-Wuh-Tang, no significant differences of copper, iron, manganese and chromium concentration were detected among the herbal infusions prepared with all five types of containers. The amounts of the trace element contents in the Shy-Wuh-Tang infusions were iron (16.13~27.84 µg/g) > mangnases (5.93~6.61 µg/g) > copper (0.95~1.03 µg/g) > chromium (0.11~0.28 µg/g). As analyzed by ICP-MS, no significant differences were detected between two herbal prescriptions prepared with five different containers. However, the amounts of the trace element contents in the Hwang-Lian-Jiee-Dwu-Tang infusions were iron (94.5~622.5 ppb) > mangnases (165.5~295.0 ppb) > zinc (47.3~307.5ppb) >copper (8.3~46.5ppb) > chromium (0.8~20.3ppb) > lead (1.9~7.6ppb); in the Shy-Wuh-Tang infusions were iron (945.0~5151.0ppb) > zinc (171.8~1322.5ppb) > manganese (151.3~249ppb) > copper (23.0~141.3ppb) >chromium (3.3~42.3ppb) > lead (3~67.5ppb).

M.Sc. (Geology)
Most rural communities in developing countries rely on borehole water as their only source of water. Since borehole water comes from underground, it is often considered pure and clean, but this is frequently not the case. Groundwater contains certain amounts of trace elements that may become deleterious to human health. The objectives of this investigation were to assess the concentration levels of Potential Harmful Trace Elements (PHTEs) and their spatial distribution patterns in borehole water in the Greater Giyani area of Limpopo, South Africa, and the potential human health risks associated with this. The method of research comprised two phases: (I) In the first phase, I assessed the occurrence and distribution patterns of PHTEs in the boreholes of the Giyani area. A total of 29 water samples were collected from boreholes (including 15 community boreholes and 14 primary school boreholes) in the Greater Giyani area during the dry season (July/August 2012), and for comparison another 27 samples (including 15 community boreholes and 12 schools boreholes) from the same localities during the wet season (March 2013). The samples were analysed for the trace elements arsenic (As), cadmium (Cd), chromium (Cr), selenium (Se) and lead (Pb) using the Inductively Coupled Plasma Mass-Spectrometry (ICPMS) technique. In order to assess the groundwater quality, PHTEs concentrations were compared with the South African National Standard of Drinking water (SANS 241-1:2011). (II) In the second phase, I evaluated the geographic variation between PHTEs and associated human health effects. This involved acquisition of data on a total of 100 cancer cases recorded during the period 2011-2014 at Nkhensani Hospital. ArcGIS Spatial analyst tool was used to create thematic maps illustrating spatial distribution of clinical data and arsenic concentrations in boreholes.

Although products of coal combustion (PCCs) such as coal ash are currently exempted from classification as a hazardous waste in the United States under the 1976 Resource Conservation and Recovery Act (RCRA), the U.S. Environmental Protection Agency (EPA) is now revising a proposed rule to modify disposal practices for these materials in order to prevent contamination of ground- and surface water sources by leached trace elements. This paper analyzes several aspects of EPA’s scientific reasoning for instating the rule, with the intent of answering the following questions: 1) Are EPA’s cited values for PCC production and disposal accurate estimates of annual totals?; 2) In what ways can EPA’s leaching risk modeling assessment be improved?; 3) What is the total quantity of trace elements contained within all PCCs disposed annually?; and 4) What would be the potential costs and feasibility of reclassifying PCCs not under RCRA, but under existing NRC regulations as low-level radioactive waste (LLRW)? Among the results of my calculations, I found that although EPA estimates for annual PCC disposal are 20% larger than industry statistics, these latter values appear to be closer to reality. Second, EPA appears to have significantly underestimated historical PCC disposal: my projections indicate that EPA’s maximum estimate for the quantity of fly ash landfilled within the past 90 years was likely met by production in the last 30 years alone, if not less. Finally, my analysis indicates that while PCCs may potentially meet the criteria for reclassification as low-level radioactive waste by NRC, the cost of such regulation would be many times that of the EPA June proposed disposal rule ($220-302 billion for PCCs disposed in 2008 alone, versus $1.47 billion per year for the Subtitle C option and $236-587 million for Subtitle D regulatory options).
text

Indiana University-Purdue University Indianapolis (IUPUI)
Mercury (Hg) has proven to be a risk to the public, mainly through the consumption of fish. Because of this, many fish consumption advisories have been issued in Indiana. Although much is known about the global cycle of mercury, little is known about how local and regional emission sources of mercury impact local and regional mercury cycling. This study’s objective was to determine the scope of mercury concentration in central Indiana by using a broad grid of soil mercury measurements. Sampling was designed to capture the net retained mercury content in soils, and to determine whether spatial patterns in exist in soil mercury contents that could be related to emission sources of mercury and post-emission transport patterns from wind. Results from this study revealed significant differences in mercury concentrations for soils in central Indiana. The core of the study area, concentrated in the urban area of Indianapolis, exhibited soil mercury contents that were 20 times higher than values in the outskirts of the study area. The spatial pattern resembled a bulls-eye shape centered on Indianapolis, and with comparison to the reported Hg emission from local sources, including a coal-fired power plant, indicates a strong regional deposition signal linked to those emission sources but marked by wind-driven transport to the northeast. This effect of local emission sources resulting in local deposition indicates that limiting mercury emissions will have a net beneficial impact on local environmental quality and human health.