Last page is titled: Appendix 1: DVD of Model Simulations (See DVD in Back Envelope). There was no DVD present for upload. / <p>Point Pelee National Park (PPNP), located in Leamington, Ontario, Canada experienced widespread application of DDT from 1950 until DDT was banned in Canada in 1970. vVbile DDT has not been applied at PPNP for over 30 years recent studies have shown that the compounds DDT, ODE and DDD are highly persistent in shallow soils at PPNP and often exceed regulatory guidelines set forth by the Ontario Ministry of the Environment and Environment Canada. Field study combined with numerical modelling was undertaken to assess the concentrations of DDT, DDE and DDD in groundwater and provide insight into the fundamental processes controlling the persistence and migration of DDT within former agricultural areas of PPNP. Results of one-dimensional pesticide fate and transport modelling from 1950 to 2003 using LEACHMP show that within former agricultural areas of PPNP, DDT is transformed primarily not DOE under aerobic conditions. Within the Camp Henry Orchard (CHO), half lives for the production of DDE are 30 years. LEACHMP modelling showed that adsoption was the most important process limiting DDT leaching to groundwater. The depth to the water table was found to influence DDT concentrations seen at the water table throughout former agricultural areas of PPNP, and DDT is most likely leaching to the water table slowly over time. Two dimensional saturated zone modelling using OW-WETLAND was used to test various loading scenarios based on LEACHMP simulated fluxes across the water table. Model outputs illustrated the bidirectional movement of contaminants toward both the marsh and Lake Erie, depending on the source location relative to the groundwater flow divide. Simulations showed only groundwater from deep within the aquifer would have elevated DDT concentrations in 2003 if DDT leached to groundwater between 1950 and 1970. Conversely, if DDT began to leach to groundwater in the 1990's, the model predicted that DDT was not present in deep groundwater in 2003. With continued loading, concentrations throughout the aquifer will continue to rise into the future and discharge of DDT to the marsh and Lake Erie will occur.</p> / Thesis / Master of Science (MSc)

<p> The distribution of Mg and Sr in speleothem from Yorkshire, England, Vancouver Island and West Virginia, was investigated. Concentrations of Mg range from 300 to greater than 3000 parts per million. Concentrations of Sr range from less than 100 to a few hundred parts per million. Sr partitioning between seepage water and calcite may be more rate sensitive than Mg partitioning.</p> <p> It is possible that Mg and Sr in speleothem could provide information on kinetics and mechanism of speleothem formation and on seepage water and source rock composition.</p> <p> It may be possible to interpret Mg concentration in speleothem in terms of temperature if equilibrium partitioning of Mg between calcite and seepage waters can be demonstrated.</p> / Thesis / Bachelor of Science (BSc)

<p> Ambient air pollution and pollution emitted from point sources, contribute to the total suspended particulate loadings measured at various monitoring stations, in any given area. Studies have shown that various meteorological variables may influence the concentration of particulates measured at these stations. 1989 data, from monitoring stations throughout Hamilton, Ontario, in conjunction with meteorological data from the Mount Hope airport, have been used to reveal, and to explain the aforementioned relationships. Results from graphical analysis, supports past findinqs from Stewart and Matheson (1967), Rouse and McCutcheon (1970), Dobroff (1990) and others, by showing that winds derived from a northern sector increase mean particulate loadings, and that wind speeds tend to be inversely related to measured particulate concentrations. In contrast to supporting findings from the graphical analysis, statistical ordinary least squares regression showed that for more stations than not, most parameter coefficients were not statistically significant. Results from the coefficient of determination show that none of regressions employed (linear, linear-log and log-log) could explain the relationship between the independent meteorological variables and the dependent variable (particulate concentration at a given monitoring site) with great precision. It follows that a non-linear correlation may well explain the dependence of particulate loading on wind speed, wind direction, mean temperature and total precipitation, and that source, (point and fugitive emissions), and other factors play important roles in this complex relationship.</p> / Thesis / Candidate in Philosophy

<p> The behaviour of iodic acid, of mixtures of iodic acid and iodine, and of various other iodine compounds as solutes in sulphuric and fluorosulphuric acids has been studied, using mainly cryoscopic and conductimetric techniques. Evidence has been obtained for the existence of polymeric species containing iodine (V), of the oxy-cation IO+, of the iodine cation, I+, in small concentrations in equilibrium with its disproportionation products, and of the cations I3+, I5+ and I2Cl+. The reaction of iodosyl sulphate with disulphuric acid has been studied. Conductimetric studies have been made of solutions of water, potassium nitrate and potassium perchlorate in fluorosulphuric acid. The results of some spectrophotometric and nuclear magnetic resonance experiments are also reported.</p> / Thesis / Doctor of Philosophy (PhD)

<p> The effects of engineering operating variables in the sulphide precipitation of Cu+2, Cd+2 and Zn+2 have been examined with a statistical experimental design. The independent (operating) variables studied were 1) the level of sulphide added, 2) the level of Fe+2 added as scavenger for excess HS- ion and 3) the pH level. The dependent variables were the concentrations of dissolved, suspended and total metals in the supernatant after treatment and the zone settling velocities of the suspensions.</p> <p> The major effect of the operating variables was to yield a precipitate which was either a stable colloid or a suspension which coagulated and settled. Stable colloid formation was associated with an excess of HS- ion. For those conditions which produced coagulant suspensions, 1) ten of the thirteen correlations between dependent and independent variables were not statistically significant at the 95% confidence level, 2) for practical purposes, variations in engineering operating variables did not alter the levels of dissolved and suspended Cu+2, Cd+2 and Zn+2 .</p> <p> When the precipitates coagulated and settled, concentrations of approximately 100 mg/l of each of Cu+2, Cd+2 and Zn+2 were reduced to mean values of 0.41, 0.33 and 0.62 mg/l total metals and 0.03, 0.01 and 0.37 mg/l dissolved metals respectively.</p> / Thesis / Master of Engineering (MEngr)

This thesis explores the use of skin iron concentration, assessed using a portable x- ray fluorescence (PXRF) analyzer, as an indicator of liver iron concentration. Ultrasound images were acquired from four sites on human cadavers: thenar eminence (TE), between the metacarpophalangeal joint 1 and 2 (MJ), patella (P), and plantar arch (PA). Skin thickness was subsequently measured using boundary detection software applied to the ultrasound images. Skin iron concentrations, from the same sites, were obtained directly from 13 cadavers using a PXRF analyzer. As the iron concentrations determined using PXRF may have been impacted due to beam attenuation through the skin, these iron concentrations were subsequently corrected using the Beer-Lambert Law accounting for the skin thickness at each site. Huber XRF is a bulk tissue measurement system that was used to measure iron concentrations from the extracted samples of the four sites. The skin iron concentrations determined using both PXRF and Huber XRF were compared to evaluate the agreement between the two methods. As such, samples from the four sites were extracted and the iron concentrations of the extracted samples were measured using a Huber X-Ray Fluorescence (XRF) analyzer as the control. A statistically significant relationship with a p-value of <0.01 and a strong correlation with a R2 value of 0.87 was seen between the corrected skin iron concentrations determined using PXRF and the skin iron concentrations determined using Huber XRF analysis of the extracted samples. Thus, the skin iron concentrations obtained using PXRF are representative of the skin iron concentrations collected by Huber XRF. For further validation, liver samples were obtained from 6 of the 13 cadavers and the liver iron concentrations were assessed using Huber XRF. The non- corrected PXRF, corrected PXRF and the Huber XRF skin iron concentrations were then compared with the liver iron concentrations. The relationships between iron concentrations measured at the PA site and in the liver were found to be statistically significant with strong correlations (R2 = 0.94 for Huber XRF, R2 = 0.87 for non-corrected PXRF, and R2 = 0.95 for corrected PXRF). Therefore, the skin iron concentrations at the PA site determined by PXRF and determined by Huber XRF analysis of skin samples could be used in the future as a surrogate marker for the liver iron concentrations in humans. / Thesis / Master of Science (MSc)

Loblolly pine (<u>Pinus taeda</u>) occurs in mixed stands with hardwood species including red maple (<u>Acer rubrum</u>) and sweetgum (<u>Liguidambar styraciflua</u>) across much of the southern United States. Rising atmospheric CO₂ concentrations over the next several decades could influence competitive interactions between these species. This research examined the effects of increased atmospheric CO₂ concentration in combination with the availability of other resources on growth and gas exchange characteristics of these species grown in direct competition in miniature stands and compared characteristics of miniature stands with field-grown stands of similar composition. In a greenhouse study, loblolly pine and red maple were grown in monoculture and 50:50 replacement mixtures at a 2.54 x 2.54 cm spacing for two growing cycles under ambient (408 ppm) or elevated (806 ppm) CO₂ concentrations and well-watered or droughted (0.5x well-watered) conditions. Loblolly pine dominated all mixed stands and was proportionally larger while red maple was smaller in mixtures versus monocultures. This pattern was also observed in weed-free f ld-grown stands after five growing seasons. Biomass data from loblolly pine and red maple grown in monocultures and 50:50 replacement mixtures at 2.54, 5.08 and 7.62 cm2 initial spacing suggest that relative dominance of species in miniature stands is not dependent on initial spacing. Dominance of red maple over loblolly pine in all mixed stands in this experiment suggests that soil medium is important in determining relative growth of these species. Photosynthesis rates and response to elevated CO₂ differed between whole stands and individual seedlings from these stands. Individual seedlings tended to be more responsive to elevated CO₂ compared to whole stands suggesting reduced responsiveness of lower canopy leaves may dampen the effect of elevated CO₂ on canopy photosynthesis rates. Growth under elevated CO₂, alone or in combination with water did not affect relative sizes of these species. These results suggest that competitive interactions will not change between these species in response to growth in high CO₂ environments. / Ph. D.

The aim of this study was to determine the levels of cadmium (Cd) and lead (Pb) in livers and kidneys of cattle slaughtered at Grootfontein abattoir in Namibia. The study design was based on the epidemiological principles to detect a single animal whose kidneys or liver contained Cd or Pb residues. The Grootfontein area of Namibia has extensive base-metal ore reserves, which were and are still extracted and processed in localities used as livestock pastures. Namibia is also an arid country which predominantly uses borehole water for livestock and human consumption. These underground water bodies share the same space as base-metal ores. The anthropogenic activities in this area under the existing geological and hydrogeological circumstances offer opportunities for Cd and Pb to enter the food chain. Entry of Cd and Pb in the food chain leads to bioaccumulation in cattle kidneys and livers to concentrations above Codex Alimentarius Commission (CAC) standards, creating a possible public health risk. The CAC withdrew the maximum limit (ML) of 1mg kg-1 Cd in bovine kidneys and liver, but it has a provisional tolerable monthly intake (PTMI) of 0.025mg kg-1 human body weight. This CAC PTMI translates to a total exposure of 1.5mg Cd for a 60kg body weight person. The CAC ML for Pb in bovine offal is 0.5mg kg-1, while its provisional tolerable weekly intake (PTWI) of 0.025mg kg-1 human body weight is under review. This investigation intended to establish if Cd and Pb in the livers and kidneys of cattle slaughtered in the study area exceeded CAC human exposure limits. Liver and kidney specimens were collected from 31 randomly sampled mature cattle (estimated over five years old based on incisor teeth examined post slaughter). The specimens were analysed at a local mine laboratory, which was the only facility available and capable of performing the tests. They were digested using wet-ashing (the oxidation procedure). All liver digestates were analysed, while one kidney analyte was insufficient. Cd and Pb were measured using flame atomic absorption spectroscopy (FAAS). The detection limit (DL), which was the minimum metal concentration FAAS could measure was 0.2mg kg-1 for Cd and 1.1mg kg-1 for Pb. The laboratory could not refine the Pb DL which was more than twice the CAC ML. All livers had Cd concentrations below 0.2mg kg-1. One discarded kidney specimen was assigned a concentration below DL for analysis purposes. The Cd concentrations in 12 kidney specimens were below 0.2mg kg-1, between 0.288 and 1.221mg kg-1 in 16 and above 1.5mg kg-1 (2.6 - 3.64mg kg-1) in 3 specimens. The mean renal Cd concentration for the population (0.71±0.96mg kg-1) was statistically lower than 1.5mg kg-1 (p <0.05). Cd was therefore shown to be a chemical hazard for consumers of kidneys and a potential environmental hazard in the study area. Pb was negative in all of the 31 liver specimens, while in all the 30 kidney specimen digestates it was detected at concentrations below 1.1mg kg,-1. This result confirmed the presence of Pb as a potential chemical hazard found in bovine kidneys. However, a more sensitive analytical method was required to assess Pb food chain and public health hazard parameters in the study area. An epidemiological investigation of the study area using geographical information systems (GIS) to explore geographical factors that could have influenced exposure to Cd and Pb was done. While proximity to operational and decommissioned mining ventures appeared to result in higher mean renal Cd concentrations, the influence was not statistically significant. Feedlot rearing also appeared to cause higher mean renal Cd concentrations but the impact was also not statistically significant. It was concluded that Cd and Pb were chemical environmental contaminants which enter the animal and human food chain in the study area. A kilogram of bovine kidney-meat from approximately one in ten cattle (9.7%) carried more than 1.5mg Cd, exceeding the recommended CAC total dietary exposure for a 60-kg man. A mathematical model was used to estimate the risk of cattle with renal Cd concentration exceeding 1.5mg kg,-1, the expected number of cattle affected and the weight of meat entering the food chain. The estimated cattle population affected monthly was 5.95%, with a range of between 5 and 11 (mean = 8±4) cattle. These cattle were estimated to yield 8 to 18 (mean 13±6) kg bovine kidney-meat per month. A WHO standard-weight man who consumes a kilogram of kidney meat in this category in a month risks exposure to Cd doses beyond the CAC PTMI. The epidemiological triad of interactions between the host (cattle), agent (Cd and Pb) and the environment (proximity to mines) was used in order to suggest risk mitigation options. Recommendations from this study included advocacy on Cd and Pb in the food chain and developing partnerships with mining entities so that risk mitigation and communication can be better coordinated. Consumers are advised to reduce their monthly intake of kidney meat as this organ tissue has higher levels that those in other bovine organs and tissues. The cattle in the study were mature breeding animals (>5 years) and it is likely that this factor increased the risk of higher levels in kidneys as temporal determinants for bioaccumulation of Cd are important. The kidneys of younger animals would thus be less likely to contain significant Cd levels. Lastly, use of mathematical modelling, to translate research findings into quantitative estimates useful for public health safety programs, is recommended. / Dissertation (MMedVet)--University of Pretoria, 2012. / Paraclinical Sciences / unrestricted

Biodegradation is the breakdown of a compound by a biological organism. Over the past few decades, the biodegradation of compounds such as phenol has been researched extensively. Phenol research has shown that certain organisms are capable of utilising it as an energy source, and a variety of methods are available for its removal. Unfortunately, there is lack of research on phenol degradation at low concentrations. The majority of research performed on phenol degradation has used concentrations above 500 mg, while phenol is highly toxic at levels below 25 mg. The aim of this research was to pursue the problem of phenol degradation at below 100 mg and develop a system able to degrade phenol at such levels. The system consisted of a bioreactor developed to run in continuous mode, using Ps. putida immobilised in calcium alginate. A standard method was modified to quantitatively analyze effluent phenol levels, and a medium designed to increase the longevity of calcium alginate beads in continuous culture. A continuous flow bioreactor was also designed using an overflow weir for use with immobilised cells. Based on the results obtained, immobilisation offers increased stability and increased protection for cells under extreme conditions and is able to use higher dilution rates than cells under continuous culture / Master of Science (Hons)

This is a M. Eng. degree project at Uppsala University carried out at Vattenfall NuclearFuel AB. The goal of it is to present a best estimate method based on the code package CASMO/SIMULATE for the purpose of calculating the isotopic concentrations of a specified number of isotopes in a fuel sample. The calculations done with the method shall produce small deviations from reliable measured values, which characterize the accuracy of CASMO/SIMULATE, but also simplicity based onthe computing time and handling of the amount of data is an important factor in the development of the method. The development of the method has been based on a sensitivity calculation with CASMO/SIMULATE on a number of relevant parameters affecting the isotope concentrations. The proposed method has then been applied on three samples irradiated in Ringhals 4 and Ringhals 3. At last the calculated isotopic concentrations have been benchmarked against measured data from Studsvik Laboratory. The sensitivity analyzes has shown that the parameters affecting the neutron moderation are very important for calculating the isotopic concentrations. The core axial resolution is also an important factor for the samples taken from top of the rod,where the power gradient is large. The comparison of the calculated and measured values has shown that SIMULATE, in the analysed cases, simulates a lower finalburnup. This has created a need to correct the final burnup in order to get better results in terms of lower relative deviations between the measured and calculated data.