Doctor of Philosophy / Water quality guidelines (WQGs) present concentrations of contaminants that are designed to be protective of aquatic ecosystems. In Australia, guidance for assessment of water quality is provided by the ANZECC and ARMCANZ (2000) Guidelines for Fresh and Marine Water Quality. WQGs are generally provided for individual contaminants, not complex mixtures of chemicals, where interaction between contaminants may occur. Complex mixtures of contaminants are however, more commonly found in the environment than singular chemicals. The likelihood and consequences of adverse effects occurring in aquatic ecosystems resulting from contaminants are generally assessed using an ecological risk assessment (ERA) framework. Ecological risk assessment is often a tiered approach, whereby risks identified in early stages, using conservative assumptions, prompt further detailed and more realistic assessment in higher tiers. The objectives of this study were: to assess and investigate the toxicity of the mixture of volatile chlorinated hydrocarbons (VCHs) in groundwater to indigenous marine organisms; to present a ‘best practice’ ecological risk assessment of the discharge of contaminated groundwater to an estuarine embayment and to develop techniques to quantify the environmental risk; and to evaluate the existing ANZECC and ARMCANZ (2000) WQGs for VCHs and to derive new WQGs, where appropriate. Previous investigations at a chemical manufacturing facility in Botany, Sydney, identified several plumes of groundwater contamination with VCHs. Contaminated groundwater containing a complex mixture of VCHs was identified as discharging, via a series of stormwater drains, to surface water in nearby Penrhyn Estuary, an adjacent small intertidal embayment on the northern margin of Botany Bay. A screening level ecological hazard assessment was undertaken using the hazard quotient (HQ) approach, whereby contaminant concentrations measured in the environment were screened against published trigger values (TVs) presented in ANZECC and ARMCANZ (2000). Existing TVs were available for 9 of the 14 VCHs present in surface water in the estuary and new TVs were derived for the remaining 5 VCHs. A greater hazard was identified in the estuary at low tide than high tide or when VCH concentrations from both high and low tides were assessed together. A greater hazard was also identified in the estuary when the toxicity of the mixture was assessed, rather than the toxicity of individual contaminants. The screening level hazard assessment also identified several limitations, including: the low reliability of the TVs for VCHs provided in ANZECC and ARMCANZ (2000); the limited applicability of the TVs to a complex mixture of 14 potentially interacting contaminants; the use of deterministic measures for each of the exposure and toxicity profiles in the HQ method and the associated lack of elements of probability to assess ‘risk’. Subsequent studies were undertaken to address these identified shortcomings of the screening level hazard assessment as described in the following chapters. A toxicity testing methodology was adapted and evaluated for suitability in preventing loss of VCHs from test solutions and also for testing with 6 indigenous marine organisms, including: oyster (Saccostrea commercialis) and sea urchin larvae (Heliocidaris tuberculata); a benthic alga (Nitzschia closterium); an amphipod (Allorchestes compressa); a larval fish (Macquaria novemaculeata); and a polychaete worm (Diopatra dentata). The study evaluated possible VCH loss from 44 mL vials for small organisms (H.tuberculata, S.commercialis and N.closterium) and 1 L jars for larger organisms (M.novemaculeata, A.compressa and D.dentata). Vials were effective in preventing loss of VCHs, however, an average 46% of VCHs were lost from jars, attributable to the headspace provided in the vessels. Test jars were deemed suitable for use with the organisms as test conditions, i.e. dissolved oxygen content and pH, were maintained, however, variability in test organism survival was identified, with some control tests failing to meet all acceptance criteria. Direct toxicity assessment (DTA) of groundwater contaminated with VCHs was undertaken using 5 indigenous marine organisms and site-specific species sensitivity distributions (SSDs) and TVs were derived for the complex mixture of VCHs for application to surface water in Penrhyn Estuary. Test organisms included A.compressa, H.tuberculata, S.commercialis, D.dentata and N.closterium. The SSD was derived using NOEC data in accordance with procedures presented in ANZECC and ARMCANZ (2000) for deriving WQGs. The site-specific SSD adopted was a log-normal distribution, using an acute to chronic ratio (ACR) of 5, with a 95% TV of 838 μg/L total VCHs. A number of additional scenarios were undertaken to evaluate the effect of including different ACRs (i.e. 5 or 10), inclusion of larval development tests as either acute or chronic tests and choice of SSD distribution (i.e. log-normal, Burr Type III and Pareto). TVs for the scenarios modelled varied from 67 μg/L to 954 μg/L total VCHs. A site-specific, quantitative ERA was undertaken of the surface water contaminated with VCHs in Penrhyn Estuary. The risk assessment included probabilistic elements for toxicity (i.e. the site-specific SSD) and exposure (i.e. a cumulative distribution function of monitoring data for VCHs in surface waters in the estuary). The joint probability curve (JPC) methodology was used to derive quantitative estimates of ecological risk (δ) and the type of exposure in the source areas in surface water drains entering the estuary, i.e. Springvale and Floodvale Drains, Springvale and Floodvale Tributaries and the Inner and Outer Estuary. The risk of possible adverse effects and likely adverse effects were each assessed using SSDs derived from NOEC and EC50 data, respectively. Estimates of risk (δ) of possible adverse effects (i.e. based on NOEC data) varied from a maximum of 85% in the Springvale Drain source area to <1% in the outer estuary and estimates of likely adverse effects (i.e. based on EC50 data) varied from 78% to 0%. The ERA represents a ‘best practice’ ecological risk assessment of contamination of an estuary using site-specific probabilistic elements for toxicity and exposure assessments. The VCHs identified in surface water in Penrhyn Estuary are additive in toxicity and act under the narcotic pathway, inhibiting cellular processes through interference with membrane integrity. Lethal toxicity to 50% of organisms (i.e. LC50) is typically reported at the internal lethal concentration (ILC) or critical body residue (CBR) of ~2.5 mmol/kg wet weight or within the range of 1 to 10 mmol/kg wet weight. To evaluate the sensitivity of the test organisms to VCHs and to determine if toxicity in the DTA was due to VCHs, the internal residue for 6 test organisms was calculated for the mixture of VCHs in groundwater and toxicity testing with seawater spiked individually 2 VCHs, chloroform and 1,2-dichloroethane. Calculated residues (at LC50/EC50) were typically between 1 and 10 mmol/kg, with the exception of the algal and sea urchin toxicity tests, which were considerably lower than the expected minimum. Mean internal residues for the groundwater, chloroform and 1,2-dichloroethane were 0.88 mmol/kg, 2.84 mmol/kg and 2.32 mmol/kg, respectively, i.e. close to the predicted value of ~2.5 mmol/kg, indicating that the organisms were suitably sensitive to VCHs. There was no significant difference (P>0.05) between the mean residues of each of the three treatments and the study concluded that the additive toxicity of the VCHs in groundwater was sufficient to account for the observed toxicity (i.e. VCHs caused the toxicity in the DTA undertaken). Evaluation of the existing low reliability ANZECC and ARMCANZ (2000) TVs for chloroform and 1,2-dichloroethane was undertaken to determine if these guidelines were protective of indigenous marine organisms. NOECs, derived from toxicity testing of 1,2- dichloroethane and chloroform with 6 indigenous marine organisms, were screened against the existing low reliability TVs. The TVs for 1,2-dichloroethane and chloroform were protective of 4 of the 6 species tested (A.compressa, D.dentata, S.commercialis and M.novemaculeata), however, the TVs were not protective of the alga (N.closterium) or the sea urchin larvae (H.tuberculata). As the existing TVs were not considered to be adequately protective, SSDs were derived using the NOEC data generated from the testing in accordance with procedures outlined in ANZECC and ARMCANZ (2000). Moderate reliability TVs of 3 μg/L and 165 μg/L were derived for chloroform and 1,2- dichloroethane, respectively, i.e. considerably lower than the existing TVs of 770 μg/L and 1900 μg/L. Differences between the existing and newly derived TVs were considered to result from the sensitive endpoints selected (i.e. growth and larval development rather than survival) and from variability inherent when deriving SSDs using a small number of test species. Ongoing groundwater monitoring indicated that the plumes of VCHs in groundwater, identified in the 1990s, were continuing to migrate towards Botany Bay. Discharge of these groundwater plumes into Botany Bay would result in significant increases in the concentrations of VCHs in the receiving environment and would likely lead to significant environmental impacts. In 2006, a groundwater remediation system was commissioned to prevent the discharge of groundwater containing VCHs into Penrhyn Estuary and Botany Bay. The success of the project had only been measured according to chemical and engineering objectives. Assessment of changes in ecological risk is vital to the success of ERA and central to the ERA management framework. Whereas monitoring of chemical concentrations provides qualitative information that risk should decrease, it cannot quantify the reduction in ecological risk. To assess the ecological risk following implementation of the groundwater treatment system, the risk assessment was revised using surface water monitoring data collected during 2007 and 2008. The ERA indicated that, following remediation of the groundwater, ecological risk in Penrhyn Estuary reduced from a maximum of 35% prior to remediation, to a maximum of only 1.3% after remediation. Using the same methodology applied in the initial risk assessment, the success of the groundwater remediation was measured in terms of ecological risk, rather than engineering or chemical measures of success. Prior to the present investigation, existing techniques for assessing ecological risk of VCH contamination in aquatic ecosystems were inadequate to characterise ecological risk. The current study demonstrated that through monitoring of surface water at the site and DTA using indigenous marine organisms, ecological risk can be assessed using site-specific, quantitative techniques for a complex mixture of VCHs in groundwater. The present investigation also identified that existing ANZECC and ARMCANZ (2000) low reliability TVs were less protective of indigenous test organisms than previously thought and therefore, new TVs were derived in the current work. The present study showed that revision of the risk assessment as conditions change is crucial to the success of the ecological risk management framework.

Permeable reactive barriers (PRBs) are one of the leading technologies being developed in the search for alternatives to the pump-and-treat method for the remediation of contaminated groundwater. A new optimising design methodology is proposed to aid decision-makers in finding minimum cost PRB designs for remediation problems in the presence of input uncertainty. The unique aspects of the proposed methodology are considered to be: design enhancements to improve the hydraulic performance of PRB systems; elimination of a time-consuming simulation model by determination of approximating functions relating design variables and performance measures for fully penetrating PRB systems; a versatile, spreadsheet-based optimisation model that locates minimum cost PRB designs using Excel's standard non-linear solver; and the incorporation of realistic input variability and uncertainty into the optimisation process via sensitivity analysis, scenario analysis and factorial analysis. The design methodology is developed in the context of the remediation of nitrate contamination due to current concerns with nitrate in New Zealand. Three-dimensional computer modelling identified significant variation in capture and residence time, caused by up-gradient funnels and/or a gate hydraulic conductivity that is significantly different from the surrounding aquifer. The unique design enhancements to control this variation are considered to be the customised down-gradient gate face and emplacement of funnels and side walls deeper than the gate. The use of velocity equalisation walls and manipulation of a PRB's hydraulic conductivity within certain bounds were also found to provide some control over variation in capture and residence time. Accurate functional relationships between PRB design variables and PRB performance measures were shown to be achievable for fully penetrating systems. The chosen design variables were gate length, gate width, funnel width and the reactive material proportion. The chosen performance measures were edge residence, centreline residence and capture width. A method for laboratory characterisation of reactive and non-reactive material combinations was shown to produce data points that could realistically be part of smooth polynomial interpolation functions. The use of smooth approximating functions to characterise PRB inputs and determine PRB performance enabled the creation of an efficient spreadsheet model that ran more quickly and accurately with Excel's standard non-linear solver than with the LGO global solver or Evolver genetic-algorithm based solver. The PRB optimisation model will run on a standard computer and only takes a couple of minutes per optimisation run. Significant variation is expected in inputs to PRB design, particularly in aquifer and plume characteristics. Not all of this variation is quantifiable without significant expenditure. Stochastic models that include parameter variability have historically been difficult to apply to realistic remediation design due to their size and complexity. Scenario and factorial analysis are proposed as an efficient alternative for quantifying the effects of input variability on optimal PRB design. Scenario analysis is especially recommended when high quality input information is available and variation is not expected in many input parameters. Factorial analysis is recommended for most other situations as it separates out the effects of multiple input parameters at multiple levels without an excessive number of experimental runs.

Concentrations of heavy metals (Cu, Cd, Cr, Zn, Mn, Fe and Pb) in the water columns, aquatic plants and sediments of fourteen lakes of varied levels of pollution were measured. Correlation analysis was carried out between heavy metal concentrations in aquatic plants and heavy metal concentrations in water and sediment. The aquatic plants which accumulated heavy metals in their tissues in proportion to that in water and sediments were identified. The aquatic plants studied were: 8/yxa auberti Rich, Cabomba caroliniana Gray, Ceratophyllum demersum L, Ceratopteris thalictroides (L.) Bron, Chara globularis, Eichhornia crassipes Solmn, Hydrilla verticillata Royle, Ipomoea aquatica Forsk, Limnophila aromatica (Lam.) Merr., Ludwigia adscendens (L) Hara, Nelumbo nucifera Gaertn, Nymphaea stallata Linn, Nymphoides indica (L.) Kuntze, Typha angustata Bony & Chaub and Utricularia aurea Lour. Metal uptake by aquatic plants varied between different species and within the same species depending on lake water contamination levels. The level of metal uptake to a great extent was a function of the environment water metal concentration. Results showed that Utricularia accumulated Mn, Zn, Cr, Cd and Pb in direct proportion to the overlying waters (r2 = 0.69, 0.63, 0.69, 0.65 and 0.39 respectively). Hydrilla accumulated Cu, Mn, Zn, Fe, Cr, Cd and Pb in direct proportion to the overlying waters (r2 = 0.65, 0.66, 0.44, 0.72, 0.38, 0.63, and 0.73 respectively). Blyxa leaves accumulated Zn, Fe, Cr, Cd and Pb in direct proportion to the overlying waters (r2 = 0.74, 0.74, 0.72, 0.60 and 0.82 respectively). Echhornia leaf accumulated only Cr in direct proportion to the overlying waters r2 = 0.81. Nymphaea leaf and Chara did not accumulate any metal in direct proportion to the overlying waters. Roots of Blyxa auberti, Ceratopteris thalictroides, and Eichhornia crassipes contained higher concentrations of heavy metals than their leaves. Roots of Blyxa accumulated Cr, Cd and Pb in direct proportion to the overlying waters (r2 = 0.91, 0.65 and 0.69 respectively). Echhornia root accumulated Cd in direct proportion to the overlying waters with r2 = 0.90. Nymphaea stem showed no significant correlations between the metal concentrations in the waters and in the plant. Utricularia accumulated Zn, Fe, Cr, Cd and Pb in direct proportion to the metals in the underlying sediment extracted by cold hydrochloric acid (r2 = 0.84, 0.51, 0.47, 0.68 and 0.80 respectively). Hydrilla accumulated Cu, Zn, Cr, Cd and Pb in direct proportion to the underlying sediment (r2 = 0.34, 0.37, 0.91, 0.49 and 0.96 respectively). Blyxa accumulated Zn, Fe, Cr, Cd and Pb in direct proportion to the underlying sediments (r2 = 0.99, 0.61, 0.82, 0.75 and 0.64 respectively) . Echhornia leaf showed significant correlation between the Cu (r2 = 0.83) and Cr (i2 = 0.88) concentration in underlying sediment and the plant. Nymphaea leaf showed a significant correlation between the Zn (r2 = 0.83) concentration in the plant and the underlying sediments. Roots of Blyxa showed significant correlation between concentrations of Cu, Cr and Pb in sediment extracted by hydrochloric acid and plant (r2 = 0.9, 0.7 and 0.9 respectively). Roots of Echhornia had no significant correlation with the sediment metal concentrations (hydrochloric acid extractable). Two techniques (cold hydrochloric acid extractable and nitric acid extractable) to extract metals from sediment were compared. Based on correlations of metal concentrations in plant tissue and metal extracted from the sediment, it was concluded that the cold hydrochloric acid extractable metal technique is more suitable for determining bioavailable sediment metal concentration in environmental studies. Laboratory studies investigations on the bioaccumulation of Zn and Cu in Hydrilla confirmed that Hydrilla is a good bioindicator of Cu as it accumulated 20360 ug/g dry weight of Cu in 72 hours. Hydrilla showed higher bioaccumulation factor with low concentration of Cu in the solution, in the laboratory studies. Hydrilla was determined to be the best indicator species as it reflected the heavy metal concentration in the environment which was supported by the laboratory studies.

The Multi-Agency Radiation Survey and Site Investigation Manual (MARSSIM) requires that Final Status Surveys be performed on materials and surfaces that vary in surface smoothness and/or uniformity. To obtain accurate survey data, it may be necessary to adjust detector response for these surface variations. NUREG-1507 refers to such surface efficiency adjustment factors as ��[subscript s], the source efficiency. This parameter is meant to be a detector-independent, yet surface and nuclide-dependent parameter that can be used to adjust observed count rate to provide a true measure of the degree of contamination present. Key measurements in the calculation of (��[subscript s]) are the energy of the radionuclide contaminant and the average height of the detector above the contaminated surface. During the last year, Oregon State University, Department of Nuclear Engineering and Radiation Health Physics provided technical support for a Final Status Survey of a commercial nuclear plant. OSU NE/RHP has conducted research and experimentation to determine site-specific source efficiency (��[subscript s]) values for concrete surfaces which had undergone simulated decommissioning activities, such as surface scabbling. Source efficiency (��[subscript s]) values were determined for seven separate scabbled concrete surfaces which had been prepared using 5 tool types. Fourteen concrete cores were intentionally contaminated with known amounts of two beta emitting radionuclides: ��������Tl and ������Tc. The ��[subscript s] values were examined as a function of the type of scabbled surface as well as the contaminating nuclide. / Graduation date: 2003

Nisin is an antibacterial peptide, which when adsorbed on a surface can inhibit bacterial adhesion and viability. The ability of noncovalently immobilized nisin to withstand exchange by the milk proteins bovine serum albumin, ��-lactoglobulin, ��-lactalbumin, and ��-casein on surfaces that had been silanized with dichlorodiethylsilane to exhibit high and low hydrophobicities was examined using in situ ellipsometry. Kinetic behavior was recorded for nisin adsorption for 1h and 8h, followed in each case by rinsing in protein-free buffer solution, and sequential contact with a single milk protein for 4h. Concerning nisin adsorption to each surface, a higher adsorbed mass was consistently recorded on the hydrophilic relative to the hydrophobic surface, independent of adsorption time. While desorption was greater from the hydrophilic surface in the 1h test, the amount desorbed was quite similar on each surface in the 8h tests. The sequential data were consistent with the assumptions that nisin organization at the interface involved adsorption in at least two different states, possibly existing in more than one layer, and that in the absence of exchange, upon addition of the second protein adsorbed mass would increase by an amount equivalent to its experimentally observed monolayer coverage. The Mass of nisin exchanged was generally higher on the hydrophobic compared to the hydrophilic surface presumably because of the presence of a more diffuse outer layer in the former case. ��-casein was the most effective eluting agent among the proteins studied, while ��-lactalbumin was the least effective, apparently adsorbing onto the nisin layers with little exchange. Both bovine serum albumin and ��-lactoglobulin were moderately effective in exchanging with adsorbed nisin, with the amount of nisin removed by bovine serum albumin being more substantial, possibly due to its greater flexibility. / Graduation date: 1995

Thesis (M. Sc.)(Microbiology)--University of Pretoria, 2005. / Includes summary. Includes bibliographical references. Available on the Internet via the World Wide Web.

Au Sénégal, dans les zones maraîchère (zone des « Niayes ») et cotonnière, le traitement des cultures se fait respectivement avec des pulvérisateurs à dos et avec des cannes centrifuges. Des enquêtes ont été réalisées sur le terrain et un ensemble de paramètres comme le temps dapplication et de rinçage, les surfaces traitées, les volumes appliqués, la température et la vitesse du vent, ont été mesurés pour analyser les facteurs de risque encourus par les opérateurs. Lanalyse statistique des résultats montre que les risques de contamination des opérateurs sont importants. En effet, en se référant à la classification établie par lOMS, plusieurs produits sont classés hautement dangereux. Le faible niveau de formation des opérateurs ne leur permet pas de prendre connaissance des informations concernant lutilisation correcte des produits. Les techniques dapplication sont insuffisamment maîtrisées, lapplication nest pas réalisée au moment où les conditions climatiques sont les plus favorables et les opérateurs travaillent sans aucune protection. Des mesures dexposition simulant les conditions de travail rencontrées en régions maraîchère et cotonnière ont été effectuées dans un tunnel aérodynamique. Quil sagisse du pulvérisateur à dos ou de la canne centrifuge, la position qui expose le moins lopérateur est la position latérale par rapport au vent. Avec le pulvérisateur à dos, la contamination se produit essentiellement au niveau des tibias, tandis quavec la canne centrifuge, la contamination est généralisée à lensemble des parties corporelles. La présence de végétation augmente lexposition par rapport à la pulvérisation sur sol nu. Ces mesures permettent dune part de proposer un équipement de protection adapté en fonction du type de pulvérisation réalisée et dautre part destimer lexposition spécifique dermique de lopérateur pendant lapplication des pesticides. Synthétisant les mesures de terrain et celles réalisées en tunnel aérodynamique, un modèle estimant lexposition du corps par voie dermique pendant la phase dapplication est proposé pour le Sénégal. Il se base sur les principes généraux de calcul dexposition adoptés dans les modèles déterministes européens. Partant de ce modèle, les doses moyennes absorbées sont estimées à 1,40 et 19,64 mg de substance active par personne et par jour, respectivement avec un pulvérisateur à dos et une canne centrifuge. Avec un équipement de protection individuelle, lestimation conduit à des valeurs dix fois plus faibles.

Bacteria are the major cause of surface water contamination in the United States. US Environmental Protection Agency (USEPA) uses the Total Maximum Daily Load (TMDL) process to regulate the E. coli loads from fecal sources in a watershed. Different point and non-point sources can contribute to the fecal contamination of a waterbody including municipal and on-site wastewater treatment plants, livestock, birds, and wildlife. Unfortunately, wildlife sources in many rural watersheds are poorly characterized. E. coli is also known to persist in waterbodies when no known fecal sources are present. In this study, E. coli from wildlife fecal material was enumerated. It was found that E. coli concentrations varied with the season the fecal samples were collected. When studying the fate of E. coli under different environmental factors, no growth was observed in soil at 4% moisture content and in water at 10 degrees C. The highest E. coli growth was recorded in water at 30 degrees C. It can be seen from these results that there was variation in the fate of E. coli under different environmental conditions. The fate of E. coli in the environment is a complex process and is influenced by many factors and their interactions, making it difficult to predict. The findings from this study along with additional studies can be used to improve the accuracy of model predictions to estimate the E. coli loads in watersheds.

The unprecedented acts of brutality, persecution, and genocide perpetrated in the Second World War caused ruptures within language, creating a need for both individual and collective re-definitions of love, privacy, truth, and survival. In recent years, there has been a resurgence of Second World War fiction in both Canada and abroad, which suggests a need among contemporary authors to analyse and to understand retrospectively the way World War II has influenced current political and racial divisions. By looking specifically at the romantic relationships depicted in The Ash Garden, The English Patient, and The Walnut Tree, three Canadian World War II novels all written approximately fifty years after the war, this thesis not only examines the question of what is necessary for survival and how the public world of war either enables or inhibits individual survival, but also isolates how race, gender, and the public world influence the characters ability to endure in reciprocal love.

The unprecedented acts of brutality, persecution, and genocide perpetrated in the Second World War caused ruptures within language, creating a need for both individual and collective re-definitions of love, privacy, truth, and survival. In recent years, there has been a resurgence of Second World War fiction in both Canada and abroad, which suggests a need among contemporary authors to analyse and to understand retrospectively the way World War II has influenced current political and racial divisions. By looking specifically at the romantic relationships depicted in The Ash Garden, The English Patient, and The Walnut Tree, three Canadian World War II novels all written approximately fifty years after the war, this thesis not only examines the question of what is necessary for survival and how the public world of war either enables or inhibits individual survival, but also isolates how race, gender, and the public world influence the characters ability to endure in reciprocal love.