Toxicity of nano-scaled Al2O3, SiO2, TiO2 and ZnO to bacteria (Bacillus subtilis, Escherichia coli and Pseudomonas fluorescens) was examined and compared to that of their respective bulk (micro-scaled) counterparts. All nanoparticles (NPs) but TiO2 showed higher toxicity than their bulk counterparts. Toxicity of released metal ions was differentiated from that of the oxide particles. ZnO was the most toxic among the three NPs, causing 100% mortality to the three tested bacteria. TEM images showed attachment of NPs to the bacteria, suggesting that the toxicity was affected by bacterial attachment. The effects of oxide NPs on bacteria cells and bacterial surface biomolecules were studied by FTIR spectroscopy to provide a better understanding of their cytotoxicity. Lipopolysaccharide (LPS) and lipoteichoic acid could bind to oxide NPs through hydrogen bonding and ligand exchange, but the cytotoxicity of NPs seemed largely related to the function-involved or structural changes to proteins and phospholipids. The three NPs decreased the intensity ratio of β-sheets/α-helices, indicating protein structure change, which may affect cell physiological activities. The phosphodiester bond of L-α-Phosphatidyl-ethanolamine (PE) was broken by ZnO NPs, forming phosphate monoesters and resulting in the highly disordered alkyl chain. Such damage to phospholipid molecular structure may lead to membrane rupture and cell leaking, which is consistent with the fact that ZnO is the most toxic of the three NPs. LPS and PE are amphiphilic biomolecules that are major constituents of the outer membrane of Gram-negative bacteria. Their micelles and vesicles were studied as model cell membranes to evaluate NP effects on membrane construction. The adsorption of polysaccharides on Al2O3 and TiO 2 NPs dispersed LPS vesicles and micelles. LPS coated Al2O 3 NPs, while it caused the aggregation of TiO2 NPs according to atom force microscopy images. Desorption from the two NPs was slow due to the firm hydrogen bonding. For PE, Al2O3 NPs induced large multilamillar vesicles, while ZnO NP converted vesicles to tiny aggregates due to molecular structure breakup. PE stability in solution was disturbed by adding NPs, but its stability was enhanced by increasing pH. The electrostatic force was the determining factor for the vesicle stability.

As a result of a water chemistry survey at Whetstone Brook in western Massachusetts, during an acid mitigation study using a limestone doser, unusually high levels of aluminum were found in sediment pore waters with an overlying layer of limestone. Because of potential fish and biotic toxicity and the problems associated with commonly used speciation techniques for aluminum, a more comprehensive scheme was proposed including aluminum determination by optimized methods of GFAAS, cation exchange on a strong acid resin, and ultrafiltration at 0.5 kd, 1 kd, 3 kd and 10 kd MW cut-offs. The method of chemical extraction into MIBK following chelation by 8-HQ was also evaluated and all the experimental results were compared to a theoretical speciation using equilibrium calculations. No experimental conditions were found that could extract a consistent fraction with all the model organic ligands for the 8-HQ extraction procedure. Recoveries ranged from 10% to 200% of the organically bound aluminum relative to inorganic standards. Cation-exchangeable aluminum, complexed with malonate, oxalate, phthalate and salicylate, matched a theoretical speciation to within 5%. Theoretical and experimental results for citrate complexed aluminum differed by 24%. Ultrafiltrate experiments indicated that size fractionation may add more information about the aggregation of aluminum-organic monomers into higher MW oligomers and polymers. In all the synthetic systems studied there appears to be aggregation at lower MW values and the citrate, phthalate and salicylate complexes have fractions greater than 10 kd. Experiments with fulvic acid showed that approximately 80% of the aluminum complexed species were noncationic. Greater than 90% of the aluminum-fulvate was recovered in the MW range above 10 kd. Comparisons with stability constants in the literature showed that none of the available constants could predict the behavior of the citrate system and although constants were found that could predict the fulvate system, the majority could not.

Flow injection and liquid chromatographic sample introduction techniques have been coupled to inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma optical emission spectrometry (ICP-OES). The analytical performances of these combinations have been evaluated. Several applications have also been developed. The fundamental FI parameter, response dispersion coefficient (D$\rm\sb{r}),$ has been studied for various elements with FI-ICP-MS in multi-element detection mode. Some interesting phenomena were observed and possible explanations have been made. A recirculating loop FI manifold which provides on-line successive dilutions has been coupled to ICP-MS. The analytical performance of the manifold was evaluated. The dilution behavior of various elements was examined. The manifold was successfully applied to the recovery study of cerium in wine. Factors affecting the speed of the dilution process were also investigated. High performance liquid chromatography including ion exchange chromatography (IC) and reverse phase liquid chromatography have also been coupled to ICP-MS for selenium speciation in selenium-enriched vegetables. The methods developed efficiently identified and semi-quantified several biologically important selenium species. The advantages and disadvantages of these methods were addressed as well. Flow injection sample introduction has also been coupled to an axially viewed ICP-OES with a segmented - array charge - coupled device detector. Various traditional pneumatic nebulizer-spray chamber systems have been examined. The best nebulizer-spray chamber combination has been identified for FI-ICP-OES. Some experiments and data treatments have been conducted under the guidance of simulation in order to achieve better analytical figures of merit.

Protection of the environment is among the most pressing public policy challenges and will continue to be so long into the future. Pollution, specifically, has played a pivotal and substantial role in the degradation of the environment. Although numerous analytical techniques and computational solutions have been proposed by theoreticians from disciplines as varied as economics to environmental engineering and decision sciences, significant methodologies that provide a rigorous analysis for the modeling, qualitative analysis, and computation to solutions to environmental problems which are typically complex and large-scale remain yet to be harnessed. The goal of this dissertation is to present a series of models in marketable pollution permits that yield the profit-maximized quantities of the firms' products and the equilibrium quantities of the firms' emissions. In addition, the equilibrium allocation of pollution licenses and their prices are obtained. Furthermore, different modes of market structure, including oligopolistic behavior and non-compliant behavior, and market imperfections such as transactions costs are incorporated into the modeling framework. Investment in technology, specifically production technology and emission-abatement technology, are explicitly considered in the models. Lastly, the dissertation concludes with a shift from the static setting to a dynamic setting and the marketable pollution permit model is analyzed within a dynamic framework that allows firms to be noncompliant. The dissertation begins with a brief historical overview of the evolution of environmental economics followed by the theoretical foundations of the mathematical framework employed. The principal methodology that is utilized for the models in the dissertation is that of variational inequalities. We will also make use of the projected dynamical systems to analyze the models within a dynamic setting. We conclude this dissertation with possible extensions of the models developed and provide suggestions for future research. The dissertation is a major step in the advancement of mathematical methodologies coupled with environmental policy analysis to contribute fundamentally to the formulation and evaluation of environment policy. This research is highly interdisciplinary as it encompasses the fields of management science and operations research, environmental economics, and applied mathematics.

The herbicide alachlor is one of the most widely used pesticides in the world; over 52 million pounds are applied to U.S. croplands annually. The acetanilide compounds 2-chloro-2$\sp\prime,6\sp\prime$-diethylacetanilide (CDA) and 2-hydroxy-2$\sp\prime,6\sp\prime$-diethylacetanilide (HDA) are environmental degradative products of alachlor. CDA, HDA and alachlor are ground and surface water contaminants; CDA and HDA are mutagenic in the Salmonella/microsome assay. There is a paucity of data on the environmental fate of CDA and HDA. The development of two competitive enzyme-linked immunosorbent assays (cELISA) for the detection of CDA and HDA is reported. cELISA3 is specific for CDA with a detection range of 0.015 to 10 $\mu$g/ml. Solid phase extraction of CDA residues from aqueous samples gives a 1000-fold concentration factor resulting in an effective detection limit of 15 pg/ml. cELISA4 is specific for both CDA and HDA in combination, with a detection range of 0.01 to 10 $\mu$g/ml. Solid phase extraction of aqueous samples prior to cELISA analysis results in an effective detection limit of 10 pg/ml. Chloroacetanilide herbicides and other alachlor metabolites that may be present in environmental samples do not interfere with the detection of CDA and HDA. cELISA3, cELISA4 and the antisera they are based on provide a means of studying the environmental fate of CDA and HDA through a variety of analytical strategies.

Using controlled-release technology, a prototype novel biodegradable sphere, which is used for controlling apple maggot fly, Rhagoletis pomonella (Walsh), designed for long-lasting residual effectiveness of feeding stimulant and insecticide has been created. The sphere body consists of 42–50% sugar entrapped in a mixture of gelatinized corn flour and wheat flour in the presence of glycerin, and coated with a layer of latex paint containing insecticide. The sphere body serves as a slow-release sugar reservoir. First, the lethal and sublethal toxicity and the effects of tree sprays of the new insecticide imidacloprid on apple maggot flies were investigated. Females tested in the laboratory showed great mortality and reduced fecundity regardless of whether exposure was by oral or by surface contact. However, foliar sprays resulted neither in significant mortality nor reduced fecundity over a 7-day period. Secondly, technical-grade or formulated insecticides were incorporated in sphere coating mixtures and evaluated for acute toxicity and residual effectiveness in laboratory, semi-field and field experiments. Results indicated that imidacloprid is a promising substitute for dimethoate as a fly killing agent on spheres. A wettable powder formulation of imidacloprid (Merit) proved better than a flowable formulation (Provado) in terms of residual efficacy. Females feeding on imidacloprid-treated spheres exhibited very little tendency to forage within host plants or to lay eggs before dying, compared with females tested on dimethoate-treated spheres and control spheres. The sucrose pH shown to stimulate maximal feeding response was 6.4, with little feeding occurring at pH values of 5.0 or less and 8.0 or greater. Males were more responsive to varying pH than females. Such information is relevant to formulation improvements of coating mixtures of sucrose and insecticide applied to lethal spheres as part of tephritid fly control programs. (Abstract shortened by UMI.)

The traditional approach to U.S. environmental policy has been to regulate emissions to air, land and water separately. Recognizing that efforts to enforce medium-specific environmental regulations are also medium-specific, we hypothesize that the enforcement of regulations pertaining to one environment medium may cause polluters to alter their releases to other media. This dissertation examines the impacts of the enforcement of air and water regulations faced by the U.S. pulp industry on their toxic chemical releases to air and water pathways and the human-health risks associated with these releases. The results suggest that pulp facilities respond to a greater number of inspections for compliance to air regulations by reducing their TRI emissions to water pathways. On the other hand, these firms seem to respond to a greater number of inspections for water regulation compliance and efforts taken against violators of water regulations by increasing their toxic chemical releases to air pathways. Using the EPA's Risk-Screening Environmental Indicators Model enforcement-induced cross-media transfers of human-health risks from air and water releases of toxic chemicals are also examined. This study finds that cross-media risk impacts can differ substantially from cross-media release impacts. Additionally, TRI release trends and their associated human-health risks are examined for the U.S. pulp industry between 1988 and 1997. This analysis finds that while combined air and water releases did not change much during the decade, the overall risk impact of these releases declined by more than 70%. The results suggest that setting environmental goals that focus solely on reducing the volume of toxic releases may produce unfortunate outcomes. This work also presents a theoretical model of firm behavior. The factors that determine whether a firm responds to a tighter control on its emissions into one medium by increasing or decreasing its emissions into another are derived; that is, whether emissions into two media can be characterized as substitutes or as complements. The analysis finds that characterizing cross-media transfers depends in large part on how the marginal costs of controlling releases into one medium are affected by a change in releases to another medium.

The prevalence of allergic disease is expected to increase with climate change. Grasses, which have highly allergenic pollen, are widely distributed across the globe. Changes in production and allergen content of grass pollen have not been specifically investigated. We tested the effects of elevated carbon dioxide and ozone on growth, pollen and allergen production of Timothy grass (Phleum pratense L.). Timothy is also used as an agricultural forage crop so changes in plant productivity can also affect humans indirectly. Plants were fumigated in eight chambers at two concentrations of ozone (O 3; 30 and 80 ppb) and carbon dioxide (CO2; 400 and 800 ppm) to simulate present and future projected levels. Destructive harvests were completed every three weeks to measure productivity. Pollen was collected in polyethylene bags placed around flowers and assessed for pollen number and concentration of the allergenic protein, Phl p 5. We found that elevated CO2 significantly increased the amount of pollen produced per flower regardless of O3 level. In addition, the amount of Phl p 5 allergen per flower was significantly increased in plants grown at elevated CO 2 / low O3 conditions. We also found that plants grown in both elevated CO2 and elevated O3 increased the amount of pollen produced per weight of flower. The Phl p 5 allergen content per pollen grain was significantly reduced by elevated O3, as was flower length and weight. However, this was partially ameliorated by elevated CO 2. Productivity was affected negatively by elevated O3 throughout the life cycle. CO2 increased shoot productivity during the intermediate stages of life and also ameliorated the negative impacts of elevated O 3. We conclude that increasing levels of CO2 will cause a 2.5 times increase in Timothy grass pollen production thus increasing human airborne pollen exposure. Increases in pollen were likely a result of increased shoot biomass in the stages leading up to reproduction. If Timothy grass is a good model for other grasses, this portends for increased allergy suffering worldwide and an important health impact of global climate change.

Incorporation of organic fertilizers/amendments on turfgrass management has been, and continues to be, a popular strategy of integrated pest management (IPM) program to reduce environmental impacts by pesticide and nitrate leaching. Most of the research on organic fertilizers for the turfgrass industry has focused upon disease suppression, improving soil physical, chemical and biological properties, and the fertility effect on high-cut turfgrass. However, little information has been reported on the response of highly maintained golf turfgrass, such as common on golf courses. The current research studied the effects of organic fertilizer as a sole source on turfgrass performance on highly maintained golf turf and its short-term effects on total soil microbial dynamics on different soil profiles. In addition, environmental impact by organic fertilizer derived dissolved organic matter (DOM) on pesticide sorption and transport in soil was also investigated. Four natural organic fertilizers were evaluated in this study which includes Milorganite (6-2-0), NatureSafe (8-3-5) and SoylMicrobial (F as flowable and G as granular, 14-1-1) and one synthetic organic fertilizer Scotts (29-3-4). In soil microbial dynamics study, application of all natural organic fertilizers increased soil bacterial populations within 4 days after fertilizer treatment (DAT) while little or no effect with the synthetic organic fertilizer was observed on all three soil profiles for the growth chamber experiment. Similar results were observed for the 2 year field trials, however, only the SoylMicrobial (F) fertilizer treatment increased total bacterial populations at 2nd and 4th DAT. In turfgrass response under organic fertilizer application experiment, weekly applications increased clipping an average of 43% compared with bi-weekly applications. Overall, native soils provided higher clipping yields than USGA sand and mixed soil profiles. SoylMicrobial provided sufficient N for acceptable turfgrass growth and Milorganite was ineffective as a sole turfgrass fertilizer. These results suggested that selected natural organic fertilizers can be used as a sole source for turfgrass fertility and the application rates and frequencies need to be adjusted for the different soil profiles. Batch equilibrium techniques were used to evaluate relative effects of organic fertilizer-derived DOM on sorption transport of three organic chemicals (2,4-D, naphthalene and chlorpyrifos) in soils. Sorption capacity was significantly reduced with additional DOM in solution for all three chemicals. The higher the concentration of DOC in solution, the more sorption was reduced. Column experiment results were consistent with batch equilibrium results suggesting that organic fertilizer-derived DOM might lead to enhanced transport of applied chemicals in soil. Results also suggested that organic fertilizers should not be applied on turf directly after pesticide application, which would reduce the impact of organic fertilizer-DOM facilitated transport of applied pesticides.

Includes bibliographical references / Changes in precipitation extremes are projected by many global climate models as a response to greenhouse gas increases, and such changes will have significant environmental and social impacts. These impacts are a function of exposure and vulnerability. Hence there is critical need to understand the nature of weather and climate extremes. Results from an ensemble of regional climate models from the Coordinated Regional Downscaling Experiment (CORDEX) project are used to investigate projected changes in extreme precipitation characteristics over southern Africa for the middle (2036-2065) and late century (2069-2098) under the representative concentration pathway 4.5 (RCP4.5) and 8.5 (RCP8.5). Two approaches are followed to identify and analyze extreme precipitation events. First, indices for extreme events, which capture moderate extreme events, are calculated on the basis of model data and are compared with indices from two observational gridded datasets at annual basis. The second approach is based on extreme value theory. Here, the Generalized Extreme Value distribution (GEV) is fitted to annual maxima precipitation by a L-moments method. The 20-year return values are analyzed for present and future climate conditions. The physical drivers of the projected change are evaluated by examining the models ability to simulate circulation patterns over the regions with the aid of Self-Organizing Maps (SOM).