Bioremediation is becoming a widely accepted solution for cleaning up contaminated sediment, water, and soil. The associated microbial, chemical, and geologic principles are still in their relative infancy compared to other common remediation strategies. The list of contaminants that are susceptible to biotransformation has grown to encompass metals as well as organic compounds. The goal of this research was to develop anaerobic bioremediation strategies for two compounds—the fuel oxygenate methyl tert-butyl ether (MTBE) and the heavy metal uranium. The potential for anaerobic degradation of MTBE as well as its metabolite tert-butyl alcohol (TBA) was tested in aquifer and freshwater aquatic sediment. Aquifer sediment amended with Fe (III) oxide plus the electron shuttling compound humic acid degraded 50 mg/l MTBE to levels below detection. The humic acid analog anthraquinone-2,6-disulfonate (AQDS) also stimulated MTBE degradation. Aquifer sediment without Fe (III) plus the electron shuttle did not degrade MTBE. Freshwater aquatic sediment converted uniformly labeled [14C]-MTBE to 14CO2 and over time. Adding Fe (III) and electron shuttling compounds did not significantly increase the rate and extent of MTBE mineralization. TBA was also rapidly degraded in the aquatic sediment in the absence of any amendments. Both 14CO2 and 14CH4 were produced when sediments were incubated with uniformly labeled [14C]-TBA. Microbial U(VI) reduction was stimulated in uranium-contaminated aquifer sediment upon the addition of acetate. U(VI) reduction was concurrent with Fe (III) reduction and preceded sulfate reduction. In sediments that also contained nitrate, nitrate first had to be completely reduced prior to the onset of U(VI) reduction. U(VI) reduction was solely a biological process; abiotic interaction with Fe (II), sulfide, or electron shuttles did not affect U(VI) in solution. Nitrate added to sediment that contained microbially reduced U(VI) re-oxidized U(IV) to U(VI) and Fe (II) to Fe (III). Over 80% of the initial reduced U(IV) was recovered as U(VI). Pure culture studies with Geobacter metallireducens confirmed that the most likely mechanism was biological oxidation of Fe (II) to Fe (III) with abiotic U(IV) oxidation via Fe (III) produced. Finally, two novel Fe (III)-reducing bacterial species were isolated from these sediments—Desulfitobacterium metallireducens and Geoferax ferrireducens.

Explosive volcanism can release large amounts of particles and gases into the atmosphere. Sulfuric acid droplets in the lower stratosphere are the primary substance interacting with the radiative fluxes over many months and possibly years. Because of their sub-micron size, they are more efficient at scattering incoming shortwave radiation from the sun back into space than absorbing and trapping longwave radiation from the earth. This results in a negative impact on the earth energy balance causing a general cooling below the aerosol layer. The magnitude of the cooling depends mostly on the amount of radiatively active aerosol particles as well as the duration of the perturbation. The cooling signal is largest in the upper troposphere through feedbacks with a slowed hydrologic cycle. At the surface, heat release, mostly from the oceans, can buffer some of the cooling. A combined approach using both observations/proxy data and a state-of-the-art coupled General Circulation Model (GCM) to analyze the volcanic effects on climate can help in our understanding of the possible range of responses. Here, the most recent large eruption of Mt. Pinatubo (June 1991) was used to verify the implementation of the aerosol parameterization in the radiation code of the GCM. From there, an analysis of the volcanic contribution since 1870 A.D. was performed. A simple way of describing the spatial aerosol distribution is presented. In general, only a handful of eruptions were found large enough to significantly perturb the radiative balance of the earth. These few events caused a global climate signal, which is clearly detectable against the background noise of internal variability of the climate system. Next to the influence of isolated events, model simulations confirm earlier suggestions that temporally closely spaced large events can cause a further cooling in climate before the system can recover. Thus, explosive volcanism must be regarded as an important player in decadal to multi-decadal natural climate variations. In case of the 20th-Century, volcanic cooling in the last decades could have offset any possible warming due to increased solar irradiation. The potential volcanic role in other important time periods in the past must be studied, including the cooling in decades generally solely attributed to the sun. Proxy records, in particular tree rings, point to a potentially large role of explosive volcanism in the past. Additionally to the radiative effects, increased atmospheric flow at high latitudes, particularly in winter, is the result of dynamical responses to changes in meridional temperature gradients in the lower stratosphere through heating in the aerosol layer. This effect helps to orchestrate the spatial distribution of the climate signal for several years after the eruption. Currently, no clear influence on other internal modes of variability, such as El Niño, could be unanimously confirmed in both observations/proxy reconstructions and the model simulations. But more work is needed, as better proxy climate data for earlier large events get available.

Women's attitudes concerning their understanding of and relationship to the environment were explored in relation to Robert Kegan's structural clinical-developmental model of ego development, using a randomly selected sample of 27 women between the ages of 40 and 49 from a Massachusetts town. Ways of thinking about the environment were differentiated qualitatively according to ego stage. Extended illustrations of stage distinctions focused on the women's feelings of relationship/connection to the environment, including the impact of religion and spirituality on their attitudes, and on their presented rationale for their environmentally related behaviors. Several additional measures were utilized to explore related questions quantitatively, including the following: Is concern for the external environment related to one's treatment of the internal environment--that is, personal, physical health? Environmental concern as measured by Weigel and Weigel's Environmental Concern Scale was significantly correlated with self-reported personal health care behaviors. Will age be related to ego stage? Within this sample of women in their 40's, age was significantly negatively correlated with ego stage. Explanations for this negative correlation are discussed within a historical context. In conclusion, educational implications and relevance to clinical practice are discussed.

The fungicide chlorothalonil (1,3-tetrachloroisophthalonitrile) is widely used in cranberry production in Massachusetts. Its partition constant, $\rm K\sb{DOC},$ with aquatic humic substances isolated from cranberry bog water was assessed in this study. Elemental analysis of humic substances indicated differences in C, H, N, and O that were consistent with published elemental ratios of aquatic humic substances. Infrared spectra were also similar with respect to C=O stretching of carboxyl and ketonic groups and showed evidence of aromatic C=C stretching. Ultrafiltration of humic acids showed 53% greater than 10,000 molecular weight cut off (MWCO). The fulvic acid fraction had 71% less than 10,000 MWCO. UV absorbance ratios at 400 and 254 nm were 0.23 and 0.16 for humic and fulvic acid, respectively indicating a more aromatic structure than Aldrich humic acid from soil. Base titration showed a charge at pH 8 of 7.5 and 13 meq g-$\rm C\sp{-1}$ for humic and fulvic acid, respectively. Measurements of the TCIN Henry's constant were made using gas-purge techniques. The value obtained, $5 \times 10\sp{-5}$ kPa $\rm m\sp3$ $\rm mol\sp{-1}$ (s = $1.7 \times 10\sp{-5},$ n = 4), was consistent with calculated values from solubility and vapor pressure. Log $\rm K\sb{DOC}$ values for fulvic and humic acid measured using gas-purge techniques were 4.3 (s = 0.6) and 4.5 (s = 0.8), respectively. These values were greater than reported $\rm K\sb{OC}$ values by as much as 1.5 orders of magnitude, suggesting that $\rm K\sb{OC}$ values may underestimate TCIN solubility enhancement in cranberry bog water. TCIN binding to aquatic humic substances corresponds to increased solubility in aqueous systems and potentially toxic levels in the presence of sorbent. Solubility in water, based on the measured $\rm K\sb{DOC}$ values, could increase by 200% with waters containing 35 mg $\rm l\sp{-1}$ DOC. Measured DOC of cranberry bog waters was in the 1 to 30 mg $\rm l\sp{-1}$ range.

Isoxaflutole is a new pre-emergence herbicide which undergoes rapid conversion to a diketonitrile metabolite (DKN) in soil. In soil the half-life of isoxaflutole is very short, but the half-life of DKN is much longer. Sorption studies were conducted with five soils varying in physical and chemical properties using the batch equilibration technique. Analysis of 14C-ring labeled isoxaflutole and DKN was performed using liquid scintillation counting, and sorption data were fitted to the Freundlich model. Isotherms of isoxaflutole and DKN in all the soils were nonlinear as depicted by the exponent ( n < 1.0), indicating differential distribution of sorption site energies in various soils. Isoxaflutole and DKN sorption increased with an increase in organic matter content of soils and decreased as the soil pH increased from 4.5 to 8.5, which was depicted by the reduction of KF values. Clay content of the soils did not have a high correlation with KF values, while the sorption of isoxaflutole was not influenced by the Ca2+ concentration in the soil solution. There was an increase in the sorption of DKN with an increase in Ca 2+ concentration of the soil solution, while the net sorption constant (Kd) was correlated to the organic matter content of the soils. A high correlation existed between the desorption coefficient, KFd and the organic matter content of soils, while the clay content did not greatly influence the desorption of DKN. Although the sorption of DKN was generally reversible, a sorption-desorption hysteresis was apparent in all soils. The site energy distribution curves emphasized the fact that DKN binds tightly to soils with higher organic matter content, and a larger proportion of DKN was retained by those soils. In soils with high organic matter content, the sorption-desorption hysteresis was mainly governed by organic matter content, but in soils with low organic matter, clay content played an important role. When isoxaflutole and DKN were added to soil, the carbonyl stretching frequency decreased as observed in the diffuse reflectance Fourier transformed infrared (DRIFT) spectra. In conclusion, the potential for leaching through soil and crop injury due to isoxaflutole and its metabolite would decrease as soil organic matter and clay content increase.

There is growing concern that South Africa's urban centres are becoming increasingly vulnerable to water scarcity due to stressed surface water resources, rapid urbanisation, climate change and increasing demand for water. Furthermore, South Africa is a water-stressed country with much of its surface water resources already allocated to meet current demands. Therefore, in order to meet the future urban water supply requirements, countries like South Africa will need to consider alternative forms of water management that focus on moving towards sustainability in urban water management. WSUD is one such approach that aims to prioritise the value of all urban water resources through reuse and conservation strategies, and the diversification of supply sources. This study investigates the capacity of the Cape Flats Aquifer (CFA), assessing the feasibility of implementing Managed Aquifer Recharge (MAR) as a strategy for flood prevention and supplementing urban water supply. The implementation of MAR on the CFA aims to facilitate the transition towards sustainable urban water management through the application Water Sensitive Urban Design (WSUD) principles. The fully-integrated MIKE SHE model was used to simulated the hydrological and hydrogeological processes of the CFA in Cape Town at a regional-scale. Using the results of the regional-scale model, four sites were selected for more detailed scenario modelling at a local-scale. Several MAR scenarios were simulated to evaluate the aquifer's response to artificial recharge and abstraction under MAR conditions. The first objective was to evaluate the feasibility of summer abstractions as a flood mitigation strategy at two sites on the Cape Flats prone to winter groundwater flooding, viz. Sweet Home and Graveyard Pond informal settlements. The second objective of the study was to assess the storage potential and feasibility of MAR at two sites in the south of the Cape Flats, at Philippi and Mitchells Plain. In addition, the migration of solute pollutants from the injected or infiltrated stormwater was simulated and climate change simulations were also undertaken to account for potential fluctuations in rainfall and temperature under climate change conditions. The results indicated that flood mitigation on the Cape Flats was possible and was likely to be most feasible at the Graveyard Pond site. The flood mitigation scenarios did indicate a potential risk to local groundwater dependent ecosystems, particularly at the Sweet Home site. Yet, it was shown that a reduction in local groundwater levels may have ecological benefits as many of the naturally occurring wetlands on the Cape Flats are seasonal, where distinct saturated and unsaturated conditions are required. Furthermore, MAR was shown to improve the yield of wellfields at Philippi and Mitchells Plain through the artificial recharge of stormwater while also reducing the risk of seawater intrusion. MAR was shown to provide a valuable means of increasing groundwater storage, improving the supply potential of the CFA for water supply while aiding the prevention or mitigation of the seasonal flooding that occurs on the Cape Flats. Furthermore, the case was made that MAR is an important strategy to assist the City of Cape Town in achieving its WSUD objectives. MAR and groundwater considerations, in general, are essential for the successful implementation of WSUD, without which, there is an increased risk of overlooking or degrading urban groundwater resources. The findings of this study resulted in a number of recommendation to urban water resources managers, planners and policy makers. First, MAR is an important means for Cape Town to move towards becoming a truly water sensitive city. This study indicated that the CFA should be incorporated as an additional source of water supply for Cape Town especially considering the recent drought conditions and due to its ability for the seasonal storage of water, this would improve the city's resilience to climate change. Furthermore, it was recommended that the application of MAR on the CFA could also be used to reduce groundwater related flooding on the Cape Flats. Second, it was emphasised that urban planning, using WSUD principles is essential for the protection of the resource potential of the CFA. Finally, for the implementation of WSUD and MAR to be successful, there needs to be appropriate policy development alongside the implementation of these strategies to ensure they are achieving their initial objectives and are not causing detriment to the aquifer.

Bibliography: pages 105-107. / This dissertation forms part of the requirements for the degree of MSc in Environmental Science and was supervised by Professor R Fuggle, Head of Department of the Department of Environmental and Geographical Science. The dissertation describes and examines the practical application of integrated environmental management (IEM) by analyzing a case study. IEM is a methodology developed in South Africa under the direction of the Council for the Environment, the purpose of which is to incorporate environmental considerations into all aspects of planning and development. A guideline document on the implementation of IEM was published in 1989 (Council for the Environment, 1989(A)), and later updated and a set of six guideline documents was published in 1992 (Department of Environment Affairs, 1992 (A) to (F)). The case study is the proposed development of a rock quarry in a peri-urban area near Johannesburg, South Africa. It was implemented in accordance with the original version of lEM. The availability of the updated guidelines and the experience gained in the case study provided potential for comparison between the original and updated procedures. Other points of relevance regarding the case study are that the site is situated in a rapidly developing area, and could therefore cause significant social impacts; the study was conducted at the most detailed level of the original IEM procedure (Class 1 ); and involved public participation, which has been emphasised in the updated IEM procedure.

The green alga, Selenastrum capricornutum, was cultured in artificial nutrient medium utilizing five-gallon carboys, each of which contained 16 1. of culture. The algal cells were separated from the nutrient medium by continuous-flow centrifugation at 7500 RPM, and were then lyophilized. The lyophilized cells were extracted by refluxing with ether, acetone, and chloroform:methanol (2:1). Free sterols and sterol esters were separated from the crude extract using preparative thin-layer chromatography. Sterol esters were saponified and both the sterols and the fatty acids were recovered. Individual sterols were separated from the free sterol fraction using argentation thin-layer chromatography. Gas chromatograms, mass spectra, and ultraviolet spectra were obtained for these sterols. The free sterol fraction was found to contain approximately 40% 24-methylcholesta-5,7-dien-3B-ol and 60% 24-ethylcholesta-5,7-dien-3B-ol. The sterol ester fraction also contained these two sterols; however, the composition and amount of esterified sterols varied as a function of culture age. Sterol ester content was higher for older cultures, and in older cultures the composition of the esterified sterols more closely resembled that of the free sterols. The fatty acids obtained from the saponification of the sterol esters were methylated and were analyzed using gas chromatography. Tentative identifications, based upon comparative retention times, were made for several of these acids. Sterols were extracted from the nutrient medium after harvest of the algal cells. Extraction was accomplished by mixing large quantities of nutrient medium with ether for several days, or by shaking small aliquots with ether. 24-methylcholesta-5,7-dien-3B-ol and 24 ethylcholesta-5,7-dien-3B-ol were isolated from the nutrient medium in approximately the same relative amounts as from the algal cells. The concentration of sterols in the nutrient medium was approximately equal to the water-solubility of cholesterol (25-29)t g./l.). Extraction procedures which release sterols from water soluble complexes were carried out on extracted cells and on extracted nutrient medium. These procedures failed to yield measurable quantities of sterols. Treatment of extracted cells with strong base and subsequent extraction showed that all sterols had been extracted without prior cell lysis or pretreatment. An extraction of algal cells was carried out using DMSO:ether as the extraction solvent. This extraction resulted in complete removal of sterols from the cells, and the sterols were accompanied by only small amounts of other lipidsoluble material.

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