Polyaromatic hydrocarbons and their various transformation products constitute a serious environmental and biological hazard. Benzo(a)pyrene, (B(a)P), a polycyclic aromatic hydrocarbon, is an acutely toxic, carcinogenic and recalcitrant industrial pollutant that enters the environment as a byproduct of petroleum refining and combustion. Traditionally, decontamination schemes have used chemical or physical methods, but during the last two decades, there has been an increasing interest in bioremediation Seventeen fungi were screened with tannic and gallic acid plate assays along with the polymeric dye R-478 decolorization assays for presumptive extracellular ligninase activity. Dye decolorization was correlated with B(a)P degradation for mycelia and extracellular filtrates. Marasmiellus troyanus, a litter rot fungus isolated from a petroleum contaminated Superfund site, and the well-studied white rot fungus, Phanerochaete chrysosporium, were chosen for further study Respectively, ELISA and mass balance analyses studies confirm the production of lignin peroxidases and manganese-dependent peroxidases by P. chrysosporium, and show this fungus is effective in metabolizing (12.9%) and mineralizing, (1.2%) B(a)P under ligninolytic conditions. Comparatively, M. troyanus metabolized (72.4%) and mineralized (8.4%) B(a)P more efficiently but without detectable peroxidases. M. troyanus degraded B(a)P in two phases. The first phase was associated with extracellular enzymatic activity and correlated to the degradation pattern of P P. chrysosporium, while the second phase was unique to M. troyanus. Furthermore, GC-MS analyses show that M. troyanus initially oxidizes B(a)P to form a phenol. We also detected the formation of a dihydrodiol and an unidentified metabolite conjugated with either glucuronic acids or sulfates The effective introduction of fungi into a bioremediation scenario is dependent upon the mass production of inoculum for application to the contaminated site. M. troyanus, encapsulated in alginate, remained viable for two years in refrigerated storage. Mass balance analyses showed that these alginate beads effectively metabolized B(a)P (64.4%) but no mineralization was detected. Nevertheless, this study indicates that the delivery of M. troyanus to soils and sludges contaminated with petroleum aromatic hydrocarbons using alginate encapsulation is a feasible and promising strategy / acase@tulane.edu

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Bibliography: leaves 281-330.

Bibliography: leaves 281-330. / xvi, 330 leaves ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Environmental Studies, 2003

<p>The adenoviruses are nonenveloped double stranded DNA viruses, which cause enteric dysentary and respiratory infection. Adenovirus has become a focus of the water treatment community because of its apparent resistance to ultraviolet disinfection; it is the basis for stringent new EPA regulations regarding all viruses in both surface and ground waters. Most of the work done so far, however, has involved the use of monochromatic (254 nm) low pressure (LP) UV sources and subsequent assay of viral infectivity in cell culture models. LP UV lamps primarily damage DNA, while polychromatic UV sources may damage other parts of the virus as well. Recent research has shown that these newer, polychromatic UV sources--such as medium pressure (MP) UV--are more effective than monochromatic LP UV for disinfection of adenovirus. The objectives of this work were to study adenoviral response to UV using both LP and MP UV as well as using both standard cell culture infectivity assays and more direct methods of assessment based on molecular biology. These include quantitative long PCR for assessment of DNA damage and SDS-PAGE for assessment of protein damage; transmission electron microscopy was used to examine the structure of UV treated viral particles. This work was only the second significant study to show the response of adenoviruses to medium pressure UV and the first to thoroughly examine the response of adenoviruses to both LP and MP UV using cell culture-independent methods. Results confirm that adenovirus is sensitive to MP UV when assayed in cell culture; they show that LP and MP UV are equally effective at inducing damage to the adenoviral genome and that MP UV is more effective than LP UV at damaging the viral proteins. This work helps deepen our understanding of UV disinfection of adenovirus.</p> / Dissertation

Air-water interface plays an important role in the transport of many contaminants in the vadose zone. It is also a limiting factor for many processes involve mass or energy transfer between air and water phases in vadose zone. In this research, the gas-phase partitioning tracer method was used to measure air-water interfacial area for eight porous media. The experimental results were used to investigate the influencing factors of the magnitude of air-water interfacial area and the relationship between the air-water interfacial area and water saturation, and capillary pressure. The porous media comprised a series of sands with narrow particle-size ranges, a sand with a wider particle-size distribution, a sandy soil, and a loamy sandy soil. The measurement range was extended to very low water contents in an attempt to determine upper limits for air-water interfacial areas. The measured values were compared to the normalized surface areas of the porous media. The results of the experiments showed that the magnitude of the air-water interfacial areas increased with decreasing water saturation, and approached that of the normalized surface areas. Generally, air-water interfacial areas were larger for media with larger specific surface areas. The change in air-water interfacial area with changing water saturation was less near saturated water contents and greater at smaller values. In addition, the change was greater for the poorly-sorted media than the well-sorted media. An empirical model was developed to describe the observed relationship between air-water interfacial area and water saturation. The coefficients of the model were found to correlate to the porous-medium uniformity coefficient. With this model and associated correlations, only bulk density, specific surface area, and uniformity coefficient are needed to estimate air-water interfacial area for a given water saturation. The model was shown to provide a reasonable description of a literature data set. Potential relationships between air-water interfacial area and capillary pressure under higher water-content conditions are investigated for unsaturated sandy porous media. A conceptual relationship between air-water interfacial area and capillary pressure is hypothesized, and is tested using air-water interfacial area data obtained from gas-phase tracer tests and saturation-pressure data obtained from water-drainage experiments. The results show that the magnitude of the air-water interfacial area increases with increasing capillary pressure, which corresponds to decreasing water content. (Abstract shortened by UMI.)

Concern for environmental management of our natural resources is most often focused on the human impacts upon these resources. Minor stresses on surface materials in sensitive desert landscapes can greatly increase the rate and character of erosion. The National Training Center, Ft. Irwin, located in the middle of the Mojave Desert, California, provides a study area of intense off-road vehicle (ORV) activity spanning a 50-year period. This study documents a case of concentrated ORV activity on sensitive desert environments, and the resulting environmental impacts. Geomorphic surfaces from two study sites within the Ft. Irwin area were mapped from 1:28,400 scale black and white aerial photographs taken in 1947. Surface disruption attributed to military activity was then mapped for the same areas from 1993, 1:12,000, black and white aerial photographs. Several field checks were conducted to verify this mapping. Images created from SPOT panchromatic and Landsat Thematic Mapper (TM) multispectral data acquired during the spring of 1987 and 1993 were analyzed to assess both the extent of disrupted surfaces and the surface geomorphology discernable from satellite data. Classified and merged images were then created from these data and demonstrate the capabilities of satellite data to aid in the delineation of disrupted geomorphic surfaces. Correlations were also established between highly disrupted surfaces and soil surface conditions on selected geomorphic surfaces. Disruption maps produced from the air photos indicate that the amount of disrupted surfaces within the study sites grew from a combined total of 1.3 km² in 1947 to 33.4 km² by 1993. A combination of 6 bands of Landsat TM data with a seventh band of SPOT panchromatic data yielded a product that delineated broad geomorphic surfaces that closely correlate with those mapped from the aerial photography. An error matrix between these two products resulted in an overall accuracy of 83.36% and a Kappa Index of Agreement of 77.28%. A 15-class unsupervised classification of the SPOT panchromatic data produced the representation of the extent and levels of disruption present in the study areas that closely matched field observations. Field sampling of soil strength and clay/silt percentages on disturbed and undisturbed surfaces reveals that these arid land surfaces react to intense ORV activity by becoming more compact and exhibiting higher percentages of clays and silts.

The discharge of untreated aquaculture effluent can pollute receiving water bodies. I tested the feasibility of using salt-tolerant plants (halophytes) with potential as forage and oilseed crops, as biofilters to treat saline aquaculture effluent. Plants were grown in draining lysimeters in greenhouses and irrigated with effluent salinized with NaCl. Irrigation water came from a recirculating tilapia culture system. I measured yield potential, water use and capacity for nitrogen and phosphorus uptake. In Experiment 1, Suaeda esteroa, Salicornia bigelovii and Atriplex barclayana (Chenopodiaceae) were grown in sand in 0.02 m³ lysimeters. Plants were irrigated with effluent of 0.5 ppt, 10 ppt and 35 ppt salinity, to meet evapotranspiration demand and to allow 30% of the applied water to leach past the plant root zone. Despite the high leaching fraction and short residence time of water in the pots, the plant-soil system removed 98% and 94% of the applied total and inorganic nitrogen, respectively, and 99% and 97% of the applied total and soluble reactive phosphorus respectively. For all species, salt inhibited (P ≤ 0.05) the growth rate, nutrient removal, and volume of water the plants could process. The salt marsh species S. esteroa and S. bigelovii performed better than the desert saltbush, A. barclayana, at 35 ppt. In Experiment 2, Suaeda esteroa, was grown in lysimeters containing approximately 0.8 m³ sandy loam soil and irrigated three times per week with 31 ppt NaCl effluent. I used five irrigation treatments, ranging in volume from 50 to 250% of the potential evaporation rate. Plant biomass and water consumption increased significantly (P ≤ 0.05) with increasing irrigation volume. Nitrate concentrations in water draining from the lysimeters decreased during the experiment, and were significantly lower in the high-volume treatments than in the low-volume treatments. Phosphorus concentrations in the leachate water increased during the experiment as a function of increasing irrigation volume. Irrigating halophyte crops with aquaculture wastewater of seawater-salinity may be a viable strategy for disposal of effluent.

The purpose of this study was to determine the removal efficiency of natural systems for the reduction of enteric protozoa (Giardia and Cryptosporidium), and enteric viruses in wastewater. The first part of the study used bench-scale soil columns to determine the potential effectiveness of Soil Aquifer Treatment (SAT) for the removal of Cryptosporidium oocysts and Giardia cyst from treated wastewater. Sand and sandy loam were used to pack 18 to 200-cm long columns. Results from this study showed that removal of oocysts increased as increasing length of the soil column. Although substantial removal of Cryptosporidium occurs (>99.99%) within 200 cm of soil, oocysts are likely to penetrate beyond this depth. Giardia was removed far below detectable levels, probably due to its larger size. The next phase of the project investigated the removal of pathogenic and indicator microorganisms from untreated wastewater by a surface flow wetland, the importance of plants in wetlands, as well as the potential for groundwater contamination passed by pathogens with the use of constructed wetlands. This small-scale study was conducted in a large tank divided into two cells. Both cells were filled with sand and one cell was planted with bulrushes and the other was unplanted. About 90 percent of all microorganisms were removed by either of the systems. Neither Giardia nor Cryptosporidium were found to penetrate through the 2-m of sand in either the planted or unplanted cells. Lower numbers of viruses and bacteria were transported through the sand in the planted wetland cell versus the unplanted cell. This could indicate that vegetated wetlands are more likely to prevent microbial transport to groundwater. The objective of the last part of this study was to determine the survival of Cryptosporidium oocysts in wastewater effluent applied to a constructed vegetated wetland, when exposed to and when protected from sunlight, and the effect of temperature during different seasons. Viability of Cryptosporidium oocysts was determined using the excystation technique. Results from this study indicated that sunlight and/or temperature play a significant role in the survival of Cryptosporidium. Thus, it was concluded that oocyst reduction in wastewater applied to wetlands can be enhanced by natural die-off due to the effects of temperature or UV irradiation in sunlight, and greater removal could be achieved if designing of wetland systems take into consideration such factors.