Thesis (M.S.)--University of Tennessee, Knoxville, 2001. / Vita. Includes bibliographical references (leaves 80-83). Also available via the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 1996. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 1996. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.

The response of several plant species to heavy metal contaminated soils was evaluated using plant bioassays with a soil substrate. A natural soil was collected from Dinwiddie County, Virginia and soil analysis was performed. The plant species, Lolium multiflorum, setaria italica and Trifolium rep ens latum, Robinia pseudoacacia, Andropogon gerardi, Asclepias syriaca, Echinacea purpurea, Rudbeckia hirta and Festuca rubra were grown in to determine the response to cupric and cadmium chloride in soils (mg Cu/kg soil). A few plant species were grown in small pots in a plant growth chamber for 28 days using control, 10, 30, 100 and 300mg Cu or Cd/kg soil. Germination proved to be less sensitive than root length. S. italica had highest ECSOs. In eu 20.7 and 15.3 in Cd. All plant species were grown for 7 days in 0.3, 1.0, 3.0 10.0, and 30.0mg Cu/kg soil and in control. Germination was not effected by metal concentrations in most species (p=0.07-0.6), except T.repens latum, R. hirta and F. rubra at 30mg/kg (p=0.0007). Root length was significantly effected by Cu concentrations for almost all species (p=0.0001-0.0112). Setaria italica had the highest EC50 at 10.86mg/kg. Robinia pseudoacacia root length was not significantly affected by CU concentrations. The other species had EC50s ranging from 3.74-7.51mg/kg. Both inhibition and stimulation of root growth were observed. Preliminary studies regarding germination rates, fungicides and rangefinding are included. / Master of Science

No description available.

Thesis (MTech (Environmental Health))--Cape Peninsula University of Technology, 2011. / Pharmaceuticals have been formulated to influence physiological systems in humans, animals, and microbes but have never been considered as potential environmental pollutants by healthcare professionals. The human body is not a barrier to chemicals, but is permeable to it. Thus after performing their in-vivo functions, pharmaceutical compound introduced into the body, exit mainly via urine and faeces. Sewage therefore contains highly complex mixtures of chemicals in various degrees of biological potency. Sewage treatment works including those in South Africa, on the other hand, are known to be inefficient in removing drugs from sewage and consequently either the unmetabolised pharmaceutical compounds or their metabolites emerge in the environment as pollutants via several trajectories. In the environment, the excreted metabolites may even undergo regeneration to the original parent molecule under bacterial influence, resulting in "trans-vivo-pharmaceutical-pollution-cycles". Although all incinerators are known to generate toxins such dioxins and furans from the drugs they incinerate, all the medicines disposed by the hospitals under research, were incinerated, as the preferred option of disposal. The incineration process employed was found to be environmentally unsafe. Expired and unused medicines which the general public discard as municipal solid waste become landfilled. Because many landfill sites are not appropriately engineered, the unwanted drugs landfilled therein, leach into the surrounding ground water, which is the influent source of water treatment plants. Water treatment plants, including those in South Africa, are also inefficient in eliminating pharmaceutical compounds, releasing them in sub-therapeutic concentrations into potable tap water as pollutants, the full effects of which are yet to be determined.

Thesis (MTech(Environmental Health))--Cape Peninsula University of Technology, 2011. / Pharmaceuticals have been formulated to influence physiological systems in humans, animals, and microbes but have never been considered as potential environmental pollutants by healthcare professionals. The human body is not a barrier to chemicals, but is permeable to it. Thus after performing their in-vivo functions, pharmaceutical compound introduced into the body, exit mainly via urine and faeces. Sewage therefore contains highly complex mixtures of chemicals in various degrees of biological potency. Sewage treatment works including those in South Africa, on the other hand, are known to be inefficient in removing drugs from sewage and consequently either the unmetabolised pharmaceutical compounds or their metabolites emerge in the environment as pollutants via several trajectories. In the environment, the excreted metabolites may even undergo regeneration to the original parent molecule under bacterial influence, resulting in “trans-vivo-pharmaceutical-pol ution-cycles”. Although all incinerators are known to generate toxins such dioxins and furans from the drugs they incinerate, all the medicines disposed by the hospitals under research, were incinerated, as the preferred option of disposal. The incineration process employed was found to be environmentally unsafe. Expired and unused medicines which the general public discard as municipal solid waste become landfilled. Because many landfill sites are not appropriately engineered, the unwanted drugs landfilled therein, leach into the surrounding ground water, which is the influent source of water treatment plants. Water treatment plants, including those in South Africa, are also inefficient in eliminating pharmaceutical compounds, releasing them in sub-therapeutic concentrations into potable tap water as pollutants, the full effects of which are yet to be determined.

Hazardous waste substances are solid, semi-solid or non-aqueous liquids that exhibit characteristics of corrosivity, reactivity, ignitability, toxicity and infectious property. Major available options for management of hazardous waste include direct disposal into landfill or chemical treatment/stabilization of wastes prior to landfill disposal. Hazardous wastes are accepted for direct disposal in engineered landfills if they conform to the chemical concentration limit criterion (determined by water leach test followed by estimation of the concentration of the contaminant) and compressive strength (the material should have compressive strength > 50 kPa) criterion. Lead is classified as extremely toxic metal. Elevated levels of lead in water (surface and ground water) primarily arise from industrial discharges, and aerial deposition. During its residence in surface water bodies, the lead may interact detrimentally with aquatic life or be abstracted into public water supplies. According to National drinking water standards, the permissible limit of lead in drinking water is 0.05 mg/l. Deposition of air-borne lead, disposal of sewage sludge on land and disposal of industrial effluents on lands are major sources of lead contamination of soils. When incorporated in soil, lead is of very low mobility. Lead retained in soils can be slowly leached to the groundwater thereby impacting human health if consumed for potable needs. Alternatively lead deposited in soils can be absorbed by vegetation (crops/trees) and can impact human health on their consumption. Given the negative impacts of lead contamination on human health, the strong affinity of soils to retain deposited lead and the possible release for human consumption, this thesis focuses on characterization and chemical stabilization of artificially lead contaminated soils in the context of their disposal in hazardous waste landfills. The main objectives of the thesis are: characterize artificially lead contaminated soils for water leachability of lead and undrained strength characteristics as per CPCB (Central Pollution Control Board) guidelines in the context of disposal criteria in hazardous waste landfills. Artificially lead contaminated soils in compacted and slurry states are used in the thesis. Red soil (from Bangalore District, Karnataka) and river sand are used in the preparation of compacted and slurry specimens. The red soil and red soil-sand specimens are artificially contaminated in the laboratory by employing aqueous lead salt solutions as remolding fluids. Lead concentrations of 160 to 10000 mg/l are used in this study. The results of characterization studies with artificially lead contaminated soils help identify contaminated soil materials that require chemical stabilization prior to disposal into engineered landfills. Based on the results of characterization studies with artificially lead contaminated soils, lime stabilization coupled with steam curing technique is resorted to immobilize lead in the red soil-sand slurry specimens and mobilize adequate undrained strength to meet the criteria for disposal of lead contaminated soils in hazardous landfills. After this first introductory chapter, a detailed review of literature is performed towards highlighting the need to undertake chemical stabilization of artificially lead contaminated soils in Chapter 2. Chapter 3 presents a detailed experimental program of the study. Chapter 4 presents the physico-chemical and mechanical characterization of the artificially lead contaminated soils. The ability of artificially contaminated soils to release (artificially added) lead during water leaching is explained using lead speciation results performed using the Visual MINTEQ program. Experimental results illustrated that contamination of compacted red soil and red soil + sand specimens with significant lead concentrations (21 to 1300 mg/kg) resulted in major fractions of the added lead being retained in the precipitated state. Results of water leach tests revealed that lead concentrations released in the water leachates are far less than (0.0011 to 0.48 mg/l) limits prescribed by CPCB (2 mg/l) for direct disposal of lead contaminated materials into hazardous waste landfills. Unconfined compressive strengths developed by the lead contaminated red soil and red soil-sand specimens were significantly higher (100-2700 kPa) than the strength requirement (> 50 kPa) for direct disposal of hazardous wastes in engineered landfills. Lead contamination did not affect the unconfined compression strengths of the specimens as matric suction prevalent in the unsaturated compacted soils had an overriding influence on the cementation bond strength created by the lead precipitates. Visual Minteq tool was helpful in predicting the amount of added lead that was converted to insoluble precipitate form. However the amounts of water leachable lead determined experimentally and predicted by Visual Minteq were very different-Visual Minteq predicted much higher amounts of water leachable lead than experimentally determined. Experimental results revealed that the levels of lead released by the red soil-sand slurries in water leach tests were in excess (13 to 36 mg/l) of the permissible lead concentration (2 mg/l) for direct disposal of hazardous waste in landfills. Owing to water contents generally being in excess of their liquid limit water contents (w/wL ratio > 1) the slurry specimens exhibited undrained strengths below 1 kPa. Lime stabilization and steam curing of the contaminated slurry specimens was therefore resorted to control the leachibility of lead and increase undrained strengths to acceptable limits. Chapter 5 deals with lime stabilization of artificially contaminated slurries that do not meet the leachate quality (lead concentration in water < 2 mg/l) or compressive strength (> 50 kPa). Procedures are evolved for lime stabilization of such artificially contaminated soils to meet both the water leachate quality and compressive strength criteria. Lime stabilization together with steam curing of the lead contaminated slurry specimens effectively immobilized the added lead (2500 mg/kg) and imparted adequate compressive strengths to the contaminated red soil-sand slurry specimens. The lime stabilized contaminated specimens released marginal lead concentrations (0.03 to 0.45 mg/l) in the water leach; these values are much lower than permissible limit (2 mg/l) for disposal in hazardous landfills or values exhibited by the unstabilized specimens (13 to 38 mg/l). Lime addition rendered the contaminated specimens strongly alkaline (pH values ranged between 10.68 and 11.66). Combination of the experimental and Visual Minteq results suggested that precipitation of lead as hydrocerrusite in the alkaline environments (pH 10.68 to 11.95) is not the sole factor for marginal release of lead in water leach tests of the 4, 7 and 10 % lime stabilized contaminated specimens. It is possible that fraction of lead ions are entrapped within the cemented soil matrix. Water leach tests performed at range of pH values (pH 2.5 to 9.6) with 7 % lime stabilized specimens suggested that immobilization of lead as hydrocerrusite or as entrapment in the cemented soil mass in the lime stabilized specimens is practically irreversible even on exposure to extreme pH conditions. The lime stabilized contaminated specimens developed unconfined compressive strengths ranging from 100 kPa (4 % lime stabilized 40 % red soil-60 % sand specimen) to 1000 kPa (10 % lime stabilized 100 % red soil specimen). The significant growth of compressive strength upon lime stabilization is attributed to growth of inter-particle cementation bonds by the CAH (calcium aluminate hydrate) and CSH (calcium silicate hydrate) compounds formed by lime-clay reactions, slight reduction in void ratios and growth of strong inter-particle cementation bonds the during steam curing at 800C. The results of this thesis bring out a procedure to immobilize high concentrations of lead and develop adequate compressive strength of lead contaminated slurry specimens by lime stabilization + steam curing technique. The red soil acted as pozzolana in reactions with lime, while, steam curing accelerated the lime-soil reactions. The procedure can be extended to non-organic slurry wastes that are devoid of pozzolanic material (example, lead contaminated smelting sands). In slurry wastes devoid of pozzolana, materials such as fly ash can be added and the reactions between lime and fly ash would immobilize lead + develop adequate compressive strength. Also, similar to the methodology being adaptable for any non-organic slurries, it can also be extended to other toxic metal bearing wastes, example, zinc, cadmium and nickel.