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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Trace elements in the Cyprus environment associated with urban development

Petronda, Andrea January 2013 (has links)
Since Cyprus entered the European Union (EU) in 2004, there has been a rapid expansion associated with the development of major motorway networks, tourist centres, commercial and industrial activity within major cities. To date, very little research has been undertaken in Cyprus, to assess the impact of such urban development on chemical levels in the environment. This research aimed to assess the possible levels of chemicals• in the southern part of Cyprus using the olive tree as a potential biomonitor for evaluating the degree of Mn, Cu, Zn, Pb, Cr, Co, Ni, V, Mo, Cd and As contamination in Cyprus. Olive tree bark, leaves, tree-rings, olives (olive oil) and surface soils were collected from four areas (rural, tourist, urban and transport). [n addition, samples were collected from different urban centres namely: Nicosia, Lamaca, Limassol and Paphos. This study confirmed that olive tree bark could be used to assess the release of chemicals from anthropogenic sources, especially from urban and transport activities. Unwashed olive bark lead levels for highways (mean 25.2; range 0.63 to 119 mg/kg Pb dry weight) were significantly higher than for rural areas (1.62; 0.08 to 3.81 mg/kg Pb d.w.). The other parts of the olive tree have provided data on the mobility and accumulation of the elements and possible links between the different media (tree-rings, leaves, olives, olive oil and surrounding surface soils). The overall elemental levels for the southern part of Cyprus were found to be lower than reported literature values. This research has also found that the highest elemental levels are in samples from urban (Nicosia) and from transport sites. This is due to construction-demolition activities, road expansion (including re-surfacing and widening) and high vehicular traffic densities. Unwashed tree ring cores in Lamaca showed high levels of copper (41 .3 to 54.9 mg/kg Cu d.w.) in segments which represented 20-30 years ago, showing the effect of the closure and decommissioning of the petroleum refinery. The elemental levels found in the tourist and rural areas were significantly lower. Rural or 'non-polluted' sites were used to provide control data for Cyprus. In addition, high elemental levels were not found in the olives and olive oil. Relatively high zinc levels (1.83 and 3.05 mg/kg Zn) were found in olive oils bought from the Cyprus and UK markets. There is no set limit for zinc which makes the evaluation of the risk difficult. Comparing the levels with the literature, the data was in agreement with levels found in other countries. Arsenic (total and speciation) analysis of the water and surrounding media (soils and poultry manure), near Nicosia, showed the highest arsenic levels to be 59.8 1J9/1 As in water, with the predominant species to be arsenate (Asv). A few groundwater As levels surpassed the World Health Organisation Guideline for drinking water (10 1Jg/l As). In conclusion, continuous monitoring is necessary, as the island is rapidly growing and developing, especially major motorways and tourist/city centres. The database created through this research will be able to assist and provide a leading start to future studies for other researchers in Cyprus and other countries, especially in the Mediterranean who grow olives and are undergoing urban development
32

Monitoring of electrical resistivity changes in the ground laboratory model caused by diesel spillage and injection of oxygen release compound

Montinaro, Antonio January 2008 (has links)
The aim of this research is to verify the effectiveness of the electrical resistivity method in the study and monitoring of the pollutant dispersion and migration in the soil. In this particular study, Diesel has been used as the detection pollutant and a laboratory model was created in a tank comprised of a bottom clay layer covered by a sandy layer. Two narrow sectors separated by a permeable screen was included to allow permanent groundwater flow through the soil. In addiction, a permeable reactive barrier was made in the model with an oxygen release compound (i.e. ORC-Advanced by Regenesis®). When the model was used in the laboratory a mini electrical resistivity array was used to monitor the electrical resistivity properties that the media displayed.
33

Bioremediation of a former manufactured gas plants (FMGP) site contaminated with a complex mixture of heavy metals, organic and inorganic substances using soil washing technique

Agbeze-Onuma, Maduka January 2009 (has links)
This study investigated the potential treatability of a representative soil sample, holding a complex mixture of metals, organic and inorganic contaminants, from the site of a Former Manufactured Gas Plant (FMGP) using a combination of soil washing technique and bioremediation. The contaminants treated included a range of heavy metals (lead, chromium, copper, mercury etc), inorganic chemicals (chlorides, sulphates, cyanides etc), and organic compounds (polycyclic aromatic hydrocarbons (PAHs), Gasoline Range Organics (GRO), Diesel Range Organics (DRO), Methyl tertiary butyl ether (MTBE), and benzene etc).
34

Mechanisms of trinitrotoluene transformation, tolerance and toxicity in Arabidopsis thaliana

Beynon, Emily January 2008 (has links)
Trinitrotoluene (TNT) is an explosive which through manufacture, use and decommissioning has polluted large areas of land. Because of the risk posed to human health and other living organisms, the remediation of TNT contaminated land is a priority. Plants have been proposed as a good clean-up system because of their innate ability to remove TNT from soil. Moreover, plant transformed TNT derivatives are sequestered within the plant and are difficult to extract. attenuating the activity of TNT in the environment. Genetic modification has been used to enhance the tolerance threshold and transformation capacity of tobacco, poplar, Arabidopsis and wheat grass to TNT.
35

Laboratory and pilot-scale studies on the bioremediation of oil contaminated soil

Althalb, Hakima January 2012 (has links)
Petroleum contamination of sandy soils is a severe environmental problem in Libya but relatively little work has been carried out to optimize the bioremediation of such soils. The purpose of this thesis was to determine the potential for bioremediation 0 hydrocarbon-contaminated soil obtained from the Zawia refinery field, Libya. Initial work involved chemical and microbial characterisation of the contaminated soil. Chemical analysis revealed high levels of petroleum contamination (up to 26532 mg TPH per kg soil) and that the soil was contaminated with a mixture of crude oil an, diesel oil. Five isolates from the contaminated soil were identified as potential hydrocarbon degraders and were able to grow on crude oil and diesel oil as a sole carbon source, Two isolates, Pseudomonas putida and Bacillus sp., were chosen for us as potential microbial inoculants because they showed superior pertormance in terms growth on hydrocarbons, emulsifying activity and ability to transform hydrocarbons in pure culture.
36

Development and use of a multi-colour tracer technique to investigate colloid facilitated transport through unsaturated vadose zone soil

Sinclair, Hazel Anne January 2011 (has links)
A novel multi-coloured method for tracing several different sizes of colloid at once was developed using fluorescently dyed latex polystyrene microspheres and employing a solvent dissolution method (SDM) developed from that used in bio-medical research for the detection of these tracers. The use of this method means that both the breakthrough characteristics, and colloidal mobilisation and deposition patterns within the soil profile, can be investigated as it allows detection of the micro sphere tracers in both water and soil samples. A series of laboratory based rainfall simulation experiments carried out on a four large intact soil cores showed that the four sizes of fluorescent microsphere used in this research (1.2Ilm, O.8Ilm, OAllm and O.2Ilm) could mimic the behaviour of the corresponding size fractions of both TP and MRP extremely successfully, though the correlation was stronger for TP. These experiments also showed that the colloidal and colloid-borne P could make a significant contribution to phosphorus losses from agricultural soils. Further, a high proportion of all four size fractions were found to be molybdate reactive, indicating that current water quality monitoring which uses MRP<OA5Ilm as a measure of bioavailable P in surface waters may result in serious underestimation. The potential impact of phosphorous losses from diffuse sources through unsaturated vadose zone soils on ecological water quality may be considerably greater than previously thought. Finally a series of similar rainfall simulations on large intact soil blocks, with special grid collection systems at their base, allowed the complex and dynamic nature of active flow pathways through unsaturated vadose zone soil, and the impact this has on colloidal mobilisation, transport and deposition, to be explored.
37

Metal removal from soil by electrokinetic processes : the effects of inorganic soil components on the process

Altaee, Ali January 2004 (has links)
No description available.
38

Ammonia emissions from slurry applications to land

Misselbrook, Thomas Henry January 2005 (has links)
Over the last 10-15 years there has been increasing concern within Europe as to the effects of ammonia emission and subsequent deposition to sensitive ecosystems, causing eutrophication and soil acidification. Transboundary transport of emissions has led to legislation at EC level with member states being given emission ceiling targets. Research has therefore aimed at quantifying national emissions, modelling emission processes and developing mitigation strategies. Agriculture accounts for &gt;80% of total UK ammonia emission, therefore an accurate and robust model is required to estimate emissions from this sector. National inventory methodology has improved as the database of emission measurements and survey data has grown and as models have evolved from discrete empirical calculations for individual sources to linked nitrogen flow models incorporating more process-based algorithms. Ammonia emissions from agriculture derive mainly from livestock manures (primarily from the urea content of urine) and land application of manures represents a major emission source. Research in this area has therefore aimed to improve our ability to predict losses, taking into account the major influencing factors, in order to improve inventory estimates, improve manure management decision support models for farmers and advisers and to highlight potential mitigation strategies. This requires the ability to make precise, accurate measurements and measurement technology has been developed for a range of scales. A key factor influencing ammonia emissions following applications of livestock slurries to soil is the rate and extent to which slurry infiltrates into the soil, where it will be largely protected from volatilisation. This has not previously been fully incorporated into process-based models and research presented here has provided a mechanism describing the infitration process in which the slurry dry matter concentration and the nature of that dry matter are among the important influencing factors. Measures aimed at reducing emissions from land spreading are generally regarded as the most cost-effective means of reducing emissions from agriculture. A number of slurry application techniques aimed at reducing emissions have been developed and assessed against the conventional method of surface broadcasting. These new techniques rely on either reducing the exposed slurry surface area from which emission occurs, reducing the air flow and temperature at the emitting surface (thereby increasing the resistance to ammonia transport from the emitting surface to the free atmosphere) or increasing the contact between slurry and soil. A more holistic approach to reducing emissions is via dietary manipulation, with the aim of reducing both the amount and form of nitrogen excreted by livestock. This can result in lower ammonia emissions at all stages of manure management i.e. livestock housing, manure storage and application to land.
39

Biosurfactant enhanced treatment of petroleum oil contaminated soils

Urum, Kingsley January 2004 (has links)
This thesis reports the experimental measurements on the ability of biological origin surfactants (i.e. biosurfactants - aescin, lecithin, rhamnolipid, saponin and tannin) on removing crude oil and a heavy fuel oil blend from various soils, through soil washing process. The greatest advantage of soil washing is that it is a physical means of separating oil from soil using water or surfactants without chemically modifying either the soil or the oil. The oil removal performance of the biosurfactants was evaluated against that of a well studied synthetic surfactant (sodium dodecyl sulphate, SDS) using water as a base case. For this purpose, different washing settings (i.e. test tubes, stirred flasks, packed column, and air bubble assisted stirred tank) were used to treat contaminated soils with high oil toxicity. The effects of operational parameters such as washing temperature (5 to 500C), washing time (1 to 20 minutes), concentration of surfactant solutions (0.004 to 0.5%-mass), volume of surfactant solution (5 to 20 cm3), flow rate (2 to 16 cm3/minutes), pore volume (10 to 70) and contamination history was investigated. The interaction of the surfactant solutions with the oil and soils was also investigated, which was used to explain the dominant mechanisms behind soil washing. The contaminated soils were prepared in the laboratory by mixing the oil and soils. Two different contamination cases were considered: weathered contamination in which freshly contaminated soils were subjected to heat treatment in a fan assisted oven (simulating weathering effect in the natural hot environments), and non-weathered contamination in which contaminated soils were not subjected to any heat treatment. The different washing techniques employed in this study yielded a novel and informative description on the selection of biosurfactants in the remediation of crude oil contaminated soils. This is believed to have major academic and industrial values for the treatment of (1) soil contaminated with oil, (2) sand produced with oil, (3) drill cuttings, (4) enhanced oil recovery, and (5) waste drilling mud and sludge from oil storage tank. In addition, the characterization of the biosurfactants in oil-water, soilwater and oil-soil systems give a general knowledge of their behaviour, which is important in the application for effective removal of oil from soil. Soil washing was found to have a considerable potential in removing oil from the different contaminated soils and results were comparable with those reported in literature. Oil removal by rhamnolipid was more effective than the other biosurfactants and water was effective at higher parameter levels. Further, biosurfactants can preferentially remove certain aromatic groups, which may be desirable for more rapid soil remediation. The rhamnolipid can be equally as efficient at removing oil from soil as SDS at a repeatability range of ± 6%. However, rhamnolipid have advantages over SDS beacuase the use of rhamnolipid will eliminate the need for removing surfactants from effluents as their release will not damage the environment due to their safe natures. Other surfactants (bio and/or synthetic) can be blended with rhamnolipid to achieve greater performance characteristics. In general, the stirred tank and air bubble assisted stirred tank reactors settings were more effective in removing oil from the weathered and the non-weathered contaminated soil samples. The most influential parameter on the oil removal was washing solution temperature with more than 80% of crude oil removal at 500C.
40

Use of ozone to accelerate biodegradation of petroleum oil contaminated soil

Ratnayake, Jayantha I. L. B. January 2004 (has links)
No description available.

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