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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.
51

Raman spectroscopy as a tool to improve Enhanced Biological Phosphorus Removal

Cope, Helen Anne January 2016 (has links)
Enhanced Biological Phosphorus Removal (EBPR) is an established process in wastewater treatment that uses bacteria to reduce phosphorus levels below regulatory discharge limits. Recently, in light of growing political concern over phosphorus sustainability, EBPR has also been recognised as a platform from which phosphorus may be recovered and recycled onto land as fertiliser. Operating EBPR to optimise performance and efficiency is therefore extremely important, but remains a challenge due to poor understanding of these bacterial ecosystems. Raman spectroscopy is a non-invasive, label-free, culture-independent technique capable of analysing live, single cells. Despite its advantages, Raman spectroscopy has been applied to study EBPR bacteria in just a handful of studies and thus has a low profile in this field of research. More work is required to investigate potential areas of application for Raman spectroscopy in EBPR research. The principal thesis presented here is that Raman spectroscopy could be used as a tool to improve EBPR. The Raman spectra used for this investigation were acquired from individual EBPR bacteria dried onto a calcium fluoride substrate. The bacterial samples were collected from three different sources, namely lab-scale sequencing batch reactors located in Edinburgh (University of Edinburgh, UK) and Boston (Northeastern University, USA), and a full-scale EBPR plant in Slough (Thames Water, UK). Using these spectra, some potential applications and limitations of Raman spectroscopy for improving EBPR were explored. In this foundation work, a particular emphasis on spectral analysis methods was kept in light of the benefits of automating analysis as well as the need for standardisation to be able to compare results between different studies and groups. Nine methods were compared for baselining Raman spectra of individual EBPR bacteria. From these, the “small-window moving average” (SWiMA) method was determined to be the best baselining technique for our purposes at the current time. In agreement with earlier studies, the Raman spectroscopic signatures of three key EBPR metabolites – polyphosphate, polyhydroxyalkanoate (PHA) and glycogen – were shown to be clearly identifiable in individual EBPR bacteria when present. The Raman shifts of characteristic spectral bands arising from polyphosphate were shown to vary significantly between samples and the implications of this were discussed. Examples of how the Raman spectra of individual bacteria can be modelled with multivariate tools to open up new areas for research were given. MCR modelling was demonstrated to offer a novel way to normalise the Raman spectra of individual EBPR bacteria prior to quantitative analysis. With the instrumental set-up in this work, the limit of detection (LOD) of aqueous polyphosphate samples was estimated to be approximately 0.08 M and 0.02 M for 10 second and 200 second acquisitions respectively. Future work is required to research ways in which a more comparable form of polyphosphate ‘standard’ might be prepared so that direct correlation can be drawn between measurements made on such a standard and measurements made in bacterial cells. Overall, several applications and challenges of Raman spectroscopy for the investigation of EBPR bacteria are presented in this work together with recommendation for how to process the spectral data. The conclusions drawn from this work indicate that Raman spectroscopy could be used as a tool to improve EBPR but further work is required to refine and apply these methods.
52

Investigation into phosphorus removal by iron ochre for the potential treatment of aquatic phosphorus pollution

Carr, Stephen Thomas David January 2012 (has links)
Phosphorus (P) pollution of waterbodies is a global issue with detrimental environmental, social and economic impacts. Low-cost and sustainable P removal technologies are therefore required to tackle P pollution, whilst also offering a technique for reclaiming P. Ochre, a waste product from minewater treatment plants (MWTPs), has been proposed as a suitable material for the removal of P from enriched waters due to a high content of Fe, Al, Ca and Mg, which have high affinities for P removal. Whilst a range of studies have been conducted investigating ochre as a P adsorbent, most of these are large-scale field experiments and lack understanding of the underlying processes of P removal by ochre. There have also been very few detailed comparisons of different ochre types. The primary focus of this thesis is thus to provide a process-based understanding of P removal by various ochres, in order to investigate the optimal conditions for the use of ochres in the treatment of aquatic P pollution. Seven ochres from six MWTPs in the UK and Ireland were investigated, one of which was in a pelleted form. The ochres were largely comprised of Al, Ca, Fe and Mg (42-68 % by dry weight), had a high B.E.T. surface area, 56-243 m2 g-1, and contained mineral surfaces with a high affinity for P adsorption, such as goethite and calcite. A novel batch experiment methodology was utilised to calculate the adsorption characteristics of ochre at discrete pH conditions. The variation of these characteristics with pH indicates the importance and requirement for such a method to study adsorption by materials at the expected pH conditions of application. At the pH conditions of wastewater streams (~pH 7), the P adsorption capacities of the ochres, determined from fitting adsorption isotherms, was 11.8–43.1 mg P g-1. Results of P adsorption batch experiments were modelled in ORCHESTRA, wherein P removal by the ochres was described well by adsorption onto hydrous ferric oxides. Three of the ochres contain relatively high calcite contents and due to a poor fit of the model to the observed datasets at high pH conditions, with equilibrium P concentrations lower in the batch experiments than the modelled result, adsorption onto calcite is suggested as a P removal mechanism for these ochres at pH > 7. Environmental application of ochre filters will require P removal under flow-through transport conditions. Column experiments were therefore conducted using two ochres, coarse-grained Polkemmet ochre and Acomb pellets (column volume 1055 cm3, pore space 490-661 cm3, typical pore volumes of experiments: 220-400). P removal efficiency increased with contact time, and the presence of competing ions had only marginal effects on P removal. Resting the column substrate for 48 hours between P applications greatly increased the P removal efficiency of a packed column of Polkemmet ochre, resulting in 81 % of influent P removed over 1000 pore volumes of operation (7.68 mg P g-1). Acomb pellets had a lower P removal efficiency than Polkemmet ochre. It is suggested that the high calcium content of the pellets, as a result of the pelletisation process, has created a substrate where the dominant P removal mechanism at neutral pH conditions is adsorption to calcite, which has slower reaction kinetics than adsorption onto goethite. Therefore, this pelleted ochre requires a higher contact time for adsorption reactions to occur. It is suggested that ochre filters are most suitable for application in situations where flow rate is constant or can be controlled e.g. septic tank effluent. Ochres which dry to a coarse particle size are preferred for use as a substrate as pelletisation requires capital, expertise and can produce substrates with slower P sorption kinetics. Resting the filter substrate between P application regenerates surface sites for adsorption, and filters should be run in parallel to maximise P removal efficiency. Acomb pellets, which are a mix of iron hydroxides and alkaline materials, may have potential application as a permeable reactive barrier substrate to treat P enriched ground waters. Further research utilising fine-grained ochres as an additive to P rich fertilisers or for use in continuously stirred tank reactors is recommended.
53

Αιωρούμενα σωματίδια στην ατμόσφαιρα της Πάτρας

Μασσαρά, Βασιλική 03 April 2012 (has links)
Η μελέτη της παρουσίας των αιωρούμενων σωματιδίων στην ατμόσφαιρα είναι μεγάλης σημασίας, καθώς η εκτίμηση των επιπτώσεών τους στον άνθρωπο και στο περιβάλλον είναι ένα εξαιρετικά πολύπλοκο ζήτημα για την παγκόσμια επιστημονική κοινότητα. Η μελέτη των αιωρούμενων σωματιδίων αποτέλεσε ερευνητικό αντικείμενο μόλις τις τελευταίες πέντε δεκαετίες και με βάση μελέτες που έγιναν, διαπιστώθηκε η επίπτωσή τους στην υγεία του ανθρώπου και την κλιματική αλλαγή. Επίσης, αποδεικνύεται ο ρόλος τους στις διεργασίες σχηματισμού των νεφών και της ομίχλης και στη διαμόρφωση του ενεργειακού ισοζυγίου του πλανήτη. Ωστόσο, τα αιωρούμενα σωματίδια δεν μπορούν να μελετηθούν εύκολα εξαιτίας του μικρού μεγέθους και της σύνθετης χημικής τους σύνθεσης. Σκοπός αυτής της διπλωματικής - ερευνητικής εργασίας είναι η εκτίμηση της ατμοσφαιρικής κατάστασης στο κέντρο της Πάτρας. Η εκτίμηση αυτή θα προκύψει από τη μέτρηση των συγκεντρώσεων των αιωρούμενων σωματιδίων, στο κέντρο της πόλης. Οι μετρήσεις έγιναν σε κεντρικές αρτηρίες της πόλης, ενώ συλλέχθηκαν και στοιχεία μετεωρολογικών παραμέτρων, ώστε να μελετηθεί η επίδρασή τους στις συγκεντρώσεις των αιωρουμένων σωματιδίων. Το καινοτόμο στοιχείο της διπλωματικής αυτής εργασίας είναι το γεγονός ότι έγιναν καταγραφές και για τις συγκεντρώσεις των αιωρούμενων σωματιδίων PM 1, για τα οποία δεν έχει θεσμοθετηθεί όριο επικινδυνότητας. Παρόλα αυτά, οι επιστήμονες θεωρούν ότι λόγω της μικρής διαμέτρου τους είναι πιθανό να εισχωρούν έως και το κυκλοφορικό σύστημα των ανθρώπων, με αποτέλεσμα οι επιπτώσεις τους στην υγεία του ανθρώπου να θέλει περαιτέρω διερεύνηση. Επιπρόσθετα, σε αυτήν την εργασία έγιναν μετρήσεις για την συγκέντρωση του μονοξειδίου του άνθρακα (CO) στις ίδιες τοποθεσίες και την ίδια χρονική στιγμή που έγιναν οι μετρήσεις για τα αιωρούμενα σωματίδια. Αυτό μας δίνει τη δυνατότητα να γίνει συσχετισμός των στοιχείων αυτών που καταγράφηκαν και να βγάλουμε συμπεράσματα για την ποιότητα της ατμόσφαιρας. Τέλος δε, θα γίνει σύγκριση της κατάστασης που επικρατεί στη Πάτρα με τη κατάσταση που επικρατεί σε άλλες πόλεις της Ελλάδας, καθώς και με τα όρια εκπομπής αιωρούμενων σωματιδίων, όπως αναφέρονται στη σχετική κατευθυντήρια οδηγία της Ευρωπαϊκής Ένωσης περί εκπομπής ρύπων. / The study of the presence of particulate matter in the atmosphere is of essential importance, as the estimation of particulate matter 's consequences on human and the environment is an exceptionally complex matter for the world scientific community. The study of particulate matter has been object of investigation just for the latest five decades and according several studies it has been notified the implications on human health and climate changes. It also has been proved their role in formation processes of clouds and fog and the formation of energy balance of the planet. However, particulate matters cannot be easily studied because of their very small size and their complex chemical composition. The main purpose of this diploma thesis is the evaluation of the atmospheric situation in the city of Patras. This evaluation will be resulted out of the measurement of the concentration of particulate matter at city center. The measurements have been taken from central drive arteries of the city, while have been collected also features of meteorological parameters, in order to study their effect on the concentrations of particulate matter. The innovation of this diploma thesis is the fact that there have been recorded also the concentrations of particulate matter PM1, for which there has not yet been any establishment of danger limits. Nevertheless, scientists consider that because of their very small diameter it is possible to penetrate into the human circulatory system, resulting consequences in human health, for which is needed further investigation. In addition in this diploma thesis have been reordered measurements of the concentration of carbon monoxide (CO) at the same locations and simultaneously with the particulate matter. This enables us to correlate these elements and make conclusions about the quality of the atmosphere. Finally, there will be a comparison of the situation of the air quality between Patras and other Greek cities, as well as the limits of particulate matter emission, as they refer in the relevant guidance instructions of European Community about pollutant emissions. In addition in this diploma thesis have been reordered measurements of the concentration of carbon monoxide (CO) at the same locations and simultaneously with the particulate matter. This enables us to correlate these elements and make conclusions about the quality of the atmosphere. Finally, there will be a comparison of the situation of the air quality between Patras and other Greek cities, as well as the limits of particulate matter emission, as they refer in the relevant guidance instructions of European Community about pollutant emissions.
54

An operational method for assessing traffic-related air pollution in urban streets

Vardoulakis, Sotirios January 2002 (has links)
Urban air quality has been a topic of major public concern and scientific research in recent years. Several theoretical and experimental studies have focused on the assessment of air quality within street canyons and other microenvironments (intersections, motorways, parking spaces, etc.), where population exposure to traffic-related pollutants is relatively high. The aim of this study was to develop a practical methodology for assessing traffic-related air pollution in urban streets, after testing available monitoring and modelling techniques. To meet this objective, a large amount of original air quality, meteorological and traffic data were collected during four intensive short-term and one long-term monitoring campaigns carried out in the region of Paris from December 1998 to December 2001. These campaigns covered three representative street canyon sites (Bd. Voltaire, Rue de Rennes, Av. Leclerc - PI. Basch) as well as a motorway service station (RN10 petrol station). Passive and active monitoring techniques were used to sample a wide range of inorganic (CO, NO X and Os) and organic gases (benzene, toluene, xylene, ethylbenzene, formaldehyde, acetaldehyde, etc.) at different heights and distances from the kerb. Indicative background measurements were also taken during the same sampling periods. Furthermore, relevant meteorological (synoptic and local) and traffic information was obtained on each site. The analysis of the data gave insights into the dispersion and transformation processes taking place within the streets. Channelling effects induced by parallel to the road axis winds gave rise to relatively high kerbside pollution levels. On the other hand, perpendicular synoptic winds generated air vortices within the canyons, which resulted in steep crossroad concentration gradients. In that case, higher pollution levels were observed on the leeward than on the windward side of the streets. A significant reduction of concentrations with height above the ground was also observed within two of the street canyons (Bd. Voltaire and Av. Leclerc). In all cases, roadside concentrations were several times higher than the corresponding urban background values. This spatial variability indicates a strong transport effect on the pollutant distribution within urban canyons, caused by the synoptic wind and influenced by the geometry of the street. That may have serious implications in terms of population exposure and compliance with air quality legislation. In this context, the siting of permanent monitoring equipment becomes crucial. A relationship between CO and benzene as well as an exponential expression linking pollutant concentrations at different heights within the canyons were empirically deduced. Five dispersion models of different levels of complexity (STREET-SRI, OSPM, AEOLIUS, CAR-International, and CALINE4) were used to calculate CO and benzene concentrations at the campaign sites. The Computational Fluid Dynamic code PHOENICS was also tested for one location. The comparison between observed and predicted values revealed the advantages and drawbacks of each model in association with the configuration of the street and the meteorological conditions. Furthermore, a sensitivity and uncertainty analysis involving three of the available models (STREET-SRI, OSPM and AEOLIUS) was carried out. OSPM was slightly modified in order to allow user access to certain internally coded parameters. An operational method combining multi-site sampling and dispersion modelling was finally proposed for assessing air quality in urban streets, taking into account the pronounced spatial and temporal variability of traffic-related air pollution, the modelling uncertainty, the practical constraints related to measurements and models, and the needs of decision makers. This methodology may find wider application in air quality management, urban and transport planning, and population exposure studies.
55

Bioavailability and toxicity of aluminium to the freshwater crayfish, Pacifastacus leniusculus

Woodburn, Katie January 2012 (has links)
Aluminium is the third most abundant element in the lithosphere and yet no biological function has been elucidated. The ubiquity and pH-dependent chemical speciation of aluminium provides multiple routes of exposure to organisms, inducing neurotoxicity, tissue necrosis and organelle dysfunction. However, many studies of aluminium toxicity lack consideration of the speciation and relevant concentration of aluminium and the route of exposure. The aim of this thesis was to examine the accumulation, distribution, excretion and toxicity of aluminium following a common route of exposure (ingestion) at a concentration likely to be encountered by the model organism (freshwater crayfish, Pacifastacus leniusculus) in the wild. Crayfish are sediment dwelling omnivorous crustaceans distributed worldwide and as such are vulnerable to multiple routes of aluminium exposure. They play a central role in aquatic food webs and are becoming increasingly popular for human consumption, raising concern about food chain transfer. Crayfish were fed aluminium chloride-spiked artificial food pellets for either 20 days, 28 days + 10 day aluminium-free clearance period, or 22 weeks + 4 week aluminium-free clearance period. In addition, systemic administration of aluminium citrate was undertaken to draw comparisons with previous mammalian work and compare the two routes of exposure. Tissue distribution and accumulation was measured in the gills, hepatopancreas, flexor muscle and antennal gland. Stress and tissue damage were analysed using biochemical and histopathological techniques. Behavioural toxicity tests and measurements of the neurophysiological parameters of the crayfish medial giant neuron were used to assess aluminium-induced neurotoxicity. In vitro neurotoxicity tests with aluminium chloride were also carried out on isolated nerve tissue to assess the suitability of in vitro studies. The key site of aluminium accumulation following ingestion was the hepatopancreas. Excretion was observed via the gills, antennal glands (in the urine) and hepatopancreas (for incorporation into the faeces). However, physiological consequences such as tissue damage, inflammation and altered neuronal activity were observed and persisted even after cessation of aluminium ingestion. Consequently there are implication for crayfish fitness and survival, the aquatic food web and human toxicity following ingestion of aluminium.
56

Geochemical associations and availability of cadmium (Cd) in a paddy field system, northwestern Thailand

Kosolsaksakul, Peerapat January 2014 (has links)
The Mae Tao watershed, northwestern Thailand, has become contaminated with cadmium (Cd) from the zinc mining activities area in the nearby Thanon-Thongchai mountains. Consumption of Cd-contaminated rice has led to documented human health impacts. The aim of this study was to clarify transfer pathways from creek and canal waters to the paddy field soils near Baan Mae Tao Mai village and to determine the relationship between Cd forms in the soil and uptake by rice plants. Soils, irrigation canal sediments and water samples were collected during the dry season and at the onset of the rainy season. Rice samples were collected at harvesting time and samples of soil fertiliser were also obtained. Water samples were filtered, ultrafiltered and analysed by ICP-MS whilst sub-samples of dried, ground soils and sediments were first subjected to micro-wave assisted acid digestion (modified US EPA method 3052). XPRD and SEM-EDX methods were used for mineralogical characterisation and selective chemical extractions have assisted in the characterisation of solid phase Cd associations. Transfer mainly occurred in association with particulate matter during flooding and channel dredging and, in contrast with many other studies, most of the soil Cd was associated with exchangeable and carbonate-bound fractions. Moreover, there was a significant positive relationship between soil total Cd and rice grain Cd (R2=0.715), but a stronger relationship between both the Tessier-exchangeable soil Cd and the BCR-exchangeable soil Cd and rice grain Cd (R2=0.895 and 0.861, respectively). Stable Isotope Exchange (gives isotopically exchangeable Cd - E value) is generally considered to provide a better measure of bioavailability. The results of this study showed that SIE gave values which significantly positive correlated with the Tessier exchangeable fraction. Biochar has a porous structure and acidic functional groups on its surface which give it a high capacity to affect heavy metal adsorption when added to soils. Biochar samples were produced from rice husk (RHC) and miscanthus (MC) since these are cheap and readily available materials in Thailand. Indeed rice husk char is already used for rice seed germination by local farmers. Evaluation of the chemical and physical properties of the chars showed that the lower temperature (350°C) chars had greater proportions of oxygen-containing functional groups than those produced at 700°C. Moreover the low temperature RHC had the greater cation exchange capacity than the MC produced at the same temperature. In abiotic feasibility tests, it was shown that RHC was more effective than MC at lowering soil available Cd. The former reduced the E values for the medium-Cd soils by 4.7% and 16.0% when 1% and 5% RHC, was added, respectively. From pot experiments, in medium-Cd soils, 1% and 5% RHC amendment showed the potential to decrease Cd uptake by rice roots. However, further work involving addition of a greater proportion of biochar with a higher number of replicates is needed to reach more robust conclusions.
57

Επιπλέοντα (floating) απορρίμματα σε θαλάσσιες περιοχές της δυτικής Ελλάδος

Δημητρίου, Ευφροσύνη 17 July 2014 (has links)
Στη παρούσα εργασία παρουσιάζονται τα αποτελέσματα της καταγραφής των επιπλεόντων απορριμμάτων σε δύο θαλάσσιες περιοχές της Δυτικής Ελλάδος: (α) το δυτικό Κορινθιακό κόλπο και (β) το βόρειο τμήμα του Στενού Κέρκυρας Ηγουμενίτσας. Ο δυτικός Κορινθιακός κόλπος χαρακτηρίζεται από ισχυρή συμβολή χερσαίων πηγών ρύπανσης (ποταμοί) ενώ οι ναυσιπλοϊακές γραμμές συνιστούν μια αξιοσημείωτη θαλάσσια πηγή ρύπανσης. Η περιοχή του βόρειου στενού Κέρκυρας-Ηγουμενίτσας ελέγχεται κυρίως από θαλάσσιες πηγές ρύπανσης (ναυσιπλοΐα). Το πλαστικό διαπιστώνεται ότι είναι το κυρίαρχο υλικό και στις δύο περιοχές (83%-82%) ενώ οι γενικές συσκευασίες (23%-21%) και οι συσκευασίες ποτών/αναψυκτικών (32%-22%) οι κυρίαρχες χρήσεις τους. Αναπτύχθηκαν μέθοδοι για τον υπολογισμό και την παρουσίαση της επιφανειακής πυκνότητας των απορριμμάτων και οι μετρήσεις αυτές ερμηνεύτηκαν με βάση τις κυρίαρχες πηγές ρύπανσης. Μέθοδοι στατιστικής ανάλυσης εφαρμόστηκαν για την σύγκριση της σύστασης (υλικό) των επιπλεόντων απορριμμάτων. / In this study, the results of the recording of floating litter in two maritime regions of West Greece are presented: (a) in the west Corinthian gulf and (b) in the north part of the narrow region between Corfu and Igoumenitsa. The west Corinthian gulf is characterized by powerful contribution of overland polluted sources (rivers) while the navigational lines institute one notable maritime source of pollution. The region of the north narrow region between Corfu and Igoumenitsa is controlled mainly from maritime sources of pollution (navigation). It is concluded that the plastic is the predominant material in both regions (83%-82%) while the general packaging (23%-21%) and the beverage packaging (32%-22%) their main uses. Methods have beendeveloped for the calculation and the presentation of the surface density of the litter and these measurements have been interpreted according to the predominant sources of pollution. Methods of statistical analysis have been implemented for the comparison of the consistency (material) of the floating litter.
58

Investigating the influence of vehicular traffic on a major trunk road on rural air quality

Obara, Paul Goodluck January 2012 (has links)
Traffic population in the UK has grown by 27% in 2002 and predicted to continue to an estimated 38% in 2016 and up to 60% by 2031. This means vehicular emissions from road transport may account for higher proportion of total emissions of pollutants resulting in air pollution with its attendant consequences. Although poor air quality concerns has often been linked to urban areas, many rural areas apparently have locations where air quality objectives may be threatened especially in the wake of increasing vehicular population. Thus, this elicits the necessity to investigate the relationship between vehicular emissions and air quality. This study investigated the influence of vehicular traffic on a major trunk road on rural air quality through continuous measurements of nitrogen dioxide, sulphur dioxide and hydrocarbon between June 2008 and April 2010 along a major trunk road in a catalogued rural environment in the UK. Collection and analysis of pollutants was by Dräger short-term tubes and Dräger passive diffusion tube techniques. Throughout the sampling period, concentrations of sulphur dioxide were not detected using the short-term tube technique but were detected by the passive diffusion tubes. The study found that variations in mean concentrations of the pollutants were synonymous with traffic frequency and were influenced by meteorological conditions especially wind speed, temperature and relative humidity. Results observed concentration decline trend with increasing distance and showed maximum concentrations during winter, mainly in areas of close proximity to anthropogenic source, and minimum in summer. Values between winter year 1 and winter year 2 monitoring campaigns showed significant difference (P<0.05 and R=0.91) as was in summer year 1 and year 2 (P<0.05 and R=0.94), spring year 1 and year 2 (P<0.05 and R=0.84) and autumn year 1 and year 2 (P<0.05 and R=0.79). When compared with the guidance limits, NO2 Page ii showed exceededance at roadside and 50 m, and at some sample sites, up to 100 m from the road. Conversely, SO2 did not show any exceedance but statistical analyses was mostly significant between concentrations and distance at p≤0.05, suggesting the variability of pollutants, as well as the influence of distance on their temporal and spatial distribution. Results also show that pollutants correlated very well with daily traffic population with strong positive r2 and R-values. Similarly, the study considered the application of hazel leave (Corylus avellana) and ryegrass (Lolium perenne) vegetation samples in monitoring rural air quality. Both samples were collected in different seasons and distances (5m, 50m, and 100m) from the A49 trunk road at four rural sites characterised with diverse traffic densities and anthropogenic activities. The aim was to determine the elemental content and trends within the samples and to investigate the influence of distance from the road, height from ground level, and sampling season on the elemental levels. The levels of Al, As, Ba, Ca, Si, Mg, S, Cd, Cr, Na, Ni, Sb, Se, Sn, Mo, Mn, C, K, P, Cl, Ti, Fe, Zn, and Pb were determined using X-ray fluorescence (XRF), inductively coupled plasma-mass spectrometer (ICP-MS), and Scanning Electron Microscopy-Energy Dispersive X-ray spectrometer (SEM-EDX). Results show that despite the traffic differentials between the sampling sites, the pollution level of heavy metals were generally low in all sampling site and concentrations of Cr, Cu, Ni, Pb, and Ti exhibited inverse relationship with distance, decreasing in levels with increasing distance from the trunk road. Although root uptake from the soil is a potential source of heavy metals, geochemistry research of the study area did not show any evidence that proves any major heavy metals deposit concerns in the soil. It is therefore possible that heavy metal emissions were deposited in a form that was not readily available for root uptake, thereby narrowing the presence of heavy metal pollutants to other potential Page iii sources. However, this study found high level of heavy metals at the roadside measurements in the order of Zn (0.703 ppm) > Ti (0.346 ppm) > Cr (0.111 ppm) > Cu (0.106 ppm) > Pb (0.026 ppm) > Ni (0.025 ppm). They were found in different magnitudes higher than their respective levels at 50 and 100 m from the trunk road and therefore tend to support traffic origin. Findings from this study show that heavy metals exhibited different degree of correlation between individual elements, ranging from very strong positive to weak, as well as negative correlations. Statistical analyses show that the elements predominantly exhibited statistically significant differences between elements and between distances from the road. Overall, findings from this study demonstrate that both vegetation species prove to be successfully useful in determining the pollution status and trends of traffic-related heavy metals.
59

Bioavailability of organic contaminants in rivers

Onogbosele, Cyril Oziegbe January 2015 (has links)
In rivers, association of organic contaminants with dissolved organic carbon may limit freely dissolved or bioavailable fractions and toxicity of organic contaminants. Consequently, assessment of toxicity of organic contaminants on the basis of their total chemical concentrations may lead to overestimation of risks to organic contaminants. Therefore, to achieve reliable and accurate risks assessment for organic contaminants, determination of bioavailability is important. The influence of humic acid on the bioavailability of organic contaminants in rivers was studied, using three chemicals with different properties as model contaminants, which at the start of the study were detected in wastewater effluents. It was hypothesized that in the presence of dissolved organic carbon, a fraction of the total concentration of an organic contaminant would not be bioavailable in river water. Therefore, the aim of the study was to determine bioavailability and its impact on toxicity. Bioavailability in the presence of humic acid was determined chemically and using a yeast estrogen screen assay. The chemical method comprised solid-phase extraction and liquid chromatography-mass spectrometry to determine freely dissolved and the fraction of the chemicals associated with dissolved organic carbon. The results indicated increased binding to dissolved organic carbon with the hydrophobicity of the test compounds except for perfluorooctane sulfonate. The dissolved organic carbon-water partition coefficient for ethinylestradiol was determined to be Log KDOC 2.36. Log KDOC values of 4.15 and 4.41 at 10 and 100 mg/L humic acid, respectively, were derived for hexabromocyclododecane indicating greater binding than ethinylestradiol due to the more hydrophobic character. The yeast estrogen screen was used as a biological method to measure the effect of humic acid on the bioavailability of ethinylestradiol and a more hydrophobic compound, dichlorodiphenyltrichloroethane. Results of the yeast estrogen screen indicated that the presence of humic acid had no effect on bioavailability of either of the chemicals.
60

Μελέτη διασποράς σωματιδίων σε αστικό περιβάλλον (Πάτρα). Επίδραση στην ανθρώπινη υγεία

Ντούνη, Χριστίνα 13 January 2015 (has links)
Στην παρούσα εργασία μελετάται η περιοχή της Πάτρας ως προς τη διασπορά των σωματιδίων καθώς και η επίδρασή τους στην ανθρώπινη υγεία. Στο πρώτο μέρος δίνονται κάποια στοιχεία όσον αφορά την ατμόσφαιρα (γενικά), την ατμοσφαιρική ρύπανση, τα ατμοσφαιρικά σωματίδια (διαχωρισμός, μέθοδοι προσδιορισμού), η νομοθεσία που αφορά την ατμοσφαιρική ρύπανση καθώς και τα πρότυπα ποιότητας αέρα για τα αιωρούμενα σωματίδια. Επίσης αναλύονται και οι επιπτώσεις των αιωρούμενων σωματιδίων στον άνθρωπο. Στο δεύτερο μέρος γίνεται η γεωγραφική και η γεωλογική τοποθέτηση της περιοχής μελέτης (Πάτρα). Στο τρίτο μέρος παρουσιάζεται η διασπορά των σωματιδίων στην περιοχή μελέτης και στο τέταρτο μέρος παρατίθενται συμπεράσματα και λύσεις. / In this paper we study the area of Patras on the dispersion of particles and their effect on human health. In the first part are some data on the atmosphere (generally), atmospheric pollution, atmospheric particles (separation, assay methods), the legislation on air pollution and air quality standards for particulate matter. And also, analyzed the effects of particulate matter in humans. In second place is the geographical and geological study of the area, (Patras). The third part shows the dispersion of the particles in the study area and the fourth part reflects conclusions and solutions.

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