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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.
411

Highway drainage as a component of metal input into the catchment

Zakharova, Yulia S. January 2010 (has links)
Highway runoff, as a nonpoint source, may exert significant pollutant load on the catchment. Finding ways to mitigate nonpoint sources of pollutants is a matter of great concern for improving water quality. It was cited by the Environment Agency in 2005 that more than 80% of English rivers were at risk of failing to achieve Water Framework Directive (WFD) objectives through diffuse pollution (Faram, 2007; p.14). The presence and behaviour of metals were analysed and compared through seasonal sampling from one of the most trafficked roads in the Midlands, M1. These were compared with other sources: local streams and sewage works. The concentration of metals in stormwater from the M1, three neighbouring rural brooks and three local sewage works, all in the same catchment, were sampled. Three metals (Fe, Cu and Zn) were used as an indicator because of their predominance and potential harmful effect on biodiversity. The data was analysed to establish any links between the total and dissolved metals and standard water quality parameters. The thesis also examines the performance of a standard highway treatment system of interceptor and lagoon for removing metals. The results indicate that evaporation and de-icer salts had the strongest effect on metal concentrations and their solubility in the runoff from the M1. As additional factors, rainfall intensity and antecedent dry weather period (ADWP) had the most important influence on metal concentrations. Fe was always at the highest concentrations for all weather conditions (total and dissolved) and all sampling locations. The results also showed that Fe was affiliated with the particulate matter; however, it was also suggested that it was solubilised by anaerobic conditions. Zntot during wet weather exceeded the environmental quality standards (EQS) both on the M1 and in Woodbrook. The sewage work effluent did not exceed the EQS at any time of sampling. It was also found that Zn solubility was increased by the presence of de-icer salts which released it from the sediment by a process of ion-exchange, as suggested by the literature. Cu concentrations had the most erratic values and varied widely but were in the lowest concentrations compared to other metals. During wet weather Cudis from the M1 runoff exceeded the EQS. It was also concluded that the analytical and sample preservation methods chosen could have an effect on the concentrations of copper. Filtration with recycled glass and pea-gravel was able to remove particles down to 5 μm, but at the typical flow rate (5 m/hr), and solids loading the filters would need regular washing. The adsorption studies showed that metals are more effectively removed by alkaline conditions than acid conditions which release metals into the environment.
412

Microbial controls on contaminant metal transport in porous media

Kapetas, Leon January 2011 (has links)
Metal contamination in groundwater aquifers poses risks to human health as well as other life forms. Previous laboratory experiments have demonstrated that bacteria found in geologic settings like aquifers are likely to adsorb metal contaminants and attenuate metal migration. However, as bacteria can also migrate through the groundwater aquifer a better understanding of the combined effect of these two processes is required. The aim of this laboratory study was to a) explore the affinity bacteria exhibit towards metals and porous media of varying composition, b) investigate the effect of mineral and solution composition on the bacterial filtration and c) use the combined data to predict the impact of microbes on metal mobility in porous media. Pantoea Agglomerans was used as a model bacterium while column materials consisted of quartz sand and iron-oxide coated sand (IOCS). Bacteria were characterised using potentiometric titrations to identify the type and concentration of sites present on their bacterial wall. Particular attention was paid to the effect of kinetics of proton and metal adsorption due to the variable contact times that solutions have with bacteria in columns. It was found that increasing the contact time between cell surfaces and protons during potentiometric titrations resulted in less reproducible results. This was due to the release of cell exudates under high pH conditions rather than cell death. Exudates were also found to adsorb protons. Moreover, zinc adsorption onto cell surfaces is higher after 60 to 90 minutes of contact time, while there is a decline in adsorption for longer contact times due to release of cell exudates in the solution. Stability constants for the adsorption of zinc onto cell surface sites, quartz and IOCS materials were determined through batch adsorption experiments, providing a mechanistic explanation of the adsorption process. Reactive transport models incorporating kinetics and surface complexation are developed to describe zinc movement through packed columns. Batch kinetic studies showed that significant Zn sorption to IOCS takes place gradually during the first two hours of contact time. Adsorption continues to take place at a slower rate for an additional 10 hours. This kinetic effect is manifested also during flow-through experiments (column dimensions: length 0.12 m, diameter 0.025 m) with a Darcian velocity 6.1·10-3 cm s-1, which is comparable to natural groundwater flow rates through sand porous media. A pseudo-second order kinetic adsorption model is combined with a numerical advection dispersion model for the first time to predict Zn transport. Model output results are of mixed quality as the model cannot successfully describe contaminant arrival time and breakthrough curve shape simultaneously. Moreover, a mechanistic surface complexation reactive transport model is capable of predicting Zn sorption under varying pH conditions demonstrating the versatility of mechanistic models. However, these models do not account for kinetics and therefore they are not intended to fit the dispersion of the contaminant due to kinetic effects of adsorption. Experiments in mixed zinc/cell systems demonstrate that transport through IOCS is dominated by the adsorption to the porous medium. This is consistent with the batch surface complexation predictions for the system. Adsorption to bacteria is reversible and zinc is stripped from the cells and redistributed onto the IOCS. Adsorption onto cells becomes significant and plays a role in mobile metal speciation only once the column is saturated with zinc.
413

A quantitative and qualitative histological assessment of selected organs of Oreochromis mossambicus after acute exposure to cadmium, chromium and nickel

19 April 2010 (has links)
M.Sc. / South Africa is renowned for its exploitable mineral resources and continues to be a major player in the world’s mineral markets. The country is well known for containing the world’s largest gold and platinum repositories and electroplating industries, which is the major cause for delivering by-products such as cadmium (Cd), chromium (Cr) and nickel (Ni). Environmental pollution caused by active mining and seepage from closed mines, continuously threatens South African water resources. Such pollution can cause a shift in water chemistry and increase the availability of certain metals to the living organisms of such a system. Even at low concentrations metals are amongst the most toxic environmental pollutants. As a result of their persistence and capacity to accumulate in the environment, metals have a lasting detrimental effect on the ecosystem. Although there is progress in the treatment of metallic wastes, the discharge thereof by industries is still a serious water pollution problem. In the past, chemical analysis of water has proven to be of great use for the detection of pollutants within the environment. The value of chemical analysis alone has become limiting, as chemical analysis supplies information on the levels of chemicals at a certain time. Furthermore, the monitoring of water quality variables often does not reflect long-term events that may play a critical role in determining the ecosystem health. It is now generally understood that measurements of only the physical and chemical attributes of water cannot be used as surrogates for assessing the health of an aquatic ecosystem. The new trend is to incorporate biological monitoring into Abstract existing monitoring strategies. Fish are entirely dependent on the aquatic environment for their survival, rendering them a good monitor of water pollution. Macroscopic changes in organs are preceded by changes at the tissue, cellular or molecular level. These changes are the net result of adverse biochemical and physiological changes within an organism. Histological analysis is a therefore very sensitive parameter and a valuable technique in determining cellular changes in target organs as a result of exposure to stressors. Fish histology can thus be used as an indicator of exposure to contaminants and assess the degree of pollution. Because of the subjective nature of morphological studies correlations with other quantitative studies are difficult. However, incorporation of quantitative methods is essential to the continued development of histopathology as a biomarker of pollution exposure, and to the interpretation of histological responses. The aim of this study is to qualitatively and quantitatively describe the toxic induced histological changes in the selected organs of Oreochromis mossambicus after acute exposure to Cd, Cr and Ni. Fish were exposed to 10% (n=20) and 20% (n=20) of the LC50 concentration of Cd, Cr and Ni respectively under controlled conditions (23 ± 1°C) for 96 hours in an environmental room with a control group (n=5) for each exposure.
414

Změny zátěže ekosystému v podélném profilu antropogenně ovlivněného toku / Changes of ecosystem loads in longitudinal profile of anthropogenic polluted river

Kohušová, Kateřina January 2011 (has links)
Disertační práce Změny zátěže ekosystému v podélném profilu antropogenně ovlivněného toku Kateřina Kohušová Changes of ecosystem load in longitudinal profile of antropogenically influenced river ABSTRACT To determine anthropogenic load of the Bílina river ecosystem we monitored concentrations of selected heavy metals (As, Cd, Hg, Pb, V, Zn) and specific organic substances (PAH, PCB, HCH, HCB, DDT) in three different matrices: surface water, biofilms and sediments. In the longitudinal profile of the river, four sampling profiles were determined (B1 - B4), mapping different parts of the river. The monitoring took place from 2005 to 2008. Concentrations of the substances monitored in surface water showed a decrease in load compared to the values from ten years ago. The concentrations found in surface water showed clear tendency of pollution in the longitudinal profile; the load increased downstream and profiles B3 and B4 mid- and downstream had the highest concentration. In the case of some concentrations of substances in surface water there is a trend of the majority of values being below the detection limit by the given methods of analysis. This shows a decrease of load in the river but the positive trend was invalidated by variations in maximum concentrations. Even though these variations were rare and...
415

Složení a aktivita mikrobiálních společenstev v půdě kontaminované těžkými kovy / Composition and activity of microbial communities in soil contaminated by heavy metals

Průchová, Pavla January 2014 (has links)
The thesis focuses on studying changes of microbial communities living in the soil contaminated by heavy metals. Two sites with different degree of contamination were selected in the Příbram area. Respiration was measured in vitro in the soil samples supplemented with various carbon sources and different concentration of cadmium. The respiration showed that even at cadmium concentration of 1000 mg.kg-1 the community is viable and capable of utilization of substrates while increasing the respiration rate. Enviromental DNA from soil samples was isolated and 16S rRNA gene of actinobacteria was amplified. The terminal restriction fragment length polymorphism analysis showed a clear difference between the profiles of both sites. The shifts in the community profiles were observed also after the addition of substrates. The quantification of total bacteria and actinobacteria was performed by quantitative PCR based on amplification of part of the 16S rRNA gene. The more contaminated site contained slightly more bacteria, but almost twice the actinobacteria than the less contaminated one. The sequencing of amplicons of a part of 16S rRNA gene by Illumina showed an increase in proportion of actinobacteria and changes of their community structure in the more contaminated site. The conclusion was made that, high...
416

Prostorové rozložení těžkých kovů v nivních sedimentech Litavky a rekonstrukce historie její kontaminace / Spatial distribution of heavy metals in aluvial sediments of Litavka river and reconstruction of contamination history

Kotková, Kristýna January 2014 (has links)
SUMMARY: This thesis is focused on identification of spatial distribution of Pb, Zn and Cu pollution in floodplain sediments of the Litavka River and reconstruction of its pollution history related to mining and metallurgy of Ag, Pb and Zn in the Příbram area. Sampling was performed in floodplain and sediments were analysed by X-ray fluorescence spectroscopy (ED XRF) in aim to understand the distribution of the target elements in the floodplain fill. The results of ED XRF were calibrated by analyses of selected sediment samples by inductively coupled plasma mass spectrometry with (ICP- MS). The same method was used to determine ratios of lead stable isotopes 206 Pb and 207 Pb. Additionally, magnetic susceptibility was measured, granulometric analysis of selected samples was performed, and cation-exchange capacity (CEC) was determined. The aim of the work was to attempt to reconstruct history of pollution of the floodplain sediments. Sediment dating was performed by 14 C, 137 Cs and 210 Pb. Key words: aluvial sediment, contamination, heavy metals, reconstruction
417

Capteurs fluorescents à base de liquides ioniques à tâche spécifique pour la quantification de traces de métaux lourds dans l’eau / Fluorescent sensors based on task specific ionic liquids for the quantification of traces of heavy metals ions in water

Bell, Jérémy 20 September 2012 (has links)
Cette thèse a pour but la réalisation de capteurs fluorescents à base de liquides ioniques à tâche spécifique pour la quantification de traces de métaux lourds dans l’eau. Dans un premier temps, des sondes moléculaires fluorescentes efficaces pour la détection du mercure, du plomb et du cadmium ont été ciblées. Une première famille de molécules d’éthers lariat d’oxyde de phosphine a montré de bonnes affinités pour le plomb et le cadmium. Tandis qu’un dérivé de séléniure de phosphine s’est révélé être un très bon chemodosimètre pour le mercure avec une limite de détection basse de 3,4 nmol.L-1. Des sondes moléculaires fluorescentes dérivées de la 8-hydroxyquinoléine comportant un groupement phosphinate ou thiophosphinate capables de complexer le mercure en milieu aqueux ont permis d’atteindre une limite de détection exceptionnelle de 0,1 nmol.L-1. Enfin, un composé dérivé de la phénantroline capable de complexer très efficacement le cadmium avec la possibilité de détecter des traces de ce cation est présenté. Après indentification des sondes spécifiques pour les métaux lourds d’intérêt pour le projet, celles-ci ont étés fonctionnalisées afin de les incorporer dans un liquide ionique hydrophobe pour former des liquides ioniques à tâche spécifique pour l’extraction et la détection de métaux lourds. En parallèle du travail concernant les sondes moléculaires, un dispositif d’analyseur de métaux lourds portatif a été mis au point, notamment un nouveau module de détection optique développé. Ce dispositif permet là aussi de détecter des traces de mercure sub-nanomolaire. / The aim of this PhD is the realization of fluorescent sensors based on task specific ionic liquids for the extraction and the quantification of trace of heavy metals ions in water. As a first step, efficient fluorescent molecular probes for the detection of mercury, lead and cadmium were targeted. Two lariat ethers derivated from phosphine oxide show good affinity for lead and cadmium, while a phosphine selenide derivative has proven to be a very good chemodosimeter for mercury with a low detection limit of 3.4 nmol.L-1. Secondly, fluorescent molecular probes derived from 8-hydroxyquinoline having a phosphinate or thiophosphinate group are described. These molecules are able to coordinate mercury in aqueous medium and allow to detect a concentration of mercury in water of 0.1 nmol.L-1. Finally, a phenanthroline derivative for detection of cadmium in aqueous medium is described. With this compound, traces of cadmium can be detected. After identification of the most efficient probes for targeted heavy metals ions, they have been functionalized to be incorporated in a hydrophobic ionic liquid to form task specific ionic liquids for the extraction and detection of heavy metals ions. In parallel of this work on molecular probes, an portable analyzer of heavy metals ions has been developed, including a new optical detection module. This device can also detect sub-nanomolar traces of mercury.
418

Etude du rôle de FW2.2 dans le développement du fruit de tomate / Study of the FW2.2 role during tomato fruit development

Azzi, Lamia 16 December 2013 (has links)
Le gène FW2.2 correspond au locus de caractère quantitatif (QTL) majeur impliqué dans le contrôle de la taille finale du fruit de tomate. FW2.2 appartient à une famille multigénique et code une protéine transmembranaire de 163 acides aminés dont la fonction demeure de nos jours inconnue. Pourtant décrite comme un régulateur négatif des mitoses, par conséquent comme un régulateur de la taille du fruit et cloné plus de 12 ans auparavant, aucune fonction biochimique, physiologique ni même développementale n’a été déterminée concernant cette protéine. Ce qui est d’autant plus étonnant car aucun lien n’a été révélé entre sa fonction protéique et sa capacité à influencer le cycle cellulaire. L’analyse d’une nouvelle version du génome de la tomate nous a permis d’identifier 17 nouvelles séquences homologues à FW2.2 (que nous avons nommé FW2.2-like) et l’alignement de ces séquences nous a permis d’observer une importante conservation du motif PLAC8 commun à cette famille multigénique. L’étude phylogénétique que nous avons réalisée ne nous a donné aucune indication quant à la fonction potentielle de transporteur de métaux lourds de la protéine FW2.2 malgré le fait que sa séquence protéique présente les mêmes caractéristiques que celles décrites chez des transporteurs de métaux lourds. Des expériences d’électrophysiologie ne nous ont pas permis de confirmer son rôle de transporteur, mais des dosages de contenu minéral réalisés sur des péricarpes de fruits de tomate présentant des niveaux d’expression différents pour FW2.2 nous ont permis d’observer une différence de stockage du cadmium dans le péricarpe de ces fruits. Nous avons également étudié le rôle de la protéine FW2.2 dans le développement des plantes en utilisant des lignées de plantes et des lignées cellulaires surexprimant le gène FW2.2. Ceci nous a mené à l’hypothèse que la protéine FW2.2 pouvait être impliquée dans la voie de signalisation des brassinostéroïdes. Pour terminer, nous avons tenté de comprendre quels mécanismes de régulation étaient déclenchés par FW2.2 en recherchant ses partenaires potentiels par le biais de l’application de la technique du Split-Ubiquitin. / The FW2.2 gene corresponds to the major Quantitative Trait Locus (QTL) governing fruit size in tomato. FW2.2 belongs to a multigene family and encodes a transmembrane protein of 163 amino acids whose actual function remains unknown. Although described as a negative regulator of cell divisions and consequently as a regulator of fruit size, any definitive biochemical, physiological and developmental function assigned to FW2.2 is still lacking although the gene was cloned more than twelve years ago. Especially the fundamental question of what kind of link is there between the FW2.2 protein function and cell cycle regulation is all even more relevant. The analysis of the recently released genome of tomato identified 17 new sequences related to FW2.2 (SlFW2.2-like genes) and the protein sequence alignments showed the conservation of the PLAC8 motif common to this multigene family. Our phylogenetic studies did not give any clues relative to the FW2.2 function even though it presents sequence characteristics described for heavy metal transporters. Electrophysiology experiments did not allow the confirmation of the ion transporter function but a total ion content measurement on tomato fruit pericarps differing by their levels of FW2.2 expression showed a difference in the fruit pericarp cadmium content. We also investigated the role of the FW2.2 protein on the plant development using plant and cell lines that overexpress this gene and it appeared that this protein may be involved in the brassinosteroid signal pathway. The regulatory mechanisms mediated by the action of FW2.2 on mitotic activity during fruit development have also been analyzed by looking for potential partners interacting with the FW2.2 protein using the technique of split-ubiquitin.
419

Förbättringsförslag till Kanalen i Sandviken : SWOT-analys av förbättringsförslagen

Lööv, Amanda January 2016 (has links)
The urban area of Sandviken is founded on industries, which also is the driving force of growth throughout the years. The industry were in need of a nearby and easily accessed water source, and therefore a channel was excavated. The name of that channel today is Kanalen and it has three uses: stormwater recipient, natural element and cultural heritage.The environmental load on Sanvikens urban areas are increasing along with Sandvikens population. This lead to issues regarding the possibility to maintain Kanalen and all its three functions in the future. The purpose of this paper is to present suitable improvements that can be made based on the present situation, limited to traffic and solid waste disposal. The physical boundary of Sandvikens community is Sandvikens’ northern urban part. The goal is to obtain knowledge of both the present situation as well as suitable improvements. To understand the so-called Strength, Weaknesses, Opportunities and Threats(SWOT) analysis is also an interest. The target group is foremost the public servants in the community, however it could also be local residents. The method and method implementation are presented in chronological order in the paper. The literature study is based on several annual reports and secondary literature, as well as database research. Visits to Kanalen were performed in order to take relevant photos and make realistic observations on the physical conditions in and around Kanalen. Interviews took place with people who could contribute to the comprehension of the complexity of Kanalen. Both regarding its significance and additional information. SWOT is the analysis used on the suggested improvements eligibility for Sandviken. The tool was consistent throughout each of the improvements suggested. The results section of the paper is meant to function as an informative foundation and a foundation up for discussion. The description of the current situation consists of figures, pictures and substance levels. The description has two main parts. The first includes the physical aspects of Kanalen and surrounding territory. Points of emission from storm drains to Kanalen and aspects of each function as presented. Further information in that chapter of the paper include an earlier event of landslip and Sandvikens green area. Focus then move to traffic and waste pollution. Specific points of pollution from traffic are roundabouts, traffic lights, and paved roads going directly across Kanalen using bridges. Leaked substances from traffic were found mainly to be nutrients like nitrogen and phosphorus, and heavy metals. The solid waste studied in this paper was concentrated on paths in very close proximity to Kanalen, which is used for walking and biking. The outcome of mapping these paths showed that all waste containers were suitable for the intended task. The environmental impact of nutrients and heavy metals retrieved from the annual report were described in general terms. The reason is to show the risks involved with unsupervised and increasing substance levels. Four improvements on traffic pollution and three on waste are presented in the result section. The improvements to traffic pollution to Kanalen in Sandvikens urban area were degreasers, bio-indicators, permeable pavement coatings and plant beds. These improvements could lead to the following positive effects, less downstream work, enhanced esthetical value despite change, and a lasting heritage. The improvements on waste pollution to Kanalen in Sandvikens urban area were to rectify unsuitable waste containers, implement new and improve illumination along Kanalen. These improvements could lead to following positive effects, preferable biological conditions, less visible waste, and the use of modern solutions that are future friendly. Possible errors associated with this study can be choice of method, use of figures and tables and content that maybe should have been included. However, the following conclusions canebe made from this study. The environmental strain could be reduced if suggested improvements are carried out. The advantages concern all three functions of Kanalen. The proportions of each improvement have an effect on the feasibility. Budget and possibility to coordinate are also decisive elements. This work is meant to lead to environmental advantageous change, both in the aquatic setting in Kanalen as well as in its physical surroundings. / Sandvikens tätort är byggd kring industrin som fick den att börja växa. Industrin behövde en vattenkälla vilket innebar att en kanal grävdes fram. Kanalen är namnet idag och har tre funktioner: dagvattenrecipient, naturinslag och kulturarv. Miljöbelastningen ökar i samband med att tätorten och Sandvikens invånarantal växter. Detta innebär problematik beträffande möjligheten att bibehålla Kanalens tre funktioner även i framtiden. Syftet med arbetet är att presentera förbättringar som kan göras baserat på nuläget vid Kanalen, avgränsat till trafik och avfallsområdena. Sandviken norra tätort är den fysiska avgränsningen i kommunen. Målen är att erhålla kompetens om både dagsläget och lämpliga förbättringar, samt att förstå Strength, Weaknesses, Opportunities and Threats(SWOT) till bästa förmåga. Målgruppen är främst Sandvikens kommun men kan likväl vara residenter i kommunen. Metoden och genomförande av metoden presenteras i kronologisk ordning. Litteraturstudien innehåller årsrapporter och sekundärlitteratur, samt databassökning på internet. Studiebesök gjordes på Kanalen för att ta fotografier och erhålla en verklighetsuppfattning av de fysiska förhållandena i och kring Kanalen. Intervjuer gjordes med personer som kunde bidra till förståelsen av Kanalens komplexa betydelse inom kommunen och kompletterande fakta. SWOT är analysmetoden vald för att analysera rekommenderade förslagens lämplighet. Analysverktyget användes konsekvent på varje förbättringsförslag. Resultatdelen med SWOT är menat att fungera som ett informativt underlag och underlag upp för diskussion. I nulägesbeskrivningen presenteras dagsläget på Kanalen med figurer, bilder och substansnivåer. Nulägesbeskrivningen är uppdelad i två huvuddelar. Första delen beskriver Kanalens fysiska utformning och de tre funktionerna. Utsläppspunkter från dagvattenledningarna till Kanalen visas, samt andra tillhörande aspekter av varje funktion. Ett tidigare ras på Kanalen och Sandvikens grönområde förekommer. Därefter presenteras föroreningskällorna trafiken och avfall. Punkter för utsläpp från trafiken som leder till trafikdagvatten i Sandvikens norra tätort är rondeller, trafikljus och vägar som går direkt över Kanalen via broar. Läckageämnen från trafiken pekade på bland annat näringsämnena kväve och fosfor, samt tungmetaller. Avfallsdelen koncentrerades till gång- och cykelbanorna i direkt anslutning till Kanalen. Utfallet från kartläggningen visade att alla sopkärl inte var optimala för ändamålen. Miljökonsekvenserna av näringsämnen och tungmetaller funna i årsrapporterna beskrevs för att visa riskerna involverade med okontrollerade och ökande nivåer. Resultatdelen med en förklaring av förbättringsförslagen och SWOT-analyser innefattar fyra förbättringsförslag på trafiken och tre förslag på avfall. Förslagen gällande trafiken är oljeavskiljare, bioindikatorer, genomsläppliga beläggningar, och växtbäddar. Föregående förslag kan leda till följande positiva konsekvenser, mindre nedströmsarbete, ökat estetiskt värde trots förändring, och ett hållbart arv. Förslagen gällande avfall är åtgärda befintliga sopkärl, introducera nya och förbättra belysningen. Effekterna kan leda till följande positiva konsekvenser, bättre biologiska förhållanden, mindre synligt avfall och moderna lösningar som kan hålla inför framtiden. Felkällor i arbetet exponeras efterföljande kapitel och berör ämnen som metodval, figur och tabellhantering, och innehåll som eventuellt borde ha inkluderats men inte gjorts. Från arbete kan följande slutsatser utvinnas. Miljöbelastningen kan minskas om förbättringsförslagen utförs. Fördelarna berör alla Kanalens tre funktioner. Omfattningarna av förslagen påverkar hur genomförbara förslagen i tätorten är. Budget och möjligheten till samordning är också faktorer som har avgörande roller. Arbetet är menat att förändra på ett miljöfördelaktigt
420

The impacts of feedlot effluent on aquatic freshwater systems

26 May 2010 (has links)
M.Sc. / This study aims to assess the potential impacts of intense feedlot activity on the aquatic freshwater environment, with reference to three feedlots, ranging in production size and all situated in the upper Vaal catchment area. Field assessments were done over a high flow and low flow period, while controlled exposures were also done to quantify a potential stress reaction to growth hormone exposure (using Clarias gariepinus as test organism). It was ascertained that water quality variables contributing towards differences between upstream and downstream environmental conditions are NH4 concentrations pH and conductivity. Lead concentrations were also periodically higher downstream from feedlot activity, in comparison with upstream. Taking the sediment assimilation potential of growth hormones into consideration, it was determined that Feedlot C showed the highest assimilation potential, while Feedlot A reflected the lowest. Alterations on family level invertebrate community structures indicated a categorical decline in abundances and species richness at sites situated downstream from feedlots. However, some clear seasonal influences were also observed. Further community and diversity analyses reflected alterations in invertebrate community structures that were not reflected in SASS 5 scores. With regards to the biomarkers applied in this study, it was noted that there was a significant (p<0.05) difference in the cellular energy allocation (CEA) between control and hormone exposed groups. The total amount of energy available (Ea) increased significantly for test organisms exposed to Diethylstilbestrol (DES), while there was a significant increase in energy consumption (Ec) of test organisms exposed to Trenbolone acetate (TBA). In addition to CEA, metabolic profiling of blood plasma was also performed, which indicated a definite ordination in metabolic constituents after fifteen days of exposure. This was established by subjecting the data to principle component analysis (PCA), which accounted for 83 % variance observed. The impacts and biotic responses identified in this study were contextualised with known literature on the effects of feedlot activity and growth hormone exposure on the aquatic environment. Finally, conclusions were drawn and recommendations made with regard to improving feedlot operational activities. The results obtained in this study contribute towards an integrated framework for the environmental management of feedlot activities.

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