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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.
11

Variation i grönsakers metallupptag : biokoncentrationsfaktorer för kadmium, bly och arsenik från litteraturen och Glasriket jämfört med Naturvårdsverkets generella värden

Lindgren, Lisa January 2014 (has links)
Kadmium, bly och arsenik är ur hälsosynpunkt de mest kritiska metall(oid)erna i Glasriket och på många andra förorenade områden. Konsumtion av grönsaker som odlas på förorenad mark kan utgöra en hälsorisk eftersom växter tar upp föroreningar. Upptag i grönsaker sker främst från porvattnet via rötterna. För att skatta föroreningsupptag kan man tillsammans med halten i jord använda biokoncentrationsfaktorer (BCFs) för den aktuella grödan. En BCF visar förhållandet mellan halten i grödan och halten i jord. Vid extraktion inför analys av dessa halter kan olika metoder användas, vilket kan ge olika resultat. I riskbedömningar av förorenad mark använder Naturvårdsverket generella BCF-värden för att skatta föroreningsupptag. Men upptaget av en given metall i en given gröda varierar och BCFs är därför inte konstanta. Detta arbete är en litteraturstudie av kadmiumupptag, blyupptag och arsenikupptag i sallad och potatis. Biokoncentrationsfaktorer för dessa ämnen varierar stort både i litteraturen och i data från Glasriket. Flera faktorer förutom de plantspecifika och totalhalten i jord styr metallupptaget. Den mest avgörande miljöfaktorn är pH som i hög grad styr metallers löslighet och därmed biotillgänglighet. Miljöfaktorers påverkan på växters metallupptag och variationen för BCFs visar på brister i tillförlitligheten då generella BCF-värden används. / Cadmium, lead and arsenic are critical metal(oid)s for human health due to consumption of vegetables from the Kingdom of Crystal in Sweden and other contaminated sites. Root uptake from pore water is the dominant pathway for metals in crops. To assess the concentration of contaminants in vegetables the soil concentration can be used in association with crop bio concentration factor (BCF). The BCF shows the ratio between the concentration of a certain contaminant in the vegetable and the soil concentration. Soil concentration values, however, depend on extraction method. In Swedish risk assessments for contaminated sites The Environmental Protection Agency uses generic BCF values. But metal uptake varies and these BCF values are not constant for a specific metal in a specific vegetable. This work is a literature study in uptake of cadmium, lead and arsenic in lettuce and potatoes. Bio concentration factors for these elements show great variety in literature and in data from Kingdom of Crystal. The uptake depends on plant specific characteristics and total metal burden in soil but is affected also by other factors. Controlling bioavailability through solubility makes pH the most crucial environmental factor. Metal uptakes dependence on environmental factors and the great variability in BCFs shows shortcomings in reliability for the use of generic BCFs.
12

Těžké kovy v sladkovodních rybách z lokalit okresu Žďár nad Sázavou

Vičarová, Petra January 2014 (has links)
The work deals with the determination of heavy metals (mercury, cadmium and lead) in carp tissues by the use of atomic absorption spectrometry. The theoretical part is focused on the heavy metals and their forms in fishes and in the environment. The anatomy of fishes and the composition of the fish meat are also discussed. The practical part summarized the results of concentrations of studied heavy metals in the carp's tail muscles and in their liver. Carps were fished in two locations - The Pilský reservoir and Domanínský lake situated in Žďár nad Sázavou district. For mercury determination was used one-purpose atomic absorption spectrometer AMA 254. The amounts of cadmium and lead were measured by the electrotermal atomic absorption spectrometry by use of spectrometr ContrAA 700. The obtained results were discussed and evaluated. Obtained concentrations of mercury and lead did not exceed the regulation limits, only concentration of cadmium in liver exceeded these limits in all samples.
13

Kadmium a olovo v rybích výrobcích z obchodní sítě České republiky

Sedláčková, Lenka January 2016 (has links)
The work is focused on the determination of heavy metals - lead and cadmium in smoked fish products which were bought from stores in the Czech Republic during 2014. These were samples of smoked tuna and marlin (Principesca) in which the above limit values of mercury had been found in a previous study within the SVOČ SPŠCH Brno and a bachelor thesis MENDELU (Ventrubová, 2015) . The theoretical part involves the issue of heavy metals (lead and cadmium), their forms as well as their entry into the environment and accumulation in fish organisms. The experimental part is devoted to the determination of lead and cadmium concentrations in the samples, evaluation and comparison of the results with the relevant hygienic limits. Lead concentrations in the samples did not exceed the allowed hygienic limit, however, cadmium concentrations exceeded the allowed hygienic limit in all samples and this was confirmed by SZPI.
14

Eliminace obsahu kadmia v máku aplikací saturačních kalů

Šebestová, Andrea January 2019 (has links)
The aim of the diploma thesis was to test the effect of the soil application of carbonation mud on the change of cadmium (Cd) content in soil and plants in the early stages of development. The experiment was based on a precise phytotron pot trial with a defined light, temperature and humidity regime. As the experimental plant, poppy (Papaver somniferum L., variety Major), was used. Silt brown soil was used for experimental vessels. The effect of carbonation mud was evaluated at the level of three variants of applied doses corresponding to 0, 5 and 10 t.ha-1. Cadmium [Cd (NO3)2] was applied in three variants: 1, 5 and 10 mg.kg-1 of soil. The parameters (soil pH, Cd content in the soil, plant weight, Cd content in the plant, Cd plant uptake) were analyzed in three terms during the experiment. From the results of the analyzes it was found that the control soil variant (6.78) and the cadmium variant without carbonation mud (6.87 - 6.88) showed the lowest soil pH. The highest soil pH was observed in variants with the highest doses of applied carbonation mud (7.64 - 7.66). With increasing doses of applied carbonation mud, the available cadmium content in the soil decreased significantly. A positive relationship of higher doses of carbonation mud and dry weight of plants was demonstrated. Plants with the highest dose of carbonation mud achieved the highest average weight. However, this effect was not proven statistically until the last sampling. Also, the content of cadmium in plants, as well as the plants cadmium uptake, was dependent on the doses of carbonation mud. The highest effect on the elimination of cadmium uptake by the plant was found in variants with the highest doses of carbonation mud.
15

Vybrané těžké kovy v produktech mořských ryb

Smolíková, Vendula January 2017 (has links)
The aim of this master's thesis was to determine the contents of cadmium, lead and mercury in sea fish. Fresh and frozen fish from 17 FAO localities were bought in Czech markets. The theoretical part of this work describes the determined heavy metals and their relation to the environment. All 30 analyzed fish species are also described here. Atomic absorption spectrometry technique was used for determination of cadmium, lead and mercury concentration in the practical part of the work. Twelve samples exceeded the maximum levels for mercury (0.5 mg/kg or 1 mg/kg for selected fish species) and three fish samples exceeded the maximum level for cadmium (0.05 mg/kg) set by Commission Regulation (EU) No 1881/2006, as amended. The maximum level of lead concentration (0.3 mg/kg) was not exceeded in any fish sample. Results of this work show, that samples of marlin (Tetrapturus albidus) and swordfish (Xiphias gladius) are one of the most contaminated fish which can pose a great risk for human health after regular consumption. Because mercury and cadmium contents in some samples were higher than maximum levels recommended by World health organization WHO and Czech legislation, our research initiated an investigation of CAFIA, which led to withdraw some batches of the fish from the Czech markets.
16

Vätskor i indirekt energiöverförande kylsystem och deras potentiella inverkan på miljön

Puskar, Aldijana January 2013 (has links)
Syftet med studien är att kartlägga innehållet hos vätskorna i de indirekt energiöverförande kylsystemen och att uppskatta deras potentiella miljöpåverkan vid utsläpp.   På vätskeprover från system 5 till 8, som är tagna i returledningen på köldbärare 1 i respektive system, har det uppmätts hög syrgashalt, konduktivitet och COD (chemical oxygen demand), vilket ger stor risk för nedbrytning och korrosion. Dessa systemvätskor borde avgasas eller bytas ut. Systemvätskan från system 3, 7 och 8 överskrider gränsvärdena för zink och nickel och de skulle ha toxisk/ - mycket toxisk effekt på vattenlevande djur och växter. Koppar, zink och nickel är nitrifikationshämmande vilket innebär att de påverkar det biologiska reningssteget vid avloppsreningsverket negativt ifall vätskan släpps ut till det kommunala avloppsledningsnätet.   Det framgick utifrån den använda värderingsmallen att de sju största miljöaspekterna är relaterade till föroreningsvariablerna: COD (chemical oxygen demand), zink, syrgas, kväve, järn, nickel och pH. Miljöeffekterna uppträder i form av påverkan från metaller och utarmning av naturtyper, biotoper, arter etc. I samband med exponering skulle metallerna ha mycket toxisk effekt på de flesta vattenlevande djur och växter. / The aim of the study is to identify the contents of the fluids in indirect cooling systems and to assess their potential environmental impact of emissions. System fluid that was collected from system 5 to 8 in the return conduit on brine 1 in each system has high oxygen content, conductivity and chemical oxygen demand (COD), which gives great risk of degradation and corrosion. These systems should be degassed or replaced. System fluid from the system 3, 7 and 8 have shown that zinc and nickel concentrations have exceeded the limit values which could have toxic / very toxic effects on aquatic animals and plants. Copper, zinc and nickel inhibits nitrification, which means that they affect the biological treatment stage, out in the wastewater treatment plant negatively. It was revealed by the valuation model that there are seven main important parameters/components namely, COD (chemical oxygen demand), zinc, oxygen, nitrogen, iron, nickel and pH which have shown elevated concentrations in the fluid. Environmental impact is primarily in the form of the influence of metals and degradation of habitat, species etc. In conjunction with the release, metals would have very toxic effect on most aquatic animals and plants.
17

Är fytoremediering en realistisk metod för att rena marken runt Glasriket på arsenik, kadmium och bly?

Gren, Amanda January 2015 (has links)
Phytoremediation is a technique using the ability of plants to absorb pollutants in their biomass from contaminated soils and remediate it. The plants are then harvested and the soil gets purified. This method is more environmental-friendly than the normally used methods for soil remediation. Glasriket in Småland is an area with large amount of pollutants including arsenic, cadmium and lead. This area must be cleaned from these metals because of the high threat to the environment ant the health of people who live here. This work has been carried out to investigate whether phytoremediation is a realistic remediation method for Glasriket or not. Phytoremediation is affected by many factors such as the environment, soil characteristics and the metals bioavailability. But the key determinant for the method is the choice of plants. The chosen plants must have the ability to survive at the location but also have a high biomass and a good ability to absorb heavy metals. Plants with these criteria do not generally grow in Sweden, which leads to the conclusion that phytoremediation not are a realistic option for Glasriket. But phytoremediation can be used as a second method or in a combination with other methods.
18

Vliv kadmia na obsah vybraných prvků v ječmenu jarním (Hordeum sativum L.) / Influence of cadmium on the content of selected elements in spring barley (Hordeum sativum L.)

Trsková, Nikol January 2016 (has links)
The theoretical part of the thesis consists of research on the spring barley and chemical composition of its grains. Attention is paid to the stress factors which has inpact on plants such as heavy metals and in particular cadmium and its influence on the plants. The last part deals with the importance of selected trace elements such as copper, iron, manganese and zinc. The experimental part of the work is devoted to the influence of cadmium contamination on content of selected elements which are copper, iron, manganese and zinc in plants of spring barley. Two experiments were performed. In both experiments, plants were hydroponically cultivated in Knop nutrient solution. Plants were divided into two parts in each experiment, the first part was cultivated without contamination and served as a control samples, the second part was contaminated. The third day of cultivation was added CdCl2.2,5 H2O at a concentration of 10-5 mol/l to the nutrient solution of the second part. In the first experiment the plants were harvested on the 10th day of cultivation and divided into roots, hypocotyls and shoots. In the second experiment were plants harvested on the 13th day of cultivation and separated into roots, hypocotyls, stem base, 1st (oldest), 2nd and 3th (youngest) leaf. From each part of the plant were prepared samples, which were mineralized and consequentely was measured using the ICP-OES method the content of the above mentioned metals in the contaminated and control-sample plants and the content of cadmium in the contaminated plants. The content of cadmium in the control-sample plants was measured by the ETA-AAS. The measured datae were analyzed and described in to the taps and graphs. Highest concentration of cadmiu was discovered in roots of the control sample plants, in case of the first experiment the roots contained 91 %, in the second 95,5 % from the entire amount of cadmium contained in the plant. As a result of the contamination changes in contents of the selected elements ocured. In both of the experimentes the amount of Cu in roots increased, in the upper part of the plants (shoots) the amount was lower comparing non-contaminated plants. The iron content in the first experiment increased in roots and hypocotyl, in the upper part of the plants (shoots) the content decreased in comparison with control variant. In the second experiment, was the iron content lower in all plant parts. The manganese content was lower in the contaminated plants in almost all parts, only in the first experiment was found minimal increase of manganese content in roots. In both experimentes was found minimal change in content of zinc in roots, in the first experimente increased zinc content in hypocotyls and decreased in the upper part of the plants (shoots), while in the second experiment there was little change of content in hypocotyls but zinc increased in the upper part of the plants (shoots). The deferences in results of both experimentes may be dependent on varions lenght of the cultivation.
19

Vliv dlouhodobého hnojení travního porostu na obsah rizikových prvků v půdě / Effect of long-term fertilizer application on content of risk elements in grassland soil

Jungová, Michaela January 2017 (has links)
The long-term Steinach Grassland Experiment is probably one of the oldest still-running fertilised grass experiments in continental Europe. The experiment was established on an alluvial meadow Alopecurus pratensis in southeastern Germany in 1933. The meadow was divided into 75 plots and fertilised with both mineral and organic fertilisers of differing compositions and amounts. The aim of this study was to provide more detailed information about the effects of long-term fertilisation by natrium (N), phosphorus (P) and potassium (K) on the contents of risk elements in soil. The effects of long-term fertilisation were investigated in the extracts of a) plant-available elements (extraction of CaCl2), b) easily mobilised elements (extraction of EDTA), c) potentially mobilisable elements (extraction of HNO3), the total concentration of elements (extraction of Aqua regia). Concentrations of risk elements As, Cr, Cu, Fe, Mn, Ni and Zn in the soil profile has increased substantially due to the phosphorus fertilisation; however, the limits for total trace elements concentration as set by the Czech legislation have been exceeded only twice, namely in the case of As and Cd. The total concentration of As (AsT) has been exceeded only once, on the plot fertilised only by nitrogen. The assumption is that that the increased level of AsT fraction in soil was probably caused in the past by fertilising with Thomas slag which is known to contain elevated concentrations of As. However, fertilising with the phosphorus-containing fertilisers has had the opposite effect on concentrations of Mn, Ni and Zn that are easily available to plants; concentrations of these elements in the soil extraction were substantially higher. In spite of the overall concentrations of Cd being lower than the Czech legislative standards, the results on several plots fertilised by mineral and organic fertilisers containing N, P and K showed higher concentrations of Cd and in one case reached the limit value. Plots fertilised by mineral fertilisers N160P44K174 (NH4)2SO4 recorded higher Cr concentrations. In overview, it could be stated that under various types of fertilising no substantial effects of long-term fertiliser applications on a higher content of risk elements in soil has been detected. Only two plots have exceeded the limits set by Notice 13/1994 Sb., in one case it was a total concentration of As and in another one that of Cd.
20

Bioackumulering av tungmetaller i vildsvin (Sus scrofa) : -analys av biotillgängligheten av bly och kadmium i vildsvinslever

Axelsson, Helena, Spångberg, Annica January 2018 (has links)
As the wild boar population increases, so does the consuming of wild boar meat. Often with the belief that this is much healthier than conventional meat. International studies have shown that wild boar meat is more likely to contain higher concentrations of soil pollutions than other game meat. The aim of this study was therefore to analyze the concentrations of lead (Pb) and cadmium (Cd) in the liver of free living wild boars (Sus scrofa), located in the south of Sweden. Samples were taken from 10 wild boars during the hunting season of spring, 2018. The lead and cadmium concentrations in wild boar livers were determined by AAS- atomic absorption spectroscopy. Our result shows a higher uptake for cadmium than lead. Cadmium also seem to increase with age in wild boars due to bioaccumulation. However, 7 out of 10 livers exceeded the maximum limit for food safety standards regarding lead (0,10 mg/kg) and 2 out of 10 for cadmium (0,50 mg/kg). Therefore, the consumer should practice vigilance, especially for wild boar meat originating from areas known to be contaminated.

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