Spelling suggestions: "subject:"kein,""
261 |
Consequences of Filtration for Risk Assessing Metal Contaminated Ground WatersÄngmyren, Elisabeth January 2016 (has links)
The purpose of this project was to optimize the filtration process when analyzing ground water for risk assessment. Particulate (>0.45 μm), colloidal (0.45 μm<diam.<0.01 μm) and dissolved metal species were studied using different filtration methods: flow filtration in the field using peristaltic pump and in-line filter; replaceable filters and syringe filter in the field; replaceable filters and syringe filter in a laboratory environment. Studies where metal concentrations in the filtrate are measured as a function of the amount of material enriched in the filter was carried out. MP-AES were used for analyzing the metals in controlled systems and the reference method was done with ICP-MS. The project was done on the behalf of Structor and evaluation were also made between the sampling methods that Structor has undertaken and the methods that was examined in this report. The results were evaluated by comparison of guideline values set by the World health organization, WHO on drinking water and the regulation and status classification and environmental quality values of ground water recommended by the Swedish Geological Survey, SGU. Produced data was assessed by conventional statistics.
|
262 |
Determination of Polyoxymethylene (POM) : Water Partition Coefficients for Alkylated Polycyclic Aromatic Hydrocarbons by Use of GC/MSBergman, Malin January 2016 (has links)
Methods to measure the concentration of freely dissolved PAHs in pore water have been developed and are based on the usage of passive samplers, in this case polyoxymethylene (POM). Spiked samples (containing PAHs with 4-5 rings, methylated PAHs with 2-5 rings and dibenzothiophenes in three different concentrations) were placed on an end-over-end shaker for 28 days, to obtain equilibrium between the amount of PAHs accumulated on the POM strips and the amount of PAHs freely dissolved in the water. Four samples (medium concentration) were removed from the shaker after 7 and 14 days, respectively, and after 28 days were 12 samples (low, medium and high concentrations) removed. The variance of the average log(KPOM) values obtained from medium concentration were statistically tested, and showed that the coefficients for all compounds did not differ significantly over time. The coefficient difference between the three concentrations for the methylated PAHs were greater amongst the more hydrophobic compounds; 7,12-Dimethylbenz(a)anthracene had log(KPOM) of 5.64, 2.77 and 3.71 (low, medium, high). The hydrophilic compounds had coefficients that were more similar in the three concentrations; 1,6-Dimethylnaphthalene had log(KPOM) of 3.80, 2.62, and 3.39 (low, medium, high). Previous studies have determined log(KPOM) for several PAHs, and merged log(KPOM) for alkylated isomeric PAHs. The coefficients from the lowest concentration of serval methylated PAHs and Benzo(e)pyrene were similar to log(KPOM) values obtained for those compounds in an earlier study. The accuracy of risk assessments of PAH contaminated areas will increase when analysing individual methylated PAHs and using individual KPOM values for methylated PAHs, as in this study, instead of merged coefficients.
|
263 |
Assessment on Groundwater Contamination from a Former Hard Chromium Plating Site in IggesundAlnehem, Isabell January 2016 (has links)
Before the persistent and toxicological properties of perfluoroalkyl and polyfluoroalkyl substances (PFASs) were known they were used worldwide. The thermal and chemical stability from the carbon-fluorine bond makes these substances desirable for industrial applications. One particular PFAS that have received much attention is perfluorooctanesulfonic acid (PFOS) which is included in the Stockholm convention. Analyses have detected PFASs, especially the ones with longer carbon chain, in the environment, wildlife and humans so replacements are being searched for. This study investigates groundwater around a former hard chromium plating site, which is one of the registered exceptions where PFOS still is used. Five different located sampling points were collected and analyzed from this site in Iggesund, which is in the northern parts of Sweden. The substances analyzed for were thirteen perfluorinated carboxylic acids (PFCAs: C4-C14, C16 and C18), five perfluorinated sulfonic acids (PFSAs: C4, C6, C8 and C10) and 6:2 fluorotelomer sulfonate (6:2 FTS). The 6:2 telomer substances is being used as a replacement for similar compounds with longer carbon chains, but are believed to undergo biotransformation to persistent alkyl acids like perfluorohexanoic acid (PFHxA) in the environment. Solid phase extraction was performed on 500 mL filtered groundwater with and the concentrated samples were analyzed on an Ultra Performance Liquid Chromatography (UPLC), tandem mass spectrometer. The glass microfiber filters used for filtrating the groundwater were analyzed for particle bound PFASs. Results from the water extraction analysis showed eight detected PFAS, with PFOS as the major contributor (72 - 9600 ng/L). The PFOS concentrations differs substantially between the five groundwater samples where the two sampling points located south of the facility, and closest to the actual hard chromium plating, were clearly higher than the other three. Two other substances detected in high concentration were perfluorobutanesulfonic acid (PFBuS), 8-1550 ng/L, and perfluorohexanesulfonic acid (PFHxS), 18-140 ng/L which can be produced as an impurity during the production of PFOS. PFCAs in all samples were detected in lower concentrations (1-25 ng/L). Additional to the PFAS analysis, the groundwater was also measured for chromium since the carcinogenic hexavalent form is used in the chromic acid bath during hard chromium plating. In the same two samples that had the highest PFAS concentration, chromium was found in high concentration, 34900-44800 μg/L. These result indicates that the chromic acid baths is the source for the elevated concentrations found in the groundwater. If the facilities are left to deteriorate it will lead to continuously spreading of chromium and the highly water soluble PFASs downstream to Iggesundså which is of concern for the environment and water living organisms.
|
264 |
Analysis of Polycyclic Aromatic Hydrocarbons in Freshwater Snails of Family Lymnaeidae from PatholmsvikenKarlsson, Malin January 2015 (has links)
Polycyclic aromatic compounds (PAHs) are a group of organic compounds that are very stable and therefore persistent. They can be pyrogenic or petrogenic and PAHs from petrogenic sources are often enriched with alkylated PAHs while pyrogenic sources often contain more of the parent PAH. In Patholmsviken, a bay located near an abandoned woodimpregnating facility, freshwater snails were collected and analysed for PAH16, alkylated PAHs, oxy-PAHs and azaarenes using GC/MS. The concentrations of PAH16 were compared with previous analyses and the results showed that the levels had declined since 2008 and 2013. The ratio between alkylated PAHs and native PAH coincide with what could be expected from a creosote source which consist of more native PAHs. Only one oxy-PAH could be detected and the levels of alkylated PAHs were low. Freshwater snails seem to be a good bioindicator since they meet many of the desired criteria for a suitable biomonitoring organism. / Polycykliska aromatiska föreningar (PAH) är en grupp av organiska föreningar som är mycket stabila och därmed långlivade. De kan vara pyrogena eller petrogena, de petrogena källorna är ofta berikad med alkylerade PAHer medan de pyrogena källorna oftare innehåller mer av icke-substituerade PAHer. I Patholmsviken, en vik som ligger bredvid en nedlagd träimpregneringsanläggning, har snäckor samlats in och analyserats för PAH16, alkylerade PAHer, oxy-PAHer och azaarener med hjälp av GC/MS. Koncentrationerna av PAH16 jämfördes med värden från två tidigare analyser och resultaten visade att nivåerna hade minskat sedan 2008 och 2013. Endast en oxy-PAH kunde detekteras och nivåerna av alkylerade PAHer var låga. De låga nivåerna av alkylerade PAH överensstämmer med vad som kan förväntas hitta från en kreosotkälla som avger pyrogena PAHer. Snäckor verkar vara lämpliga att använda som bioindikatorer eftersom de uppfyller många av de kriterier som finns för dessa.
|
265 |
Techniques for Determining Alcohol Levels in Wine and Mulled WineBrus, Camilla January 2015 (has links)
The aim of this study is to in cooperation with Grythyttan Vin compare and evaluate the accuracy and precision of the Alcolyzer Wine. The Alcolyzer Wine is a Near Infrared based instrument that was compared to GC-FID, GC-MS and distillation. Samples were taken from cisterns at Grythyttan Vin along with finished product samples. These were then analysed using the mentioned analytical techniques. Multiple improvements can be made for the different techniques, such as use of internal standards. The relative standard deviations are higher than desired. Considering aspects such as precision, accuracy, cost, time consumption and user friendliness the preferred method of use is the Alcolyzer Wine. Even though it has limitations in the need to know sugar content it is the fastest and easiest instrument to use. Further studies have to be made to ensure the accuracy and precision of the GC-MS and the GC-FID.
|
266 |
Adsorption of Cr(VI) on Mill ScaleKöpberg, Linus January 2016 (has links)
Mill scale is a by-product from hot rolling of steel. It has a high content of iron oxide which has the ability to adsorb ions. Hexavalent chromium is a pollutant which could be adsorbed to mill scale. Different pre-treatment of the mill scale was tested to optimize the adsorption of hexavalent chromium. For an efficient adsorption of hexavalent chromium the pH had to be below 6 in the aqueous phase. Optimal adsorption was obtained on mill scale treated at a low temperature, as sintering at higher temperatures decreased the surface area, with the optimal pre-treatment being heating at 200 °C followed by a rapid cooling of the mill scale. This study also showed that the mill scale used for adsorption can be reused after desorption with only a slight decrease in capacity. A large heterogeneity of the material was noticed during the adsorption tests and the capacity fluctuated significantly between 50 % and 85 % for the different samples. The content of organic matter in the material and its removal was also studied. Chemical treatment with NH3 and NaOH showed no increase in removal of organic matter only heating at different temperatures showed success. This indicates that the present organic matter most likely is stable long chained hydrocarbons e.g. lube oil.
|
267 |
Leaching of Lead and Other Heavy Metals from Brass Couplings under Different Hydrochemical ConditionsJernberg, Torgny January 2016 (has links)
Brass couplings are used in most piping systems for tap water. The alloy contain a variety of metal composition, amongst these metals lead is included. Lead is a toxic metal that can leach from brass when it is in contact with aqueous solutions. There are several physical and chemical conditions that affect the leaching of lead. Stagnation time, material composition and water quality are some of these conditions. The aim of this project is to generate a dataset that can be used for evaluation of the leaching of heavy metals from brass couplings during different hydrochemical conditions. By exposing brass couplings to synthetic waters various properties, analyse the results and comparing these to limits set by approval procedures it is possible to obtain a prediction on how the brass couplings might leach lead when installed in tap water systems. Results shows that at least one of the brass couplings included in this test could be unfit for usage in drinking water system installations.
|
268 |
Development of a Liquid Chromatography Method to Separate and Fractionate EPA’s 16 Priority Polycyclic Aromatic Hydrocarbons (PAHs)Sinioja, Tim January 2016 (has links)
Polycyclic Aromatic Hydrocarbons (PAHs) are persistent, toxic and carcinogenic environmental pollutants consisting of two or more aromatic rings. The estimation of the toxicity of PAHs can be challenging and time-consuming due to the complexity of PAH-mixtures found in the environment, for example at contaminated sites. To solve the problem of a high complexity, PAH-mixtures can be divided into fractions. In the present study, Normal Phase (NP) and Reverse Phase (RP) Liquid Chromatography (LC) methods were evaluated and developed to separate and fractionate 16 U.S. Environmental Protection Agency’s (EPA) priority PAHs. Two stationary and six mobile phases, different column temperatures, flow rates, injection volumes, gradient and isocratic elutions were evaluated in order to achieve the best separation and fractionation. Best separation of PAHs was achieved with the RP-LC method using a phenyl stationary phase and gradient elution with mixture of methanol, acetonitrile and water. Fractionation was performed based on PAHs’ retention time windows, as well as peaks’ threshold and slope values. The elution order of fractions was verified by identification and quantification of the PAHs by GC-MS. Fractionation of a soil extract with the developed RP-LC method resulted in successful separation and fractionation of five EPA’s priority PAHs naphthalene, fluorene, phenanthrene, anthracene and chrysene, as well as two non-priority PAHs carbazole and 4H-Cyclopenta[d,e,f]phenanthrene. The study shows that developed RP-LC method can be further optimized to fractionate complex mixtures of alkyl substituted, oxygenated and other polycyclic aromatic compounds (PACs).
|
269 |
Adsorption of heptyl xanthate at the metal sulphide/aqueousinterfaceFredriksson, Andreas January 2004 (has links)
In sulphide mineral flotation a sufficient hydrophobicity of the mineral surfaces is obtained by the adsorption of collector chemicals at the metal sulphide/aqueous interface. This surface alteration is of fundamental and applied interest. In this thesis, attenuated total reflection infrared spectroscopy has been used to monitor the adsorption kinetics and the orientation of heptyl xanthate when adsorbed onto three solid surfaces - germanium, zinc sulphide and lead sulphide in-situ. The choice of using the ATR technique is because it is very suitable when working with water as solvent, and the choice of germanium as internal reflection element is because of its small penetration depth due to a high refraction index. The Chemical Bath Deposition method has been used to deposit metal sulphides onto germanium internal reflection elements. For determining the adsorption of heptyl xanthate onto lead sulphide a novel method has been tested, and verified as capable in recovering information about surface reactions at a lead sulphide/aqueous interface. In the study of surface reactions the substrate is of vast importance, implying that the chemistry of the surface has to be well characterised. This work has utilized X-ray Photoelectron spectroscopy, and ATR spectroscopy, in the characterisation of the different surfaces. The adsorption kinetics has been followed to adsorption equilibrium at different concentrations. In the case of heptyl xanthate adsorbed at the zinc sulphide/aqueous interface, an adsorption isotherm has been calculated from the equilibrium data. On the assumption that the adsorption step was rate controlling a second order rate equation was derived and adsorption rate data tested according to this equation. In addition, an orientation study of the heptyl xanthate molecule at the different interfaces was performed, which requires polarised infrared light. In the case of heptyl xanthate adorbed onto germanium, both surface excess and a degree of alignment of the alkyl chain from the surface normal has been calculated. / Godkänd; 2004; 20070127 (ysko)
|
270 |
Studies of artificial mass bias in isotopic measurements by inductively coupled plasma mass spectrometryAndrén, Henrik January 2004 (has links)
Mass spectrometry, and especially inductively coupled plasma mass spectrometry (ICP-MS), suffers heavily from mass bias, or instrumental mass discrimination. The nett result of this effect is the preferential transmission, most often of heavier ions through the mass spectrometer. Most work regarding this phenomenon in ICP-MS dates back quite far, and has been interpreted in terms of the space-charge effect. This means that Coulombic forces acting on the beam of positively charged particles extracted from the ICP result in greater dissipation of lighter, and hence more mobile ions from the beam axis. In this work the importance of the space-charge effect as a universal explanation for mass bias is challenged by the results of high precision measurements of isotope ratios. Other than considering some commonly known sources of isotope ratio measurement bias, a not previously considered mechanism of isotopic fractionation has been investigated, i.e. diffusion in solution. It was established that, indeed, diffusion does lead to isotopic fractionation in solution, and although this is a long term process, may contribute to the minor isotopic variations observed in certain aquatic environments. Furthermore it was established that spectral interferences of argone oxide ions could be discerned from the ions of iron using high resolution ICP-MS, thus eliminating this potential source of artificial fractionation. Most significant was the discovery that the extent of mass bias varied throughout the volume of the plasma, and was further affected by sample characteristics, such as analyte concentration and acid strength. This identifies the plasma itself as the major source of instrumental mass discrimination. Varying the sampling position, i.e. the point at which ions are extracted from the plasma, not only affected the measured isotope ratios, but also the precision of such measurements. From these results, it is not recommended to measure at the sampling position providing maximum signal, since the variability in the isotope ratio is also at its' maximum there. Instead, the ions should be sampled from a point below the maximum, where the stability of the ratios will be better. / Godkänd; 2004; 20070128 (ysko)
|
Page generated in 0.0353 seconds