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Razinų mikrobinės taršos tyrimai / Analysis of raisins microbiological contaminationIzotova, Viktorija 05 March 2014 (has links)
Darbo tikslas: įvertinti Lietuvos rinkoje esančių razinų mikrobinę taršą. Tyrimo objektas: buvo tiriamos šešių skirtingų gamintojų (importuotojų) Sultana rūšies razinos. Iš viso surinkti 42 razinų mėginiai, iš kurių 28 mėginiai buvo paimti iš supakuotų razinų ir 14 razinų mėginiai sudarė sveriamos razinos. Mielių ir pelėsinių grybų skaičiui (KSV/g) nustatyti naudotas YGC (Yeast Extract Glucose Chloramphenicol) agaras. E.coli auginimui naudota chromogeninė terpė Chromocult coliform agar. Visuose tirtų skirtingų gamintojų (importuotojų) razinų mėginiuose buvo aptikta mielių ir pelėsinių grybų tarša. / The aim of work: to analyze micriobiological contamination in raisins of Lithuanian market. The object of work: six different Sultana raisin producers were examined. 42 samples were collected, 28 were collected from packed raisins and 14 from unpacked. YGC (Yeast Extract Glucose Chloramphenicol) agar was used to count yeasts and molds number. For E. coli identification was used Chromocult coliform agar. In every raisin sample yeasts and molds were identified.
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Pieno bakterinio užterštumo nustatymas / Determination of milk bacterial contaminationMelkūnienė, Ingrida 18 June 2014 (has links)
Maisto produktų bakterinis užterštumas yra labai svarbi ir aktuali tema, ypač šiuo metu, kai žmonės grįžta prie natūralaus maisto. Nors maisto produktų saugą reglamentuoja ne vienas teisės aktas, tačiau dėl bakterinės maisto produktų taršos, vis dar kyla dideli epidemijų protrūkiai, kurie sukelia sveikatos sutrikimus tūkstančiams žmonių visame pasaulyje.
Darbo tikslas: nustatyti karvių žalio ir pasterizuoto pieno bakterinį užterštumą.
Rezultatai: Surinkus žalio ir pasterizuoto pieno mėginius iš skirtingų prekybos vietų ir atlikus tyrimus, nustatyta, kad 44 proc. žalio pieno mėginių viršijo didžiausią leistiną bakterinio užterštumo lygį (EB Nr. 853/2004). Tuo tarpu, nei vienas pasterizuoto pieno mėginys neviršijo leistinos EB Nr. 853/2004 ribos. Palyginus žalio pieno bakterinį užterštumą tarp skirtingų prekybos vietų nustatėme, kad didžiausias užterštumas buvo mėginiuose, imtuose iš ūkininkų, kurie gautą produkciją suvartoja savo reikmėms. Vidutiniškai užteršti – iš ūkininkų, kurie gautą produkciją parduoda, o mažiausiai užteršti mėginiai, imti iš prekybos centruose, esančių automatinių pieno aparatų. Gauti rezultatai parodė, kad 50 proc. žalio pieno mėginių buvo užteršti S. aureus bakterijomis. Nei vienas mėginys neviršijo nustatytos leistinos normos pagal HN 26:2006 „Maisto produktų mikrobiologiniai kriterijai”. Tuo tarpu nei viename pasterizuoto pieno mėginyje S. aureus bakterijos nebuvo išskirtos. Escherichia coli bakterijos nei viename žalio pieno bei pasterizuoto pieno... [toliau žr. visą tekstą] / Bacterial contamination of food products is a very important and relevant topic, especially nowadays, when people are beginning to use natural food again. Although food safety is regulated by more than one legal act, however, due to bacterial contamination of food, there is a large epidemic outbreak, causing health problems for thousands of people around the world.
Objective: to determine bacterial contamination of raw and pasteurized cow milk.
Results: After collecting samples and carrying out researches of raw and pasteurized milk from different markets, it is determined that 44 % of raw milk samples has exceeded the maximum allowable level of bacterial contamination (EB Nr. 853/2004). Meanwhile none of the samples of pasteurized milk exceeded allowable limits (EB Nr. 853/2004). Comparing bacterial contamination of raw milk between different markets we determined that the highest contamination was found in samples from farmers, who consume production for their own needs. On average contaminated samples was taken from farmers who sells their production. The lowest contamination was found in samples from automatic milk machines from supermarkets. The results showed that 50 % of the raw milk samples were contaminated with S. aureus bacteria. None of samples exceeded the limit laid down in accordance with the HN 26: 2006 "Microbiological criteria for foods". Meanwhile in pasteurized milk samples S. aureus bacteria were not found. Escherichia coli bacteria were not identified in... [to full text]
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Evaluation of Well Seal Integrity and Its Relative Importance in Assessing Groundwater QualitySt-Germain, Pascale L. 25 November 2011 (has links)
Unlike municipal water supplies, provincial regulations do not require systematic testing of domestic well water, which may adversely impact local residents should contamination occur. Private wells are typically shallow relative to municipal wells, and thus, are particularly vulnerable to sources of surficial contamination if preferential recharge pathways such as natural fractures or faulty seals are present.
In order to determine the relative importance of well seal integrity as a preferential pathway, a practical detection method was developed based on infiltrometry. This method successfully detected faulty well seals in a wide range of geological settings across Canada, including: Hobbema, Alberta; Lindsay, Ontario; and Chelsea, Québec. It was most successful in areas of minimal heterogeneity and where the surficial geology is composed of fine-grained sediments.
The community of Chelsea (Québec) was also the primary study site to examine a range of factors affecting water quality including physical characteristics, faulty well seals, other anthropogenic activities and seasonality. Water samples were collected over a period of 14 months and analyzed for bacteria and major-ion chemistry. The results show that the consideration of physical features alone is not enough to predict vulnerability in the study area. Seasonal fluctuations in ionic concentrations (e.g. ionic strength, NO3-N and Cl-) and coliform bacteria are observed and result from disperse and rapid recharge events. Multivariate analysis techniques (e.g. principal components analysis and hierarchical cluster analysis) demonstrate that preferential recharge pathways and anthropogenic activities, such as domestic effluents affect the groundwater quality. The data and findings of this study were used to assist in the design of a probabilistic risk assessment model based on the Poisson distribution.
This study demonstrates the complexity and the challenges related to bacterial contamination in drilled wells. In spite of these challenges, this analysis was useful as a baseline to assess the impact of anthropogenic activities, and may be used in future studies to assist municipalities in the evaluation and protection of groundwater supplies.
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Water Ice Films in Cryogenic Vacuum ChambersLabello, Jesse Michael 01 December 2011 (has links)
The space simulation chambers at Arnold Engineering Development Complex (AEDC) allow for the testing and calibration of seeker sensors in cryogenic, high vacuum environments. During operation of these chambers, contaminant films can form on the components in the chamber and disrupt operation. Although these contaminant films can be composed of many molecular species, depending on the species outgassed by warm chamber components and any leaks or virtual leaks (pockets of gas trapped within a vacuum chamber) that may be present, water vapor is most common, and it will be the focus of this dissertation. In this dissertation, some properties of the water molecule and low pressure ice are reviewed with a focus on the optical properties. The method of angular coefficients is utilized to calculate flux distributions for general three dimensional situations and the program written is applied to a model of the AEDC 10V space simulation chamber. The optical effects of varying amounts of contamination on a generic germanium window and gold mirror, along with the effects on two components specific to the space chambers, is determined. Also, an experiment to measure the thickness and other properties of contaminant films is discussed, and initial results are given for the first two tests of the experimental setup.
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Optimal Management of Renewable Resources: A Dynamic Model of Surface Water Contamination From Pesticide Use in Rice Production in the Mekong Delta, VietnamDang, Phuong M. 12 1900 (has links)
Both rice production and fish culture in the Mekong Delta, Vietnam have a close mutual relationship with the use of water and land resources. First, they are competitive in the use of land and water. Second, rice production discharges pesticides into water bodies causing an external cost to fish culture, which, in turn, leads to an increase in fish cost and price. A dynamic model for maximizing the social surplus is developed for optimal management of resources as well as production. Its first-order conditions provide some important quantitative as well as qualitative interpretation that explains the dynamic relationships among prices, water quality, and shadow price. The time paths and phase diagrams of the model show the variations and the changes in prices, outputs, and water quality over time, and the initial position in regions leading to divergence or convergence. As a result, effective policies are set up to maximize social welfare. Data are collected and used in estimations of demand functions of rice and fish, the function of assimilative capacity, the fish cost function, and the parameter of pesticide discharge. The total loss of fish culture (total external cost in the year 2001) due to pesticide use is about 9 billion $US. Two cases of linear and nonlinear forms are simulated with scenarios of initial values for the year 2001. The simulation shows optimistic results with prices going down and water quality going up over time, meaning the social surplus will rise. The phase diagram shows that the social manager should look for policies to raise the initial value of water quality to get an optimal solution. A comparative analysis of the model simulation shows the directions of change in parameters leading to a change in the steady state values. How to change the parameter values is analyzed and the analysis suggests different policies.
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Risk-Based Approach to On-site Wastewater Treatment System Siting Design and ManagementCarroll, Steven Paige January 2005 (has links)
The use of on-site wastewater treatment systems (OWTS) for the treatment and dispersal of domestic effluent is common in urban fringe areas which are not serviced by centralised wastewater collection systems. However, due to inappropriate siting and soil characteristics, the failure of these systems has become a common scenario. The current standards and guidelines adopted by many local authorities for assessing suitable site and soil conditions for OWTS are increasingly coming under scrutiny due to the public health and environmental impacts caused by poorly performing systems, in particular septic tank-soil adsorption systems. In order to achieve sustainable on-site wastewater treatment with minimal impacts on the environment and public health, more appropriate means of assessment are required. The research described in the thesis details the processes adopted for the development and implementation of an integrated risk based approach to OWTS siting, design and management. This involved detailed investigations into resolution of some of the inherent deficiencies identified in the existing OWTS codes and guidelines, including more thorough site and soil assessment and data analysis, integration of the key risk facets of OWTS siting and design, environmental and public health, and the incorporation of scientific knowledge into the assessment processes. The research undertaken focused on four key research areas; (i) assessment of soil suitability for providing adequate treatment and dispersal of domestic wastewater; (ii) contamination of ground and surface waters as a result of OWTS failure and the major factors influencing contaminant fate and transport; (iii) assessment of environmental and public health risks due to poor OWTS performance; and (iv) the development of an integrated risk assessment framework for OWTS siting, design and management. The research conducted was multidisciplinary in nature, with detailed investigations of the physical, chemical and biological processes involved in on-site wastewater treatment and dispersal. This involved extensive field investigations, sampling, laboratory testing and detailed data analysis across the fields of soil science, groundwater and surface water quality, chemical and microbiological contamination, and contaminant fate and transport processes. The interactions between these different disciplines can be complex, resulting in large amounts of data being generated from the numerous field investigations and sampling processes undertaken. In order to understand the complex relationships that can occur, multivariate statistical techniques were utilised. The use of these techniques were extremely beneficial, as not only were the respective relationships between investigated parameters identified, but adequate decisions based on the respective correlations were formulated. This allowed a more appropriate assessment of the influential factors, and subsequently the inherent hazards related to OWTS, to be conducted. The primary research objectives for this research were investigated through a series of scientific papers centred on these key research disciplines. The assessment of soil suitability was achieved through extensive soil sampling throughout the study area and detailed laboratory testing and data analysis. The studies undertaken are described in Chapters 3, 4 and 5. Paper 1 (Framework for soil suitability evaluation for sewage effluent renovation) outlines a framework for assessing the renovation ability of the major soil groups located throughout Southeast Queensland. This framework formed the basis for the assessment of OWTS siting and design risks employed in the developed risk framework. Paper 2 (Use of Chemometric Methods and Multicriteria Decision-Making for Site Selection for Sustainable On-site Sewage Effluent Disposal) details and justifies the multivariate data analysis techniques used in establishing the soil framework. Paper 3 (Assessment of soil suitability for effluent renovation using undisturbed soil columns) describes investigations of the use of undisturbed soil cores for the assessment of long term soil renovation ability. This study was undertaken to validate the research outcomes achieved through the established framework developed in Paper 1. Papers 4, 5 and 6 (Chapters 6 - 8) focus on contamination issues of ground and surface waters resulting from poor OWTS treatment performance, and the different factors that influence pollutant fate and transport. The investigation of ground and surface water contamination, detailed in Paper 4 (Assessment of High Density of Onsite Wastewater Treatment Systems on a Shallow Groundwater Coastal Aquifer using PCA) and Paper 5 (Environmental and anthropogenic factors affecting fecal coliforms and E. coli in ground and surface waters in a coastal environment) was achieved through extensive ground and surface water sampling and testing from several monitored study sites. Analysis of the resulting data indicated that several key factors, including rainfall, site and soil conditions and on-site system density can significantly influence the fate and transportation of pollutants emitted from OWTS. An additional issue found during this research in assessing faecal contamination of water resources was the necessity to ensure that the respective sources of contamination were actually OWTS. The inherent difficulty in identifying the actual source of contamination was resolved by employing a source tracking method, namely antibiotic resistance analysis of faecal coliforms (Paper 6; Sourcing fecal pollution from onsite wastewater treatment systems in surface waters using antibiotic resistance analysis). Finally, Paper 7 (Integrated Risk Framework for On-site Wastewater Treatment Systems) describes the development of the final generic integrated risk assessment framework and how the outcomes, as discussed through the previous 6 papers, were combined to assess the environmental and public health risks inherent in OWTS siting and design. The outcomes of this research have significantly contributed to knowledge of best practice in OWTS siting, design and management. The developed soil suitability framework allows more appropriate assessment of soil characteristics for providing effluent renovation. This is generally not done in the current assessment techniques for OWTS. Additionally, the use of this framework incorporates scientific knowledge into the assessment of OWTS, allowing a more rigorous and scientifically robust assessment process. The processes and techniques used in the soil suitability framework, although based on the common soil types typical of South East Queensland, can be implemented in other regions, provided appropriate soil information is collected for the area of interest. The integrated risk framework has also been developed on a generic level, allowing easy implementation into most assessment processes. This gives the framework the flexibility to be developed for other areas specifically targeting the most influential OWTS siting and design factors, and the potential environmental and public health hazards within those regions. The resulting research outcomes achieved through the studies undertaken were subsequently applied to a case study for the development of the integrated risk framework for the Gold Coast region. The developed framework, based on scientific research, has allowed a more appropriate means of assessing site suitability for OWTS and appropriate management and mitigation of the environmental and public health risks inherent with poor OWTS performance
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Integrated land capability for ecological sustainability of on-site sewage treatment systemsAl-Shiekh Khalil, Wael R. January 2005 (has links)
The research project was formulated to solve serious environmental and possible public health problems in rural and regional areas caused by the common failure of soil disposal systems used for application of effluent from on-site domestic sewage treatment systems. On-site sewage treatment systems adopt a treatment train approach with the associated soil disposal area playing a crucial role. The most common on-site sewage treatment system that is used is the conventional septic tank and subsurface effluent disposal system. The subsurface effluent disposal area is given high priority by regulatory authorities due to the significant environmental and public health impacts that can result from their failure. There is generally very poor householder maintenance of the treatment system and this is compounded by the failure of the effluent disposal area resulting in unacceptable surface and groundwater contamination. This underlies the vital importance of employing reliable science-based site suitability assessment techniques for effluent disposal. The research undertaken investigated the role of soil physico-chemical characteristics influencing the behaviour of effluent disposal areas. The study was conducted within the Logan City Council area, Queensland State, Australia. About 50% of the Logan region is unsewered and the common type of on-site sewage treatment used is a septic tank with subsurface effluent disposal area. The work undertaken consisted of extensive field investigations, soil sampling and testing, laboratory studies and extensive data analysis. In the field study, forty-eight sites were investigated for their effluent application suitability. The sites were evaluated based on the soil physico-chemical characteristics. The field investigation indicated that there were nine soil orders in the study area. These soil orders were Dermosols, Chromosols, Kandosols, Kurosols, Vertosols, Sodosols, Tenosols, Rudosols and Anthrosols. The soils in all the investigated sites were acidic soils in the pH range between 5 and 6.5. The complexity of the large data matrix obtained from the analysis was overcome by multivariate analytical methods to assist in evaluating the soils' ability to treat effluent and to understand the importance of various parameters. The analytical methods selected to serve this purpose were PROMETHEE and GAIA. The analysis indicated that the most suitable soils for effluent renovation are the Kandosols whilst the most unsatisfactory soil order was found to be Podosol. The GAIA analysis was in agreement with quantitative analysis conducted earlier. An extensive laboratory column study lasting almost one year was undertaken to validate the results of the data analysis from the field investigation. The main objectives of this experiment were to examine the soil behaviour under practical effluent application and to investigate the long-term acceptance rate for these soils. Twelve representative soils were selected for the column experiment from the previously investigated sites and undisturbed soil cores were collected for this purpose. The results from the column study matched closely with the evaluation conducted at the earlier stages of the research. Soil physico-chemical analysis before and after effluent application indicated that the soils' acidity was improved toward neutrality after effluent application. The results indicated that soils have a greater ability to handle phosphorus than nitrogen. The most favorable cation exchange capacity for soils to treat and transmit effluent was between 15 and 40 meq/100g. Based on the results of the column study, the long-term acceptance rate (LTAR) was determined for the investigated twelve soil types. Eleven out of twelve soils reported specific LTAR values between 0.18-0.22 cm/day. For the duration of the laboratory study, the Podosol order did not reach its LTAR value due to the extremely sandy nature of the soil. The time required to achieve LTAR varied between different soils from 40 to 330 days. The outcomes of this research was integrated into a soil suitability map for on-site sewage treatment systems for Logan City Council. This will assist the authorities in providing sustainable solutions for on-site systems failure.
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Biomarkers of Cadmium, Lead and Selenium Toxicity in the Marine Bivalve Molluscs Tellina deltoidalis and Anadara trapezia: Linking Exposure, Dose and ResponseTaylor, Anne Marie, n/a January 2009 (has links)
The relationships between metal exposure, dose and response were investigated in two
sediment dwelling marine bivalves: a deposit feeder Tellina deltoidalis and a filter feeder
Anadara trapezia. The bivalves were exposed in the laboratory to individual metal spiked
sediments: Cadmium 10 and 50 Ag/g; lead 100 and 300 Ag/g; selenium 5 and 20 Ag/g dry
mass, T. deltoidalis for 28 days A. trapezia for 56 days. A. trapezia was also exposed in the
laboratory for 56 days to sediments from three sites along a metal contamination gradient of
cadmium, lead, selenium, zinc and copper from Lake Macquarie, NSW. Metal total tissue
dose was measured in whole tissue of T. deltoidalis over 28 days and in gill, hepatopancreas
and haemolymph tissues in A. trapezia over 56 days. Subcellular metal distribution,
biologically active metal (BAM) versus biologically detoxified metal (BDM) was measured
in whole tissues of T. deltoidalis at day 28 and in gill and hepatopancreas tissues of
A. trapezia at day 56. Biomarkers of response measured in spiked sediment exposed, at day
28 T. deltoidalis and day 56 A. trapezia were: total antioxidant capacity (TAOC); glutathione
peroxidase enzyme activity (GPx); total glutathione concentration (GSH+2GSSG); reduced to
oxidised glutathione ratio (GSH:GSSG); lipid peroxidation (TBARS); lysosomal membrane
stability and micronuclei frequency. Response indices measured in A. trapezia exposed to
Lake Macquarie sediments were: TAOC, TBARS, lysosomal membrane stability,
micronucleus frequency and condition index. Native A. trapezia and sediments were also
collected from Lake Macquarie and measured for sediment and tissue metal concentrations,
TAOC, TBARS, lysosomal membrane stability and condition index to allow comparison
between chronically exposed and previously unexposed organisms.
T. deltoidalis and A. trapezia accumulated metal over time in all sediment metal exposures
with most reaching equilibrium tissue metal concentrations by the end of the exposure period.
T. deltoidalis generally reached equilibrium with the exposure concentration for cadmium and
lead but had significantly higher selenium tissue concentrations than the sediment metal at the
5 Ag/g exposure. A. trapezia tissue lead was below the sediment concentration for all
exposures including in the native organisms. A high proportion of accumulated lead and
copper in A. trapezia was in the haemolymph, probably associated with haemoglobin which
has a high affinity for these metals`. A. trapezia cadmium tissue concentrations were higher
than the sediment metal in the 10 Ag/g spiked sediment exposure and between half and one
eighth the sediment concentrations in other treatments, including in native organisms.
A. trapezia including the native organisms exposed to selenium sediment concentrations at or
below 5 Ag/g in the Lake Macquarie mixed metal sediments accumulated significantly higher
than ambient selenium tissue concentrations while those exposed to 5 and 20 Ag/g selenium
spiked sediments had lower than ambient selenium tissue concentrations. The majority of
accumulated cadmium, selenium and zinc was associated with the gill/mantle tissues.
A. trapezia hepatopancreas contributed significant selenium concentrations in the later part of
the exposure period indicating and increased contribution from dietary derived selenium.
Native A. trapezia had significantly lower tissue concentrations of selenium, copper and zinc,
higher cadmium and approximately equal lead compared to organisms exposed to similar
sediment metal concentrations in the laboratory.
T. deltoidalis detoxified around 50 % of accumulated cadmium and 70 % of lead while
A. trapezia detoxified around 70 % of accumulated cadmium and 60 % of lead. Much of
T. deltoidalis BDM cadmium was converted to metal rich granules (MRG), while A. trapezia
had most in the metallothionein like proteins (MTLP) fraction. The conversion of lead to
MRG was 75 % of the total BDM in T. deltoidalis while A. trapezia had an even distribution
between MRG and MTLP. The majority of recovered selenium in both species was
associated with the nuclei+cellular debris fraction, probably as protein bound selenium
associated with plasma and selenium bound directly to cell walls. Selenium exposed
organisms had increased BDM selenium burdens which were associated with both MRG and
MTLP fractions, indicating selenium detoxification. The majority of BAM cadmium, lead
and selenium was associated with the mitochondrial fraction in both species with increases in
cadmium burden in this organelle of T. deltoidalis up to 7200 fold; lead 154 fold; and
selenium 7 fold and in A. trapezia up to 84 fold cadmium, 50 fold lead and selenium 7 fold in
exposed organisms compared to controls. The subcellular distribution of all three metals in
T. deltoidalis and A. trapezia indicates active metal detoxification processes which at these
exposure concentrations were unable to prevent significant metal burdens from accumulating
in sensitive organelles.
A contamination gradient of zinc, lead, copper, cadmium and selenium was established in
Lake Macquarie sediments which emanated from the same source. A. trapezia accumulated
all metals in each sediment exposure. Accumulation and tissue distribution patterns of
cadmium, lead and selenium were similar to those of the single metal spiked sediment
exposures. Cadmium and lead BAM burdens increased at all exposures while selenium, zinc
and copper did not.
T. deltoidalis and A. trapezia in the spiked sediment metal exposures generally had reduced
GPx activity. This resulted in an increase in total glutathione concentrations which the
reduced GSH:GSSG ratios indicated was due to a build up of oxidised glutathione.
T. deltoidalis and A. trapezia had reduced TAOC in all laboratory sediment metal exposures
which corresponded with increased TBARS concentrations, lysosomal destabilisation and
micronucleus frequency. A. trapezia exposed to Lake Macquarie metal contaminated
sediments also had a reduction in physiological condition, indicated by the reduced condition
index, after 56 days at the higher metal exposures.
Clear exposure - dose - response relationships have been demonstrated for T. deltoidalis and
A. trapezia exposed to single cadmium, lead and selenium spiked sediments and for
A. trapezia exposed to Lake Macquarie mixed metal contaminated sediments. Detoxification
of all metals was evident in both T. deltoidalis and A. trapezia but detoxification capacity was
exceeded for cadmium, lead and selenium leading to significant accumulation of these metals
in sensitive organelles. The significant relationships, in the laboratory exposed T. deltoidalis
and A. trapezia, between TAOC reduction with increased TBARS, lysosomal destabilisation
and micronuclei frequency and between increased TBARS with lysosomal destabilisation and
micronuclei frequency indicates that increased tissue metal dose and BAM burdens caused
significant impairment of the antioxidant reduction capacity which resulted in a cascade of
effects from lipid peroxidation to cellular perturbation and genotoxic damage. The reduction
in physiological condition in the organisms with the highest tissue metal doses suggests the
response goes beyond subcellular perturbations to whole organism and potentially population
effects.
Chronically metal exposed native Lake Macquarie A. trapezia did not show a clear metal
exposure - dose - response relationship. Accumulation of the essential elements zinc, copper
and selenium appeared to be regulated while cadmium and lead were not. TAOC was
significantly reduced and TBARS significantly increased compared to reference organisms
but lysosomal stability and condition were not significantly affected.
The suite of interrelated biomarkers used offers a weight of evidence approach for
demonstrating adverse effects of metal tissue accumulation in T. deltoidalis and A. trapezia
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Applications of grazing-angle reflection absorption Fourier transform infrared spectroscopy to the analysis of surface contaminationHamilton, Michelle LoAnn January 2007 (has links)
Cleaning validation of pharmaceutical manufacturing equipment is required by legislation. Generally, wet chemical techniques are employed using swabbing and/or rinse sampling methods. These are generally either selective and time consuming, or less selective and give results in a shorter period. The infrared reflection absorption spectroscopy (IRRAS) technique explored here attempts to deliver accurate, selective surface contamination information in real time to complement current methods and reduce down-time. The IRRAS instrument used in this research is a Fourier transform infrared (FTIR) spectrometer coupled by an IR fibre-optic cable to a grazing-angle sampling head with a fixed incidence angle of 80°. The introduced flexibility permits collection of in situ spectra from contaminated surfaces. Calibration models are developed using the multivariate, linear partial least squares (PLS) statistical method. The research focuses on sodium dodecyl sulfate (SDS), a model cleaning agent, on metal (aluminium and stainless steel) and dielectric (glass, EPDM and silicone) surfaces. The effects of surface finish are investigated for SDS on stainless steel. Calibrations for SDS and paracetamol in the presence of each other on glass surfaces are examined, as well as a common industrial cleaner (P3 cosa® PUR80) on polished stainless steel. For the calibration sets in this thesis, RMSECV values were < 0.41 µg cm⁻², corresponding to conservative surface residues detection limits of better than ~0.86 µg cm⁻². However, RMSECV values depend on the calibration loading range, and the detection limits were typically ~0.2 µg cm⁻² for loading ranges 0-2.5 µg cm⁻². These are below visual detection limits, generally taken to be 1-4 µg cm⁻², depending on the analyte and substrate. This shows that IRRAS is a viable method for the real-time detection and quantification of surface contamination by surfactants and active pharmaceutical ingredients on metals and dielectrics.
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Bacillus cereus in the housing environment of dairy cows : contamination routes, effect of teat-cleaning, and measures to improve hygiene in the cubicles and alleys /Magnusson, Madeleine, January 2007 (has links) (PDF)
Diss. (sammanfattning) Alnarp : Sveriges lantbruksuniv., 2007. / Härtill 5 uppsatser.
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