The genotoxicity of energetic compounds (i.e., explosives) that are known to be present in contaminated soils at military training sites has not been extensively investigated. Thus, the Salmonella mutagenicity and Muta(TM)Mouse assays were employed as in vitro assays to examine the mutagenic activity of twelve explosive compounds, as well as three soil samples from Canadian Forces Base Petawawa. Salmonella analyses employed strains TA98 (frameshift mutations) and TA100 (base-pair substitution mutations), as well as the metabolically-enhanced YG1041 (TA98 background) and YG1042 (TA100 background), with and without exogenous metabolic activation (S9). For Salmonella analyses, the results indicate that ten of the explosive compounds were mutagenic, and consistently elicited direct-acting, base-pair substitution activity. All three soil samples were also observed to be mutagenic, eliciting direct-acting, frameshift activity. Mutagenic potencies were significantly higher on the metabolically-enhanced strains for all compounds and soil samples. For Muta(TM)Mouse analyses on FE1 cells, the results indicate that the majority of explosive compounds did not exhibit mutagenic activity. All three soil samples elicited significant positive responses (PET 1 and PET 3 without S9, and PET 2 with S9), and although there is some evidence of a concentration-related trend, the responses were weak. Correspondence of the mutagenic activity observed with the two assay systems, for both the explosive compounds and soil samples, was negligible. The differential response is likely due to differences in metabolic capacity between the two assay systems. Furthermore, it is likely that there are unidentified compounds present in these soil samples that are, at least in part, responsible for the observed mutagenic activity. Additional testing of other explosive compounds, as well as soil samples from other military training sites, using a variety of in vitro and in vivo assays, is warranted in order to reliably estimate mutagenic hazard and subsequently assess risk to human health.

In this study we evaluated the use of microarray technology in Bacterial Source Tracking (BST), with the intent of identifying candidate genes to be used to differentiate between closely related strains of Escherichia coli. We anticipate that genes differentially expressed in response to stress by both a laboratory strain and environmental isolate could be used as marker genes on a microarray in BST. Using microarrays we characterized the transcriptional response of E. coli K12 MG1655 (K12), maintained for about 80 years in an artificial environment versus E. coli 43(C)-4A or E43, a strain recently isolated from the natural environment. The responses were to a temperature decrease from 37°C to 21°C, and to growth in a diluted LB broth (dLB). Overall we found that there were more genes differentially expressed between the strains than either strain's response to the stresses. At the 4-fold threshold, at reduced temperature there were only 26 genes differentially regulated by K12 and 9 by E43, respectively. In K12 the functions of some differentially expressed genes were linked to the general stress response and biofilm formation. A few genes differentially expressed by E43 were involved in the stress response. Similarly, in response to dLB there were 46 and 11 genes differentially expressed by K12 and E43 respectively. While it appeared that genes differentially expressed by K12 were involved in dealing with nutrient deficiencies, the genes differentially expressed by E43 did not show a similar pattern. Of these genes, none were obvious candidate genes for a microarray to be used in BST. However, we did find that 169, 286 and 254 genes were differentially expressed between K12 and E43 at 37°C, 21°C, and in dLB, respectively. Many of these genes were differentially expressed under all 3 growth conditions. Several of the genes differentially expressed between the strains were in the O-antigen-lipopolysaccharide gene family and are genes that could potentially be used on a microarray in BST. We found that E43, isolated from the natural environment, did not respond to the growth conditions in the same way as the model strain, E. coli K12, indicating that strains of E. coli isolated from the natural environment may not be identical to the model strain K12. It is suggested that other strains isolated from the natural environment be investigated. Such studies could also reveal genes differentially expressed between the strains that could be used on a microarray for use in BST.

Food production in urban areas has been conducted worldwide as a subsistence strategy and source of income. Recently, however, it is recognized that urban agriculture has the potential to contribute to the development of sustainable urban environments. This study examines the benefits of urban food production in North American cities, as well as focusing on some of the critical barriers to its widespread expansion and acceptance. It also explores the potential for contamination of produce from the ambient atmosphere in mid-sized urban centres. Through interviewing nine urban farmers and one urban planner, in the city of Victoria, British Columbia, I documented each producer’s knowledge of the benefits and limitations associated with urban food production. Each interviewee impressed upon me the numerous benefits that can be accrued through the practice of urban agriculture, but they also painted a picture of the struggles that urban farmers face. Issues identified included: a real and perceived risk of contamination, problems with land ownership and access, and lack of meaningful support for urban farmers. Although urban agriculture has been accepted in principle by the City of Victoria and other Canadian cities, there are many challenges that must be overcome for urban food production to truly produce a viable, sustained food system. A coordinated, comprehensive government policy for involvement in the urban food system is critical to effectively addressing urban food issues. Investigations of heavy metal levels in lettuce (Lactuca sativa) grown in sampling sites across an urban/rural gradient showed that atmospheric contamination by heavy metals is greatest at urban sites, but also affects residential and rural sites. Sampling site types included: a control area (rural farms and properties outside of Victoria); residential sites (yards in residential neighbourhoods in the City of Victoria); and, industrial/business sites (heavily trafficked and industrialized areas in downtown Victoria). Site types were intended to reflect areas perceived as safe, probably safe, and probably not safe, and were selected based on expert opinion and land use. Results indicate that caution should be exercised in growing leafy greens at downtown sites, and that growing food in most residential neighbourhoods and green spaces is typically no worse than growing greens in rural Victoria. In fact, due to the proximity of urban agriculture to the market, growing food locally eliminates the need for transportation and extra processing; reducing the extra exposure crops otherwise might face during these phases. Urban food production requires the support of communities and governments in order to contribute to both urban food security and urban sustainability. The City of Victoria has started on a path to ensuring that this food system receives the required support, but it requires concerted effort and action. Further research into urban food systems is necessary to ensure that urban food production is able to become a viable, sustained food system. / Graduate

Studien har gjorts mot bakgrund av den pågående diskussionen gällande införandet av sprutbytesverksamhet i Jönköpings län och vill till den diskussionen tillföra de skilda erfarenheterna som finns i fyra olika existerande sprutbytesprogrammen i Sverige, att jämföra likheter och skillnader i praxis och att relatera dessa erfarenheter till deras mål och resurser. Trots att lagen om sprutbyte trädde i kraft år 2006 är sprutbyte fortfarande ett kontroversiellt ämne i Sverige. I denna omtvistade form av preventiv verksamhet finns det dock en viktig del som gör ämnet mer relevant och det är de goda, sociala bieffekter som programmen medför. Dessa omnämns i studien som paramedicinsk vård. Metoden som ligger till grund för studien är kvalitativa, semistrukturerade intervjuer. Materialet har sedan analyserats för betydelsen av sitt innehåll och genom organisationsteori. Utgångspunkten är avhandlingar, vetenskapliga artiklar och litteratur i ämnet sprutbyte. Vid sprutbytesprogrammen i Sverige skiljer sig uppfattningarna åt gällande behovet och implementeringen av den paramedicinska vården i verksamheten. Likaså går åsikterna isär mellan de forskare, politiker och professionellt verksamma som intervjuats. En gemensam nämnare är dock synen på paramedicin i stort som något betydelsefullt för personer i aktivt missbruk, oavsett om det är landstinget eller socialtjänsten som bedriver den. Studiens konklusion blir således att denna form av verksamhet kräver ett holistiskt perspektiv av den vård som ska bedrivas. Samarbete utanför landstingens och kommunens gränser verkar gynnande. Landstinget har större inflytande än kommunen men kommunen har å andra sidan större resurser när det gäller paramedicinska vårdinsatser. I de landsting där eventuella sprutbytesverksamheter diskuteras kan studien ge exempel på goda respektive mindre goda paramedicinska insatser vid de program som idag är verksamma. / In light of the ongoing discussion regarding the possible introduction of needle exchange programs in Jönköping county, this study aims to compare similarities and differences in practice at four different needle exchange programs in Sweden and to relate these experiences to their objectives and resources. Despite the fact that the law of needle exchange entered into force 2006, needle exchange programs are still a controversial subject of discussion in Sweden. In this contested form of infection care there is an important part though which makes the subject more legitimate. That is the positive social side effects which come as a result of the programs. These effects are mentioned in the study as paramedic care. The method underlying the study is qualitative, semi structured interviews. The material has been analyzed for the relevance of its content and also through organization theory. The starting point is theses, scientific articles and literature on the subject of needle exchange. At the needle exchange programs in Sweden the perceptions regarding the need for and the implementation of paramedical care differs as well as the views of researchers, politicians and professionally active that we interviewed on the subject. A common denominator, however, is the perception of paramedical care at large as something significant for people in active addiction, whether it is the country council or the social services that engaged in it. The conclusion of the study is thus that this form of activities requires a holistic perspective of the care that should be conducted. Cooperation outside the county and municipal boundaries seems favorable. The county councils have more influence than the municipalities but the municipalities on the other hand have greater resources in terms of paramedical care efforts. In the county councils where any needle exchange activities are up for discussion this study could give examples on favorable and less favorable paramedical activities at programs that are currently active.

This thesis addresses gaps that exist in the theory and knowledge of ancient DNA (aDNA). Much of the underlying basis of the field has been neglected in the excitement that followed the first aDNA studies. Therefore the results of many studies have been based on untested assumptions about the nature of post mortem DNA damage, sample preservation, contamination, and the efficacy of sample decontamination techniques. The validity of such results is questionable if the assumptions prove false. Hydrolytic post mortem DNA damage may modify recovered aDNA sequences. This thesis reports new insights into the biochemical basis of, predisposition of certain sequences and nucleotide positions towards, and subsequent effects of, such damage. Parallels of post mortem damage with in vivo mutation also enable insights into DNA sequence evolution. The long-term survival of DNA, and contamination of samples with exogenous DNA are two related problems characteristic to aDNA. The survival of endogenous DNA within bone, teeth and hair samples, the susceptibility of such samples to contamination, and the efficacy of decontamination techniques used to remedy such problems are investigated. The results highlight serious flaws in using bone and teeth as a DNA source. In contrast, the results demonstrate that hair may present a valuable DNA source for future studies. Numerous studies have reported the retrieval of ancient pathogen DNA from human samples. Analyses of the DNA content within teeth extracted from putative victims of the 2^nd plague argue that such studies are at great risk from DNA degradation, and contamination arising due to environmental microorganisms. An extrapolation of these results using basic physical and chemical theory is used to evaluate the potential survival of aDNA in ancient Egyptian remains. This suggests that positive results from such samples are unlikely.

Lietuvos žaliavinio pieno užterštumo B grupės teršalais analizė 2005-2010 metais. Tyrimo metu gautų rodiklių palyginimas su Europos Sąjungos šalių narių rodiklių palyginimas. / Lithuania milk contamination Group B contamination analysis in 2005-2010 years. The study of performance comparison with the European Union member states are shown.

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.

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]

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.

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.