Rivers all around the world have become increasingly polluted with heavy metals, largely due to industrialization and urbanization. Organisms exposed to high concentrations of heavy metals have shown evidence of biotoxicity and physical deformities. With biomagnification in mind, the possibility that this contamination may soon directly affect humans is a real concern, and policies in manufacturing industries worldwide may have to be reformed. In this study, we measured the concentrations of arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni), and lead (Pb) in the Hatillo River and compared these values to those measured in the Tarcoles River, a highly polluted river, and Terciopelo Creek, a relatively clean river. The results showed that the Hatillo River had significantly lower levels of most detected heavy metals than both the Tarcoles and Terciopelo. Overall, sediments in all rivers showed high levels of heavy metal content--especially in chromium, copper, nickel, and lead--which could build up and affect organisms over a long period of time.

Irthing Road is situated 20 kilometres north of the small town of Lumsden in Northern Southland, New Zealand. Irthing Road is accessed from State Highway 97 and leads north-west for 7 kilometres up the Irthing Creek Valley. The research site is situated 4.4 kilometres from the Irthing Road - State Highway 97 intersection and the area is at 300 metres elevation above sea level on gently south sloping Quaternary alluvial deposits. The study was initiated by Environment Southland and Southern Geophysical Ltd with the intention of investigating the potential uses of near surface geophysics in the mapping of shallow groundwater contamination, specifically agriculturally sourced nitrates and leachates. The changes in land use and the introduction of high density grazing of dairy cattle on free draining soils in Southland has created cause for concern around the ease at which large volumes of contaminants could potentially gain access to the shallow groundwater system. The investigation of the Irthing Road field site included: (1) background research into historical land use changes that may have affected the area 2) a study of the Lumsden area geological and hydrogeological setting 3) six trips to the field site throughout the year to collect near surface geophysical data using a Geonics Ltd EM31-MK2, Dualem Inc. DUAL-EM 421s, and Sensors & Software pulseEKKO Pro GPR system; 4) ground- water testing conducted by Environment Southland; 5) an evaluation of the geophysical and groundwater data sets to identify whether leachate concentrations were high enough to register an anomalous response 6) the identification of how the groundwater system at the Irthing Road field site behaves 7) a conclusion as to the effectiveness of all three near surface geophysical techniques in this application. The major conclusions that emerged from this study are: (1) the groundwater system is transporting a large volume of water beneath the site and this leads to such effi- cient removal of contaminants that the concentrations are not high enough to register a response in the geophysical data 2) the groundwater system is highly sensitive to rain- fall and this is a contributing factor to the variation within the geophysical data 3) the Geonics Ltd EM31-MK2 and Sensors & Software pulseEKKO Pro GPR system returned highly consistent results and have great potential in further contaminated groundwater applications 4) Environment Southlands' DUAL-EM 421s needs more consistency, how- ever the device has a lot of potential once reliability can be ensured 5) further research is needed to determine the contamination ow paths and destinations at a larger, regional scale.

Neurodegenerative diseases have been shown to correlate positively with an ageing population. The most common neurodegenerative diseases are amyotrophic lateral sclerosis (ALS), Parkinson’s disease and Alzheimer’s disease. The cause of these diseases is believed to be the interaction between genetic and environmental factors, synergistically acting with ageing. BMAA (β-methylamino-L-alanine) is one kind of toxin present in our environment and might play an important role in the development of those diseases. BMAA was initially isolated from cycad seeds in Guam, where the incidence of ALS/Parkinsonism-dementia complex among the indigenous people was 50 – 100 times higher than the rest of the world in the 1950’s. BMAA can induce toxic effects on rodents and primates. Furthermore, it can potentiate neuronal injury on cell cultures at concentrations as low as 10 µM. BMAA was reported to be produced by cyanobacteria, and could bio-magnify through the food chain. In this thesis, work was initially focused on the improvement of an existing analytical method for BMAA identification and quantification using liquid chromatography coupled with tandem mass spectrometry.  Subsequently, the refined method was applied to environmental samples for probing alternative BMAA producer(s) in nature and to seafood samples for estimation of human exposure to this toxin. In Paper I, a systematic screening of the isomers of BMAA in a database was performed and seven potential isomers were suggested. Three of them were detected or suspected in natural samples. In Paper II, a deuterated internal standard was synthesized and used for quantifying BMAA in cyanobacteria. In Paper III, Diatoms were discovered to be a BMAA producer in nature. In Paper IV, ten popular species of seafood sold in Swedish markets were screened for BMAA. Half of them were found to contain BMAA at a level of 0.01 – 0.90 µg/g wet weight. In Future perspectives, the remaining questions important in this field are raised.

With rapidly urbanizing societies, waste management needs attention. In 2008, EUs Waste Framework Directive (WFD) set new concepts, like reducing usage of natural materials. Thus, the interest for alternative materials increased. In Skellefteå, since the 1970’s, iron sand has often substituted natural gravel in road construction. But, today stricter regulations might forbid iron sand for further use. The issue is whether leachate from iron sand causes heavy metal pollution or not. This thesis tried to provide more knowledge into iron sand’s environmental impact. In order to investigate this, a sediment sample (<53 cm deep) collected in Inre-viken, a lake 50m from a road with iron sand, were analyzed for Zn, Pb and Cu concentrations. Enrichment factor (EF), national benchmarks, and reference data were used to evaluate anthropogenic impact and age-determine the sediment. The results showed: (1) Inre-viken has elevated heavy metal levels compared to pre-industrial levels, with highest Cu (133 mg/kg) and Zn(204 mg/kg) concentrations found in the surface layer. (2) Zn and Cu showed an increase between 41-0 cm depth (1970-2015), but only Cu reaches high concentrations, while Zn and Pb range between low to very low concentrations. (3) The metal enrichment is low compared to the reference lake. The findings show that there are elevated levels in Inre-viken compared to pre-industrial levels. However, identifying the main source of pollution is difficult, because many pollution sources exist in the area. To determine if iron sand is the culprit, further studies are necessary.

Le contrôle de l'aérocontamination fongique est devenu un objectif majeur pour préserver la santé humaine et animale. L'évaluation de l'aérocontamination fongique fait classiquement appel aux techniques de mise en culture ou de dosage de composants fongiques présents dans l'air. Ces techniques présentent des inconvénients. C'est la raison pour laquelle, nous nous sommes fixés comme objectif de mettre au point des méthodes d'analyse alternatives utilisant des outils de biologie moléculaire. Dans un premier temps, nous avons comparé plusieurs techniques de prélèvements d'air dans des environnements intérieurs présentant une contamination plus ou moins élevée. Nous avons, par la suite, optimisé les conditions d'extraction de l'ADN fongique à partir de prélèvements d'air. L'ADN extrait a été amplifié par PCR " semi-nichée " avec des amorces universelles permettant d'amplifier une partie de l'ARNr 18S de champignons. Par la suite, nous avons utilisé la TTGE (Temporal Temperature Gradient Electrophoresis) et la D-HPLC (Denaturing High Performance Liquid Chromatography) pour séparer les amplificats. Chaque produit de PCR a été identifié par séquençage direct après purification. La comparaison des espèces identifiées par ces techniques avec celles qui sont obtenues par la méthode classique (culture) apporte de meilleurs renseignements sur la qualité fongique d'un même prélèvement d'air. L'application de ces techniques dans des environnements à différents niveaux de contamination a permis de déduire que l'étude de l'évaluation de l'aérocontamination fongique se fait par l'association de la culture et des méthodes moléculaires

The bacterium Aeromonas hydrophila is a known fish and opportunistic human pathogen commonly occurring in surface waters supplying drinking water distribution systems. The major concern of government and drinking water providers is that A. hydrophila may invade and become established in the biofilm of a distribution system, thus potentially leading to outbreaks of disease. The purpose of this study was to survey source water, distribution system biofilm, and to establish a simulated distribution system to explore the possibility of A. hydrophila invading and becoming established under normal and disrupted treatment conditions. A. hydrophila (AH) medium and the API-20E system were used for identification, while Ampicillin-Dextrin Agar (ADA) was used for enumeration. Presumptive counts were high in source water approaching 103 CFU/ml during summer months. Biofiim from an actual distribution system showed the presence of A. hydrophila in 10 % of the samples. In the simulated distribution system A. hydrophila was never found in the bulk water or biofilm under normal treatment condition, showing disinfectant efficiency. Under disrupted treatment conditions A. hydrophila was not able to colonize a pre-established biofilm over a 14 week period. / Department of Biology

Recently the EPA placed Aeromonas hydrophila on the Candidate Contaminant List (CCL). It has long been known to be a pathogen of cold blooded animals and now is a suspected human opportunistic pathogen as well. Among the various virulence factors produced by A. hydrophila, the cytolytic enterotoxin (AHCYTOEN) is by far one of the most important contributors to the pathogenicity of the organism. This factor is also produced by other pathogenic Aeromonas spp. In this study, PCR technology was used to detect AHCYTOEN gene from a simulated water distribution system. A set of primers was selected to amplify the unique sequence of a pathogenic island, AHCYTOEN gene. To examine the sensitivity of the PCR, serial dilutions of pure A. hydrophila culture were tested. The PCR technique used was sensitive enough to detect samples containing less than 10.0 cells/ml. Source water, bulk water, and simulated distribution biofilm samples were examined for the gene. Biofilm and bulk water samples exposed to raw source water were collected on 4 occasions during a 24-day period. PCR technology detected the AHCYTOEN gene from 100 % of the bulk water samples and 85% of tightly bound biofilm (TB) samples from a simulated water distribution system while no positive results were observed in loosely bound biofilm samples (LB). After the inlet line of the system was changed to normally treated distribution water, 11 biofilm samples were collected on 3 occasions during 15 day sampling period along with bulk water samples. No positive results were observed from the bulk water and LB samples while 91% of TB samples tested for the presence of the gene. No significant difference was observed in detection by PCR from biofilm samples before and after the switch to chloraminated water. / Department of Biology

Quality control procedures during food processing may involve either lengthy enrichment steps, precluding enumeration of bacteria in contaminated food, or direct inoculation of food samples onto appropriate selective media for subsequent enumeration. However, sublethally injured bacteria often fail to grow on selective media, enabling them to evade detection and intervention measures and ultimately threaten the health of consumers. This study compares traditional selective and nonselective agar-based overlays versus two commercial systems (Petrifilm and Easygel) for recovery of injured Escherichia coli B-41560, originally an isolate from ground beef. Bacteria were propagated in tryptic soy broth (TSB), ground beef, or infant milk formula (IMF) to a density of 106-108 CFU/mL, and stressed for six minutes either in lactic acid (pH of 4.5) or heat-shocked for 3 min. at 60°C. Samples were pour- plated in basal layers of either tryptic soy agar (TSA), Sorbitol MacConkey (SMAC), or Violet Red Bile (VRB) agar and resuscitated for 4h prior to addition of agar overlays. Other stressed bacteria were plated directly onto the commercial media Petrifilm and Easygel. Our results indicate that the use of selective and nonselective agar overlays for sensitive recovery and accurate enumeration of E. coli B-41560 is dependent on the stress treatment and food system. These data underscore the need to implement food safety measures that address sublethally- injured bacteria such as E. coli O157:H7, without the use of enrichment steps, in order to avoid underestimation of true densities for target pathogens. / Department of Biology

In some environmental situations, environmental effects caused by elevated metals resulting from past mining and smelting activities can be observed in nearby receiving water bodies several decades after mine and smelter closure. There is a growing need for managing the hazardous solid wastes such as mining wastes as well as for assessing water quality and for sustainable management of sediment quality. The work presented in this thesis examined the mobilization of metals from two metal sources: mining wastes from a mine site in Vietnam and sediments from a contaminated lake in Sweden in order to test the hypothesis that mobilization of metals will be increased, when the environmental conditions change by e.g. exposure of mining wastes to oxidative weathering, change of redox conditions at the water-sediment interface and resuspension of sediments. The results from this work under field and laboratory conditions have verified the hypothesis. The exposure of sulphidic mining wastes in oxidative weathering conditions may cause long-term production of ARD and the resultant long-term mobility of metals. The oxidation/resuspension of sediments is an important factor for the release of trace metals Zn, Cu and Cd into the solution and substantial amounts of particles and, hence, associated metals into overlying water. The concomitant changes in pH during oxidation/resuspension of sediment play a significant role in the metal release both to redox sensitive elements Fe and Mn and trace elements Zn, Cu and Cd. The concomitant change in DOC during oxidation/resuspension can also contribute to the increased mobility of study metals. The field study was coupled to intermittent operation of a hydropower plant. The mobility of the metals was higher under operation compared to non-operation and, thus, the potential impacts on dispersal of metal pollution to downstream aquatic environments. The sudden increase in water flow upon the hydropower plant upon shifts from inactive to active state could cause immediate release of particles and thus particulate metals in the overlying water. However, the magnitude and its integrated effects in fluxes of metals over the season call for further research. There is a need to further investigate the impacts of hydropower generation in a longer period of time and at a higher frequency of observations at the very start of the hydropower operation. The results from this multidisciplinary approach would give a basis for an optimal operation of the hydropower plant to minimize the metal pollution associated with the water flow. / <p>The series number is changed from 410 to 430 and the ISBN is changed from 978-91-85895-56-4 to 978-91-7393-926-3.</p>

The development of a scum in a commercial sports drink is of concern because the product would be of poor quality, which may result in financial losses due to consumer rejection of the product and hence a decrease in the firm’s market share. The scum could be harmful to health and as such the firm could be litigated. Several factors, including microbial proliferation, may be the cause of the development of a scum in sports drink, but the actual cause seems not to have been established. The aim of this study was to characterise the scum in sports drink and determine the effects of preservation factors (pasteurisation, chemical preservatives and refrigeration) on its development. Samples of the sports drink were taken at different stages of processing to determine the effect of preservatives, pasteurisation and storage temperature on scum development. Some samples were kept at room temperature (approx. 25°C) and others were kept in the refrigerator (approx. 4ºC) during the study. A total of 150 samples were analysed over a period of four months. The structural characteristics of the scum that developed in the sports drink were determined by scanning electron microscopy (SEM) and elemental analysis. The sports drink samples were analysed for their microbial load and microbial types. Consumer acceptability of pasteurised and non-pasteurised drink was compared by conducting sensory evaluation using a consumer panel of 60 panellists. Customer complaints recorded by the sports drink manufacture that were due to scum development in the drink were also reviewed to establish the impact of scum development on consumer acceptability of the drink. The results of the study indicated that scum development was due to microbial contamination of the drink. The causative organism of the scum was identified as Acinetobacter baumanii. Acinetobacter baumanii is a gram negative non-spore forming coccobacilli and does not ferment sucrose. Acinetobacter baumanii forms the scum in sports drink as a means of protection from environmental stresses. The scum was found to be a compound of C, Si and O. The non-pasteurised samples were slightly more acceptable to consumers compared to the pasteurised samples. The consumer acceptability of pasteurised drink samples was negatively affected by the loss of aroma and flavour during pasteurisation. The preservation factors (chemical preservatives, pasteurisation and refrigeration) had no effect on scum development. To prevent post pasteurisation contamination, it is recommended that the pasteurisation process be done at the filling stage instead of at the holding stage. The frequency of changing rubbers and gaskets on the filling line should be at least every two months. The drink is pasteurised at 90ºC for 20 seconds, this needs to be reduced to a level where it will not have an influence on the loss of taste and aroma of the pasteurised drink, but without reducing the effectiveness of pasteurisation. / Thesis (M.Sc.Agric.)-University of KwaZulu-Natal, Pietermaritzburg, 2013.