Author: Megan A. Mave
Publisher:
ISBN:
Category : Geology
Languages : en
Pages : 62

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Author: Haihong Song
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Microcystins, potent toxins produced by cyanobacteria, occur widely in aquatic systems across the world, and are a known environmental and public health hazard. Therefore, it is important to understand their fate in aquatic systems. As an important component of aquatic systems, sediments play multiple roles in the distribution and natural attenuation of microcystins. However, systematic studies identifying the effects of environmental variables on the variability of microcystins in lake sediments are lacking, and the contribution of sediments to the removal of these toxins in the water body are not yet clear. Hence, this research aimed to: (a) investigate the variability of microcystins in lake sediments; and (b) identify the relative contribution of the biodegradation and adsorption ability of sediments to the removal of microcystins from the water. As research into microcystins in lake sediments has been hindered by the lack of an effective analysis method, a further aim of this study was to develop a method to quantify these toxins in sediment samples using supercritical carbon dioxide. The first part of this research involved a field study, analysing microcystin concentrations in lake sediments and their correlation with environmental variables. Microcystins were detected in all sediment samples, even at one of the sampling sites with negligible cyanobacterial biomass present in the water. The concentration of these toxins in lake sediments had a weak, but significant correlation with intracellular microcystins, total microcystins and cyanobacterial biomass in the water. Furthermore, their variability of in lake sediments could be explained by a combination of total microcystins in the water, cyanobacterial biomass in the water, pH and temperature. In the second part of this research, changes in the concentration of microcystin-LR (MCLR) in the water in the presence of sediments were quantified in a laboratory experiment. The results of this experiment showed that each time MCLR was added to sterile lake water in the presence of sediments, MCLR concentration decreased significantly following an exponential decay curve, with no observed lag phase. Comparison between different treatment conditions implied that the adsorption and biodegradation ability of sediments caused the MCLR removal and that biodegradation was the dominant mechanism. The final part of this research investigated the use of supercritical carbon dioxide in quantifying microcystins in sediment samples. A protocol was developed which included the optimisation of extraction conditions using supercritical carbon dioxide. This protocol was use to quantify microcystin concentrations in natural field samples. The results showed that for sediment samples with added MCLR, the conventional method recovered more spiked MCLR but fewer microcystin variants. In contrast, supercritical carbon dioxide with water as modifier extracted a higher amount of total microcystins. Overall, this research highlights the wide occurrence of microcystins in the sediments of the studied lake, and the biodegradation ability of sediments to remove microcystins quantitatively from the water. This study suggests that researchers and water management authorities should include sediments when assessing the potential hazards and fate of microcystins in aquatic systems.

Author: Arthur Zastepa
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Author:
Publisher:
ISBN: 9781840570984
Category : Water
Languages : en
Pages : 18

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Author: H. Kenneth Hudnell
Publisher: Springer Science & Business Media
ISBN: 0387758658
Category : Medical
Languages : en
Pages : 955

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With the ever-increasing incidence of harmful cyanobacterial algal blooms, this monograph has added urgency and will be essential reading for all sorts of researchers, from neuroscientists to cancer research specialists. The volume contains the proceedings of the 2005 International Symposium on Cyanobacterial Harmful Algal Blooms, and has been edited by H. Kenneth Hudnell, of the US Environmental Protection Agency. It contains much of the most recent research into the subject.

Author: Ian R. Falconer
Publisher: Academic Press
ISBN:
Category : Cooking
Languages : en
Pages : 248

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Some taxonomic and biologic aspects of toxic dinoflagellates / Karen A. Steidinger -- Methods of analysis for algal toxins: dinoflagellate and diatom toxins / John J. Sullivan -- Mode of action of toxins of seafood poisoning / Daniel G. Baden, Vera L. Trainer -- Paralytic shellfish poisoning / C.Y. Kao -- Diarrhetic shellfish poisoning / Tore Aune, Magne Yndestad -- Ciguatera fish poisoning / Raymond Bagnis -- Control measures in shellfish and finfish industries in the USA / James Hungerford, Marleen Wekell -- Seafood toxins of algal origin and their control in Canada / A.D. Cembella, E. Todd -- Taxonomy of toxic cyanophyceae (Cyanobacteria) / Olav M. Skulberg [and others] -- Measurement of toxins from blue-green algae in water and foodstuffs / Ian R. Falconer -- Mechanism of toxicity of cyclic peptide toxins from blue-green algae / Ian R. Falconer -- Diseases related to freshwater blue-green algal toxins and control measures / Wayne W. Carmichael, Ian R. Falconer.

Author: World Health Organization
Publisher: World Health Organization
ISBN: 9240031308
Category : Medical
Languages : en
Pages : 164

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Book Description
Use of coastal, estuarine and freshwater recreational environments has significant benefits for health and well-being, including rest, relaxation, exercise, cultural and religious practices, and aesthetic pleasure, while also providing substantial local, regional and national economic benefits. These guidelines focus on water quality management for coastal and freshwater environments to protect public health. The guidelines: 1. describe the current state of knowledge about the possible adverse health impacts of various forms of water pollution; and2. set out recommendations for setting national health-based targets, conducting surveillance and risk assessments, putting in place systems to monitor and control risks, and providing timely advice to users on water safety.These guidelines are aimed at national and local authorities, and other entities with an obligation to exercise due diligence relating to the safety of recreational water sites. They may be implemented in conjunction with other measures for water safety (such as drowning prevention and sun exposure) and measures for environmental protection of recreational water use sites.

Author: Ingrid Chorus
Publisher: Springer Science & Business Media
ISBN: 3642595146
Category : Science
Languages : en
Pages : 374

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Book Description
Toxic cyanobacteria are increasingly recognised as a potential hazard in water for human use. The recent availability of methods for quantitative screening is leading to a surge of research on their occurrence. This book presents a novel compilation of extensive screening results showing the cyanotoxin levels that may be expected when certain taxa dominate. These results indicate cyanotoxins to be the most widespread among the chemicals of concern in water used for drinking and recreation. It further combines field data with results from laboratory culture experiments to suggest a unifying view of how environmental factors control the cyanotoxin levels in natural waters. A practical section is dedicated to the exposure of humans through drinking-water and recreation.

Author: Susan Holdsworth
Publisher: DIANE Publishing
ISBN: 1437941311
Category : Nature
Languages : en
Pages : 10

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Book Description
This is a print on demand edition of a hard to find publication. Report of a survey conducted by the EPA and its state and tribal partners of the nation's lakes, ponds and reservoirs. This National Lakes Assessment is designed to provide statistically valid regional and national estimates of the condition of lakes. It uses a probability-based sampling design to represent the condition of all lakes in similar regions sharing similar ecological characteristics. Consistent sampling and analytical procedures ensure that the results can be compared across the country. The National Lakes Assessment helps build state and tribal capacity for monitoring and assessment and promotes collaboration across jurisdictional boundaries in the assessment of water quality. Charts and tables.

Author: Rolf Gimbel
Publisher: IWA Publishing
ISBN: 1843391201
Category : Science
Languages : en
Pages : 580

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Book Description
Slow sand filtration is typically cited as being the first "engineered" process in drinking-water treatment. Proven modifications to the conventional slow sand filtration process, the awareness of induced biological activity in riverbank filtration systems, and the growth of oxidant-induced biological removals in more rapid-rate filters (e.g. biological activated carbon) demonstrate the renaissance of biofiltration as a treatment process that remains viable for both small, rural communities and major cities. Biofiltration is expected to become even more common in the future as efforts intensify to decrease the presence of disease-causing microorganisms and disinfection by-products in drinking water, to minimize microbial regrowth potential in distribution systems, and where operator skill levels are emphasized. Recent Progress in Slow Sand and Alternative Biofiltration Processes provides a state-of-the-art assessment on a variety of biofiltration systems from studies conducted around the world. The authors collectively represent a perspective from 23 countries and include academics, biofiltration system users, designers, and manufacturers. It provides an up-to-date perspective on the physical, chemical, biological, and operational factors affecting the performance of slow sand filtration (SSF), riverbank filtration (RBF), soil-aquifer treatment (SAT), and biological activated carbon (BAC) processes. The main themes are: comparable overviews of biofiltration systems; slow sand filtration process behavior, treatment performance and process developments; and alternative biofiltration process behaviors, treatment performances, and process developments.