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The occurrence and removal of cyanobacterial metabolites microcystin-LR and geosmin from source waters with powdered activated carbon

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dc.contributor.authorSam, Victor, author
dc.contributor.authorÖmur-Özbek, Pinar, advisor
dc.contributor.authorLegare, Marie, committee member
dc.contributor.authorCarlson, Ken, committee member
dc.date.accessioned2007-01-03T08:37:20Z
dc.date.available2014-01-01T08:10:42Z
dc.date.issued2012
dc.description.abstractCyanobacteria blooms may result in the release of problematic algal metabolites, such as geosmin and microcystin-LR in source waters. The World Health Organization has set a guideline limit of 1 μg/L for the Microcystin-LR in drinking water to prevent adverse health effects. Microcystin-LR is the most common and potent cyanotoxin which can cause severe gastro-enteritis and hepatoritis. Unlike microcystin-LR, geosmin is not known to be harmful however, it imparts an unpleasant earthy off-flavor to drinking water detectable to humans at 2-10 ng/L. Understanding the occurrence of these metabolites is the first step in mitigating waters contaminated with these algal metabolites. To understand their occurrence in Northern Colorado, environmental sampling was performed in local rivers, lakes and municipal waters. Results of environmental sampling in the Northern Colorado area revealed that microcystins frequently was detected with geosmin however; geosmin alone, without microcystin-LR, was more frequently detected. This common co-occurrence of both compounds may be helpful in the surveillance, prevention and elimination of geosmin and microcystin-LR from drinking water sources. Since neither of the metabolites can be sufficiently removed by most conventional water treatment processes. This study also investigated the concurrent removal of microcystin-LR and geosmin from spiked raw Horsetooth Reservoir water, in Fort Collins CO, by powdered activated carbon (PAC). Water samples were spiked with microcystin-LR and geosmin to achieve various concentrations from 2 to 10 μg/L and 10 to 50 ng/L respectively, with PAC concentrations ranging from 10 to 30 mg/L. Jar testing was employed for the experiments with 30 min mixing and 30 min settling. Geosmin was quantified by solid phase micro-extraction and gas chromatography/mass spectrometry. Microcystin-LR was quantified by liquid chromatography/mass spectrometry coupled with electrospray ionization. A PAC dose of 30 mg/L removed microcystin-LR concentrations up to 6 μg/L below WHO guidelines of 1 μg/L. Geosmin concentrations up to 50 ng/L were removed below human detection threshold (5 ng/L) with 20 mg/L of PAC. Competitive absorption by PAC was observed between microcystin-LR and geosmin where the removal efficiency of both metabolites; because of its smaller size geosmin was slightly better absorbed by PAC than microcystin-LR. PAC is a viable method to remove both metabolites. To evaluate the toxicity of microcystin-LR, H4IIE, rat liver cells were cultured and exposed to microcystin-LR in-vitro. Cell viability and histological observations concluded that the toxin induced cellular apoptosis and cell viability is cyanotoxin concentration dependent.
dc.format.mediumborn digital
dc.format.mediummasters theses
dc.identifierSam_colostate_0053N_11508.pdf
dc.identifierETDF2012400447CVEE
dc.identifier.urihttp://hdl.handle.net/10217/75122
dc.languageEnglish
dc.language.isoeng
dc.publisherColorado State University. Libraries
dc.relation.ispartof2000-2019
dc.rightsCopyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright.
dc.subjectpowdered activated carbon
dc.subjectH4IIE
dc.subjectnorthern Colorado
dc.subjectmicrocystin-LR
dc.subjectcyanobacteria
dc.subjectgeosmin
dc.titleThe occurrence and removal of cyanobacterial metabolites microcystin-LR and geosmin from source waters with powdered activated carbon
dc.typeText
dcterms.embargo.expires2014-01-01
dcterms.embargo.terms2014-01-01
dcterms.rights.dplaThis Item is protected by copyright and/or related rights (https://rightsstatements.org/vocab/InC/1.0/). You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).
thesis.degree.disciplineCivil and Environmental Engineering
thesis.degree.grantorColorado State University
thesis.degree.levelMasters
thesis.degree.nameMaster of Science (M.S.)

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