Theoretical copper sulfate dosing;the effect of alkalinity and humic acid on ionic copper toxicity to algae

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dc.contributor.authorSirois, David J.en
dc.contributor.departmentEnvironmental Sciences and Engineeringen
dc.date.accessioned2014-03-14T21:30:29Zen
dc.date.adate2010-03-02en
dc.date.available2014-03-14T21:30:29Zen
dc.date.issued1991en
dc.date.rdate2010-03-02en
dc.date.sdate2010-03-02en
dc.description.abstractThe chemistry of copper sulfate dosing for effective algal kill was investigated in laboratory studies with Selenastrum capricornutum and Microcystis aeruginosa. The goal was to give practical information for water treatment plants operators who often must apply copper sulfate for algae control in impoundments. Research focused on the theoretical relationships involved in copper dosing, with emphasis on the applicability of these relationships to Virginia freshwater. Concentrations of alkalinity and humic acid were varied to study their effect on percentages of ionic copper available. Long-term (2 weeks) growth-rate studies were performed to study the effect of humic acid on the toxicity of ionic copper to algae. Some protection of algae from copper by humic acid was observed. As the humic acid concentration was increased, more ionic copper was complexed and, thus, was unavailable for algal kill. The only case in which humic acid was not demonstrably protective was at a low concentration (4 mg/L TOC). It is possible that in a long-term test, low humic acid levels may not protect algae, because the copper may be released from the humic acid complex. Alkalinity and the humic acid concentration (TOC) both complex ionic copper, however alkalinity appears to be more important in determining available ionic copper in freshwater. At alkalinities greater than 10 mg/L (as CaCO₃) and humic acid less than 8.0 mg/L, alkalinity predominated in determining available ionic copper. A short term (4-hour) procedure involving measurement of oxygen production by algae exposed to copper was also used to determine the effect of humic acid on ionic copper toxicity to algae. The data showed that short-term tests were best used to predict trends shown in the long-term tests. Both Selenastrum capricornutum (a green alga) and Microcystis aeruginosa (a blue-green alga) were protected from ionic copper by humic acid. Oxygen production was found to be best used to approximate toxic concentrations of a suspect compound, as opposed to being used to precisely determine toxic concentrations.en
dc.description.degreeMaster of Scienceen
dc.format.extent228 leavesen
dc.format.mediumBTDen
dc.format.mimetypeapplication/pdfen
dc.identifier.otheretd-03022010-020227en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-03022010-020227/en
dc.identifier.urihttp://hdl.handle.net/10919/41332en
dc.language.isoenen
dc.publisherVirginia Techen
dc.relation.haspartLD5655.V855_1991.S5644.pdfen
dc.relation.isformatofOCLC# 25404363en
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subject.lccLD5655.V855 1991.S5644en
dc.subject.lcshAlgae -- Controlen
dc.subject.lcshCopper sulfateen
dc.subject.lcshCopper -- Toxicologyen
dc.titleTheoretical copper sulfate dosing;the effect of alkalinity and humic acid on ionic copper toxicity to algaeen
dc.typeThesisen
dc.type.dcmitypeTexten
thesis.degree.disciplineEnvironmental Sciences and Engineeringen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

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