Publication:
Microbial and redox-dependent aspects of selenium biogeochemistry in a selenium contaminated lake - Lake Macquarie, NSW

dc.contributor.author Carroll, BI en_US
dc.contributor.author Peters, G en_US
dc.contributor.author Barford, JP en_US
dc.contributor.author Nobbs, DM en_US
dc.contributor.author Maher, WA en_US
dc.contributor.author Chapman, P en_US
dc.date.accessioned 2021-11-25T13:23:38Z
dc.date.available 2021-11-25T13:23:38Z
dc.date.issued 1998 en_US
dc.description.abstract The ecosystem of Lake Macquarie, N.S.W., has been subject to heavy metal and metalloid inputs since 1897 from a lead-zinc smelter, and subsequently coal-fired power stations, coal mines and washeries and sewage treatment plants. Reports in 1994 of contamination of commercial fish species from the Lake with selenium levels up to twelve times those recommended for human consumption has lead to calls for bans on commercial and recreational fishing in the Lake, which could potentially devastate local fishing and tourism industries. Selenium biogeochemical cycling in estuarine environments such as Lake Macquarie is subject to factors including sediment redox potential, sediment characteristics, solubility of Se-containing mineral phases, ligand complexing ability, and microbially-mediated oxidation-reduction, mineralisation and methylation reactions. Understanding this biogeochemistry is important so as to evaluate the potential risk to ecosystems and human health posed by selenium, and to determine the likely impact of potential management strategies. The research described in this paper examines the importance and role of two of these specific factors which impact selenium biogeochemical cycling in Lake Macquarie: sediment redox potential and microbial methylation reactions. The role of sediment redox potential was examined utilising sediment from the Lake, dosed with known quantities of selenium and then studied under different conditions, comprising: addition of various macrofauna to the sediments to examine the impact of bioturbation on sediment redox status and therefore selenium availability; and exposure of sediment plugs to oxygenated and deoxygenated seawater to quantify selenium release. Bioturbation caused deepening of the oxidised conditions in the sediment, impacting upon speciation and mobility of selenium, whilst exposure of contaminated reduced sediment to oxidising porewater arising from bioturbation resulted in selenium mobilisation from the strongly binding “organic fraction” of the sediment. Separately, bacterial cultures were isolated from the Lake with the ability to tolerate high selenium levels. Organisms were cultured in flasks with nutrient broth containing selenate (Se(VI)) at 100mg/l and incubated at 28oC for several weeks. Analysis by hydride generation atomic absorption spectroscopy revealed that the mass balance on the flasks would not close, indicating loss of selenium to the culture headspace. Samples of culture headspace gases were then collected using a cryogenic trapping system and injected into a GC/MS where methylated selenium species including dimethylselenyl sulfide and dimethylselenyl disulfide were identified. These experiments indicated that both sediment redox potential and microbial methylation are important in the biogeochemical cycling of selenium in Lake Macquarie. The impact of bioturbation upon sediment redox potential is important for any consideration of capping sediments, as the depth of the cap must be sufficient to prohibit bioturbative organisms from accessing the sediment below the cap, whilst the demonstrated ability of indigenous microorganisms from the Lake to methylate selenium may represent a potential remediation options for contaminated sediments or selenium-containing waste streams. en_US
dc.identifier.uri http://hdl.handle.net/1959.4/39541
dc.language English
dc.language.iso EN en_US
dc.publisher Elsevier en_US
dc.rights CC BY-NC-ND 3.0 en_US
dc.rights.uri https://creativecommons.org/licenses/by-nc-nd/3.0/au/ en_US
dc.source Legacy MARC en_US
dc.title Microbial and redox-dependent aspects of selenium biogeochemistry in a selenium contaminated lake - Lake Macquarie, NSW en_US
dc.type Conference Paper en
dcterms.accessRights metadata only access
dspace.entity.type Publication en_US
unsw.accessRights.uri http://purl.org/coar/access_right/c_14cb
unsw.publisher.place Amsterdam en_US
unsw.relation.faculty Engineering
unsw.relation.ispartofconferenceLocation Wollongong, Australia en_US
unsw.relation.ispartofconferenceName Second International Conference on Environmental Management (ICEM2) en_US
unsw.relation.ispartofconferenceProceedingsTitle Second International Conference on Environmental Management (ICEM2) en_US
unsw.relation.ispartofconferenceYear 1998 en_US
unsw.relation.ispartofpagefrompageto 221-228 en_US
unsw.relation.originalPublicationAffiliation Carroll, BI en_US
unsw.relation.originalPublicationAffiliation Peters, G, Civil & Environmental Engineering, Faculty of Engineering, UNSW en_US
unsw.relation.originalPublicationAffiliation Barford, JP en_US
unsw.relation.originalPublicationAffiliation Nobbs, DM en_US
unsw.relation.originalPublicationAffiliation Maher, WA en_US
unsw.relation.originalPublicationAffiliation Chapman, P en_US
unsw.relation.school School of Civil and Environmental Engineering *
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