Biological interactions of selenocyanate: Bioprocessing, detection and toxicity

Radhika Burra, James D. Fox, Gonzalo A. Pradenas, Claudio C. Vásquez, Thomas G. Chasteen

Research output: Contribution to journalArticle

6 Scopus citations

Abstract

The selenocyanate anion, SeCN-, has been reported in wastewater from refineries whose petroleum comes from Se-rich marine shales. A metalloid-resistant bacterium was exposed to aqueous solutions of SeCN - to examine the relative toxicity of SeCN-, and the results were compared with the toxicity of selenate and selenite and another G16 metalloid oxyanion, tellurite. We also determined the volatile organo-selenium species produced by bacterial cultures amended with selenocyanate anion, and we investigated a solid phase preconcentration technique for collecting SeCN - from aqueous samples with different ionic strengths and subsequent detection using capillary electrophoresis. The relative toxicity of SeCN - is comparable to that of selenate and selenite using the metalloid-resistant bacterium LHVE as the test organism. Tellurite was more toxic at all concentrations examined than all three selenium-containing anions, SeO42-, SeO32-, SeCN-. Live cultures of LHVE amended with 1 mM NaSeCN produced volatile organo-sulphides and organo-selenides that could be collected in headspace using a solid phase microextraction fibre. The bioprocessing, i.e. the reduction and methylation of SeCN-, is similar to that of selenate and selenite by other metalloid-resistant bacteria. An aqueous 1.0 mM solution of SeCN - could be captured from solution on solid-phase extraction (SPE) cartridges using an aminopropyl-based stationary phase. Selenocyanate anions, slowly pumped into a wetted SPE cartridge, were trapped on the cartridge's solid phase and were subsequently eluted, thereby providing an increase in concentration above that of the original SeCN- containing solution. Preconcentration factors of 3.9 were achieved using a mixed sodium hydroxide/methanol elution solvent and by adding NaCl to aqueous SeCN- before loading on the SPE cartridge.

Original languageEnglish (US)
Pages (from-to)1327-1335
Number of pages9
JournalEnvironmental Technology
Volume30
Issue number12
DOIs
StatePublished - Nov 1 2009

Keywords

  • Environmental selenium
  • Petrochemical wastewater
  • SeCN
  • Solid phase extraction of metalloid anions
  • Specific growth rate

ASJC Scopus subject areas

  • Environmental Chemistry
  • Water Science and Technology
  • Waste Management and Disposal

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  • Cite this

    Burra, R., Fox, J. D., Pradenas, G. A., Vásquez, C. C., & Chasteen, T. G. (2009). Biological interactions of selenocyanate: Bioprocessing, detection and toxicity. Environmental Technology, 30(12), 1327-1335. https://doi.org/10.1080/09593330902998082