Hydrogen Cyanide Accumulation and Transformations in Non-polluted Salt Marsh Sediments

A. Kamyshny*, Harry Daniel Oduro, Z. F. Mansaray, J. Farquhar

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    7 Citations (Scopus)

    Abstract

    While cyanide is known to be produced by many organisms, including plants, bacteria, algae, fungi and some animals, it is generally thought that high levels of cyanide in aquatic systems require anthropogenic sources. Here, we report accumulation of relatively high levels of cyanide in non-polluted salt marsh sediments (up to 230 mu mol kg(-1)). Concentrations of free cyanide up to 1.92 mu mol L-1, which are toxic to aquatic life, were detected in the pore-waters. Concentration of total (free and complexed) cyanide in the pore-waters was up to 6.94 mu mol L-1. Free cyanide, which is released to the marsh sediments, is attributed to processes associated with decomposition of cord grass, Spartina alterniflora, roots and possibly from other sources. This cyanide is rapidly complexed with iron and adsorbed on sedimentary organic matter. The ultimate cyanide sink is, however, associated with formation of thiocyanate by reaction with products of sulfide oxidation by Fe(III) minerals, especially polysulfides. The formation of thiocyanate by this pathway detoxifies two poisonous compounds, polysulfides and hydrogen cyanide, preventing release of free hydrogen cyanide from salt marsh sediments into overlying water or air.

    Original languageEnglish
    Pages (from-to)97-113
    Number of pages17
    JournalAquatic Geochemistry
    Volume19
    Issue number2
    DOIs
    Publication statusPublished - Mar 2013

    Keywords

    • Hydrogen cyanide
    • Metallo-cyanide complexes
    • Thiocyanate Sulfide oxidation intermediates
    • Inorganic polysulfides
    • Sulfide
    • AQUATIC SYSTEMS
    • WASTE-WATER
    • SULFUR
    • THIOCYANATE
    • SULFIDE
    • IRON
    • KINETICS
    • SEAWATER
    • REMOVAL
    • AMMONIA

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