Assessing the influence of compost and biochar amendments on the mobility and toxicity of metals and arsenic in a naturally contaminated mine soil

Luke Beesley, Onyeka S. Inneh, Gareth J. Norton, Eduardo Moreno-Jimenez, Tania Pardo, Rafael Clemente, Julian J.C Dawson

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195 Citations (Scopus)

Abstract

Amending contaminated soils with organic wastes can influence trace element mobility and toxicity. Soluble concentrations of metals and arsenic were measured in pore water and aqueous soil extracts following the amendment of a heavily contaminated mine soil with compost and biochar (10% v:v) in a pot experiment. Speciation modelling and toxicity assays (Vibrio fischeri luminescence inhibition and Lolium perenne germination) were performed to discriminate mechanisms controlling metal mobility and assess toxicity risk thereafter. Biochar reduced free metal concentrations furthest but dissolved organic carbon primarily controlled metal mobility after compost amendment. Individually, both amendments induced considerable solubilisation of arsenic to pore water (>2500 μg l−1) related to pH and soluble phosphate but combining amendments most effectively reduced toxicity due to simultaneous reductions in extractable metals and increases in soluble nutrients (P). Thus the measure–monitor-model approach taken determined that combining the amendments was most effective at mitigating attendant toxicity risk.
Original languageEnglish
Pages (from-to)195-202
Number of pages8
JournalEnvironmental Pollution
Volume186
Early online date1 Jan 2014
DOIs
Publication statusPublished - Mar 2014

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Keywords

  • soil contamination
  • organic amendments
  • trace elements
  • speciation
  • pore water

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