Cu and Ni mobility and bioavailability in sequentially conditioned soils

Lenka Maderova, Julian Dawson, Graeme I. Paton

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

The potential ecological hazard of metals in soils may be measured directly using a combination of chemical and biological techniques or estimated using appropriate ecological models. Terrestrial ecotoxicity testing has gained scientific credibility and growing regulatory interest; however, toxicity of metals has often been tested in freshly amended soils. Such an approach may lead to derivation of erroneous toxicity values (EC50) and thresholds. In this study, the impact of metal amendments on soil ecotoxicity testing within a context of ion competition was investigated. Four coarse-textured soils were amended with copper (Cu) and nickel (Ni), incubated for 16 weeks and conditioned by a series of total pore water replacements. RhizonTM extracted pore water Cu, Ni, pH and dissolved organic carbon (DOC) concentrations were measured after each replacement. Changes in ecotoxicity of soil solutions were also monitored using a lux-based biosensor (Escherichia coli HB101 pUCD607) and linked to variations in soil solution metal and DOC concentrations, pH and selected characteristics of the experimental soils (exchangeable calcium (Ca) and magnesium (Mg)). Prior to conditioning of soils, strong proton competition produced relatively high EC50 values (low toxicity) for both, Cu and Ni. The successive replacement of pore waters lead to a decline of labile pools of metals, DOC and alleviated the ecotoxicological protective effect of amendment impacted soil solution chemistry. Consequently, derived ecotoxicity values and toxicity thresholds were more reflective of genuine environmental conditions and the relationships observed more consistent with trends reported in historically contaminated soils.
Original languageEnglish
Pages (from-to)63-73
Number of pages11
JournalWater, Air and Soil Pollution
Volume210
Issue number1-4
Early online date2 Oct 2009
DOIs
Publication statusPublished - Jul 2010

Keywords

  • metal
  • biosensor
  • terrestrial ecotoxicity testing
  • ion competition
  • dissolved organic matter
  • biotic ligand model
  • springtail folsomia-candida
  • contaminated soils
  • copper toxicity
  • organic-matter
  • calcareous soils
  • metal sorption
  • heavy-metals
  • field soils
  • complexation

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