title: Development and validation of a terrestrial biotic ligand model predicting the effect of cobalt on root growth of barley (Hordeum vulgare).
abstract: A Biotic Ligand Model was developed predicting the effect of cobalt on root growth of barley (Hordeum vulgare) in nutrient solutions. The extent to which Ca(2+), Mg(2+), Na(+), K(+) ions and pH independently affect cobalt toxicity to barley was studied. With increasing activities of Mg(2+), and to a lesser extent also K(+), the 4-d EC50(Co2+) increased linearly, while Ca(2+), Na(+) and H(+) activities did not affect Co(2+) toxicity. Stability constants for the binding of Co(2+), Mg(2+) and K(+) to the biotic ligand were obtained: logK(CoBL)=5.14, logK(MgBL)=3.86 and logK(KBL)=2.50. Limited validation of the model with one standard artificial soil and one standard field soil showed that the 4-d EC50(Co2+) could only be predicted within a factor of four from the observed values, indicating further refinement of the BLM is needed.
authors.affiliation: Ghent University, Laboratory of Environmental Toxicology and Aquatic Ecology, J Plateaustraat 22, Ghent, Belgium. koen_lock@hotmail.com
authors.forename: K
authors.initials: K
authors.lastname: Lock
authors.forename: K A C
authors.initials: KA
authors.lastname: De Schamphelaere
authors.forename: S
authors.initials: S
authors.lastname: Becaus
authors.forename: P
authors.initials: P
authors.lastname: Criel
authors.forename: H
authors.initials: H
authors.lastname: Van Eeckhout
authors.forename: C R
authors.initials: CR
authors.lastname: Janssen
mesh_terms: D001682:Biological Availability; D002118:Calcium / Q000378:metabolism; D003035:Cobalt / Q000032:analysis / Q000493:pharmacokinetics / Q000633:toxicity*; D017753:Ecosystem; D004781:Environmental Exposure / Q000009:adverse effects; D001467:Hordeum / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism; D006859:Hydrogen / Q000378:metabolism; D007477:Ions / Q000378:metabolism; D008024:Ligands; D008274:Magnesium / Q000378:metabolism; D008954:Models, Biological; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism; D011188:Potassium / Q000378:metabolism; D018570:Risk Assessment / Q000379:methods; D012964:Sodium / Q000378:metabolism; D012987:Soil / Q000032:analysis; D012989:Soil Pollutants / Q000032:analysis / Q000493:pharmacokinetics / Q000633:toxicity*
chemical_list: D007477:Ions; D008024:Ligands; D012987:Soil; D012989:Soil Pollutants; D003035:Cobalt; D006859:Hydrogen; D012964:Sodium; D008274:Magnesium; D011188:Potassium; D002118:Calcium