Development and validation of a terrestrial biotic ligand model predicting the effect of cobalt on root growth of barley (Hordeum vulgare)
2007
Lock, K. | Schamphelaere, K.A.C de | Becaus, S. | Criel, P. | Eeckhout, H van | Janssen, C.R.
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 Ca2+, Mg2+, Na+, K+ ions and pH independently affect cobalt toxicity to barley was studied. With increasing activities of Mg2+, and to a lesser extent also K+, the 4-d EC50Co2+ increased linearly, while Ca2+, Na+ and H+ activities did not affect Co2+ toxicity. Stability constants for the binding of Co2+, Mg2+ and K+ to the biotic ligand were obtained: log KCoBL = 5.14, log KMgBL = 3.86 and log KKBL = 2.50. Limited validation of the model with one standard artificial soil and one standard field soil showed that the 4-d EC50Co2+ could only be predicted within a factor of four from the observed values, indicating further refinement of the BLM is needed. Biotic Ligand Models are not only a useful tool to assess metal toxicity in aquatic systems but can also be used for terrestrial plants.
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