Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
4421927 | Ecotoxicology and Environmental Safety | 2009 | 7 Pages |
The effects of widely ranged pH and some cations on nickel (Ni) toxicity to barley root elongation were determined using a biotic ligand model (BLM) in solution culture. The results showed that Ni toxicity decreased with increases of Mg2+ and Ca2+ activities, but not for Na+ and K+ activities. Higher H+ activity decreased the toxicity through H+ competition with Ni2+ bound to biotic ligands at pH<7.0 or through the change of Ni species in solution at pH≥7.0. When pH≥7.0 the Ni2+ plus NiHCO3+ were found to be toxic to barley root elongation. The conditional binding constants for Ni2+, NiHCO3+, H+, Mg2+ and Ca2+ with biotic ligand were obtained: log KNiBL, 4.83; logKNiHCO3BL, 5.36; log KHBL, 4.29; log KMgBL, 4.01 and log KCaBL, 1.60. It is suggested that in solutions with pH≥7.0 free Ni2+ as well as NiHCO3+, Mg2+ and Ca2+ competitions with Ni2+, should be considered for BLM development.