Zinc toxicity to nitrification in soil and soil-less culture can be predicted with the same biotic ligand model
Zn toxicity to nitrification in 12 different soils was compared to Zn toxicity in soil less solutions of Nitrosospira sp. NpAV with variable ionic composition. Zn concentration at which nitrification was reduced by 20％ (ZnEC2) varied between 7 and 1200μM Zn in soil pore water and between 5 and 150μM Zn in soi-less solutions. Increasing H, (a<2> and Mg<2> concentrations exerted protective effects towards Zn toxicity, expressed as Zn<2>: activity, in both systems. Zinc speciation analysis revealed that 60％ 90％ of the Zn in pore water and 35％ 70％ of Zn in soil less solutions was present as Zn<2>. The critical Zn<2> activity was modelled using a biotic ligand model and a Freundlich type model, incorporating competitive effects of H, Ca<2> and Mg<2> for bind-ing at biotic ligands, Both models performed equally well, and critical Zn<2> activities of soils and soil less cultures were predicted within a factor of 4 using a single set of parameters for both systems. The results suggest that thc nitrifying organisms in soil are exposed to Zn through the free Zn ions in pore water.
Biotic Ligand Model cation competition Freundlich type model Nitrosospira sp. NpAV soil zinc
Jelle Mertens Fien Degryse Dirk Springael Erik Smolders
Division of Soil and Water Management. KULeuven, Kasteelpark Arenberg 20, 3001 Heverlee
国际会议
第九届痕量元素生物地球化学国际会议(9th International Conference on the Biogeochemistry of Trace Elements)
北京
英文
540-541
2007-07-15（万方平台首次上网日期，不代表论文的发表时间）