Vertical Zinc Migration in Various Soil Types

In this contribution the zinc content in selected soil types and soil reaction on zinc loading in kinetic model conditions with knock-down columns filled with soil samples are evaluated. The total zinc content after their draining, finish and decomposition by HF + HClO₄ mixture and its fractions content in extract of 2 mol dm^-3 HNO₃, in extract of 0.05 mol dm^-3 EDTA and in extract of 0.01 mol dm^-3 CaCl₂ using atomic absorption spectrometry method were determined.

The knock-down columns filled with soil samples in model kinetic conditions were used for observation of zinc sorption measure. The maximal water capacity of soils was determined and then solution of 280 mg zinc (ZnSO₄.2H₂O) per kilogram of soil was applied. The zinc contents in extraction solutions 2 mol dm^-3 HNO₃, 0.05 mol dm^-3 EDTA and 0.01 mol dm^-3 CaCl₂ in drained 0.05 m high soil columns by atomic absorption spectrometry method were determined.

The obtained results were evaluated by mathematical-statistical methods - multiple range analysis and linear regression. Achieved data were compared to allowed limit values.

The results show different behavior of individual soil types against zinc loading. The soils showed different properties, where zinc migration to the lower column layers was determined. The accent is given to zinc dynamics in neutral and acid soils. The limit value A (140 mg kg^-1) was observed in Luvic Cambisol. The limit value A1 (40 mg kg^-1) was observed in Eutric Regosol and Luvic Cambisol in upper layer of soil in column. The obtained results show high mobility of zinc in tested soils and thus its risk for ecosystems.