Suitability of Different Extraction Agents for the Determination of Plant-Available Part of Soil Arsenic

Abstract

Several soil-extraction agents were tested for the determination of plant-available As showing the following decreasing order of As extractability from soil: 2 mol.l^-1 HNO₃ > 0.43 mol.l^-1 CH₃COOH > 0.5 mol.l^-1 NaHCO₃ > 0.01 mol.l^-1 CaCl₂ >= 0.005 mol.l^-1 DTPA > 0.1 mol.l^-1 NaNO₃ > 1 mol.l^-1 NH₄NO₃. The relationship between As released by the indidual extraction agents and As concentrations in radishes was obtained by linear-regression analysis. The As concentration in leaves seem to more closely correlate with the soil-extractable As than the concentrations in roots. The 0.01 mol.l^-1 CaCl₂ proved the suitable extraction agent for the evaluation of availability of the soil As by plants.