Bioavailability of metals and As from acidified multicontaminated soils: Use of white lupin to validate several extraction methods

摘要

White lupin is an annual crop that has been used for phytostabilization of acidified multi-contaminated (heavy metals and As) soils from the Aznalcollar spill-affected area, Southern Spain. One of the most important factors for successful phytostabilization is monitoring the pollutant bioavailability in the soil. The aim of this work was to determine the best-suited method for assessing the bioavailability of heavy metals together with As in the Aznalcollar spill-affected area, by means of a systematic comparison between different extraction methods (Ammonium bicarbonate-diethylenetriamine pentaacetic acid (AB-DTPA), CaCl_2, NaNO_3, BCR, (NH_4)_2SO_4 and rhizo). Both AB-DTPA and the first step of the BCR method were found to be unsuitable for assessing the bioavailability of heavy metals and As to plants growing in acidic soils. However, CaCl_2-extractable As, Cu, and Zn and NaNO_3-extractable As and Zn were well correlated with their concentrations in plant organs. Rhizo and (NH_4)_2SO_4, with the highest determination coefficients, were the most recommended simple extraction methods to assess the bioavailability of As, Cu, Fe, Mn, and Zn in acidified multicontaminated soils using white lupin as an excluder model plant.