Institution: | 1.Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS), CSIC,Seville,Spain;2.Department of Forest and Soil Sciences,BOKU, University of Natural Resources and Life Sciences Vienna,Tulln,Austria |
Abstract: | PurposeThis study evaluates the effects of two soil amendments and the growth of two plant species on labile trace element (TE) fractions in two different contaminated soils.Materials and methodsWe studied the effects of two organic amendments (biosolid compost and alperujo compost) and two plant species (Medicago polymorpha and Poa annua) on pH, total organic carbon (TOC), and TE availability, by three extraction methods (CaCl2 aqueous solution, soil pore water (SPW), and diffusive gradient in thin film (DGT)), in two contaminated soils with contrasting pH values (Aznalcázar, 6.53, and Vicario, 3.48) in a 118-day pot experiment. The effects of the composts on labile TE fractions were compared with element concentrations in plants.Results and discussionNo relevant effects of amendments and plants were found on the physical and chemical characteristics of the Aznalcázar soil. However, the addition of amendments was essential for plant species growing in the acid Vicario soil. In this soil, amendments and plant growth increased pH and TOC and reduced substantially TE bioavailability. Although absolute values of bioavailable TE contents obtained by the three methods were very different and followed the trend CaCl2 extraction?>?SPW?>?DGT, these values follow a similar behavior in the two studied soils and for the two species.ConclusionsThe results demonstrate that the application of organic amendments are suitable for remediating acid TE-contaminated soils, for the establishment of a vegetation cover on previously bare soils for reducing wind and water erosion and for reducing labile TE fractions to prevent leaching of pollutants into subsoil or groundwater layers. Moreover, the results obtained in this study pointed out that under microcosm conditions, the three methods tested (CaCl2 extraction, SPW, and DGT) to predict TE bioavailability were highly correlated. |