Evaluation of phytostabilizer ability of three ruderal plants in mining soils restored by application of organic amendments

Abstract

Abandoned mines involve a serious environmental problem because these soils contain high levels of trace elements. The aim of the study was selecting the most adequate autochthonous plant species to stabilize contamination and improve soil quality of a contaminated soil from an abandoned mine. For this purpose three plant species were studied: Poa annua, Medicago polymorpha and Malva sylvestris, in combination with two organic amendments (biosolid compost (BC) and "alperujo" compost (AC)) and a soil without amendments (CO). Soil pH increased due to the effect of amendments under all studied plants, which promotes the immobilization of trace elements in soil. Water soluble C (WSC) increased with the addition of both amendments and the highest concentration was found in soils under M. polymorpha. The evolution of trace element availability in soil depended on the amendment, plant species and characteristics of the element. The best treatment to stimulate biomass production was AC. The highest concentration of As and Pb was found in P. annua whereas the highest concentration of Mn and Zn was found in M. sylvestris. Considering chemical and biochemical properties, and concentrations in shoots M. polymorpha would be the most suitable plant to stabilize trace elements and improve soil quality. Nevertheless, the best results were obtained with the plant-amendment combination