Native Plant Capacity for Gentle Remediation in Heavily Polluted Mines

María Noelia Jiménez,Mauro Casti,Francisco Bruno Navarro,Gianluigi Bacchetta,Emilia Fernández-Ondoño

doi:10.3390/app11041769

Abstract

The use of plant species to stabilize and accumulate trace elements in contaminated soils is considered of great usefulness given the difficulty of decontaminating large areas subjected to mining for long periods. In this work, the bioaccumulation of trace elements is studied by relating the concentrations in leaves and roots of three plants of Mediterranean distribution (Dittrichia viscosa, Cistus salviifolius, Euphorbia pithyusa subsp. cupanii) with the concentrations of trace elements in contaminated and uncontaminated soils. Furthermore, in the case of D. viscosa, to know the concentration of each element by biomass, the pool of trace elements was determined both in the aerial part and in the roots. The bioaccumulation factor was not high enough in any of the species studied to be considered as phytoextractors. However, species like the ones studied in this work that live on soils with a wide range of concentration of trace elements and that develop a considerable biomass could be considered for stabilization of contaminated soils. The plant species studied in this work are good candidates for gentle-remediation options in the polluted Mediterranean.

Highlights

Industrial activity, such as mining, has generated large amounts of waste over time, giving rise to major environmental problems worldwide [1]
For all elements, the concentration was higher in contaminated soils than in non-contaminated soils, no significant differences were detected for Cu and Fe concentrations under C. salviifolius or for Mn under E. pithyusa
The highest values corresponded mainly to soils under E. pithyusa for all the elements except for Mn, which had a higher concentration in uncontaminated soils under C. salviifolius, and Pb, which was more abundant in soils under D. viscosa

Summary

Introduction

Industrial activity, such as mining, has generated large amounts of waste over time, giving rise to major environmental problems worldwide [1]. In the Sulcis-Iglesiente region (Sardinia, Italy), after more than 2000 years of mining activities, numerous spoil heaps of various types of waste material persist from the extraction process as well as the chemical and electrolytic treatments [2]. The trace-metal content is highly variable, as well as the characteristics of the contaminated soils [3]. The most abundant elements in the spoil heaps include Fe, Zn, Mn, Pb, and Cu. The most abundant elements in the spoil heaps include Fe, Zn, Mn, Pb, and Cu The bioavailability of these elements relates to their total concentration and to soil characteristics such as pH, clay content, soil organic matter, CaCO3 , Al, Mn and Fe oxides and hydroxides [4]. The use of native plants can be a solution to stabilize these sediments, avoid or minimize erosion and eventually accumulate and eliminate part of the trace elements

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