Phytoremediation capability of native plant species living on Pb-Zn and Hg-As mining wastes in the Cantabrian range, north of Spain

Abstract

Purpose phytoremediation with native species is a low cost technique for recovering contaminated soils avoiding ecological risks associated to the use of non-native species. Materials and methods six ancient mining tailings extremely contaminated by heavy metal(oid)s (Pb, Zn, As and Hg) were sampled in the Principality of Asturias (northern Spain) (3 from Hg-As mining tailings: Caunedo, Soterraña and Terronal, and 3 from Pb-Zn mining: Carmina; San Jose and Mánforas Mánforas). In order to both analyze soil-plant interactions and identify plant species with phytoremediation potential. In this survey, 118 samples of plants and the corresponding soils were taken within the abovementioned sites. Soil and plant samples were analyzed for total concentrations of relevant metals and metalloids by ICP-MS. In soils, exchangeable metal concentration, pH, conductivity and CIC, were determined. Eighty representative plant species (13 of them replicated in several locations) were finally evaluated. Results and discussion this survey identified Coincyamonensis as a Zn hyperaccumulator with high soil to pant transfer factor for Cd. Among grasses, the endemic Agrostis durieui tolerated high tissue Pb concentrations and this species was dominant at Pb-Zn spoil heaps at Carmina. Holcus lanatus and Festuca rubra excluded Hg and As more efficiently than Dactylis glomerata. Among the legume species Cytisus striatus, Cytisus scoparius, Genista legionensis and Lotus corniculatus were efficient excluders. Prevailing tree species also were efficient excluders, excepting willows. Conclusions the mining area of the Asturian Principality is an important reservoir of a large number of plant species with high potential for phytostabilization or phytoextraction of soils contaminated by Hg, As, Zn and/or Pb.