Metal Uptake by Spontaneous Vegetation in Acidic Mine Tailings from a Semiarid Area in South Spain: Implications for Revegetation and Land Management

Abstract

Tailings are frequently a source of pollution in mining areas due to the spread of metals from their bare surfaces via wind or runoff water. Phytostabilization is an interesting and low-cost option to decrease environmental risks in these sites. In this study, an acidic mine tailing (pH 3-4) located in a semiarid area in Southeast Spain and the spontaneous vegetation which grow on were investigated. Soil samples were taken to characterize metal contamination, and three plant species, Lygeum spartum, Piptatherum miliaceum, and Helichrysum decumbens, were sampled in order to determine plant uptake of metals. The rhizosphere pH of H. decumbens was measured to be 6.7, which was significantly higher than the bulk soil (pH 3). The electrical conductivity values were around 2-5 dS m −1 . Total metal concentrations in soil were high (9,800 mg kg −1 for Pb and 7,200 mg kg −1 for Zn). DTPA-extractable Zn and Pb were 16% and 19% of the total amount, respectively. The three selected plant species accumulated around 2-5 mg kg −1 Cu in both shoots and roots. Zn concentration was 100 mg kg −1 in P. miliaceum roots. DTPA-extractable Zn was positively correlated with Zn plant uptake. These plant species demonstrated to grow well in acid tailings taking up only low concentrations of metals and therefore are good candidates to perform further phytostabilization works.

Measuring reactive metal in soil: a comparison of multi‐element isotopic dilution and chemical extraction

“…Extraction with DTPA generally under‐estimated the E‐value in all soils. The DTPA method has been successfully applied as an empirical prediction of plant uptake (Conesa & Faz, ) and was originally developed for diagnosing trace metal nutrient deficiency in calcareous soils (Hooda, ). Therefore, it was never intended to simply dissolve all metals present as carbonates.…”

Environmental and health risk assessment of metals in different land uses

“…Highest concentrations in mining, agricultural and natural soils in both mining district were found for Fe, Pb, Zn, Mn and As (Table 7.1), which is in accordance with results obtained in other studies in the same mining districts (Martínez-Pagán et al 2011;Conesa and Faz, 2011). Concentrations of As, Cd, Cu, Pb, and Zn exceed the limits to consider a soil as contaminated (Table 7.2) while for Fe and Mn does not exist threshold values or background levels in European legislations.…”

Metal and Phosphorus Uptake by Spontaneous Vegetation in an abandoned iron mine from a Semiarid Area in Center Morocco: Implications for Phytoextraction

“…Tolerant plants have TF values << 1 and hyperaccumulators >> 1 (Conesa and Faz, 2011). In our case, E. ilicifolium Lam had four TF values > 1: 1.23, 3.74, 6.99 and 537.72 for Cd, Cu, Pb and P, respectively, and one close to 1 (0.95) for Zn, C. lanatus L. C. arabicus (L.) Cass and S. capensis Thunb had three TF values > 1, E. triquetrum Vahl, C. acaulia subsp caulescens, E. spinosis and B. hordeaceus had two TF values > 1, L. hispidilus (Delile) Boiss and S. hispanicus L. had only one TF value > 1 and for other plants all TF values are < 1 (Table 7).…”

“…Plants growing on contaminated soils respond to elevated concentrations of heavy metals in the soil to varying extents, depending on the total soil metal concentrations, soil physicochemical conditions (especially pH) and the cultivars of plant (Wu and Zhang, 2002;Alexander et al 2006). The spontaneous plant colonization in mine tailings is usually slow since the physicochemical characteristics of these sites are not suitable for most of the plant species (Conesa and Faz 2011). Nevertheless, some of the tolerant plant species can spread easily in these environments due to the lack of competitors (Conesa and Faz 2011).…”

“…The spontaneous plant colonization in mine tailings is usually slow since the physicochemical characteristics of these sites are not suitable for most of the plant species (Conesa and Faz 2011). Nevertheless, some of the tolerant plant species can spread easily in these environments due to the lack of competitors (Conesa and Faz 2011).…”