Is aided phytostabilization a suitable technique for the remediation of tailings?

Abstract

Mining activity in Cartagena‐La Union mining district (SE Spain) dates back more than 2500 years. Consequently, large amounts of sterile materials with large metal(loid) contents (mostly Zn and Pb) have accumulated in tailings ponds. A reclamation strategy based on aided phytostabilization was carried out to reclaim one tailings pond to reduce environmental and public health hazards. The main goal of this study was to determine the effectiveness of the aided phytostabilization strategy after 30 months from its implementation in enhancing soil quality and fertility and reducing mobility of the metals. Marble waste, raw pig slurry and its solid phase after physical separation were applied as amendments, and 13 Mediterranean native plant species were planted or sown. Various soil physicochemical and biochemical properties, together with the pseudo‐total and bioavailable fraction of the metal(loid)s, As, Cd, Cu, Pb and Zn, were monitored for 30 months. Results showed that pH, total organic carbon (TOC), total nitrogen (TN), cation exchange capacity (CEC), available phosphorus (P), exchangeable potassium (K), microbial biomass carbon (MBC), basal soil respiration (BSR) and enzyme activities increased with the application of the amendments and development of vegetation. In addition, the available fraction of metals markedly decreased (90–99%). Most plant species present in the area did not transfer large amounts of trace elements to the aerial tissues. The roots of Lygeum spartum loefl. Ex L. and Piptatherum miliaceum (L.) Coss. accumulated the largest amounts of As, Pb and Zn. Thus, the application of marble waste to increase pH and immobilize metal(loid)s, and pig slurry as a source of organic matter and nutrients, together with the development of vegetation to immobilize metal(loid)s in the roots and rhizosphere, and the effect of microbial communities on organic matter stabilization and development, have contributed to improve soil quality and fertility. Once the soil quality of mine tailings was improved, the development of vegetation and microbial colonization increased, promoting integrated reclamation of the area. Therefore, aided phytostabilization was a suitable technique for remediation of this tailings pond. Highlights We evaluated effectiveness of mid‐term and large‐scale aided phytostabilization. Marble waste, pig slurry and native plants were used for reclamation of a tailings pond. Increased soil quality promoted plant development and microbial colonization. Lygeum spartum and Piptatherum miliaceum are good candidates to phytostabilize Pb, Zn and As.

Chemical Composition, Antioxidant and Anti-Inflammatory Activities of Clary Sage and Coriander Essential Oils Produced on Polluted and Amended Soils-Phytomanagement Approach

“…However, increased concentrations of TE may impair plant growth and weaken the success of the method [ 1 , 6 ]. Phytostabilisation can hence be supported through the addition of amendments, aiming at further reducing TE bioavailability, while improving soil quality and plant’s growth [ 7 ]. Among the available amendments, microbial inoculants and in particular arbuscular mycorrhizal fungi (AMF), able to develop symbiotic associations with most of the terrestrial plants, have long been described for their contribution towards an improved plants’ fitness in agroecosystems [ 8 , 9 ].…”

Are the soils and vegetation of a forest close to tailings ponds affected by metals and arsenic?

“…The concentration of metal(loid)s in the studies soils (Table 1) exceeded in all cases the toxicity levels for soils (Table 2). The establishment of sampled specimens in soils, with concentrations of trace elements above toxicity levels, may be due to the fact that these species are resistant, because they do not translocate the metal present in their rhizosphere, called phytostabilizer plants (Martı ´nez-Martı ´nez et al, 2019;Parra et al, 2016), or because they absorb them but it does not affect them (Behmer et al, 2005;Conesa et al, 2006;Lam et al, 2018). However, it is likely that plants can grow in these soils because the labile Metals and arsenic concentrations toxic to plant growth and in leaf tissues (Kabata-Pendias, 2001;Mendez and Maier, 2008) b Metal and arsenic levels tolerable for cattle (NCR, 2005) fractions present in the soil are below those limits.…”

Special section on soil and human health – An editorial

“…In addition, most of the plant species took up small amounts of metal(loid)s or concentrated those that they did take up in their root systems. Martínez‐Martínez et al () concluded that their amendments were successful in transforming the low‐productivity soil into one that would support a thriving soil ecological system, which in turn enhanced phytostabilization of the contaminants at the study site. This would, in turn, provide benefits to human health.…”