Wild Plants for the Phytostabilization of Phosphate Mine Waste in Semi-Arid Environments: A Field Experiment

Abstract

The management of mine waste has become an urgent issue, especially in semi-arid environments. In this context, and with an aim to inhibit the oxidation of the sulfide tailings of the abandoned mine of Kettara in Morocco, a store-and-release (SR) cover made of phosphate mine waste (PW) was implemented. In order to guarantee its long-term performance, phytostabilization by local wild plant species is currently the most effective and sustainable solution. This study aimed to assess the growth performance and phytostabilization efficiency of five local wild plant species to grow on the SR cover made of PW. A field experiment was conducted for two growing seasons (2018 and 2019), without amendments and with the minimum of human care. PW and the aboveground and belowground parts of the studied plant species were collected and analyzed for As, Cd, Cu, Ni, and Zn. The bioconcentration factor (BCF) and translocation factor (TF) were also calculated. Despite the hostile conditions of the mining environment, the five plant species showed promising growth performances as follows: Atriplex semibaccata > Vicia sativa > Launaea arborescens > Peganum harmala > Asparagus horridus. The five plants showed high accumulation capacity of the trace elements, with the highest concentrations in belowground tissue. Principal component analysis distinguished A. semibaccata as having a high concentration of Cu and As, while Asparagus horridus had higher concentrations of Cd and Zn. In contrast, P. harmala, V. sativa, and L. arborescens demonstrated affinity regarding Ni. According to the BCF (<1) and TF (<1), these plant species could be used as effective phytostabilizers of the studied trace elements. The present study showed that local wild plant species have a great potential for the phytostabilization of PW, and could ensure the long-term efficiency of SR cover.

Review of global trends in meeting the ecological challenges of the mining industry. Part I: International research

“…After two ve getation seasons, it was found that the rooting depth of Atriplex semibaccata, Vicia sativa, Launaea arborescens, Peganum harmala and Asparagus horridus contained essentially higher concentrations of As, Cd, Cu, Ni and Zn. From the evidence of the field studies and lab-scale tests, the listed plants were assumed suitable for phyto-stabilization of the whole surface area of tailings dumps [30].…”

Enhancing Hygiene and Technical Properties of Ceramic Tiles through Moroccan Phosphate Additives

“…Morocco's mining heritage is very rich in phosphates; it has been reported that it contains three quarters of the world's reserves, which allows it to rise among the four main universal producers and exporters (Hakkou et al, 2008;Hakkou et al, 2009;El Berkaoui et al, 2021). Moreover, around ten other minerals (zinc, lead, anthracite, iron, copper, barite, antimony, fluorite, cobalt, silver, and manganese) are regularly produced, and make it possible to enrich this heritage (Mehahad and Bounar, 2020;Zine et al, 2020). In addition, clays from Morocco occupy a predominant place in all sedimentary rocks.…”

Native plant diversity for ecological reclamation in Moroccan open-pit phosphate mines

“…Native flora is known to establish a self–sustaining vegetative cover on marginal land such as mine deposits and support the resilience and recovery of the historical ecosystem ( Prach et al 2013 ). According to Mukhopadhyay (2010) , Sheoran et al (2010) and Zine et al (2021a) , native plants are known for their fast growth, ability to easily establish themselves in stressed environments and high tolerance to harsh climatic conditions ( Zhang et al 2020 ). Using native plants to restore a landscape can help to reverse a species loss trend caused by harmful anthropogenic activities given that in the long run, these plant communities require little maintenance ( Minas 2015 ).…”