Screening of Native Plants Growing on a Pb/Zn Mining Area in Eastern Morocco: Perspectives for Phytoremediation.

Said El Hasnaoui,Laila Rhazi,Catherine Keller,Abdelaziz Smouni,Mouna Fahr,Abdelkarim Guedira,Bernard Angeletti,Zine El Abidine Triqui,Fabrice Colin,Perrine Chaurand,Clément Levard

doi:10.3390/plants9111458

Abstract

Screening of native plant species from mining sites can lead to identify suitable plants for phytoremediation approaches. In this study, we assayed heavy metals tolerance and accumulation in native and dominant plants growing on abandoned Pb/Zn mining site in eastern Morocco. Soil samples and native plants were collected and analyzed for As, Cd, Cu, Ni, Sb, Pb, and Zn concentrations. Bioconcentration factor (BCF), translocation factor (TF), and biological accumulation coefficient (BAC) were determined for each element. Our results showed that soils present low organic matter content combined with high levels of heavy metals especially Pb and Zn due to past extraction activities. Native and dominant plants sampled in these areas were classified into 14 species and eight families. Principal components analysis separated Artemisia herba-alba with high concentrations of As, Cd, Cu, Ni, and Pb in shoots from other species. Four plant species, namely, Reseda alba, Cistus libanotis, Stipa tenacissima, and Artemisia herba-alba showed strong capacity to tolerate and hyperaccumulate heavy metals, especially Pb, in their tissues. According to BCF, TF, and BAC, these plant species could be used as effective plants for Pb phytoextraction. Stipa tenacissima and Artemisia herba-alba are better suited for phytostabilization of Cd/Cu and Cu/Zn, respectively. Our study shows that several spontaneous and native plants growing on Pb/Zn contaminated sites have a good potential for developing heavy metals phytoremediation strategies.

Highlights

Soil contamination by heavy metals has become one of the major environmental problems around the world [1]
Our result showed that Pb accumulated in Stipa tenacissima shoots exceeds the hyperaccumulation thresholds, more than 1000 mg Pb/kg dry weight (DW)
Native plant species identified in these areas present a high ability to tolerate and accumulate several metals in their tissues

Summary

Introduction

Soil contamination by heavy metals has become one of the major environmental problems around the world [1]. Heavy metals persist a long time in the soils as these elements are not biodegradable [2,5]. This contamination affects the taxonomic, Plants 2020, 9, 1458; doi:10.3390/plants9111458 www.mdpi.com/journal/plants. There are several technologies to remediate heavy metals contaminated soils (e.g., excavation of contaminated material and chemical/physical treatment). Many of these technologies are costly or do not achieve a long-term nor aesthetic solution [9,10]

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Conclusion