Analysis of arsenic and antimony distribution within plants growing at an old mine site in Ouche (Cantal, France) and identification of species suitable for site revegetation

Abstract

One of the objectives of this study was to assess the contamination levels in the tailings of an old antimony mine site located in Ouche (Cantal, France). Throughout the 1.3 ha site, homogenous concentrations of antimony and arsenic, a by-product of the operation, were found along 0-0.5 m-deep profiles. Maximum concentrations for antimony and arsenic were 5780 mg kg(-1) dry tailings and 852 mg kg(-1) dry tailings, respectively. Despite the presence of the contaminants and the low pH and organic matter contents of the tailings, several patches of vegetation were found. Botanical identification determined 12 different genera/species. The largest and most abundant plants were adult pines (Pinus sylvestris), birches (Betula pendula) and the bulrush (Juncus effusus). The distribution of the metalloids within specimens of each genera/species was analysed in order to deduce their concentration and translocation capacities. This was the second goal of this work. All plant specimens were highly contaminated with both metalloids. Most were root accumulators with root to shoot translocation factors <1. Whereas contamination levels were high overall, species with both a low translocation factor and a low root accumulation coefficient were identified as suitable candidates for the complete revegetation of the site. Species combining those characteristics were the perennials P. sylvestris, B. pendula, Cytisus scoparius and the herbaceous Plantago major, and Deschampsia flexuosa.