Figure 1: Tolerance of Frankia alni spp. strains to tailing sands stressors. (a) alkalinity, (b) NaCl, (c) Na2SO4, (d) napthenic acids, (e) naphtenate salts, (f) amalgam (NaCl, Na2SO4 and naphtenic acids). In f) the [x] indicates the multiple of the concentrations found on site. Each bar represents the strains tolerance; meaning the maximal concentration/value of stressor that allows the strains to produce at least 25% of MTS reduction signal compared to control condition (without stressor).