Prediction of the edaphic factors influence upon the copper and cobalt accumulation in two metallophytes using copper and cobalt speciation in soils

peer reviewedBackground and aims: Among the unique flora on copper and cobalt rich soils, some species are able to hyperaccumulate the Cu and Co in their shoots, however, the unexplained high variations of Cu and Co concentrations in shoots have been highlighted. A good comprehension of the Cu and Co accumulation variations would go through a characterization of the Cu and Co speciation in soils. We examined the covariations of Cu and Co speciation in soils and Cu and Co concentrations in plants. Methods: Plant samples of two species and soil samples (n = 146) were collected in seven pedogeochemically contrasted sites. Cu and Co speciation in soils was modeled by WHAM 6.0. Results: Variation in copper accumulation in plant shoots were mostly influenced by Cu adsorbed by the Mn and Fe oxides fractions, whereas Co accumulation variations were strongly influenced by Co free and Co adsorbed by the OM and Fe fractions. Conclusions: Availability of Cu and Co seems to be species-specific and is not explained only by the free Cu and Co content in the soil solution, but also strongly by the part linked to colloidal fractions. Availability of Cu and Co is a complex mechanism, closely related to all the biogeochemical processes which occur in the rhizosphere. Future work should perform experiments in controlled conditions to examine the soil parameters that influence the Cu and Co availability. © 2014 Springer International Publishing Switzerland