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

Abstract

Background 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.

Assessment of soil metal distribution and environmental impact of mining in Katanga (Democratic Republic of Congo)

“…Fungurume 5, Goma 2 and Kolwezi D are natural Cu-Co undisturbed hills from the TenkeFungurume region and Kolwezi region, respectively (Fay and Barton, 2012;Cox et al, 2003;Kaya Muyumba et al, 2015;Lange et al, 2014;Schuh et al, 2012). Etoile, Kalabi, Niamumenda and Ruashi are disturbed sites (Malaisse and Grégoire, 1978 ;Faucon et al, 2011 ;Lange et al, 2014, Pourret et al, 2015Ilunga wa Ilunga et al, 2015).…”

“…Etoile, Kalabi, Niamumenda and Ruashi are disturbed sites (Malaisse and Grégoire, 1978 ;Faucon et al, 2011 ;Lange et al, 2014, Pourret et al, 2015Ilunga wa Ilunga et al, 2015). Mine de l'Etoile site corresponds to a former Cu-Co hill in the Lubumbashi region whereas Niamumenda and Kalabi sites correspond to two Cu-Co hills locally disturbed by reworked substrate (due to artisanal mining) (Faucon et al, 2012b).…”

“…To address this issue, the metal speciation in soil is studied in order to provides complementary information about the metal concentration bounded to organic matter and Fe-and Mn-oxides (Pourret et al, 2015), and the proportion of free metal (i.e., phytoavailable) remaining in the soils (e.g., Lange et al, 2014).…”

“…In order to study such effects, metals and metalloids have often been studied around mines and smelters (Ettler et al, 2005;Khalil et al, 2013;Kříbek et al, 2010;Tembo et al, 2006). A special attention has been paid to the the potential uptake of these elements by plants (Faucon et al, 2009;Lange et al, 2014) and on their bioaccessibility for humans (Banza et al, 2009;Cheyns et al 2014). …”

Effect of manure, clay, charcoal, zeolite, and calcium oxide on some properties of soil contaminated with cobalt

“…Their initiation is determined to the greatest degree by soil reaction. Research by Collins and Kinsela (2010), similarly as that by Lange et al (2014), shows substantial contribution of organic substances to an increase in pH, and therefore a reduction of assimilable forms of cobalt occurring in the soil solution. According to Kwiatkowska and Maciejewska (2008), the introduction of carbon into soil contributes to the improvement of soil properties due to an increase in soil reaction and cation exchange capacity, and a reduction of hydrolytic acidity.…”