High cadmium concentrations in Jurassic limestone as the cause for elevated cadmium levels in deriving soils: a case study in Lower Burgundy, France

Abstract

Cadmium (Cd) is a highly toxic element and its presence in the environment needs to be closely monitored. Recent systematic surveys in French soils have revealed the existence of areas in eastern and central France, which show systematically high cadmium concentrations. It has been suggested that at least part of these anomalous levels are of natural origin. For the Lower Burgundy area in particular, a direct heritage from the Jurassic limestone bedrock is highly suspected. This potential relationship has been studied in several localities around Avallon and this study reports new evidence for a direct link between anomalously elevated cadmium contents of Bajocian and Oxfordian limestone and high cadmium concentrations in deriving soils. Soils in this area show cadmium concentrations generally above the average national population values, with contents frequently higher than the 'upper whisker' value of 0.8 lg g -1 determined by statistical evaluation. In parallel, limestone rocks studied in the same area exhibit cadmium concentrations frequently exceeding the mean value of 0.030-0.065 lg g -1 previously given for similar rocks by one order of magnitude with a maximum of 2.6 lg g -1 . Mean ratios between the cadmium concentrations of limestone bedrock and deriving soils (Cd soil /Cd rock ), calculated for different areas, range from 4.6 to 5.7. Calculations based on the analyses of both soils from a restricted area and fragments of bedrock sampled in the immediate vicinity of high-concentration soils are around 5.5-5.7. Cd soil /Cd rock is useful in determining the potential of soils in Lower Burgundy to reflect and exacerbate the high concentrations of cadmium present in parent bedrocks.

Elucidating the formation of terra fuscas using Sr–Nd–Pb isotopes and rare earth elements

“…Atteia et al (1995) suggested that the chemical bedrock (carbonate) content only partly explains the major and trace element enrichments and that also anthropogenic atmospheric deposition might have contributed to the anomalous Cd content in these soils. Moreover, Rambeau et al (2010) showed that there is a direct link between the unusual high Cd concentrations in the Bajocian and Oxfordian limestones and those in the overlying soils. Thus, the Cd is assumed to concentrate by progressive carbonate dissolution (Baize et al, 1999;Rambeau et al, 2010).…”

“…Only few studies highlighted unusual high Cd contents for soils derived from Bajocian and Oxfordian limestones in other European regions, e.g. Burgundy (France) (Rambeau et al, 2010) and the Swiss Jura (Atteia et al, 1994;1995;Quezada-Hinojosa et al, 2009;2015). According to Rambeau et al (2010), Cd enrichments can represent up to five times the content of the underlying Jurassic limestone/marl complexes (especially from Bajocian to Oxfordian formations), which are enriched in trace elements compared to other carbonate rocks.…”

“…Burgundy (France) (Rambeau et al, 2010) and the Swiss Jura (Atteia et al, 1994;1995;Quezada-Hinojosa et al, 2009;2015). According to Rambeau et al (2010), Cd enrichments can represent up to five times the content of the underlying Jurassic limestone/marl complexes (especially from Bajocian to Oxfordian formations), which are enriched in trace elements compared to other carbonate rocks. Atteia et al (1995) suggested that the chemical bedrock (carbonate) content only partly explains the major and trace element enrichments and that also anthropogenic atmospheric deposition might have contributed to the anomalous Cd content in these soils.…”

Origin of high Zn contents in Jurassic limestone of the Jura mountain range and the Burgundy: evidence from Zn speciation and distribution

“…Jurassic limestone of the Jura mountain range (JMR) and the Burgundy bear anomalously high zinc (Zn) and cadmium (Cd) concentrations (Baize and Sterckeman 2001;Dubois et al 2002;Jacquat et al 2009a;Laveuf et al 2009;Quezada-Hinojosa et al 2009;Rambeau et al 2010). Up to 92 mg/kg Zn and 21 mg/kg Cd have been reported for limestone of Bajocian age and up to 207 mg/kg Zn and 1 mg/kg Cd for limestone of Oxfordian age (Jacquat et al 2009a;Rambeau 2006), whereas mean Zn and Cd contents in marine carbonate rocks are considered to be close to 20 and 0.03 mg/kg, respectively (Alloway 1995;Tuchschmid 1995).…”

“…Up to 92 mg/kg Zn and 21 mg/kg Cd have been reported for limestone of Bajocian age and up to 207 mg/kg Zn and 1 mg/kg Cd for limestone of Oxfordian age (Jacquat et al 2009a;Rambeau 2006), whereas mean Zn and Cd contents in marine carbonate rocks are considered to be close to 20 and 0.03 mg/kg, respectively (Alloway 1995;Tuchschmid 1995). As a consequence, numerous soils in the Burgundy and the JMR were identified to be naturally enriched with Zn and Cd originating from the parent rock (Baize and Sterckeman 2001;Dubois et al 2002;Jacquat et al 2009a;Laveuf et al 2009;Rambeau et al 2010). The origin of elevated Zn (and Cd) contents in the limestone however is still unclear.…”