An ombrotrophic peat core (10 × 10 × 81 cm) was collected from Etang de la Gruère (Switzerland) and divided in 27 slices of 3 cm. Humic acids (HAs) were extracted from each slice after freeze-drying and fine milling. All raw peat and HA samples were analyzed using Energy-dispersive miniprobe X-ray fluorescence multielement analyser (EMMA-XRF), fluorescence spectroscopy and Low Background γ-spectrometry (LB γ-spec). The abundance and distribution of major and trace elements and radionuclides were measured in raw peat and corresponding HAs to possibly evaluate their affinity for organic ligands and establish which organic fraction might affect their behaviour along the profile. Raw peat samples show higher concentrations of Fe, Mn, Pb, Sr, Ti and Ca in comparison to the corresponding HAs, while Cu is more abundant in HAs. Zinc presents greater concentrations in raw peat in the first 24 cm of depth. All elements, with the exception of Fe, seem to be bound stably to HAs, although at different extent. The activity of 241Am is limited to the raw peat of a specific section of the profile, while that of 137Cs is recorded both in HAs and raw peat, even below the depth one would expect, suggesting the scarce mobility of the former and a different impact of these radionuclides on the environment.
Enrichment and depletion of major and trace elements, and radionuclides in ombrotrophic raw peat and corresponding humic acids
ZACCONE C.;
2007-01-01
Abstract
An ombrotrophic peat core (10 × 10 × 81 cm) was collected from Etang de la Gruère (Switzerland) and divided in 27 slices of 3 cm. Humic acids (HAs) were extracted from each slice after freeze-drying and fine milling. All raw peat and HA samples were analyzed using Energy-dispersive miniprobe X-ray fluorescence multielement analyser (EMMA-XRF), fluorescence spectroscopy and Low Background γ-spectrometry (LB γ-spec). The abundance and distribution of major and trace elements and radionuclides were measured in raw peat and corresponding HAs to possibly evaluate their affinity for organic ligands and establish which organic fraction might affect their behaviour along the profile. Raw peat samples show higher concentrations of Fe, Mn, Pb, Sr, Ti and Ca in comparison to the corresponding HAs, while Cu is more abundant in HAs. Zinc presents greater concentrations in raw peat in the first 24 cm of depth. All elements, with the exception of Fe, seem to be bound stably to HAs, although at different extent. The activity of 241Am is limited to the raw peat of a specific section of the profile, while that of 137Cs is recorded both in HAs and raw peat, even below the depth one would expect, suggesting the scarce mobility of the former and a different impact of these radionuclides on the environment.
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