Rare earth elements in surface waters and sediments of the Mgoua watershed, south western Cameroon


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Article: article d'un périodique ou d'un magazine.
Rare earth elements in surface waters and sediments of the Mgoua watershed, south western Cameroon
Arabian Journal of Geosciences
Josephine Ndjama, George Mafany, Raoul Gustave Nkoue Ndondo, Biram Eric Belmond, Armel Zacharie Ekoa Bessa
Statut éditorial
Date de publication
The concentrations and distribution spectra of 14 stable rare earth elements (REE) were studied for surface waters (n = 30)
and sediments (n = 30) of the tropical zone Mgoua watershed in southwest of Cameroon. Samples were analyzed using the
inductively coupled plasma mass spectrometer (ICP-MS) method. The ∑REE concentrations of the surface waters vary
from 0.11 to 6.60 µg/L with an average value of 1.18 µg/L. This average is 150 times lower than the average values of the
Post-Archean Australian Average Shale (PAAS). In the sediments, the concentrations range from 282.12 to 727.67 ppm
with an average value of 550.05 ppm, making it 2.5 times higher than the PAAS. Rare earth spectra normalized to PAAS are
spread out and show heavy rare earth enrichment; positive Eu anomalies; negative, low, or no Ce anomalies; and a gradual
decrease in heavy earths in river and well waters and sediments, but are sawtooth with strong negative Ce anomalies in efuent waters and sediments. A low rare earth fractionation is noted in river and well waters [(La/Yb)N ~ 0.35–1.19], while it is
high in efuent waters [(La/Yb)N ~ 0.42–56.99]; a slight depletion of rare earths in all environments [(La/Sm)N ~ 0.69–2.35],
as well as a depletion of heavy rare earths [(Gd/Yb)N ~ 0.58–1.94]. In the sediments, the same characteristics are found with
elemental ratio values difering slightly [(La/Yb)N ~ 1.15–1.99]; [(La/Sm)N ~ 0.75–1.36]; and [(Gd/Yb)N ~ 1.15–2.01]. This
study shows that the Mgoua watershed does not have a high concentration of REE, although in the sediments they are well
above the average PASS value while they are insignifcant in the waters.
Création de la notice
25/11/2022 15:44
Dernière modification de la notice
18/07/2023 16:33
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