Origin, distribution, and behaviour of rare earth elements in river bed sediments from a carbonate semi-arid basin (Tafna River, Algeria)

Abstract

A B S T R A C TThe behaviour and sources of rare earth elements (REE) in river sediments were investigated at ten stations and two dams of the Tafna basin (Northern Algeria) during contrasting hydrological conditions and using a combination of normalisation procedures, REE anomalies, various REE ratios, and multivariate statistical analysis. The ranking and REE concentrations were in the range of other carbonated areas. The classical fractionation of the heavy REE(HREE) erosion pattern, evidenced from upstream to downstream by the La/Yb or Sm/Yb ratios, was disturbed by the presence of dams, which retained the light REE (LREE) in particular. The hydrological conditions, particle size, and geochemical characteristics controlled the REE patterns. The LREE were associated with clay minerals and HREE with coarse silts, whereas carbonate and particulate organic carbon (POC) did not influence the transport downstream. The total concentration of REE in sediments was not strongly affected by anthropogenic inputs from various sources (industrial activities, and domestic or medical wastes). Indeed, some LREE enrichment and anomalies were detected at a few stations and locally for Gd, Tb, and Yb. However, the anthropogenic contribution can partially be hidden by dilution due to particle erosion. High flow increased the LREE and MREE enrichment and LREE/HREE fractionation in some places due to erosion processes and anthropic influences (dam releases and local wastes inputs). Middle REE (MREE) and HREE were the most extractable elements unlike LREE (which are the most concentrated), particularly during high water conditions. Finally, the REE demonstrated the impact of natural processes (hydrological, geochemical, and physical) and some anthropogenic disturbances (waste inputs, fertilisers, and dams). This might inspire to develop such investigations in other similar semi-arid basins undergoing various pressures. The use of local bedrock as a reference and a set of geochemical and statistical tools, is recommended.

Causes of variations of trace and rare earth elements concentration in lakes bottom sediments in the Bory Tucholskie National Park, Poland

“…Moreover, in Ostrowite Lake and additionally in Kocioł, Kacze Oko and Rybie Oko a negative anomaly of Yb and Tm was observed respectively. The formulas presented by Benabdelkader et al 65 were used to confirm the above observations. It was assumed that the computations of Eu, Gd, Yb and Tm anomalies will have values above > 1.1 or below < 0.9, which indicates the occurrence of positive and negative anomalies, respectively.…”

“…This is confirmed by earlier studies by Sojka et al 32 , obtained for Lake Wadąg located in north-eastern Poland. Benabdelkader et al 65 demonstrated that reservoirs play an important role in REE retention (LREE) and to delay the release of MREE and HREE downstream. There was slightly more MREE in the individual lakes than HREE.…”

“…Anomalies in the REE concentration enable one to identify potential sources of pollution and the influence of natural processes on their concentration 32 . In order to calculate the Eu, Gd and Yb anomaly, the equations proposed by Benabdelkader et al 65 were used. In the last stage the REE values were calculated for three groups: light (LREE—sum of La, Ce, Pr and Nd concentrations), medium (MREE—sum of Sm, Eu and Gd concentrations) and heavy (HREE—sum of Tb, Dy, Ho, Er, Tm, Yb and Lu concentrations).…”

Avaliação da concentração de metais, elementos terras raras e traço presentes em perfis de sedimentos em reservatórios, estado de São Paulo

“…Na verdade, eles são conhecidos por sua afinidade às frações finas em solos e sedimentos e pelas associações com várias frações químicas. Carbonatos, óxidos de ferro e matéria orgânica estão entre os fatores de controle mais importantes dos ETR (BENABDELKADER et al, 2019).…”

“…O crescente uso médico dos ETR nas últimas décadas, juntamente com suas aplicações de alta tecnologia, demonstram a necessidade urgente de investigações sobre esses elementos. (BENABDELKADER et al, 2019;TANSEL, 2017 (SIGRH, 2004b).…”