Rare earth elements in intertidal sediments of Bohai Bay, China: Concentration, fractionation and the influence of sediment texture

Abstract

a b s t r a c tSurface sediments from intertidal Bohai Bay were assessed using a four-step sequential extraction procedure to determine their concentrations of rare earth elements (REEs) and the chemical forms in which those elements were present. The normalized ratios La/Gd and La/Yb showed that LREE contents were not significantly higher than the middle REEs or HREE contents. A negative Ce anomaly and positive Eu were observed in sand and silty sand sediments, whereas no significant Ce or Eu anomaly was found in clayey silt sediments. Residual fraction of REEs accounted for the majority of their total concentrations. Middle REEs were more easily leached than other REEs, especially in clayey silt sediment. REEs contents in the surface sediment from the intertidal Bohai Sea were consistent with data from the upper continental crust and China shallow sea sediments, indicating that they were generally unaffected by heavily anthropogenic effects from adjacent areas.

Rare earth elements in surface sediments of a marine coast under heavy anthropogenic influence: The Bohai Bay, China

“…The dCe in our present study are quite in line with those of the Changjiang River (1.00), Huanghe River (1.00), Po River (1.00) (Yang et al, 2002;Kramer et al, 2002) and the intertidal zone of the Bohai Bay reported in our early study (Zhang et al, 2014). Hoyle et al (1984) suggested that Ce behaved coherently with its neighboring elements as a result of estuarine mixing so that Ce anomaly is not generated in estuary.…”

“…These results showed that the sampled area was not heavily Zhang et al (2014), probably due to their similar material source and sedimentary environment evolution. In surface sediments from the coastal Bohai Bay, the normalized concentration ratios of La/Gd and La/Yb were lower than 1.00 except at DLJ-2 and DLJ-3 (both were 1.03) (Fig.…”

“…The geochemical characteristics of some environmental quality assessment related trace metals in surface sediments of this region indicated a general state that they were subject to apparent anthropogenic influence (Gao and Chen, 2012;Gao and Li, 2012), which was also the condition in many other areas along the coastal waters of the Bohai Sea . The results of this investigation also indicated that the REEs in the intertidal surface sediments of this region were generally unaffected by the heavy anthropogenic effects (Zhang et al, 2014). Although rivers transports both industrial and domestic waste effluents from the land to the sea, the role of rivers in conducting REEs from the land to the Bohai Bay has not yet been estimated.…”

“…The scheme partitions elements into four operationally defined geochemical fractions, including acid-soluble (exchangeable and bound to carbonates), reducible (bound to Fe/Mn oxyhydroxides), oxidizable (bound to organic matter and sulfides) and residual (contained within lithogenic minerals). The details of the sequential extraction protocol used in this study have been described elsewhere in Gao et al (2008Gao et al ( , 2010 and Zhang et al (2014).…”

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

“…Indeed, they are known for their high affinity for fine grain size fractions in soils or sediments (Cullers et al, 1975;Ramesh et al, 2000;Caetano et al, 2013;Bayon et al, 2015), and also for their association with several chemical fractions (Zhang et al, 1998;Gu et al, 2001;Aubert et al, 2004;Davranche et al, 2008). Carbonates, iron oxides, and organic matter are thought to be among the more important controlling factors of REE (Leybourne and Johannesson, 2008;Zhang et al, 2014). The grain size, mineralogy, and carbonate content of sediments could thus contribute to the significant differences in the distribution and fractionation of REE (Yang et al, 2002;Feng, 2010;Suja et al, 2017).…”