Sources and geochemical behaviors of rare earth elements in suspended particulate matter in a wet-dry tropical river

Guilin Han; Man Liu; Xiaoqiang Li; Qian Zhang

doi:10.1016/j.envres.2022.115044

Sources and geochemical behaviors of rare earth elements in suspended particulate matter in a wet-dry tropical river

Environ Res. 2023 Feb 1:218:115044. doi: 10.1016/j.envres.2022.115044. Epub 2022 Dec 10.

Authors

Guilin Han¹, Man Liu², Xiaoqiang Li², Qian Zhang³

Affiliations

¹ Institute of Earth Sciences, China University of Geosciences (Beijing), Beijing, 100083, China. Electronic address: hanguilin@cugb.edu.cn.
² Institute of Earth Sciences, China University of Geosciences (Beijing), Beijing, 100083, China.
³ Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences, Beijing, 100101, China.

PMID: 36513127
DOI: 10.1016/j.envres.2022.115044

Abstract

The processes of rock weathering and soil erosion, and hydrochemical characteristics are significantly affected by the climate in a basin. However, the sources of rare earth elements (REEs) in suspended particulate matter (SPM) under soil erosion, as well as the geochemical behaviors of REEs with changes in hydrochemical properties between seasons, have received little attention in the tropical monsoon zone. In this study, the temporal and spatial characteristics of the REEs in SPM were investigated in the Mun River (a wet-dry tropical river), Northeast Thailand. During the dry season, the compositions of the major elements and REEs in SPM were very similar to those in local soils. However, there was a clear difference between the compositions of these major elements and REEs in SPM and those in local soils during the rainy season. This suggests that the SPM and its REEs during the dry season were primarily derived from soil materials, while those during the rainy season were primarily derived from soil materials and products of rock weathering. The ∑REE contents in SPM decreased from 191.2 mg kg^-1 to 170.6 mg kg^-1 along the flow direction during the dry season, while they increased from 100.7 mg kg^-1 to 135.3 mg kg^-1 during the rainy season. The δEu (mean 1.26) and δGd (mean 1.58) values in SPM during the rainy season were higher than those (mean δEu 1.21 and mean δGd 1.12) during the dry season, and both of them were mainly controlled by the relative contributions of rock weathering products and soil materials to SPM. The results suggest that the temporal differences of REE geochemical characteristics in SPM were closely associated with SPM sources, while their spatial variations were mainly affected by the water-particle interaction in the tropical monsoon zone.

Keywords: Geochemical characteristics and behaviors; Northeast Thailand; Rare earth elements; Suspended particulate matter; Wet-dry tropical river.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Environmental Monitoring
Metals, Rare Earth* / analysis
Particulate Matter*
Rivers / chemistry
Seasons
Soil

Substances

Particulate Matter
Metals, Rare Earth
Soil