Geochemical characteristics and influencing factors of dissolved rare-earth elements in rivers of coal grain composite area in eastern China

Rare-earth elements are widely used in the study of source tracing and geochemical characteristics, which can reflect the degree of influence of human activities on water environment. In order to reveal the additive effects of various human activities on the geochemical characteristics of rare-earth elements in the surface water environment, the content of rare-earth elements in the river in the coal grain composite area of eastern China was determined by inductively coupled plasma mass spectrometry (ICP-MS). The results showed that all water samples were alkaline, ΣREE content ranged 0.18–0.88 μg·L⁻¹, with an average value of 0.28 μg·L⁻¹. All the water samples showed significant enrichment of light rare-earth elements due to a combination of natural processes and external inputs. The spatial distribution and fractionation characteristics of rare-earth elements show that rare-earth elements (especially Ce) are prone to adsorption/complexation reactions with colloidal particles, resulting in their removal from rivers, Eu anomaly is related to plagioclase crystallization and human activities (coal development, agricultural production, urbanization process), and Gd anomaly is only related to human activities. The research results can provide scientific reference for revealing the distribution of rare-earth elements and geochemical environmental behavior in rivers environment under the superimposed influence of various human activities.