Distribution characteristics and influencing factors of rare earth elements in surface sediments of the southern nearshore waters of the North Yellow Sea

Based on the results of grain size and rare earth element (REE) testing of surface sediments from 52 stations in the nearshore waters of the southern part of the North Yellow Sea and sediment samples from seven major rivers, the planar distribution characteristics of grain size and REE content in the study area were analyzed, and the factors influencing the distribution of REEs were discussed. The results show that the surface sediments in the study area are roughly characterized by finer grain size from nearshore to sea sediments. The content of rare earth elements in the study area is generally higher than that in the Yangtze River, Yellow River and China Loess areas, and is generally characterized by the enrichment of light rare earths and loss of heavy rare earths. The content and distribution of rare earth elements are affected by various factors such as grain size, mineral composition, weathering and material source, among which the mineral composition has a more significant influence on the rare earth elements in the study area, and the high content of rare earth elements may be related to the enrichment of land-sourced detrital minerals (feldspar minerals, titanium-containing minerals, etc.); the influence of the grain size is reflected in the fact that the heavy rare earth elements are more likely to be enriched in the sediments with high content of fine-grained components; the effect of weathering on the sediment is also reflected in the fact that the heavy rare earth elements are more easily enriched in the sediments with high content of fine-grained components; the effect of weathering on the sediment is more significant. The effect of weathering on rare earth elements is mainly accomplished through the mixing of multiple sources; the source of rare earth elements in the study area is dominated by the Yellow River source sediments.