First Report of Rare Earth Elements and Other Chemical Elements in Sediments of Rivers throughout Chile

Abstract

The increase in demand for emerging technologies has also increased the presence of rare earth elements and other lesser-known elements in the environment that were previously stable in the Earth's crust. The aim of this study was to determine the current status of five rare earth elements such as cerium (Ce), lanthanum (La), neodymium (Nd), praseodymium (Pr) and yttrium (Y), and barium (Ba), niobium (Nb), rubidium (Rb), thorium (Th) and zirconium (Zr), in superficial sediments from rivers of northern, central and southern Chile. Data showed that the order of abundance of elements in the river sediments was Ba > Nd > Pr > La > Ce > Zr > Rb > Y > Th > Nb. We found higher Ba, Ce, La, Nd and Pr contents in northern and central Chile. Our findings showed that probably these chemical elements are adsorbed into sediments, which could facilitate remobilization to the water column, thus being more bioavailable to biota. Considering that rivers of northern and central Chile are usually used for human consumption and irrigation purposes, further studies to understand the processes involved in the recycling of elements in the watersheds are necessary. Our results may serve as a basis for environmental impact studies that are required by the Chilean legislation before any productive investment.

Risk Characteristics of Rare Earth Elements in Surface Soil of Paddy Field Downstream of Ionic Rare Earth <i>in-situ</i> Leaching Area

“…They formed during the crust weathering and differentiated in different soil-forming conditions [1]. Rare earth elements (REE) develop under hot and humid climate conditions are easily leached out under weathering and leaching, while those developed under dry and cold climate conditions are often enriched in the topsoil profile [2,3]. Ionic rare earth ores share commonality with other types of rare earth ores, and also have their own characteristics, such as light rare earths (LREE) are easily enriched in the upper layer of regolith, while heavy rare earths (HREE) are relatively enriched in the lower layer [4].…”