Geochemical characteristics of rare earth elements (REEs) in the paddy soil and rice (Oryza sativa L.) system of Kočani Field, Republic of Macedonia

In the Republic of Macedonia, information about rare earth elements (REEs) distribution patterns, transportation and speciation characteristics (from soil to plants) is very rare. Therefore, the concentrations of REEs in Kočani paddy soils and rice samples from the Republic of Macedonia were measured and evaluated. The elevated concentrations of REEs in paddy soils can be explained by contributions from acidic and intermediate igneous rocks, which are one of the main source materials for Kočani paddy soils. Low percentages of REEs were bound to the water-soluble and exchangeable fractions, revealing low mobility of REEs in the investigated paddy soils. Furthermore, small amounts of REEs were detected in rice (Oryza sativa L.) grain samples. The calculated transfer values (TF) for REEs in rice samples were also very low, confirming a small accumulation of REEs (La, Ce, Pr, Nd and Sm) by the studied crops and in the Kočani soil–plant system.