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

Abstract

This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues.Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. 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.

Rare Earth Elements in the Soil Environment

“…Regarding REE, this aspect deserves a special attention, because our understanding on the biological role of these elements is still in its early stages [2] and little is known about their effects in ecosystem function, which is especially relevant in areas affected by anthropogenic activities that alter natural concentrations of REE in soils.…”

“…The following elements are part of the HREE group: Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Y. These elements have higher atomic masses, smaller solubility, and alkalinity [2]. However there is no absolute definition in the scientific community worldwide to classify each element within the group of LREE or HREE.…”

Rare earth elements (REE) in freshwater, marine, and terrestrial ecosystems in the eastern Canadian Arctic

“…not bioavailable) in soils. 14,15 However, recent laboratory studies show the potential for both toxicity and bioaccumulation of REEs in many species, including microorganisms and phytoplankton, [16][17][18] aquatic plants, 5,19 terrestrial plants, [20][21][22][23][24] terrestrial and aquatic invertebrates, 1, 10, 13, 25 as well as in fish. [26][27][28] Anthropogenic REE enrichment, and subsequent bioaccumulation in biota, may therefore lead to REE concentrations closer to estimated toxicity thresholds, as is the case in the Yellow River region in China.…”

Lithological distribution of rare earth elements in automorphic and alluvial soils in the Bregalnica river basin

“…Because of industrialization, urbanization, and uncontrolled discharge of wastewater from industry, mining and flotation, there are highеr levels of pollution in terms of the introduction of higher contents of certain toxic metals into the soil [23][24][25][26][27]. Pollution is often particularly high in the lower courses, as is the case for the Bregalnica riv-er in its lower course through the Kočani valley [28,29].…”