Sources of rare earth elements in the environment and their impact on living organisms

Abstract

This review paper aims at understanding natural and anthropogenic sources of rare earth elements (REEs) in the environment, their mechanisms of action, individual toxicity of REEs and individual toxicity of their mixtures, including with other toxicants. We also summarized the scientific knowledge on REE bioaccumulation by plants, animals and fungi. The purpose of the work was to analyze published scientific information and identify unsolved scientific issues in the selected areas. At present, both natural positive geochemical anomalies of REEs and "spots" of anthropogenic origin are discovered. There is a relationship between natural and anthropogenic sources of REEs in the environment. Increasing REE mining leads to the exposure of rock layers rich in target elements, which are then leached from natural and waste rocks. As a result, the total content of REEs in soils of their extraction areas reaches 2.3 µg/kg, and in the snow of cities it is found from 0.411 µg/kg to 1.463 µg/kg, which is comparable with natural anomalies of elements. Most often such levels of REE accumulation are not dangerous for biota. REEs, like many trace elements, have an essential effect in low concentrations and have harmful effects only when the dose is increased. However, stimulation effects proven for agricultural plants and animals in the natural environment can influence the change in population and community structures. The effects of REE compounds have many uncertainties under the conditions of their joint action with each other and with other substances containing biogenic or potentially toxic elements. The article provides examples of additive, synergistic and antagonistic action of a mixture of elements. Further, it is shown that the bioaccumulation of REEs is comparable to the accumulation of heavy metals in living organisms. Data on the transfer of REEs along trophic chains are single and contradictory. Thus, REEs contribute to the toxic load on living organisms. The main “blank spots” in knowledge about the action of REEs that require further research are identification of the most sensitive and vulnerable species, establishment of long-term effects, and clarification of the joint action of REEs with other substances.

The Effect of Phosphorus-Containing Technogenic Waste on Hydrobionts

“…Шетелдік зерттеулерде фосфор қалдықтарының құрамында сирек жер элементтерінің (СЖЭ) мөлшері жоғары болатыны көрсетіледі [16,17], Шымкент қ. құрамында фосфоры бар қалдықтардың элементтік құрамында сирек жер элементтерінен, әсіресе La, Ce, Nd үлесі жоғары болатыны, фосфорлы қалдықтары құрамында таралған микроағзалар арқылы бағалы компонеттерді бөліп алудың тиімділігі зерттеліп, таныстырылды [18], сонымен қатар Шымкент қ. фосфор қалдықтарындағы микроағзалар популяциясының таралымы анықталды [19]. СЖЭ кейбір микроағзалар үшін уытты болып келуі мүмкін, қалдықтардың құрамында кездесетін басқа метал иондарына тірі ағзалар сезімталдығы әртүрлі деңгейде болады [20][21][22]. Осыған орай зерттеу жұмысымыздың міндеттерінің бірі болып құрамында фосфоры бар қалдықтардың тест-нысан ағзаларға әсерін бағалау арқылы биологиялық қасиетін зерттеу болды.…”

Accumulation and Translocation of Rare Trace Elements in Plants near the Rare Metal Enterprise in the Subarctic

“…The chemical composition of plants in impact areas of mining tailings is affected directly by dust deposition from the atmosphere, and indirectly by uptake of chemical elements from contaminated soils [10,11]. The accumulation and integration Toxics 2023, 11, 898. https://doi.org/10.3390/toxics11110898 https://www.mdpi.com/journal/toxics of pollutants into plant physiological cycles cause a variety of stress reactions, such as a decrease in photosynthetic activity, height, yield, oxidative cellular stress, and many others [12][13][14][15], which consequently lead to the migration of potentially toxic elements through food chains [16][17][18] and cause risks for humans [19][20][21]. Naturally, in the mining zone of REE-containing ores, REE can enter the environment and be accumulated in various ways, creating a potential threat to the ecosystem and public health [22,23].…”