Levels of Rare Earth Elements in Food and Human Dietary Exposure:

Overview

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Key numbers

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Biological Trace Element Research (2025) 203:2240–2256
Rare earth elements (REEs) are a group consisting of the following 17 metals: Ce, Dy, Er, Eu, Gd, Ho, La, Lu, Nd, Pr, Pm,
automotive, among other relevant industrial sectors. In 2021,
emerging contaminants associated with new technologies. important end use for REEs. It accounted for 43% of the
According to the International Union of Pure and Applied demand (USGS, 2023 a,b).
erbium (Er), europium (Eu), gadolinium (Gd), holmium 1970s and 1980s, battery research led to the development
yttrium (Y) (66, 67). REEs are usually divided into heavy critical, specialized properties of REEs, which contribute to
Ho, Er, Tm, Yb, Lu, Sc and Y, and light rare earth elements been increasing their visibilities through many media (48). It
(1, 74). REEs are currently playing an increasing important properties, such as unique magnetic and optical properties. It
joseluis.domingo@urv.cat 1990s, and currently, China has globally the dominance in
School of Medicine, Laboratory of Toxicology the world’s REEs (1, 66, 67). Nowadays, REEs are used as
43201 Reus, Catalonia, Spain
Some well-known examples are computer monitors and hard Table 1 summarizes the studies that focused on determin-
displays, among others. Although the use of REEs in this et al. (77) measured the concentrations of 14 REEs in sixty
(68)). Therefore, the use of REEs in electronics is currently concentrations of total REEs were 2.66 ± 2.28, 4.69 ± 1.32,
essential, not having any substitute. In addition, their use in 0.03 ± 0.03 and 0.07 ± 0.02 µg/g, for mollusk, barnacle,
having in our modern societies, the global environmental isms. Also in China, Yang et al. (73) carried out a survey
effects, the potential environmental risk associated with that aimed at comparing the concentrations of 14 REEs in
or the potential adverse human health effects of REEs are of China). The concentrations of 14 REEs were analyzed in
information is rather scarce (8, 26, 45–47, 75). For non- which were obtained from local markets and supermarkets
occupationally exposed individuals, it is well established within 17 cities of the Shandong Province. The selected fish
exposure to metals (23, 69). Consequently, to know the dong population. It was found that freshwater fish had a
dietary intake of REEs should be an issue of notable relatively higher ΣREEs than marine fish (34.0–37.9 μg/kg
interest. The objective of the current paper was to review wet weight (ww) vs. 12.7–37.6 μg/kg ww). The assessment
data were reported. Those studies conducted by regional, REEs industry, Ma et al. (38) collected samples of water and
authorities, are not included in the present review. We have as oysters of the same place. The levels of 14 REEs were
nih.g ov/) and Scopus (https://w ww.s copus.c om/). The in the Pearl River Delta oysters ranged between 1.8–9.1 and
elements”, “REEs”, “food”, “dietary intake” and “human June 2017, respectively. It was concluded that in the Pearl
Province, Jiao and co-workers (2021) measured the levels
of 14 REEs in 120 commercial mantis shrimp (O. Oratoria)
was 25.1 ng/g (range: 9.04–75.1 ng/g). The levels of REEs
It is well-known that fish, and especially marine fish, constitute reported by Jiao et al. (32) were similar to those previously
an important part of the human diet. This means that its quality found for marine fish (12.7 to 37.6 ng/g) by Yang et al. (73),
and its safety aspects are issues of interest (12, 13, 51). For their but lower than those found for Pearl River Delta oysters (1.8
health benefits, people worldwide consume fish and seafood, to 9.1 μg/g) by Ma et al. (38). The mean concentrations of
which provide vitamins and minerals, proteins, low saturated the 14 analyzed REEs in O. oratoria followed the following
nutrients (13, 14, 24, 44). In contrast to these benefits, various > Yb > Eu > Tb > Ho > Tm > Lu. Recently, Wang et al. (72)
years, the concentrations of metals in a number of species of the potential human health risk of these 15 REEs was also
fish and seafood have been measured in various areas/zones assessed. The ∑REEs ranged between 1.02 and 178.55 μg/
around the world (23, 25, 33, 50). However, studies regarding kg, with a mean concentration of 27.14 μg/kg. The highest
Table 1 A summary of REE levels in freshwater and marine species
Shenzen coastal region, China mollusk, barnacle, shrimp, fish 14 ∑REEs: 2.26, 4.69, 0.03 and Higher levels of LREEs than Zhang et al. (77)

Methods (brief)

wide range of electronic devices means only a small part of samples of marine organisms, which were collected at six
issues of considerable importance on which the current muscle samples of four freshwater fish and six marine fish,
data were reported. Those studies conducted by regional, REEs industry, Ma et al. (38) collected samples of water and
here used the databases PubMed (https://pubmed.ncbi.nlm. determined in all samples. The sum of REEs concentrations
terms used for the search were the following: “rare earth 0.9–2.6 μg/g for the samples collected in December 2016 and
Levels of REEs in Freshwater and Marine samples, which were collected from the coast of three sites
Region/country Analyzed samples Analyzed REEs Mean values and/or ranges Remarks Reference
Northwestern Mediterranean Sea, Fish, mussels, oysters La and Ce Fish levels < LOD for La and Ce; No specific remarks Squadrone et al. (59)
Italian aquarium Spotted dogfish (samples of blood, 16 ∑REEs: 4.1, 30, 15 and 13 µg/ No specific remarks Squadrone et al. (64)
Tokyo Bay, Japan 5 species of bivalves (samples of 14 The individual concentrations of REEs levels in soft tissues were Akagi and Edanami (2)
∑REEs; samples of muscles: No specific remarks determined the concentrations of 21 trace elements in fish
collected from aquaculture marine ecosystems of the NW
of marine seaweed, which were collected at 3 different sites
1.53 also measured the concentrations of 10 REEs in 70 samples
of different matrices of marine origin collected from the
Ligurian Sea (NW Mediterranean Sea). Samples of vari-
17 15 16 15 16 turn, the levels of REEs were also determined in samples of
zooplankton collected from the Ligurian Sea. The highest

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The five most recent substantive edits to this page, classified major (evidence or structure moved), correction (a published value or statement was wrong and has been fixed), or minor (narrative rewritten without changing the underlying evidence). Each description is derived from what the edit did to this page; the linked commit is the authoritative record, routine regeneration passes are excluded, and the full version history lives in git. When DOI minting comes online (see schema docs), each entry below will also link to a version-pinned DataCite DOI.

Commit	Date	Change	Description
3171d06	2026-08-02	major	1 section added
bc84bfc	2026-08-02	major	6 sections added; narrative text revised