Biological monitoring of exposure to rare earth elements and selected metals in the Inuit population of Nunavik, Canada

Toxic Effects of Rare Earth Elements on Human Health: A Review

Rare earth elements (REEs) are a new type of material resource which have attracted significant attention in recent years. REEs have emerged as essential metals in modern-day technology due to their unique functions. The long-term, large-scale mining and utilization of rare earths has caused serious environmental pollution and constitutes a global health issue, which has raised concerns regarding the safety of human health. However, the toxicity profile of suspended particulate matter in REEs in the environment, which interacts with the human body, remains largely unknown. Studies have shown that REEs can enter the human body through a variety of pathways, leading to a variety of organ and system dysfunctions through changes in genetics, epigenetics, and signaling pathways. Through an extensive literature search and critical analysis, we provide a comprehensive overview of the available evidence, identify knowledge gaps, and make recommendations for future research directions.

Associations between maternal urinary rare earth elements during pregnancy and birth weight-for-gestational age: Roles of cord blood vitamin D levels

Prenatal exposure to rare earth elements (REEs) may contribute to adverse birth outcomes in previous studies. Cord blood vitamin D has been suggested to modify or mediate the effects of environmental exposures. However, none has investigated these roles of cord blood vitamin D in the associations of prenatal exposure to REEs with fetal growth. Maternal trimester-specific urinary concentrations of 13 REEs, cord blood total 25-hydroxyvitamin D at delivery, and birth weight (BW)-for-gestational age (GA) were determined in 710 mother-newborn pairs from Wuhan, China. Higher maternal average urinary concentrations of europium (Eu), gadolinium (Gd), dysprosium (Dy), holmium (Ho), erbium (Er), and ytterbium (Yb) across three trimesters, either individually or jointly, were significantly associated with lower BW-for-GA Z-scores and higher odds of small for gestational age (SGA) [β = -0.092; 95 % confidence interval (CI): -0.149, -0.035 for BW-for-GA Z-scores, and odds ratio = 1.60; 95 % CI: 1.14, 2.24 for SGA involved in each unit increase in weighted quantile sum index of REEs mixture]. When stratified by cord blood vitamin D levels, the associations mentioned above persisted in participants with relatively low vitamin D levels (<13.94 μg/L, the first tertile of distribution), but not among those with relatively high levels (≥13.94 μg/L) (all p-values for interaction < 0.05). The mediation analyses taking account of exposure-mediator interaction showed that the relationships between REEs (as individual and mixture) exposure and lower BW-for-GA were partly mediated through decreasing cord blood vitamin D levels. The proportions mediated by cord blood vitamin D levels were 24.48 % for BW-for-GA Z-scores and 29.05 % for SGA corresponding to the REEs mixture exposure. Conclusively, our study revealed that prenatal exposures to Eu, Gd, Dy, Ho, Er, and Yb were related to fetal growth restriction. Cord blood vitamin D might alleviate toxic effects of these REEs and its reduction might partly mediate REE-induced fetal growth restriction.

Human biomonitoring of inorganic elements in a representative sample of the general population from Cape Verde: Results from the PERVEMAC-II study

Inorganic elements such as heavy metals and other potentially toxic elements are frequently detected in humans. The aim of the present study was to analyze the blood concentrations of 49 inorganic elements in a cohort of 401 subjects from Cape Verde. The study was performed in the frame of the Pesticide Residues in Vegetables of the Macaronesia project (PERVEMAC-II). Concentration of inorganic elements, including elements in the ATSDR's priority pollutant list and rare earth elements (RREs) were measured by ICP-MS in the whole blood of participants. A total of 20 out of 49 elements (40.8%) were detected in ≥20% of participants. Arsenic, copper, mercury, lead, selenium, strontium and zinc were detected in ≥99% of samples. Among the REEs, 7 showed detection frequencies above 20%. The median number of different elements detected was 15. In the present series, 77.0, 99.2 and 33.4% of the participants showed values of arsenic, mercury and lead higher than Reference Values 95%. These percentages were much higher than those reported in similar studies. Niobium and tantalum showed the highest median concentrations: 1.35 and 1.34 ng/mL, suggesting an environmental source of these valuable REEs in Cape Verde. Age appeared as the most important factor influencing the blood levels of inorganic elements. Lifestyle had an effect on the concentration of some of these elements. Those subjects whose water source was pond water had significantly higher arsenic levels. The concentration of ∑REEs was significantly higher among individuals who purchase their food in supermarkets (P = 0.013). These variables are of relevance since they can be controlled individually to reduce exposure to these contaminants. Our results may be useful for the implementation of public health measures by the competent authorities.

Quantification of 26 metals in human urine samples using ICP-MSMS in a random sample collective of an occupational and environmental health care center in Aachen, Germany

Despite several studies on metal exposure in the general population, the knowledge on the background burden of distinct metals is still sparse (e.g. Cu, In, Mn, Pb, Sn, Sr, Ta, Te). While up to date reference values exist for 16 distinct metals as Biological Reference Value (BAR) or the 95th percentile for Al, As, Ba, Be, Cd, Co, Cr, Hg, Li, Mo, Ni, Pt, Sb, Se, Tl and U respectively, the background burden of the general population for the remaining elements is unknown or yet no matter of scientific counselling. We established and validated an inductively coupled plasma triple quadrupole mass spectrometry (ICP-MSMS) human biomonitoring method (HBM), that enabled us to determine 26 metals in urine. Al, As, Ba, Be, Cd, Co, Cu, Ga, Gd, Hg, In, Li, Mo, Ni, Pb, Sb, Se, Sn, Sr, Ta, Te, Tl, V and Zn were analyzed. The method was applied to 88 urine samples collected in the ambulance of the Institute for Occupational, Social and Environmental Medicine (IASU) Aachen, Germany. Patients from two major metal processing companies (steel and copper) and a more heterogenous group of occupational exposed and non-exposed persons were defined and distinguished. HBM data from about 88, in general occupationally unexposed persons against certain metals served as a collective representing the general population in first approximation. For these the 95th percentiles are reported. Significant differences of urinary metal concentrations of the employees of the two metal processing companies compared to the third group were observed among others for Cu, Cr, Ni, Mn and are discussed, thus demonstrating the usefulness of the method for both environmental and occupational purposes.