Assessment the Exposure Level of Rare Earth Elements in Workers Producing Cerium, Lanthanum Oxide Ultrafine and Nanoparticles

Abstract

In order to assess occupational exposure level of 15 rare earth elements (REEs) and identify the associated influence, we used inductively coupled plasma mass spectrometry (ICP-MS) based on closed-vessel microwave-assisted wet digestion procedure to determinate the concentration of Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu in urinary samples obtained from workers producing ultrafine and nanoparticles containing cerium and lanthanum oxide. The results suggest that La and Ce were the primary component, together accounting for 97 % of total REEs in workers. The urinary levels of La, and Ce among the workers (6.36, 15.32 μg.g creatinine, respectively) were significantly enriched compared to those levels measured in the control subjects (1.52, 4.04 μg.g creatinine, respectively) (p < 0.05). This study simultaneously identified the associated individual factors, the results indicate that the concentrations in over 5 years group (11.64 ± 10.93 for La, 27.83 ± 24.38 for Ce) were significantly elevated compared to 1-5 years group (2.58 ± 1.51 for La, 6.87 ± 3.90 for Ce) (p < 0.05). Compared the urinary levels of La and Ce at the separation and packaging locations (9.10 ± 9.51 for La, 22.29 ± 21.01 for Ce) with the other locations (2.85 ± 0.98 for La, 6.37 ± 2.12 for Ce), the results show urinary concentrations were significantly higher in workers at separation and packaging locations (p < 0.01). Inter-individual variation in levels of La and Ce in urine is the result of multi-factorial comprehensive action. Further researches should focus on the multiple factors contributing to the REEs levels of the occupationally exposed workers.

Detection and imaging of gadolinium accumulation in human bone tissue by micro- and submicro-XRF

“…Rare-earth elements (REE) mining and processing can be mentioned in this respect, although the reports on the occupational exposure associated with negative health outcomes other than pneumoconiosis are sporadic. Li et al found higher urinary levels of La, Nd, Ce and Gd in exposed workers dealing with Ce and La oxides ultrafine particles and nanoparticles compared to non-exposed 31 , however the next paper from the group (presumably on the same subjects), on creatinine adjusted urinary levels of REEs, did not show significant difference in gadolinium levels 32 . We were unable to find reports on deposition of gadolinium in occupationally exposed subjects.…”

Indoor/Outdoor Relationships and Anthropogenic Elemental Signatures in Airborne PM2.5 at a High School: Impacts of Petroleum Refining Emissions on Lanthanoid Enrichment

“…To date, very few measurements of the trace elemental composition of indoor and outdoor PM 2.5 have been performed for United States’ schools, − although more data are available for homes and residential buildings. − These studies have largely focused on representative and transition elements, with one study showing the indoor enrichment of several elements including hazardous air pollutants such as Sb and Pb . In contrast, a unique aspect of Houston area aerosols is their lanthanoid (i.e., rare earths) enrichment emanating from fluid catalytic cracking (FCC) units. ,,, Airborne rare earth elements are readily absorbed by humans , leading to a variety of toxicological symptoms . Additionally, children exposed to refinery emissions exhibit increased wheezing, bronchial inflammation, reduced lung function and other symptoms , necessitating this research.…”

“…25 In contrast, a unique aspect of Houston area aerosols is their lanthanoid (i.e., rare earths) enrichment emanating from fluid catalytic cracking (FCC) units. 13,14,18,20 Airborne rare earth elements are readily absorbed by humans 30,31 leading to a variety of toxicological symptoms. 32 Additionally, children exposed to refinery emissions exhibit increased wheezing, bronchial inflammation, reduced lung function and other symptoms 33,34 necessitating this research.…”

Comparative study of two methods for rare earth elements analysis in human urine samples using inductively coupled plasma-mass spectrometry

“…Li et al (2016) found higher levels of La, Ce, Nd, and Gd in the urine of workers manufacturing cerium and lanthanum oxide ultrafine and nano-sized particles. Li et al (2017) found higher levels of La and Ce in the urine of the same kind of workers. The levels of Y, La, Ce, Pr, Nd, and Sm were higher in the urine of children living near the Bayan Obo mining area (Liang et al, 2018).…”

“…Li et al (2016) explored a sensitive and reliable indicator of the exposure level to REEs in urines. Li et al (2017) identified the occupational exposure to REEs by analyzing urines using ICP-MS based on closed-vessel, microwave-assisted wet digestion. Bettinelli et al (2002) developed a method with electrothermal vaporization ICP-MS (ETV-ICPMS) for determining REEs in urine, in which the sample was injected into the graphite tube and trifluoromethane (Freon-23) and was used as a chemical modifier to reduce vaporization temperature and the memory effect of most of the lanthanides.…”