Standard interpretation of radiological protection requirements for the production places of rare earths / 中国辐射卫生

Chinese national standard GBZ139—2019 Radiological Protection Requirements for the Production Places of Rare Earths was published to replace GBZ 139—2002 Radiological Protection standards for the production places of rare-earth elements and implemented from April 1, 2020. Herein, background on which the new standard was based, the main modifications and the foundations were explained. More specific requirements for the production places of rare earths were stipulated in the new standard, which will play an important role in occupational health protection of the workers engaged in the mining, mineral processing and smelting of rare earths.

Worker Safety in the Rare Earth Elements Recycling Process From the Review of Toxicity and Issues

Although the rare earth elements (REEs) recycling industry is expected to increase worldwide in high-tech industry, regulations for worker safety have yet to be established. This study was conducted to understand the potential hazard/risk of REE recycling and to support the establishment of regulations or standards. We review the extensive literature on the toxicology, occupational safety, and health issues, and epidemiological surveys related to the REEs, and propose suitable management measures. REE recycling has four key steps such as collection, dismantling, separation, and processing. In these processes, hazardous substances, such as REEs-containing dust, metals, and chemicals, were used or occurred, including the risk of ignition and explosion, and the workers can be easily exposed to them. In addition, skin irritation and toxicities for respiratory, nervous, and cardiovascular systems with the liver toxicity were reported; however, more supplementary data are needed, owing to incompleteness. Therefore, monitoring systems concerning health, environmental impacts, and safety need to be established, based on additional research studies. It is also necessary to develop innovative and environment-friendly recycling technologies, analytical methods, and biomarkers with government support. Through these efforts, the occupational safety and health status will be improved, along with the establishment of advanced REE recycling industry.

Efeito do cério na qualidade fisiológica de sementes de milho e no desempenho agronômico das plantas / Effect cerium on the physiological quality maize seed and agronomic performance of plants

Os elementos químicos terras raras, tais como Cério (Ce), podem ser utilizados como fertilizantes no manejo químico das culturas, visando a otimização no fornecimento de nutrientes às plantas, quando se buscam incrementos na produtividade agrícola. O objetivo do trabalho foi avaliar a qualidade fisiológica e o desempenho agronômico da cultura do milho, após tratamento das sementes com Ce. As sementes da cultivar Pioneer 30F53, foram imersas em solução aquosa, nas concentrações de 0, 5, 10, 15, 20 e 25 mg de Ce L-1, por uma hora. Após a imersão, foram realizados os testes de germinação, primeira contagem da germinação, classificação do vigor, comprimento e massa seca de plântulas, em laboratório. Em campo, sementes tratadas com a concentração de 12 mg de Ce L-1, escolhida após a primeira etapa de testes de laboratório, foram semeadas e durante o ciclo da cultura foram avaliados além do rendimento, número de dias até emergência de 50 % das plantas, número de folhas, diâmetro do colmo, estatura de plantas e número de dias até 50 % do florescimento. Concluiu-se que a aplicação de Ce em sementes de milho aumenta a germinação e o vigor das sementes, mas não influencia o crescimento vegetativo e reprodutivo. O tratamento com Ce pode induzir ao aumento do rendimento da cultura do milho.

The search for alternatives that provide increases in crop yields in agricultural systems is still present today. Chemical elements rare earths such as cerium (Ce) represent alternatives in the search for increases in agricultural productivity and has been used in several countries and many cultures. The objective of this study was to evaluate the physiological quality and agronomic performance of corn after seed treatment with Ce. Corn seeds Pioneer 30F53, since they were immersed in aqueous solution at concentrations of 0, 5, 10, 15, 20 and 25 mg L-1 Ce, for one hour. After the immersion, were performed tests of germination, first count germination, vigor classification, length and seedling dry weight in the laboratory. In the field, the seeds treated with a concentration of 12 mg L-1 Ce, previously chosen by laboratory tests were sown and during the course of the culture were measured as well as yield, number of days until emergence of the plants 50%, number leaf, stem diameter, plant height and number of days until 50% flowering. It was concluded that the application of Ce increases in corn seed germination and seed vigor, but no effect on the vegetative and reproductive growth. The treatment with Ce can induce an increase of the yield of corn.

Toxicological Evaluations of Rare Earths and Their Health Impacts to Workers: A Literature Review

In concert with the development of new materials in the last decade, the need for toxicological studies of these materials has been increasing. These new materials include a group of rare earths (RE). The use of RE nanotechnology is being considered in some green applications, to increase their efficiency by using nano-sized RE compounds, and therefore hazard evaluation and risk assessment are highly recommended. This review was conducted through an extensive contemplation of the literatures in toxicology with in vitro and in vivo studies. Major aspects reviewed were the toxicological evaluations of these elements and metallic compounds at the molecular and cellular level, animal and human epidemiological studies and environmental and occupational health impacts on workers. We also discuss the future prospect of industries with appliances using RE together with the significance of preventive efforts for workers' health. To establish a safe and healthy working environment for RE industries, the use of biomarkers is increasing to provide sustainable measure, due to demand for information about the health risks from unfavorable exposures. Given the recent toxicological results on the exposure of cells, animals and workers to RE compounds, it is important to review the toxicological studies to improve the current understanding of the RE compounds in the field of occupational health. This will help to establish a sustainable, safe and healthy working environment for RE industries.

Solvent Extraction of Rare Earths with Mixtures of Di-(2-ethylhexyl) Phosphoric Acid and sec-Nonylphenoxy Acetic Acid / 分析化学

The solvent extraction of rare earths with mixtures of di-( 2-ethylhexyl) phosphoric acid (D2EHPA,H2A2) and sec-nonylphenoxy acetic acid (CA100,H_2B_2) has been carried out. The separation abilities among rare earths were determined and compared with those with D_2EHPA alone. The mechanism of synergistic extraction of lanthanum was discussed. The methods of slope analysis and constant mole were used to examine the extraction stoichiometry. Effects of acidities,concentrations of extractants,and temperature on the extractabilities have been investigated. The results showed that the synergistic effects decrease with increasing atomic numbers of rare earths. At proper ratios of the extractants,the separation abilities of some rare earths with D2EHPA +CA100 were higher than those with D2EHPA alone,which may be applied to the separation of these rare earths. The extracted complex of lanthanum with D2EHPA + CA100 was determined as LaH5A6B2. The synergistic extraction is endothermically driven.

Distribution Pattern of Rare Earth Elements in Hair Samples of Young Children Aged 0-3yrs in Rare Earth Ore Area / 环境与健康杂志

Objective To study the distribution pattern of rare earth elements (REEs) in hair of young children. Methods REEs level and distribution pattern in hair of young children aged 0～30 months in RE ore area were studied. All the lanthanide elements were determined with inductively coupled plasma mass spectrometer (ICP_MS) in 20 hair samples of young children aged 0_3yrs, 10 samples from RE ore area and 10 samples as controls from Xunwu county, Jiangxi, China. Results 15 kinds of REEs in each sample were all detected. There were significant differences between higher children's hair REEs levels of RE ore area and those lower levels of control site (P