Health Effects of Rare Earth Elements

稀土元素在新的工业技术领域中是必不可少的。关于它们对健康的影响和器官分布的信息很少。进行了两种类型的动物研究：从职业健康的角度进行吸入暴露，以及静脉注射进行剂量-效应研究。从17个稀土元素中选择了Ce和Sm作为暴露元素。这些元素主要分布在肺部，吸入时在睾丸中的浓度很低。静脉注射后观察性别差异。给孕鼠注射Ce或Sm后，未见胎儿死亡、生长迟缓或肉眼可见的体征。这些稀土元素似乎对后代没有生殖毒性和不良影响。这些稀土元素在胎儿体内的浓度显著低于母亲体内。提示胎盘屏障对这些稀土元素是不通透的。

Rare earth elements (REEs) are essential in the field of new industrial technologies. There has been little information about their health effects and organ distribution. Two types of animal studies were conducted; inhalation exposure for the standpoint of occupational health, and iv-injection for dose-effect study. As the elements for exposure Cerium (Ce) and Samarium (Sm) out of 17 REEs were selected. These elements were mainly distributed in the lung and very low concentration in testes in case of inhalation. After iv-injection sex differences were observed. After Ce or Sm was injected to pregnant mice, there was no fetal death, growth retardation, or macroscopically observable signs. These REEs seem to have no reproductive toxicity and adverse effect on the offspring. The concentrations of these REEs in fetus were significantly lower than those in mothers. It was suggested that the placental barrier was impermeable to these REEs.