An estimation of biological effects of rare earth elements on health of workers in high technology field

为了探讨稀土元素对人体健康的生物学效应，研究了稀土在小鼠体内的分布和排泄以及稀土在人体尿液中的排泄情况。1. 检测良好的稀土元素暴露指数：成年雄性小鼠分别以1和10 mg元素/kg的剂量静脉注射TbCl_3 a或YbCl_3。测定尿液和粪便中器官分布和排泄的时间和剂量依赖性变化。给药元素在血浆中的浓度迅速下降。这些元素主要分布在肝脏和脾脏。Th的排泄量小于Yb。1 mg/kg组和10 mg/kg组7天内尿中Yb的排泄量分别为给药剂量的30%和3%，Tb的排泄量分别为11%和0.5%。在所有组中，粪便中的排泄量对应于剂量的10%至16%。这些结果表明，尿液中的稀土含量是接触微量稀土的良好指标。2. 稀土元素富集法：高频等离子体质量可以实现亚ppb级稀土元素的灵敏测定，但容易受到共存元素的影响。由于尿液中碱性和碱土元素含量较高，因此对去除共存元素和富集稀土元素的过程进行了研究。采用巴赫法和小柱法对两种剪切树脂Chelex 100和Muromac A-1进行了测定。两种树脂均可用，采用Muromac A-1在线色谱柱法。3. 在尿样中的应用：该方法对尿样中稀土元素的回收率在80%以上。观察了缓冲液中元素的污染情况和用于pH调节的电极中元素的逃逸情况。4. 人类尿液中稀土元素的测定：对照尿液样本中稀土含量为0.01 ppb或更少。25名电池厂工人（镍镉电池和镍氢二次电池）尿液中镉的浓度在检测限以内至1 ppb左右。对照者稀土浓度正常范围及工人尿液中稀土与工种、工期关系的研究正在进行中。少

To investigate the biological effects of rare earth elements on human health, distribution and excretion of administered rare earths in mice and excretion of them in human urine were studied. 1. Examination of a good index of exposure to rare earth elements : Adult male mice were intravenously administered with TbCl_3 a or YbCl_3 3 independently at 1 and 10 mg element/kg. Time-course and dose-dependent change in organ distribution and excretion in urine and feces were determined. The concentrations of administered elements in plasma decreased rapidly. The elements were distributed mainly in liver and spleen. Excretion of Th were smaller than Yb. Excretion amounts of Yb within 7 days in urine corresponded to 30 and 3% of administered dose in 1 and 10 mg/kg groups, respectively, and those of Tb corresponded to 11 and 0.5%. Excretion in feces corresponded from 10 to 16% of dose in all groups. These results suggested that the rare earth contents in urine were good index of exposure to trac … More e amounts of rare earths. 2. Concentrating method of rare earth elements : High-frequency plasma-mass can perform sensitive determination of rare earth elements at sub-ppb levels, however, is easily affected by coexisting elements. Since urine contains high levels of alkaline and alkaline earth elements the process for removing coexisting elements and for concentrating rare earth elements were examined. Two kinds of cheleting resin (Chelex 100 and Muromac A-1) were tested with bach and mini-column methods. Both resins were available and on-line column method with Muromac A-1 was adopted. 3. Application to urine sample : Recovery rate of rare earths from urine samples were 80% or more by this method. The element contamination of buffer and element elusion from electrode used for pH adjust were observed. 4. Determination of rare earth elements in human urine : Urine sample from control contained 0.01 ppb or less rare earths. The concentrations in urine from 25 workers of battery factory (Ni-Cd battery and Ni-H_2 second battery) were in the range from under detection limit to about 1 ppb. Father studies about normal range of rare earths concentrations in control persons and the relation between rare earths in worker's urine and their job, working periods are in progress. Less