1998 Fiscal Year Final Research Report Summary
An estimation of biological effects of rare earth elements on health of workers in high technology field
| Project/Area Number |
09670365
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Hygiene
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| Research Institution | Juntendo University School of Midicine |
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Principal Investigator |
SHINOHARA Atsuko Juntendo Univ.School of Medicine lecturer, 医学部, 講師 (90157850)
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| Co-Investigator(Kenkyū-buntansha) |
CHIBA Momoko Juntendo Univ.School of Medicine, associate profrsser, 医学部, 助教授 (80095819)
WATANABE Hiromi Juntendo Univ.School of Medicine, research associate, 医学部, 助手 (20255657)
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| Project Period (FY) |
1997 – 1998
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| Keywords | Rare earth elements / Concentration in urine / Workers in high technology field / Index of rare earths exposure |
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| Research Abstract |
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
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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
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Research Products
(2 results)
