著者

古田 悦子 横田 繁昭 油井 多丸 吉沢 幸夫

出版者

公益社団法人 日本アイソトープ協会

雑誌

RADIOISOTOPES (ISSN:00338303)

巻号頁・発行日

vol.56, no.8, pp.443-453, 2007-08-15 (Released:2011-03-01)

参考文献数

18

被引用文献数

2 3

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市販されている靴用脱臭材6種類から放出されるγ線を測定した。その結果, これらの製品にはTh及びU系列の娘核種と40Kが含まれていることが明らかになった。調べた脱臭材の内, 少なくとも3種類は意図的に放射性核種が添加された放射性コンシューマプロダクトであると考えられる。これらの製品中の放射能を求め, 被ばく線量を算出した。原子炉等規制法に触れる試料はなかった。靴箱用脱臭材の一製品は他の試料より高い放射能を示し, 224Raと放射平衡にある娘核種の濃度合計が90Bq/gを超えていた。1mの距離における全身被ばく線量は8.6×10-4μSv/hであった。また, 「マイナスイオン」効果を謳った靴中敷による1mmの距離における皮膚表面の局部被ばく線量は1.9μSv/hであった。家庭内での使用が浸透した脱臭材は流通量が多いので, 原材料及び製品に含まれる放射能量に十分な監視の目を向ける必要があることが示唆された。

著者

古田 悦子 中原 弘道

出版者

日本保健物理学会

雑誌

保健物理 : hoken buturi (ISSN:03676110)

巻号頁・発行日

vol.43, no.4, pp.341-348, 2008-12

被引用文献数

2 4

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Cosmetics claiming hormesis effects are available through Internet. Although the hormesis effect is explained in each product of cosmetics, there is no explanation about the radiation source. The existence of the progeny nuclides of Th and U series (RI) was comfirmed by the γ-ray spectroscopy using a HPGe detector. The highest radioactivity densities were 68Bq/g of the Th-series included in the hormesis powder. Because the particles containing RI were of the size of 1-10 micrometer by observing and analyzing SEM-EDX, there is a risk of inhaling the powder to the deep into the lungs. Furthermore, as about 1% RI was dissolved in water, the uptake of the RI to the body would be possible. The highest value of the evaluation of uniform radiation exposure to some organs by the continuous usage for 10 years was 5.5mSv/y of the hormesis powder inhalation to the lung. Furthermore, the calculated quantity of the radioactivity of progeny of ^<222>Rn deposited in the body after continuous use of the hormesis cream every day for one year becomes 24Bq. The possibility of accumulation of the radioactivity in the body from the hormesis cosmetics cannot be denied. The addition of the radioisotope to cosmetics is prohibited in some EU countries by the regulation. It's proposed in this paper that the legitimacy of the addition of the radioisotope should be seriously re-examined.

著者

古田 悦子

出版者

日本保健物理学会

雑誌

保健物理 (ISSN:03676110)

巻号頁・発行日

vol.45, no.3, pp.253-261, 2010 (Released:2011-07-12)

参考文献数

15

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Recently many Japanese wear jewelry as personal ornaments, particularly bracelets. The jewelry is made of gems, jewels, noble metals and so on. Some kinds of jewelry include much amount of radioactive elements more than that of natural range in ores which are in our living-environment. The radioactive concentrations of 25 kinds of jewels and gems, which were easily purchased on a market or through the Internet, were analyzed by HPGe. The bracelet which was made of ceramics showed the highest radioactive concentration and it was estimated as approx. 800 Bq g-1 of 232Th and 140 Bq g-1 of 238U by assuming radioactive equilibrium among the nuclides in the decay series. Moreover, there was a high radioactive concentration gem including 60 Bq g-1 of 232Th and 300 Bq g-1 of 238U. The radioactive materials added in the ceramics should be monazite analyzed by a prompt gamma-ray activation analysis method. Though the ceramics became the object of the NORM management by the concentration, the radioactivity of one bracelet does not exceed 8,000 Bq. So, all these jewelry samples do not have to manage as NORM as consumer products according to the guideline by Japanese government. However, the jewelry's activity by deliberate addition of radioactive materials is deemed to be unjustified exposure, that the ICRP led the consideration. It is considered that the NORM guideline should take in the consideration of ICRP and prohibit the addition of radioactive materials to jewelry.

著者

古田 悦子 草間 経二

出版者

一般社団法人 日本家政学会

雑誌

日本家政学会誌 (ISSN:09135227)

巻号頁・発行日

vol.63, no.3, pp.157-162, 2012-03-15 (Released:2013-10-03)

参考文献数

4

著者

古田 悦子 森田 裕子 吉沢 幸夫

出版者

日本保健物理学会

雑誌

保健物理 : hoken buturi (ISSN:03676110)

巻号頁・発行日

vol.42, no.4, pp.341-348, 2007-12

被引用文献数

1 2

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Internal exposure to alpha particles emitted from <222>^Rn (radon) and its daughters is the second leading cause of lung cancer. As a source of indoor radon in home, there are interior building materials that contain radioactive minerals. These radioactive consumer products have been claimed by distributors to have effect of "minus-ion" or "radon spring" for healthy promotion. We analyzed radioactive nuclides contained in the interior building materials, and measured radon levels released from them. The results of gamma-ray spectrometry revealed that these interior building materials contain U- and Th-series nuclides. The densities of some radioactive nuclides in the tile used for a bathroom exceeded the exempt limits of International Basic Safety Standards. However, the radon densities released from the tile was lower than detectable limit. In contrast, one of the wallpaper released 34Bq・m^<-3> of radon gas in a 50-liter container. This value is two times higher than the average radon level in Japanese homes. The "minus-ion effect" wallpapers are thought to be a cause of residential exposure to radon.

著者

古田 悦子

出版者

特定非営利活動法人 化学生物総合管理学会

雑誌

化学生物総合管理 (ISSN:13499041)

巻号頁・発行日

vol.4, no.2, pp.146-153, 2008 (Released:2009-04-28)

参考文献数

29

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天然の放射性物質を含んだ日用品(NORM)は、生活圏内に多数存在する。これら日用品は、ホルミシス効果、マイナスイオン効果、遠赤外線効果などを謳った、健康に良いとされる商品である場合が多い。これらの効果は、その商品独自に調べられているケースは見受けられず、一般論にすぎない。すなわち、個々のNORMの有効性やリスクの評価は充分になされていない。これらNORMに含まれる放射性物質の量および濃度は、国内法に照らした場合、ほとんどの商品が違法性はない。しかし、例えば日本では、EUにおける放射性物質添加禁止対象品目である化粧品の一部がNORMである。放射性物質を添加する必要性があるのか、使用による危険性は問題となる水準ではないのか等、NORMは存在の正当性の議論をすべきである。

著者

古田 悦子

出版者

日本放射線安全管理学会

雑誌

日本放射線安全管理学会誌 (ISSN:13471503)

巻号頁・発行日

vol.12, no.2, pp.91-91, 2013 (Released:2013-11-06)

著者

古田 悦子

出版者

Japan Health Physics Society

雑誌

保健物理 : hoken buturi (ISSN:03676110)

巻号頁・発行日

vol.45, no.3, pp.253-261, 2010-09-01

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Recently many Japanese wear jewelry as personal ornaments, particularly bracelets. The jewelry is made of gems, jewels, noble metals and so on. Some kinds of jewelry include much amount of radioactive elements more than that of natural range in ores which are in our living-environment. The radioactive concentrations of 25 kinds of jewels and gems, which were easily purchased on a market or through the Internet, were analyzed by HPGe. The bracelet which was made of ceramics showed the highest radioactive concentration and it was estimated as approx. 800 Bq g^-1 of ²³²Th and 140 Bq g^-1 of ²³⁸U by assuming radioactive equilibrium among the nuclides in the decay series. Moreover, there was a high radioactive concentration gem including 60 Bq g^-1 of ²³²Th and 300 Bq g^-1 of ²³⁸U. The radioactive materials added in the ceramics should be monazite analyzed by a prompt gamma-ray activation analysis method. Though the ceramics became the object of the NORM management by the concentration, the radioactivity of one bracelet does not exceed 8,000 Bq. So, all these jewelry samples do not have to manage as NORM as consumer products according to the guideline by Japanese government. However, the jewelry's activity by deliberate addition of radioactive materials is deemed to be unjustified exposure, that the ICRP led the consideration. It is considered that the NORM guideline should take in the consideration of ICRP and prohibit the addition of radioactive materials to jewelry.