ST U DY ON TRACE METALS IN BIO MATERIALS 11. 11. Cadmium Content in Polished Rice 本 Masumi MORITSUGU and jun KOBAYASHI In In this paper ， the analytical results on cadmium of rice ，which is the staple f∞d of the japanese ， are described. There are observed three general trends for for the cadmium content of rice samples. First ， the local difference of cadmium content content of polished rice is remarkable. Se condly ， the difference of cadmium content content among varieties is small as compared with the local di 百erence. Thirdly ， the the cadmium content of the bran layer is higher than that of the endosperm ， although although the difference is not so remarkable as in the content of other inorganic elements. elements. Nicaud et a1. (1942) and others (Baader 1951 ， Friberg 1959 ，Piscator 1962) ha ve clarified that the chronic or acute cadmium intoxication occurs in alkaline battery battery factories with the symptoms ofbone trouble ， kidney damage and excretion of proteinuria. Furthermore ， several workers (Perry et a1. 1961 ， Schroeder and Balassa 1961) ， in their analytical investigations on human tissues ，have demonstrated demonstrated that a considerable amount of cadmium is present in kidney as compared with other tissues ，and its content in human tissues increases progres- sively sively with age. In addition ， their analytical results have indicated that the cadmium content of the japanese belongs to high group in the world. It is therefore therefore of importance to investigate the cadmium content of the s回 ple fl ∞d of the the japanese. We have found that cadmium is present in various agricultural products and waters (unpublished data) ，and as described in the former report (1962) ， even ‘ ayu' in japanese or tlecoglossus altiuelis ， one of the river fish ， contains cadmium in detectable amount. Pre μration ザRice Samtles As shown in Fig. 1， about 200 samples of rice were collected from various prefectural prefectural agricultural experiment stations. The other samples were coopera- tively tively offered from the Tokyo Food 0 伍ce of Ministry of Agriculture and Forestry ，U. S. Rice Experiment Station in Luisianna and others. The 回 mples were polished to the uniform degree by a test cleaning machine until until the weight of polished rice decreased to 90 percent of unpolished rice ， except except for the ones previously polished. (The unpolished rice is prepared by removing the hulls from the rough rice) * This is the English edition of the article pub Ii shed in Nogaku Kenkyu 50(1): 37-49 ， 1963. 146 146 Berichte d. Ohara Instituu. (Bd. 12 ，H t. 2， Fig . 1. Sampling places of J apanese rice which w 剖 sent from various prefectura1 prefectura1 agri c1 tura1 experiment stations The number in this chart is the same as the number of agricu1tural experiment stations in tab1e 1. And star mark express 回 the situation situation of each agricultura1 experiment station. Method Method of Analysis The analysis was carried out on 20 grams of polished rice. The sample ， which had been taken in a ceramic crucible ，was ignited overnight in the electric 1964) 1964) Moritsugu & Kobayuhi :Study on trace meta 1s in bio materials. II 147 muffie muffie furnace at 475 0 C. Next day ，1 rnl of 10 percent solution of sodium sulfate and the same volume of concentrated nitric acid was added to hasten the oxi$tion of residual carbon. The mixture in the crucible was heated quietly on a sand bath until nitric fumes disappeared and then placed in the muffle furnace ， set at 350 0 to 450 0 C ， for 10 to 20 minutes. A trace of carbon which was still remaining was removed by the repetition of nitric acid treatment followed followed by mu ff) e ignition. Thus ， the carbon-free ash was obtained within 2.5 rnl rnl of nitric acid added. The final ash ，peachblow coloured ，was analyzed by the colorimetric method of Sa ltzman (1 953) ，slightly modified. In order to prevent the interference of considerable considerable amounts of magnesium derived from the initial sample ， the volume of sodium-potassium tartrate solution was always increased from 1 rnl in the original original method to 5 ml (Moritsugu 1964). Especially ， in the analysis of unpol ・ ished ished rice ， it was essential to use a large amount of sodium-potassium tartrate ， because because unpolished rice contained more magnesium than polished rice. As described described above ，sodium sulfate solution was also added to accelerate ashing. In In addition ， thallium separation was not carried out ， because the s戸 ctral line line of thallium was invisible nevertheless the spectral line of cadmium was distinctly distinctly visible on the plat 回 which are the results of the spectrochemical analyses analyses of the ashes of rice 姐 mples. ANAL YTICAL RESULτ3 1. 1. Lo cal Difference of Cadmium Content The cadmium content of samples from the various agricultural experiment stations stations shows a great di 官erence as can be seen in Table 1，and Fig. 2. TABLE 1 Cadmium content of ]apanese rice Name of C1usifica ・ iI Name of C1usifica ・ expenment expenment Variety name tion by Cadmiuml Variety name tion by Cadmium grow 町∞Mentlmfzzrnt growing content statlon statlon period (μg /kg) I period (ug /kg) Norin Norin 34 e 19 11111194zRJ296 Hokkaido Hokkaido Fukuyuki e 20 2. Norin 17 l Aomori Aomori Fujisaka 5 m Eiko Eiko m 33 m Mimasari Mimasari m 15 Mutsuhikari Terunishiki Terunishiki 1 12 Towada m Toyohikari Toyohikari 1 15 Aomori-m 田 hi 14 m Average Average 19 Average mmme11111116364755 mem-mnaT Norin 16 3. 3. Norin 17 aq4n3， 4. 氏 Norin 17 Iwate Iwate Fu ・isaka 5 u' Miyagi 且 Norin 24 Rikuu Rikuu 132 何 RJGua-- Sasashigure Sasashigure ・4 Fuiisaka 5 一 Ch okai iq Shin 6 m ， Suashigure Average Average h Average 148 148 Be richte d. Ohara Instituts. (Bd. 12 ， Ht. 2， T ABLE 1 continued 5. 5. ~o~!ll!? ~ ~~ 16~ ，_ _<_ ~orin!? m ~ Akita Akita !，!o~in .• .~~ 1 2~ 1 Yamagata ~o~.in. 4! m .~~ lta lta Hatsunishiki e 36 1 ~ Fujisaka 5 e 131 Chokai m 71 1 Sasashigure 1 51 Towada e 61 1 Ginmasari 1 1 侃 Average 66 1 Average 75 7. 7. ~o~.i_~._ 2! m ~~ 18~ L_ ~orin ，! e n~2 sFAauksjiaibssahae F. ultusmmak h. sFAauksjiaibssahae S aS' ashillure kiga u 5e22Ibaragim 21 1 - Norin 2914e2Z81 131 m 9 1 Tone-wase e 113 Sekiminori Sekiminori m 15 1 Koshihikari e 182 Average 17 1 Average 148 910. 24m31 ochilli 'T‘ ochilli I、Ta.' 。 qc G Norin25122 locmgl 円 o Ti n 且 mι~ I ¥..7 unma Norin 25 I 1195* Norm 16e l7 Norm251310* Norm24e 16 Noi2930 Norm29m22No r in 48m 30 Norm48m34 C h -r Ln • h ・ロ，1 cn Averalle Averalle 23 ~~lDa-asam 且 U:7 verage verage .1.':> 1 Saitama ・mochi e 34 AVerage 36 1. 11. 112. Norin 17 e 160 Chiba 1 Tokyo Tozan 38 I 472 Mixed-52YashimMezEbon1421 Tone-w 剖 e e 89 Yamabiko m 174 Average 2:63 13. 13. Norin 8 m 19 114. Yoneyama ー 140 Kanagawa Norin 23 m 30 1 Niigata Nihonkai - 30 Norin 29 e 19 1 Koshiji-wase e 24 Norin 32 e 29 1 Koshiiakae - 44 Yamabiko m 27 1 Koshihikari m 53 Av.erage Av.erage 25Average 58 15.Sanin l71413 16.Sanin 171258 Tovama Sh 刊。 Ishikawa Haya-norin e 72 且 UYamammaSan-aLOKoshiji ・wase e 97 Honen-wase e 47 167 167 Horsen-wage e74 ShAirvogerai ShAirvogerai m m 189 yomotukari ー 130 rage rage Average 126 17. 17. Norin 23 I 75 118. Norin 22 1 36 Fukui Norin 30 e 113 1 Yamanashi Norin 31 1 30 Honen-wase e I∞ Kinmaze 1 31 Manryo - 317 1 W 桃山a m 6 Fukuininori Fukuininori m 153 1 Yamabiko ー 7 Average 152 1 Average 22 19. 19. Norin 10 I 9 120. Aichi-asahi m 30 Nagano Norin 17 m 34 1 Shizuoka Shimotsuki 1 55 Akibae m 34 1 Mihonishiki m 21 Yomohikari ー l∞ Yaeho e 30 Chikuma 1 132 1 Hamayu - 31 Average 62 1 Average 33 qa elm-ml，-。，.，a'Aa場 1. 21. Norin 17 122 Norin 22 eelm- 35 Aichi Aichi Tokai-senbon Mie Norin 29 53 Kinmaze 。，i守・ a'A'A'Aι Toyosenbon 104 Shin-yamabuki 守 Hatsushimo 'n Koganenishiki 51 ヨ白 Minonishiki 86 Mibonishiki Mibonishiki Average 66 Average 3 • Yielded from test field of mine-a fF ected are a， leaved out from aぜerage account . I964J I964J Moritsugu & Kobayaahi : Study on trace metals in bio materials. 11 149 T ABLE 1 continued n4a''Aa--auqd内，‘， 23. 23. 24. Norin 17 e la--qLqLeo Shiga e Kyoto A 岨 hi 4 m Norin 29 132 Nakate-shinsenbon - 57 Shin-yamabuki Kinmaze 1 Average 95 Akebono 1 Average 'in4nL'n4n3勾 eee--mle 25. 25. Norin 151 26. Hyogo Norin 12 Nara - 17 17 Tokai ・asahi 129 Norin Shin-kinmaze 一 54 Asahi 11 leI 9 Ake 加 no 82 Senbon-asahi Senbon-asahi Koganenishiki 121 Kinmaze 15 Asahi-mochi 173 Mihonishiki Mihonishiki 12 Average Ukonnishiki Ukonnishiki 10 112 Average 30 mmemmmll 27. 27. 28. Norin 22 93 a Wakayama Norin 22 emmmel--守 Tottori Norin 29 61 RJhuJRJ Shuho Norin 37 18 Takane 55 Kinmaze Hoki-asahi Hatsushimo 103 'nu句 Yamabiko 57 Koganeniohiki Yaeho Average 1∞ Tsubasa 123 Average 76 melmmoo'inwd'aa--a'3co'aq403nwd。 ell-e 29. 29. Norin 22 !3O. Norin 22 81 Shimane Kinki 33 Okayama Asahi 122 Mihonishiki Mihonishiki Akebono 33 Takane Mihonishiki 1ω Yaeho Koganenami ω Average Average 86 93cDOORJn4RJ。3'aqLnunwd 't。， lemlm 1. 31. Norin 17 e 32. Norin ，a『，句， 130 Hiroshima Norin 22 m Yamaguchi Norin 。•.