J.RADIOANAL.NUCL.CHEM.,LETTERS 128 Ill 35-42 11988[ ACCUMULATION AND DISTRIBUTION OF ELEMENTS IN RICE /SEED, BRAND LAYER, HUSK/ BY NEUTRON ACTIVATION ANALYSIS L. Tran Van x, D.K. Teherani Institute of Biology, Research Center Selbe~sdorf, A-2444 Se~bersdorf, Austria XVietnam Atomic Energy Commission, Dalat Nuclear Research Center, Radiation Protection Department, Dalat, Vietnam Received ll April 1988 Revised 3 June 1988 Accepted 9 June 1988 Various rice samples /seed, brand layer, husk/ from Vietnam were analyzed for Se, Hg, Cr, Ni, Sc, R b, Fe, Zn and Co by neutron activation analysis. The concentration values found Iseed/ were the following: Se 0.04-0.07 ppm, Hg 0.02-0.07 ppm, Cr 2.13-8.65 ppm, Ni 1.56-4.95 ppm, Sc 0.02-0.06 ppm, Rb 0.84-2.71 ppm, Fe 26.31-96.07 ppm, Zn 10.65-27.39 ppm and Co O.02-0.15 ppm. The values were report- ed in ppm /dry weight/. Statistibal analysis /t-test, t = 0.05/ showed that the content of elements Varies between sorts of rice; the content of Rb, Fe, Ni, Cr of rice husk was significantly higher than in rice seed and brand layer. INTRODUCTION The chemistry of metals, such as Cu and Zn, in flooded soils has been less studied than that of Fe and Mn I. Cop- per and zinc do not undergo valence change in flooded 35 Elsevier SequO~ & A., L~sanne Ak~dm~ K~6, Bud~est TRAN VAN, TEHERANh ACCUMULATION OF ELEMENTS IN RICE soils but their equilibria are sometimes dependent on the stability of other solid phases which are sensitive to these conditions. Thus Tiller 19582 ascribed the losses of Cu and Zn from seasonally waterlogged soils to the breakdown of host iron oxide minerals. The re- lease of Co in waterlogged soils is undoubtedly attrib- utable to the instability of Mn minerals, which often contain other metals, especially Co, As a consequence, the uptake of Co by plants is increased by waterlogging of the soil. In so far as the solid-solution equilibria of trace metals are controlled by sorption reactions, even minor dissolution of the adsorbing surfaces of Fe and Mn oxides can significantly affect the trace metal distributions. When such changes are accompanied by con- current changes in acidity, in nature and amount of li- gands, and their distributions between soil surfaces and solution, the final effects on trace metals may become very considerable. It is the complexity of these pos- sible interactions which has limited progress in under- standing the effects of submergence of soils on such trace metals as Cu and Zn. Nutritional problems of field- grown rice involving trace metals have mainly concerned Fe, Mn and Zn deficiencies and Fe toxicity 19703 . Rice yields have occasionally been increased by applications of copper sulphate in India 4-6, Portugal 7 and Japan 8. Ostrovskaya 9 stimulated seedlings growth of rice grain / containing only 2 ~g Cu per gram by presoaking seeds in CuSO 4 solution. Heavy metals, as environmental Conta- minants of terrestrial ecosystems, are not a recent phe- nomenon. They are ubiquitous in trace concentrations in soil and vegetation, and in fact many are required by plants and animals as micronutrients. In addition, na- turally occurring surface mineralizations can produce metal concentrations in soils and vegetation that are 36 TRAN VAN, TEHERANI: ACCUMULATIONO F ELEMENTS IN RICE as high, or higher, than those found around man-made sources. The searches by prospectors for such metal de- posits, frequently using biogeochemical techniques, are a part of our history. These cases of natural \"pol- lution\" are, however, relatively localized, and it was not until the recent era of industrialization that wide- spread contaminations by heavy metals /and other clas- ses of pollutants as well/ have occurred. In this article we wish to consider the accumulation of several elements /Se, Hg, Cr, Ni, Sc, Rb, Fe, Zn, Co/ and their distribution within the rice, brand layer as well as rice husk, EXPERIMENTAL Samples Various kinds of rice /Table i/ were separated and homogenized in seed, brand layer and husk by using grind\" er and sieve. Neutron activation analysis Rice samples weighing from 0.08 to 0.14 g, chemical standards evaporated onto filter paper, were sealed in quartz ampoules and irradiated for 20 h at a thermal -2 -i neutron flux of 9xlO 13 n.cm .s in the core of an AUSTRA-REACTOR. After 4 weeks the samples and standards were counted /75Se, 203Hg, 51Cr, 58Co for Ni, 46Sc, 86Rb, 59Fe, 65Zn and 6Oco/. Samples were measured on a Canberra 4000-channel analyzer connected to a 80-cm 3 Ge/Li/ detector of 5% efficiency and of 1.7 keV resolution at 1332.4 keV. 37 TRAN VAN, TEHERANI: ACCUMULATIONO F ELEMENTS IN RICE TABLE 1 Concentration /ppm/ of Se, Hg, Cr, Ni, Sc, Rb, Fe, Zn Nr Rice-species V-14 a b c CR-203 a b c VN-86 a Se Hg Cr Ni 1 O.O5_+0.O1O .O3+0.O1 2.13_+O.44 4.35+1.88 0.04_+0.02O .O3_~O.O1 5.12+1.73 5.07,+0.77 0.05_+0.02 0.04_+O.O1 19.O6+2.63 19.21_+O.76 0.04_+0.02O .O2+O.O1 6.O2+1.92 4.95+0.22 0.O2+0.01 O.03~O.O1 8.95+2.26 5.30~1.32 O.O5_~O.O30.02_~O.O1 24.24+4.11 14.85_+1.41 2 3 b 0.~.01 O.04+O.01 0.03+O.01 4.25+1.90 2.68_+1.26 0.02~.01 5.47~.~ 4.77_~.51 4 c IR-21 a IR-17 a b c V-15 a b c O.O9~O.O2 0.O3+0.O1 16.94+3.20 12.65+1.37 O.O5+0.O1 0.O7_+O.O1 6.3_0~O.32 2.57_+O.11 b e 0.02~.01 o.ot~01 6s5+i.08 4.34+0.s7 0.02_~ Ol O.O29.O1 12 ~2 84 27 42_~5 ~ 5 0.06+0.O1 O.03+0.O1 8.65_+3.36 4.25+1.O2 O.04TO.OI O.O2~O.O1 15.40_+1.72 8.16_~2.10 0.07~O.O1 0.05~0.O1 38.+3.68 14.67+2.O3 O.O7+0.O1 O.O2_+0..O1 5.12_+O.76 1.56+0.16 0.O6~O.O1 0.O2_+O.O1 9.45_+0.47 4.~1.26 0.Ii_~O.050 .03_+O.01 27.55+6.83 10.75-+1.50 6 a: seed of rice; b: brand layer; c: husk of rice. RESULTS AND DISCUSSION The main values and standard deviations of nine elements /Se, Hg, Cr, Ni, Sc, Rb, Fe, Zn and Co[ in various rice samples and their parts can be found ~n Table'l. Statistical analysis of significant difference between kind of rice and their parts were performed in Fig. i, and T-test for their seed /t = 0.05[ /Ref. 12/, showing in Fig. 2. 38 TRAN VAN, TEHERANI: ACCUMULATIONO F ELEMENTS IN RICE and Co in various rice frcm Vietna~ Sc Rb Fe Zn Co 0.04_~.01 2.71+0.96 .52_+12.03 26.20_+5.86 0.02_~.01 0.04+0.02 2.45~.97 123.65+15.52 24.46+1.28 0.24+0.07 0.033.01 9.01_~1.701 ~2.58~33.u 33.85_~2.~ 0.223.0~ 0.O3+0.01 0.94_+0.36 78.32Z5. 18.31_+5.23 0.O3+0.O1 0.023.O1 2.11+0.12 .Z14.22 26.81Z1.20 0.07~0.01 0.06_+0.02 4.65_~O.65 166.49Z30.28 23.55~4.21 O.18_~0.O4 0.02+0.003 0.84_+0.27 96.07_+29.22 27.39+7.40 0.15_+0.02 O.O1~0.005 1.30+0.43 88.05+15.82 40.43~6.52 0.16+0.03 0.02_+0.008 1.53_+0.27 32.23Z10.55 10.65_+O. 0,i_0~0.07 0.03+0.009 2,06_+0.42 67.62_+9.29 28.10-+4.92 0.12+0.07 0.O4~0.002 2.71+0.20 235.38+18.52 41.32+2.04 0.45~0.04 0.023.001 2.503.12 2n.19~20.n 38.5~7.11 0.03_~.01 0.06_~.002 2.+0.48 38.1G_+6.36 21.37+4.26 0.05+0.02 0.03+0.008 2.G13.13 158.79z23.51 24.17~2.23 0.32~.06 0.043.009 7.5t~.37 176.95z17.70 67.35~3.24 0.4t~.01 0.02_~.~7 2.35_~.33 26.31_+8.41 15.66+4. 0.05+0.01 0.04_~.010 2.n_~.68 104.39_+19.17 24.09~4.16 0.18~.04 0.02_~,006 5.41_~.41 116.23_+14.45 21.93_~4.84 0.34_~.04 The highest value of Se was found in the seed of rice, namely V-15, which was tested in The Vietnam Agricultural Science and Technology Institute. Wereas the highest value of Hg was found in the seed of rice IR-21, brought from IRRI fInternational Research of Rice Institute, Philippines/ to Vietnam, and was test- ed under the conditions in Vietnam at the South Viet- nam agricultural Technical Institute. For rice samples CR-203 and VN-86, grown in acidic soil, have Fe content in seed higher than another. 39 ~P, AN VAN, TEHERANI: ACCUMULATIONO F ELEMENTS IN RICE (,,,):!xl , I ~ I ~ I ' ~ \"-,1\" ~ Q ~ \",-1\" ~\"~ 0 ~,~ ~ r',~ 0 ' ' ~ \",,'f\" ~ 0 ~ I \"1\" N 0 .~ 0 ~_ E I] ~o ,.q\" O ~ ~ \"..,1\" 0 ~ Ill co -4\" 0 e.~ co .~ O e4 go ...I\" O e~ ~o .,,.t O ~ u L~ x ~.o CO -4\" N O r ~1\" ~ O q,0 .,,1, N O ~ -..,1P N O q) ,~ e~ O (.) eo ,N ~ O r ,N ~ O ~ N ~ O oo N ~ O ~ N ~ O eo e~ ~ O D3 ,-,'~ -,1\" e,,~ O ,-, ~ ,-,lr ~ O 9 ,- .~ '-4,\" N O ~ ,,, .,<,1\" e~ O ~ 9 ro ,-~ , ,, oo ,,-~ C:i \".,1\" 0 0 ~ \" ' ,...: - . ,,,.,.: . , ~ Go -.1\" 0 ~o .~.~ ~x/,I l ~L-A f;OZ-~3 gg-NA J I, o LL-~T ~- h ,o~ -el LT.-U 1 40 TRAN VAN, TEHERANh ACCUMULATIONO F ELEMENTS IN RICE 5e 12 3456 Hg 1 23456 Cr 123456 65 ~ 1 11 t tt tt t U- e- il-,, 4 Ni 123456 LEi,t Sc 1 2 3456 _ il\" t 1 t 3 It 12 fit tttf Rb 3456 - 6 --T--r-r--T--r- 5 3 I o. ~. i 12 5 ~ Zn 3456 0= 1 12 5 Fe 1 2 3 4 5 6 6 ---r--r-T--r~-- t,- Co 3456 6 ---T--r-r-T- ~ 4 - q- *- q-l 3- ~ '- tt 3 \" 4,,~ i It t~'~'~ []; ~ 1 I 2 1 ! ittttl It t t t7 Indicates higher I'--'l No statistically difference Fig. 2. Statistical analysis /t-test/ of Se, Hg, Cr, Ni, Sc, RS, Fe, Zn and Co in rice seed Both are common rice in Vietnam, but they contain less Rb than rice, types IR-17, IR-21, V-14, V-15. Fe, Rb, Ni, Cr and Co contents in the husk were much higher than in other parts with all types of rice, ex- cept the Co content in VN-86. Teherani IO found in various rice, marketed in Austria: 0.03 ppm Se, 0.-1.87 ppm Cr, 0.36-0.96 ppm Ni, 1.6-6.4 41 TRAN VAN, TEHERANI: ACCUMULATIONO F ELEMENTS IN RICE ppm Rb, 24.3-139.8 ppm Fe, 0.03-0.06 ppm Co and 0.002-0.02 ppm Hg. Our results have the same degree of these values. Be also found high values of Se an~ Fe in rice from Bel- gium [long seed, and super patna[. Co may vary from 0.5 ppm in a non accumulator to as high as 1.8% dry weight in accumulator species such as Crotolaria Cobaltlcola II. Although only few dataare available, it appears that plants reflect fairly well the mercury content in their environment I0 . REFERENCES i. F.N. Ponnamperuma, Adr. A@ron., 24 [1972[ 29. 2. K,G. Tiller, J. Soil. SCI., 9 {1958[ 225. 3. A. Tanaka, S. Yoshlda, IRRI Tech. Bull., No. i0, 1970. 4. N.V. Joshi, S.G. Joshl, J. Indlan Soc. Soil. Sci., 5 [1957[ 210 5. P.C. Rahaja, K.S. Yawalka~ R. Singh, Ind. J. A@ron., 3 [1959[ 2. 6. S.V.G. Rajah, G.H.G. Rao, J. Indian Soc. Soil Sci., 12 [19[ 355. 7. P. Candido, P. Ricardo, J.M. Arriaga, E. Cunha, Agro- n omia lusit., 29 [1968[ 57. 8. T. Yamasakl, IRR~ John Hopkins Pressr Baltimore, 1965. 9. L.K. Ostrovskaya, Fiz~olo~lya Rast., 3 /1956[ 7~. 10. D.K. Teheranl, J. Radloanal. Nucl. Chem., Lett,, 117 [1987[ 133. ii. P.J. Peterson, Nuclear Activation Techniques in the Life Sciences, IAEA, Vienna, 1972, 323. 12q L. Sachs, Statlst• Berlin, 1972, Methoden, Springer-Verlag, 42
