Some results of NAA collaborative study in white rice performed at Dalat nuclear research institute

tions. The HPGe detector with 
SOME RESULTS OF NAA COLLABORATIVE STUDY IN WHITE RICE ... 
78 
multichannel analysis system was used to 
measure the gamma rays from the sample after 
irradiation. The concentration of the elements 
was calculated using the relative method and/or 
k-zero method. 
III. RESULTS AND DISCUSSION 
A. The content of elements in white rice 
samples 
The result of standard reference material 
was shown in Table II and the result of fifteen 
elements concentrations in eighteen samples of 
white rice are in Table III. 
In Table II, The average result are 
caculated through 3 times analysis, it's not 
much different to the value of certificate. The 
Z-score of all elements is lower than 2, that 
mean this results are satisfactory. 
Table II. Result of standard reference material IAEA-V-10 
No. Ele. Aver. Sd. Cert. Z-score Ana/Cert 
1 Mg 1579 121 1360 1.81 1.161 
2 Ca 20865 2892 21600 -0.25 0.966 
3 Cl 7360 100 - - - 
4 Mn 46 5 47 -0.20 0.979 
5 Na 507 9 500 0.78 1.014 
6 K 20119 3530 21000 -0.25 0.958 
7 Br 7.3 0.5 8 -1.40 0.913 
8 Sc 0.016 0.002 0.014 1.00 1.143 
9 Cr 6.6 0.5 6.5 0.20 1.015 
10 Fe 196 21 186 0.48 1.054 
11 Co 0.15 0.03 0.13 0.67 1.154 
12 Zn 25.5 2.2 24 0.68 1.063 
13 Rb 7.7 0.5 7.6 0.20 1.013 
Aver: Average result; 
Sd: Standart deviation 
Cert: Certificate 
In Table III, the concentration of Mg 
element are not analyzed in all samples, elements 
concentration of Al, Ca and Fe are not obtained 
and reported limit of detection, the result of other 
elements are included concentration and 
uncertainty. The highest concentration are K 
element, the lowest come from Co and Cs. The 
other elements have no significant differences 
between all samples except Rb. 
B. Comparing the elements concentration in 
white rice of 8 countries 
Results of fifteen elements: Al, As, Br, 
Ca, Cl, Co, Cr, Cs, Fe, K, Mg, Mn, Na, Rb and 
Zn in rice samples determined by eight 
participating countries are summarized in Table 
4. The results of quality control analysis for 
fifteen elements are summarized as a relative 
error (%) with absolute value and are shown in 
Fig. 1. The relative error of most of the 
elements evaluated in Fig. 1 were less than 
15%, except for some few elements such as Al 
of Malaysia; Co of Vietnam; Mg of China, 
Korea and Vietnam, Mn and Na of Korea rice 
samples. 
TRAN QUANG THIEN et al. 
79 
Table III.The analytical results of eighteenwhite rice samples in Vietnam 
No. Type 
Al As Br Ca Cl Co Cr Cs Fe K Mg Mn Na Rb Zn 
C. U. C. U. C. U. C. U. C. U. C. U. C. U. C. U. C. U. C. U. C. U. C. U. C. U. C. U. C. U. 
1 
Ham Chau 
Rice 
<3 
0.12 0.02 0.43 0.05 <165 
294 11 0.031 0.006 <0.4 
0.026 0.007 <14 
518 10 NA. 
8.0 0.2 22.6 0.3 1.5 0.3 23.0 0.5 
2 IR 50404 Rice <8 
0.16 0.04 0.17 0.05 <160 
242 11 0.026 0.008 <0.5 
0.061 0.010 <10 
1649 17 NA. 
15.9 0.2 11.5 0.2 11.4 0.6 21.3 0.6 
3 
Japan 504 
Rice 
<4 
0.06 0.02 0.78 0.07 <120 
407 14 0.022 0.008 <0.4 
0.019 0.008 <14 
527 11 NA. 
5.1 0.1 48.5 0.3 1.0 0.3 21.7 0.8 
4 
Jasmine 85 
Rice 
<5 
0.13 0.03 0.31 0.07 <185 
235 30 0.028 0.008 <0.5 
0.056 0.012 <18 
1543 17 NA. 
19.1 0.1 18.2 0.3 10.3 0.7 22.8 0.8 
5 Jasmine Rice <4 
0.12 0.02 0.22 0.04 <100 
192 10 0.030 0.008 <0.5 
0.052 0.007 <20 
453 9 NA. 
3.5 0.1 9.0 0.2 1.9 0.4 19.2 0.6 
6 OM 4218 Rice <5 
0.15 0.04 0.22 0.06 <130 
282 25 0.031 0.008 <0.6 
0.045 0.009 <17 
1548 16 NA. 
12.8 0.1 17.1 0.3 8.3 0.6 22.2 0.7 
7 OM 4900 Rice <7 
0.10 0.03 0.34 0.07 <140 
346 31 0.043 0.008 <0.5 
0.044 0.010 <19 
1780 18 NA. 
16.0 0.1 14.8 0.3 5.9 0.5 26.2 0.7 
8 OM 5451 Rice <7 
0.15 0.03 0.29 0.06 <120 
199 23 0.036 0.007 <0.6 
0.046 0.008 <16 
1254 16 NA. 
11.8 0.1 18.8 0.3 11.4 0.7 22.6 0.7 
9 OM 5472 Rice <4 
0.11 0.03 0.26 0.06 <100 
293 22 0.034 0.007 <0.5 
0.047 0.011 <22 
1414 15 NA. 
11.9 0.1 14.9 0.2 9.7 0.6 24.8 0.7 
10 OM 5976 Rice <5 
0.11 0.03 0.18 0.05 <110 
186 11 0.031 0.009 <0.6 
0.043 0.011 <17 
1227 14 NA. 
12.7 0.1 11.3 0.2 10.7 0.6 24.0 0.7 
11 OM 6162 Rice 
<1
0 
0.08 0.03 0.17 0.05 <120 
307 13 0.043 0.009 <0.4 
0.039 0.011 <16 
1509 16 NA. 
13.9 0.2 12.6 0.2 8.3 0.6 23.7 0.7 
12 OM 6377 Rice <7 
0.14 0.03 0.23 0.06 <120 
266 27 0.058 0.009 <0.6 
0.063 0.011 <13 
1636 16 NA. 
16.8 0.1 13.1 0.2 15.7 0.7 23.4 0.8 
13 OM 6976 Rice <6 
0.11 0.03 0.34 0.05 <100 
382 14 0.027 0.007 <0.5 
0.038 0.009 <19 
1487 16 NA. 
6.7 0.3 13.5 0.2 4.8 0.5 25.0 0.7 
14 Otim Rice <4 
0.17 0.03 0.47 0.04 <100 
225 11 0.044 0.009 <0.3 
0.051 0.013 <28 
568 11 NA. 
7.5 0.1 14.4 0.2 2.8 0.5 21.4 0.7 
15 Seri Rice <4 
0.22 0.02 0.18 0.04 <135 
236 11 0.041 0.009 <0.4 
0.074 0.011 <21 
501 9 NA. 
5.4 0.1 13.5 0.2 8.2 0.7 21.1 0.7 
16 
Tai Nguyen 
Rice 
<3 
0.06 0.02 0.65 0.07 <100 
378 12 0.039 0.009 <0.5 
0.016 0.007 <16 
470 9 NA. 
5.2 0.1 40.9 0.3 1.0 0.3 17.5 0.7 
17 Taiwan Rice <5 
0.11 0.03 0.23 0.04 <110 
330 12 0.024 0.010 HL 
0.066 0.010 <22 
842 13 NA. 
5.9 0.1 10.5 0.2 7.5 0.6 24.8 0.9 
18 Thom Lai Rice <3 
0.08 0.02 0.40 0.04 <110 
208 9 0.031 0.008 <0.5 
0.029 0.007 <14 
463 8 NA. 
3.9 0.1 7.8 0.2 1.2 0.4 19.8 0.6 
Average <5 0.12 0.33 <124 278 0.034 <0.5 0.045 <18 1077 NA. 10.1 17.4 6.8 22.5 
Unit: mg/kg; C. : Concentration; U. : Uncertainty; NA. : Not Applicable 
SOME RESULTS OF NAA COLLABORATIVE STUDY IN WHITE RICE ... 
80 
Table IV. The analytical results of white rice (unit: mg/kg) [1] 
Ele. 
a
China Indonesia 
b
Japan Korea 
c
Malaysia 
d
Philippine Thailand 
e
Vietnam 
(This work) 
Al <4.46 <20.52 <1.66 <1.38 <2 <2.82 <2.33 <5 
As 0.55 0.08 0.1 0.13 0.11 0.07 0.09 0.12 
Br 0.35 0.45 0.5 0.19 13.6 5.35 0.43 0.33 
Ca N.A <4.53 49.5 53.9 <10 39.1 <15 <124 
Cl 264 210 239 193 225 236 239 278 
Co <0.3 0.77 N.A 0.005 0.026 N.A 0.022 0.034 
Cr 0.25 0.38 N.A <0.01 <0.08 N.A <0.4 <0.5 
Cs <0.07 0.09 N.A 0.009 0.016 N.A N.A 0.045 
Fe N.A 4.65 N.A 1.58 <5 N.A <16 <18 
K 977 739 611 660 573 637 620 1077 
Mg 379 131 149 241 <150 90 59 N.A 
Mn 9.25 9.95 7.66 9.06 6.19 7.89 9.23 10.1 
Na 10.3 7.7 5.69 4.1 13.7 5.17 4.58 17.4 
Rb <3.35 7.64 N.A 1.39 2.1 3.24 1.34 6.8 
Zn 15.3 24.2 18.5 15.3 10.1 15.4 21.4 22.5 
N.A: not applicable; (a) Mean values are derived from four different samples; (b) Mean values from a sample 
of known origin and two samples of unknown origin; (c) Mean values are derived from two different 
samples; (d) Mean values from four samples of unknown origin; (e) This work, average value of eighteen 
samples from known origins. 
As can be seen from Table IV, the Al 
concentrations in rice saples from all 
participating countries were below the 
detection limit, hence only the limit of 
detection (LOD) were reported. Indonesia had 
an LOD value of 20.52 for Al, highest 
compared to other countries. Korea and Japan 
had the lowest LOD values in the eight 
countries. K concentration range is from 553 to 
1077 mg/kg. K in Vietnam rice samples had 
the highest value which is 1077 mg/kg. Cl and 
Mg have similarly eminent values. Seven 
elements of As, Br, Cl, K, Mn, Na and Zn were 
determined by all participating countries, but 
LODs were not reported. As content of China 
had the highest value, 0.55 mg/kg and the other 
countries have equivalent levels of As, 0.1 
mg/kg. Br concentrations of Malaysia, 
Indonesia and the Philippines were more than a 
dozen times higher than those of other 
countries. Five elements Cl, K, Mn, Na and Zn 
did not differ significantly and the average 
content of the standard deviation were 236±27, 
737±178, 8.67±1.32, 8.58±4.84 and 17.8±4.7 
mg/kg respectively. Concentrations of Mg 
were reported by six countries excluding 
Malaysia and Vietnam. Thailand showed the 
lowest levels of Mg, 59 mg/kg, while the Mg 
content of China was the highest at 379 mg/kg. 
Only three countries namely Japan, South 
Korea and the Philippines reported Ca data 
which were 49.5, 53.9 and 39.1 mg/kg 
respectively. In addition, the levels of Cr, Cs 
and Fe in Indonesian rice were higher 
compared to those of other countries. 
TRAN QUANG THIEN et al. 
81 
C. Dietary intake level of the toxic elements 
and nutrition elements of 8 countries 
To estimate the dietary intake level of 
inorganic constituents on consumption of white 
rice, it was necessary to conduct a survey of 
daily consumption of rice. For example, the 
amount of the average daily consumption of 
rice in Korea in 2000 was 256 grams, or in 
Vietnam in 2010 is 360 gram [3, 4]. However, 
rice consumption varies in different countries, 
and therefore a consensus value of 300 
grams/day was set, to be able to compare the 
intake of As, Cl, K, Mn, Na and Zn from rice 
consumption in all participating countries. This 
is to assess whether or not, the ingested levels 
of the elements can be considered as harmful 
or beneficial to human health. Data are shown 
in Table V. 
Fig. 1. The absolute value of the relative error (%) of the value analysis to value certification/reference. 
Table V. The RDA value of 6 elements each day through white rice, assuming consumption 
of 300 grams /day for adults[1] 
Ele. China Indonesia Japan Korea Malaysia Philippine Thailand 
Vietnam 
(This work) 
As (µg) 165 24 30 39 33 21 27 36 
Cl (mg) 79.2 63 71.7 57.9 67.5 70.8 71.7 83.4 
K (mg) 293 222 183 198 172 191 186 323 
Mn 
(mg) 
2.78 2.99 2.30 2.72 1.86 2.37 2.77 3.03 
Na (mg) 3.09 2.31 1.71 1.23 4.11 1.55 1.37 5.22 
Zn (mg) 4.59 7.26 5.55 4.59 3.03 4.62 6.42 6.75 
The WHO has established a Tolerable 
Intake Level for weekly consumption, which is 
15 mg/kg of body weight for As [5]. Assuming 
a body weight of 70 kg of an adult, the 
Tolerable Intake Level for As daily 
consumption will be 150 microgram As. In 
addition, the Institute of Medicine (IOM) in the 
United States has established the value of the 
Recommended Dietary Allowance (RDA) or 
adequate intake (AI) for the necessary elements 
[6, 7]. Zn has the highest RDA of 11 mg/day 
for men. AI highest values for Cl, Mn defined 
by the IOM is 2.3 g/day for all adults, for Na 
and K, the highest AI values are respectively 
1.5 and 4.7 g/day. 
0
5
10
15
20
25
Al As Br Ca Cl Co Cr Cs Fe K Mg Mn Na Rb Zn
E
rr
o
r,
 %
China Indonesia Japan/Philippines
SOME RESULTS OF NAA COLLABORATIVE STUDY IN WHITE RICE ... 
82 
Calculations for the RDA or AI for the 
elements As, Cl, K, Mn, Na, Zn are shown in 
Figure 2.Tolerable Intake Level of As in China 
is higher than Tolerable Intake Level of WHO 
which was about 10%, for the other countries. 
The level of Mn is almost equal to the value of 
the RDA of IOM. This shows just rice 
consumption of 300 g/day may provide 
sufficient Mn necessary for the human body. 
The intake level for the remaining elements 
(Cl, K, Na and Zn) were below the RDA or AI. 
In the case of Zn, the range of daily 
consumption from 21.6% (Malaysia, 
Indonesia) to 51.9% (Indonesia) can only 
supply approximately 21.6% to 51.9% Zn 
necessary for the human body. Similarly, 
consumption of Cl at 2.5% to 3.6%, K at 3.7% 
to 6.2% and 0.3% Na were below the 
recommended values. These essential elements 
can be obtained anyway, from other foods such 
as meat, fish, vegetables, eggs, milk, etc. which 
are eaten together with the rice. 
IV. CONCLUSIONS 
A collaborative study on the 
determination of elemental abundance in rice 
using NAA was participated in by eight 
countries namely China, Indonesia, Japan, 
Korea, Malaysia, the Philippines, Thailand and 
Vietnam. A total of fifteen elements in thirty 
five samples of white rice collected from eight 
countries were determined by INAA method. 
Within the framework of project participants 
FNCA/NAA, NAA laboratory of Vietnam has 
collected and analyzed fifteen elements in 
eighteen samples of white rice types. Results of 
Vietnam’s rice has been compared with the 
results of the seven countries participating 
members. 
The analytical data were compared 
between the participating countries and 
assessed according to the daily intake using the 
guideline values set by the WHO and IOM. 
The results showed an elevated amount of As 
in Chinese rice which exceeded by 
approximately 10%, the RDA recommended 
by WHO. In addition the research gave an 
overview of the levels of nutritional elements 
Na, Mn, Cl, K and Zn in rice consumed in the 
eight countries. Information on the intakes of 
Mn (of approximately 100%), Zn, Na, Cl 
(21.6÷51.9) % and K (lower than 10%) in 
comparison to the requirements of IOM was 
obtained from the study. 
Fig. 2. Assess daily nutrient consumption (%) for the six elements through white rice. 
0.1
1.0
10.0
100.0
1000.0
As Cl K Mn Na Zn
%
R
D
A
China Indonesia Japan Korea
Malaysia Philippines Thailand Vietnam 
TRAN QUANG THIEN et al. 
83 
In future, FNCA will carry on to expand 
the scope of research in elemental abundance in 
food samples to strengthen the collaboration 
between Asian countries for the continued 
application of NAA in the assessment for 
contamination and mineral potentiality in the 
basic foodstuffs. 
ACKNOWLEDGEMENTS 
We would like to thank the MEXT of 
Japan for support of this research. 
REFERENCES 
[1] J. H. Moon et. al, A NAA collaborative study 
in white rice performed in seven Asian 
countries, Journal of Radio- analytical 
Chemistry, Volume 291, Issue 1, pp 217-221 
(January 2012). 
[2] Center for Analytical Techniques (CATech), 
Dalat Nuclear Research Institute (NRI), 
“TCCS-MSH from 01 to 03”, Dalat, (2011). 
[3] Ministry of Agriculture and Forestry, 
Agricultural and forestry statistical yearbook 
2003. Ministry of Agriculture and Forestry, 
Seoul, (2003). 
[4] National Institute of Nutrition, A review of the 
nutrition situation in Vietnam 2009-2010, 
Medical Publishing House, Hanoi, (2011). 
[5] World Health Organization, Evaluation of 
certain food additives and contaminants, 
(Thirty-third report of the Joint FAO/WHO 
Expert Committee on Food Additives). WHO 
Technical Report Series, No. 776, (1989). 
[6] Institute of Medicine, Food and Nutrition 
Board, Dietary reference intakes for vitamin A, 
vitamin K, arsenic, boron, chromium, copper, 
iodine, iron, manganese, molybdenum, nickel, 
silicon, vanadium, and zinc, National Academy 
of Sciences, Washington DC, (2001). 
[7] Institute of Medicine, Food and Nutrition 
Board, Dietary reference intakes for water, 
potassium, sodium, chloride and sulfate. 
National Academy of Sciences, Washington 
DC, (2004).