IAEA Reference Materials

Reference Sheets

REFERENCE MATERIAL
IAEA-375
RADIONUCLIDES AND TRACE ELEMENTS IN SOIL

Intended Use  
    This sample is intended to be used as a reference material for the measurement of radionuclides in soil samples. It can also be used as a quality control material for the assessment of a laboratory's analytical work, for the validation of analytical methods and for quality assurance within a laboratory.

Origin and preparation of the material  
    The material (top soil to a depth of 20 cm) was obtained from the "Staryi Viskov" collective farm in Novozybkov, Brjansk, Russia in July 1990. The material was air dried and milled to give a grain size less than 0.3 mm by the Brjansk Centre for Agricultural Radiology and Chemistry. The material was packed into 25 polythene sacks (containing approximately 20 kg of soil each) and dispatched to the Agency’s Laboratories at Seibersdorf in November 1990. 
    The bulk material was recombined and homogenized at the Agency’s Laboratories at Seibersdorf by mixing the powder in a 3000 L drum for 24 hours and then dispensed into plastic bottles in 250 g units. Subsequently, the samples were irradiated to a dose of 2.5 x 104 Gy using a 60Co source to ensure long-term stability of the material by inhibiting microbial action.
Date of Release:  
August 1994
 Unit Price:  
90 €
 Unit Size:  
250 g
Producer:  
Chemistry Unit 
Agency's Laboratories, Seibersdorf
A-2444 Seibersdorf, Austria		 Supplier:  
Analytical Quality Control Services 
Agency's Laboratories, Seibersdorf 
A-2444 Seibersdorf, Austria
Reference Sheet: IAEA-375(.pdf)

Reference Date for decay correction: 31st December 1991
Analyte
Status
Activity Concentration
[Bq/kg]
(Based on dry weight)
95% C. I.
[Bq/kg]
N*
40K
R
424
417 – 432
84
90Sr
R
108
101 – 114
43
106Ru
R
56
53 – 58
26
125Sb
R
77
74 – 79
38
129I
R
0.0017
0.0013 – 0.0021
10
134Cs
R
463
454 – 472
87
137Cs
R
5280
5200 – 5360
91
226Ra
R
20
18 – 22
37
228Th
I
21
17 – 25
6
232Th
R
20.5
19.2 – 21.9
11
234U
I
25
17 – 32
5
238U
I
24.4
19.0 – 29.8
7
238Pu
I
0.071
0.056 – 0.085
10
239+240Pu
I
0.30
0.26 – 0.34
20
241Am
I
0.13
0.11 – 0.15
6

Analyte
Status
Concentration
[mg/kg]
(Based on dry weight)
95% C. I.
[mg/kg]
N*
As
I
2.56
2.24 – 2.88
6
Ba
I
335
316 – 354
6
La
I
17.6
15.3 – 19.9
5
Ni
I
9.7
7.9 – 11.6
5
Rb
I
48
44 – 52
8
Yb
I
1.73
1.24 – 2.22
5
Th
R
5.2
5.0 – 5.4
26
U
R
1.86
1.66 – 2.05
30

* 
Number of accepted laboratory results which were used to calculate the recommended or information values and their respective confidence intervals about the mean value.
(R/I) 
Classification assigned to the property value for Analyte (Recommended/Information)


The values listed above were established on the basis of statistically valid results submitted by laboratories which had participated in an international intercomparison exercise organized in 1992. The details concerning the criteria for qualification as a recommended value can be found in the report (IAEA/AL/075) "Report on the Intercomparison Run IAEA-375: Radionuclides in Soil" [1]. This report is available free of charge upon request.    

Homogeneity  
    The homogeneity of the bottled material was assessed using marker analytes for trace elements (U), b-emitters (90Sr) and g-emitters (134Cs and 137Cs) for intake masses of 0.2g (trace elements) and 6g (radionuclides) respectively. For this study, seven bottles were chosen at random and three determinations were made from each bottle. Taking into account the statistical uncertainties on the observed results, this material can be considered sufficiently homogeneous for it’s intended purposes at or above the specified intake masses.

Note: Some evidence has been presented to suggest that this material may be contaminated with "hot particles" resulting from the Chernobyl accident. The frequency of the occurrence of these "hot particles" is unknown and consequently, it is possible that significantly elevated activities may be observed for anthropogenic radionuclides in some sub-samples.  

Dry weight determination  
    All recommended values are expressed on a dry weight basis. Therefore the dry weight must be determined at the time of analysis, using separate sub-samples of at least 500 mg dried to constant weight in a drying oven set to 105 °C. Subsequent weighings should differ by less than 5 mg.   

Instructions for use  
    The recommended minimum intake masses for analysis of trace elements and radionuclides are 0.2g and 6g respectively. 
    Analysts are reminded to take appropriate precautions in order to avoid contamination of the material during handling. No special precautions are required for the storage of this material.  

References: 
[1]

Last updated 30 March 2004


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