Implementation Manual
for the 17th Inter-laboratory Comparison Project on Soil
2015
1. Introduction
Since 1998, various QA/QC activities for EANET monitoring have been carried out
by the National Centers and the Network Center/Interim Network Center (NC/INC)
for EANET according to the Quality Assurance / Quality Control (QA/QC) programs
in EANET. The Inter-laboratory comparison project is one of the activities suggested
in the QA/QC programs and these projects for soil monitoring have been carried out
since 1999 by NC/INC.
In the 2015 project, based on the results of data evaluation of previous attempts, NC
is providing soil samples to laboratories in charge of soil monitoring in the
participating countries for the purpose below.
2. Purpose
The purpose of this project is through the statistical evaluation of the analytical
results and information provided on the analytical equipment used and their operating
condition, it would be possible to recognize the analytical precision and accuracy of
each participating laboratory, including the within-laboratory and inter-laboratory
precision. This will enable the laboratory to improve:
(1) its capability to conduct analysis on soil monitoring for EANET
(2) the reliability of its analytical data through the use of suitable analytical
methods and techniques.
3. Working procedure
(1) Participating laboratories
Laboratories in charge of chemical analysis for soil monitoring of the
participating countries of EANET
(2) Activities
Soil samples (No.151s and No.152s) are distributed to the above-mentioned
laboratories. Samples were air-dried, sieved, mixed well, and sterilized using
radioisotope (20kGy). The information on the analytical precision and accuracy,
within-laboratory-precision, inter-laboratories precision on individual parameters
with equipment analysis and/or titration methods can be obtained through
statistical analysis of submitted analytical data.
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(3) Analytical Parameters
All participating laboratories shall measure and submit the data as follows:
Unit
Criterion
Parameters
a) Moisture Content
wt %
M
b) pH (H2O)
M
c) pH (KCl)
M
d) Exchangeable Ca
cmol(+) kg-1
M
-1
e) Exchangeable Mg
cmol(+) kg
M
f) Exchangeable K
cmol(+) kg-1
M
-1
g) Exchangeable Na
cmol(+) kg
M
h) Exchangeable Acidity
cmol(+) kg-1
M
-1
i) Exchangeable Al
cmol(+) kg
M
j) Exchangeable H
cmol(+) kg-1
M
M: Mandatory items
4. Outline of samples
In the package sent to the participating laboratories, two kinds of soil, Sample
No.151s and No.152s, are contained. Chemical characteristics of these samples are
not informed for fair evaluation of the program. The outline of the samples is
summarized in the following table.
Table 1. Outline of samples
Name
Amount of
sample
Container
Number of
samples
Note
Soil sample
Sample No.151s
About 500g
Poly-propylene
bottle 500ml
1
air-dried and sterilized
using radio isotope
(20kGy)
Soil sample
Sample No.152s
About 400g
ditto
1
ditto
5. Preparation of sample, and analytical method
(1) Special attention of handling and analysis of the samples
1) Keep the samples in a cool and dark place after the arrival. Don’t keep the
sample bottle open for long time.
2) Analysis of the samples should be done carefully and intentionally, since
the samples volume are limited.
3) In respective laboratories, all the parameters should be analyzed three times
under the same conditions (analyst, time, and instrument are the same).
Under within-laboratory-reproducibility condition (part or all of analyst,
time, and instrument are different), the analytical procedures should be
repeated twice for except of moisture contents.
4) Moisture contents should be analyzed with three replicates, and the average
is used for calculation of all the parameters.
(2) Procedure
All the procedures for chemical analysis should be carried out basically
according to the “Technical Documents for Soil and Vegetation Monitoring in
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East Asia (March 2000, Adopted at: The Second Interim Scientific Advisory
Group Meeting of Acid Deposition Monitoring Network in East Asia)”.
In the 15th Project,
1) Atomic absorption spectrometry (AAS) or Inductively Coupled Plasma
(ICP) method should be used basically for analysis of Ex-Ca, Mg, K and
Na. (If it is impossible to use AAS, Flame (emission) photometry method
is allowable for Ex-K and Na).
2) Titration method should be used for analysis of EX-acidity, Al and H.
3) Calibration curve method should be used for determination of Ex-Ca, Mg,
K and Na.
4) The Samples should be extracted and diluted with 1M CH3COONH4 (pH
7.0) for analysis of Ex-Ca, Mg, K and Na. Then, 1M CH3COONH4 (pH
7.0) solution should be used to prepare each standard solution as the
solvent.
5) Sr should be added to the samples and each standard solution to eliminate
the interference of the sample for analysis of Ex-Ca and Mg. These are to
be the same concentration Sr. (If Sr can not be obtained, La is allowable.)
For the analysis of Ex-Ca, Mg, K and Na, Annex I should be refereed. For the
analysis of Ex-Acidity, Ex-Al and Ex-H, Annex II should be followed certainly.
Followings are analytical methods for the 15th Project.
Table 2. Analytical methods for the 15th Project
Parameter
Analytical method
Moisture Content
According to the “Technical Documents for Soil
and Vegetation Monitoring in East Asia”
pH (H2O) and pH (KCl)
Ex-Ca and Mg
Atomic absorption
Atomic absorption
(Flame (emission) photometry)
Titration
Ex-K and Na
Ex- acidity, Al and H
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6. Report
(1) Preparation of report
The report format and “Technical Documents” are available from the following URL.
URL : http://www.acap.asia/~interlab/os/index.html
Complete the reporting formats (Microsoft Excel), considering the following issues.
1) Fill in the information of “Personnel in charge of measurement”, “Measurement
condition” in green columns on the sheets.
2) Fill in the values in green columns on the sheets of “Analytic value of
Exchangable base cations” and “Analytic value of Exchangable acidity, Al and
H”. (Calculated contents are automatically filled in yellow columns.)
(2) Preparation of report
Submit the data reporting formats together with all of the copies of calibration curve
certainly.
(3) Deadline date of the report submission
29 February 2016 (arrive at NC)
(4) Address of Report Submission and Contact Persons of the NC
Submit the report to the NC through the National Center of each participation
country. Address of the NC is as follows. Please be aware that e-mail address was
changed:
Hajime Akimoto Dr., Hiroyuki Sase Dr., and Naoyuki Yamashita Dr.
Data Management Department
Asia Center for Air Pollution Research
1182 Sowa, Nishi-ku, Niigata-shi, 950-2144 Japan
Tel. +81-25-263-0560,
Fax. +81-25-263-0567,
E-mail: datasubmit@acap.asia
Please do not hesitate to contact the Contact Persons, if you have any question on
this project.
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Annex I
Analysis for Ex-Ca, Mg, K, Na
1. Sample
The samples have been air-dried, sieved, mixed well, and sterilized using radioisotope
(20kGy).
2. Reagents
1) 1M CH3COONH4 (pH 7.0) solution: Dissolve 385g CH3COONH4 in deionized
water and make to 5L. Adjust the pH to 7.0 with ammonia or acetic acid 1M.
2) 100g-Sr/L solution : Dissolve 180.9g of SrCl2 (or 304.3g of SrCl2･H2O) in
deionized water and make to 1L.
3. Procedures
1) Extract from air-dry sample with 1M CH3COONH4 (pH 7.0) solution. (According
to the “Technical Documents for Soil and Vegetation Monitoring in East Asia”)
2) Pipette an appropriate aliquot of the soil extract into volumetric flask and add
100g-Sr/L solution to be 1000mg-Sr/L as final concentration Sr. (SrCl2 solution
eliminates the interference of the sample.) And then make to volume with 1M
CH3COONH4 (pH 7.0). This solution is named “Prepared sample”.
3) Prepare all together three such “Prepared sample”.
4) Prepare each standard solution with diluting 1M CH3COONH4 (pH 7.0) solution.
5) Add 100g-Sr/L solution to each standard solution to be the same concentration
SrCl2 as the sample.
6) Analyze the standard solution and the prepared samples by AAS or ICP.
7) Store the calibration curves certainly and report them together using the reporting
formats.
8) Repeat the procedure 1) - 7) twice.
4. Calculation of content in the soil
Content in the soil could be calculated by the following formulas:
Ex-Ca (cmol(+)/kg soil) = [A B V  mcf]/[10 20.04  S]
Ex-Mg (cmol(+)/kg soil) = [A B V  mcf]/[10 12.15  S]
Ex-K (cmol(+)/kg soil) = [A B V mcf]/[10 39.10  S]
Ex-Na (cmol(+)/kg soil) = [A B V mcf]/[10 23.00  S]
Where
A = Measurement values of prepared (diluted) samples (mg/L)
B = Dilution ratio
(B = 2, if 25mL sample was diluted to 50 mL for making prepared sample.)
mcf = Moisture correction factor
(Measured value)
S = Weight of air-dry sample (g)
V = Volume of extract (mL)
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Annex II
Analysis for Ex-Acidity, Al and H
The analysis should be carried out according to the “Technical Documents for Soil and
Vegetation Monitoring in East Asia” basically.
1. Repeat analysis
Prepare 3 samples. Analyze each sample and at least one blank. And repeat this
procedure again.
2. Calculation of content in the soil
Content in the soil could be calculated by the following formulas:
Exchangeable Acidity (cmol (+)/kg) = [(ANaOH - blNaOH ) * MNaOH * c * 100 * mcf] / S
Exchangeable Al (cmol (+)/kg) = [(AHCl - blHCl)* MHCl * c * 100 * mcf] / S
Exchangeable H (cmol (+)/kg)
= [(ANaOH - blNaOH)* MNaOH– (AHCl - blHCl )* MHCl ] * c * 100 * mcf] / S
Where
ANaOH = Titration volume of 0.025 M NaOH solution needed for percolate (mL)
AHCl = Titration volume of 0.02 M HCl solution needed for percolate (mL)
blNaOH = Titration volume of 0.025M NaOH solution needed for blank (mL)
blHCl = Titration volume of 0.02M HCl solution needed for blank (mL)
MNaOH = Molarity of NaOH solution (mol/L)
MHCl = Molarity of HCl solution (mol/L)
S = Weight of air-dry sample (g)
c = Aliquot factor
(c = 2, if 50mL percolate of 100mL is used.)
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Alternative method of soil extraction for exchangeable base cations
-Buchner funnel extraction procedure and centrifuge procedureReference: “ Methods of Soil Analysis Part3－Chemical Methods” p560, SSSA BOOK
SERIES No.5, American Society of Agronomy, USA, 1996
Reagent:
1. Ammonium acetate solution (NH4OAc), 1M: Dissolve 385 (or 77) g NH4Ac in water
in a 5 (or 1) L beaker and make to 5(or 1) L. Adjust the pH to 7.0 with ammonia or
acetic acid 1 M.
I. Buchner funnel procedure (alternative method 1)
1. Place 10 g of < 2- mm, air dried soil in a 125 mL Erlenmeyer flask.
2. Add approximately 40 mL of 1M NH4OAc to the above flask.
3. Swirl and let stand for 1 hr or more.
4. Transfer the soil and solution to a 5.5-cm Buchner funnel fitted with a number
40 or 42 (more fine) Whatman filter paper and connected to a 250-mL suction
flask.
5. Transfer the remaining traces of the soil to the funnel by adding 10 mL
portions of 1M NH4OAc to a final volume in the suction flask of 90 mL for soils
with a cation exchange capacity (CEC) of 20 cmolkg-1 or less, or 225 mL for
soils with higher CECs.
6. Pour the extract into a 100- or 250-mL volumetric flask, and make up to
volume by rinsing the suction flask with fresh 1M NH4OAc( If the extract is
muddy, it’s recommended to filtrate it with 0.45 μm-pore size membrane
filter.).
II. Centrifuge procedure (alternative method 2)
1. Place 5 g of < 2-mm air·dried soil in a 50·ml centrifuge tube.
2. Add 25 ml of 1M NH4OAc, stopper, alld shake for 30 min.
3. Place the tube in a centrifuge, and spin at 2,000 rpm for 10 min.
4. Pour the supernatant into a 50ml volumetric flask.
5. Repeat with an additional 25 ml, and filially bring up to a volume of 50 ml with
1M NH4OAc (For soils with CEC's in excess of 20 meq/l00g, use only 2 g of
soil.).
III. Preparation of sample for Atomic Absorption Spectrometry
Determine cations as with standard method (See Annex I)
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Supplementary instruction for soil analysis
on the Inter-laboratory Comparison Project on Soil 2015 (17th attempt)
Network Center for EANET
Network Center (NC) was requested to give the participating laboratories more detailed instructions
on oven-drying period and repeat analyses for the inter-laboratory comparison project on soil at the
Third Session of the Scientific Advisory Committee (SAC3) in November 2003.
The participating laboratories would be expected to take the following instructions into account
when they analyze the samples for the 2015 project (17th attempt).
1) Oven-drying period for the moisture contents
The oven-drying period for measurement of the moisture contents should be “overnight
(more than 12 hours)” at 105°C.
The oven-drying period for measurement of moisture contents was varied from 4 to 48 hours
among the laboratories in the 4th project 2002, and it was suggested that oven-drying period was
one of the effective factors for variation of measured moisture contents.
The oven-drying period was described in the Technical Manual to be “overnight”, and it seems
still unclear. NC was requested to show more detailed guideline for the oven-drying period, e.g.
more than 12 hours.
2) Repeat analyses
Repeat analyses should be carried out with several-day interval (three days or more) in
order to estimate actual within-laboratory reproducibility.
Interval between the repeat analyses was varied from zero (in the same day) to 31 days among
the laboratories in the 4th project 2002. It was suggested that repeat analyses would be carried
out with certain interval (e.g. several days) in order to estimate actual within-laboratory
reproducibility.
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