Malé Declaration
on Control and Prevention of Air Pollution
and its Likely Transboundary Effect for South Asia
Report of the Inter – Laboratory Comparison of
Precipitation Chemistry Analyses among the NIAs
of the Malé Declaration
First attempt Nov. 2007
August, 2008
This report has been prepared based on the inputs from the following institutes:
National Implementation Agency and National Focal Point
Bangladesh
Bhutan
India
Iran
NFP: Ministry of
Environment and Forest
NFP and NIA: National
Environnent Commission
NFP: Ministry of
Environment and Forests
NFP and NIA: Department
of the Environment, Tehran
NIA: Department of
Environment Dhaka
NIA: Central Pollution
Control Board, New Delhi
Maldives
Nepal
Pakistan
Sri Lanka
NFP: Ministry of
NFP: Ministry of
Environment Science and
Technology
NFP: Ministry of
Environment
NFP: Ministry of
Environment and Natural
Resources
NIA: International Centre
for Integrated Mountain
Development(ICIMOD)
Kathmandu
NIA: Pakistan
Environment Protection
Agency, Islamabad
NIA: Central
Environmental Authority,
Colombo
Environment, Energy
and Water
NIA: Department of
Meteorology
Secretariat
United Nations Environment Programme (UNEP)
Regional Resource Centre for Asia and the Pacific (RRC.AP)
Outreach Building, AIT, P.O. Box 4
Klongluang, Pathumthani 12120, Thailand
Fax: 66 2 516 2125
Technical Support
Environmental Engineering and Management
School of Environment, Resources and Development
Asian Institute of Technology
Klongluang, Pathumthani 12120, Thailand
Fax: 662 524 5625
Funding
Sida, the Swedish International Development Cooperation Agency, is funding this part of the Malé
Declaration Implementation as part of the Regional Air Pollution in Developing Countries
(RAPIDC) programme.
2
Tale Contents
1. INTRODUCTION....................................................................................................................................................... 4
2. INTER – COMPARISON PROCEDURE ............................................................................................................ 4
2.1 PARTICIPATING LABORATORIES ............................................................................................................................ 4
2.2 ARTIFICIAL RAINWATER SAMPLES......................................................................................................................... 5
2.3 ANALYTICAL PARAMETERS AND METHODS ............................................................................................................ 5
2.4 ANALYTICAL DATA CHECKING PROCEDURE .......................................................................................................... 6
2.5 DISTRIBUTING THE ARTIFICIAL SAMPLES TO NIAS LABORATORIES ....................................................................... 7
3. RESULTS .............................................................................................................................................................. 8
3.1. SAMPLE-WISE COMPARISON ................................................................................................................................... 13
3.2 PARAMETER-WISE EVALUATION ......................................................................................................................... 19
1) pH ....................................................................................................................................................................... 19
2) EC ....................................................................................................................................................................... 20
3) SO42- .................................................................................................................................................................... 21
4) NO3- .................................................................................................................................................................... 22
5) Cl- ........................................................................................................................................................................ 23
6) Na+...................................................................................................................................................................... 24
7) K+ ........................................................................................................................................................................ 25
8) Ca2+ ..................................................................................................................................................................... 26
9) Mg2+ .................................................................................................................................................................... 27
10) NH4+ .................................................................................................................................................................. 28
3.3. CIRCUMSTANCE OF SAMPLE ANALYSIS ................................................................................................................. 30
4. RECOMMENDATION FOR IMPROVEMENT OF MEASUREMENT ACCURACY AND PRECISIONS ...34
4.1 FUNDAMENTAL FACTORS TO IMPROVE DATA QUALITY ........................................................................................... 34
APPENDIX 1: PARTICIPATING LABORATORIES............................................................................................................ 38
APPENDIX 2: RESULTS BY PAKISTAN NIA LABORATORY ............................................................................................. 39
APPENDIX 3: CALCULATION OF R1 AND R2 FOR ARTIFICIAL RAIN WATER SAMPLE ...................................................... 40
APPENDIX 4: DATES OF EVENTS ................................................................................................................................... 42
3
1. INTRODUCTION
Malé Declaration on Control and Prevention of Air Pollution and Its Likely Trans-boundary Effects
for South Asia (Malé Declaration) is an intergovernmental agreement to tackle the issue of
transboundary air pollution through regional cooperation in South Asia since 1998. Participating
countries are Bangladesh, Bhutan, Iran, India, Maldives, Nepal, Pakistan and Sri Lanka with a
National Implementing Agency (NIA) established in each country.
The main objective of the Malé Declaration Programme is to promote the establishment of a
scientific base for prevention and control of air pollution in South Asia to encourage and facilitate
coordinated interventions of all the stakeholders on transboundary and shared air pollution problems
at national and regional levels. One monitoring site was established in each participating country
and the monitoring network is being implemented based on the common methodologies and
standards. The inter-laboratory comparison is a required quality assurance (QA) measure to ensure
the harmonization and quality of the data. This inter-laboratory exercises have been practiced by
other regional monitoring networks such as Acid Deposition Monitoring Network in East Asia
(EANET) for rain water samples or Air Pollution Regional Research Network (AIRPET) for
particle composition samples.
This is the first attempt of the inter-laboratory comparison project which involves a round-robin
analysis of uniformly prepared artificial rainwater samples by the NIA laboratories of the Malé
Declaration project. The overall objective of the inter-laboratory comparison is to recognize the
analytical precision and accuracy of the data in each participating NIA laboratory and consequently
to provide an opportunity to improve data reliability/quality. The protocol highlighting the
methodology of this inter-laboratory comparison has been developed based on Quality
Assurance/Quality Control (QA/QC) procedure for Malé Declaration network with reference to the
inter-laboratory comparison reports of the EANET project. The sample preparation, distribution and
analysis with necessary QA/QC are included in the protocol which was circulated and agreed upon
by all NIAs in September 2007, i.e. before the inter-laboratory exercise started.
Artificial rainwater samples contained major ions, were prepared and distributed to NIAs by the
reference laboratory at the Asian Institute of Technology (AIT) in November 2007. Seven of eight
participating laboratories submitted the analytical data to AIT in time. Obtained data for pH, EC and
concentrations of SO42-, NO3-, Cl-, NH4+, Na+, K+, Ca2+, Mg2+ from these 7 laboratories were
compared with the prepared values and statistically treated. List of the participating laboratories,
individual analytical data, and various statistical parameters are included in this report.
2. INTER – COMPARISON PROCEDURE
2.1
Participating laboratories
All eight laboratories of the eight countries of the Malé Declaration Programme (one laboratory per
NIA) have participated in this inter-laboratory comparison exercise. The name and the contact
addresses of the participating laboratories are included in Appendix 1. However, only seven out of
eight participating laboratories submitted their analytical data to AIT before the Malé the Sixth
4
Regional Refresher and Training Course in March 2008 when the prepared concentrations were
revealed and the NIA results of this first attempt were briefed to the participants. One NIA (Lab.
No.7) submitted the results after this event hence the results were not included in this report but the
results are included in Appendix 2 for the reference purpose only.
2.2
Artificial rainwater samples
Two concentration levels were prepared at the AIT laboratory: the higher concentration sample (No.
M11) and the lower concentration sample (No. M12). The ranges of the ten (10) parameters
specified in QA/QC of the Malé Declaration including pH, electrical conductivity (EC) and
concentrations of ionic species (SO42-, NO3-, Cl-, NH4+, Na+, K+, Ca2+, Mg2+) are presented in Table
1. The broad ranges of each parameter in the prepared samples (Table 1) were informed to NIAs at
the time the sample distribution. Summary information on the proposed artificial samples is
presented in Table 2. These ranges as well as the actual concentration levels for each sample were
selected based on the frequency distribution of each parameter prepared from the available data on
the rainwater samples of Malé Declaration Programme that NIA participating laboratories had
submitted to the UNEP RRC.AP office.
Table 1 Concentration Ranges in the Artificial Rain Water Samples
2.3
Parameter
Range
Parameter
Range
pH
4-6.5
Na+
1 – 150 µmol/L
EC
0.2-10 mS/m
K+
1 – 50 µmol/L
SO42-
1 – 100 µmol/L
Ca2+
1 – 50 µmol/L
NO3-
1 – 100 µmol/L
Mg2+
1 – 50 µmol/L
Cl-
5 – 150 µmol/L
NH4+
1 – 100 µmol/L
Analytical parameters and methods
Participating laboratories were expected to use the analytical methods specified in the “Technical
Document for Wet and Dry Deposition Monitoring for Malé Declaration” and closely followed the
“Quality Assurance/Quality Control (QA/QC) Programme for Wet and Dry Deposition Monitoring
for Malé Declaration” protocol which is summarized in Table 2.
If NIA uses other methods (than the methods specified by the Malé Protocol) for the routine
analysis of rainwater samples and if the practice has already been approved by the UNEP
RRC.AP then the NIA should use these methods for the artificial rainwater samples.
Thus, the NIA analyzed the artificial rainwater samples following the routine methods they use to
get the data that they report to the Malé network. In addition, the NIA were also encouraged to
run and report results by other methods if relevant. It was recommended that NIA do at least 3 runs
5
for each parameter and reported the average concentration value and one standard deviation
(Average  STD).
To ensure the accuracy and precision of the data and for proper assessment of the operation
conditions, the persons, who were responsible for analyzing wet deposition samples at the NIA,
were also required to analyze these artificial rainwater samples of inter-laboratory comparison.
An excel data template was provided to the NIA for the data reporting.
Table 2 Analytical methods specified in the Technical Documents for Wet and Dry
Deposition monitoring for Malé Declaration
Parameter
Analytical/Instrument method
pH
Glass electrode
Electrical Conductivity Conductivity Cell
Chloride
Argentrometric method
Nitrate
Cadmium reduction method-Spectrophotometry
Sulphate
Spectrophotometry
Sodium
Flame photometry
Potassium
Flame photometry
Calcium
Titrimetry (EDTA method)
Magnesium
Titrimetry
Ammonium
Spectrophotometry (Indophenol)*
*- no biocide of Thymol is expected in the prepared samples hence the method can be used
Sources: QA/QC program for wet and dry deposition monitoring for Malé Declaration
2.4
Analytical data checking procedure
The analytical results by NIAs were checked and assessed by AIT using the procedures specified in
the “Technical Document for Wet and Dry Deposition Monitoring for Malé Declaration” and
closely follow the “Quality Assurance/Quality Control (QA/QC) Programme for Wet and Dry
Deposition Monitoring for Malé Declaration” protocol. Thus, the criteria for ion balance (R1) and
for agreement between calculated and measured electronic conductivity (R2) were used.
The allowable ranges of R1 and R2, according to the Malé QA/QC protocol, are given in Table 3
and 4, respectively. Detailed methods of the calculation of R1 and R2 for the high and low artificial
rainwater samples are presented in Appendix 3. It is noted that, however, only 4 NIA laboratories
submitted the results of all 10 required analytical parameters thus it was possible to calculate the 2
criteria only for these 4 sets of the results.
Table 3
Allowable ranges for R1 in different concentration ranges
6
Ceq + Aeq (µeq/L)
R1 (%)
<50
±30
50-100
±15
>100
±8
Sources: QA/QC program for wet and dry deposition monitoring for Malé Declaration
Table 4
Allowable ranges for R2 for different ranges of EC
Λ measured (mS/m)
R2 (%)
< 0.5
± 20
0.5 – 3
± 13
>3
±9
Sources: QA/QC program for wet and dry deposition monitoring for Malé Declaration
2.5
Distributing the artificial samples to NIAs laboratories
The artificial rainwater samples were stored in the 1L polypropylene bottle. Each bottle contains
800 mL of sample. Two bottles containing the samples (M11 and M12) were placed in an ice box
with dry ice and sent to the member laboratories through express post (DHL). The first batch was
departed from AIT on Nov. 13, 2007 to all 8 laboratories. However, only 6 laboratories informed
AIT and UNEP RRC.AP that they had received the samples (Lab no.1, Lab no.2, Lab no.3, Lab
no.5, Lab no.6 and Lab no.8,). The Lab no.6 reported that it did not get enough samples for all
analyses. The sample package sent to Lab no.4 seemed to be lost. Lab no.7 did not report receiving
of the package. Therefore, the second batch of samples was sent again to the Lab no.6 and Lab no.4
early in March 2008 and the analytical results from these NIAs were received before the Malé
regional training workshop at AIT in March 2008 while the samples to Lab no.7 were handled to
the NIA participants at the workshop directly. During the workshop in March 2008, AIT staff
discussed with NIA representatives in order to clear inquiries as well as to fill up the missing
information. NIA promised to send the clarifications. However, some missing information is present
in the final data set presented in this report.
During the first 2 months after departing the samples, AIT laboratory analyzed the samples (one
was refrigerated and 1 was kept in the laboratory) every 1-2 weeks in order to track any changes
due to sample storage and handling with the purpose to check if the concentrations were altered
during the shipment period to different laboratories. The results of the analysis during the 2 months
show non-significant variations for all parameters. Examples are shown in Appendix 4.
7
It is noted that all the NIAs were requested to analyze the samples within a week after arrival
(Protocol for inter-laboratory comparison of precipitation chemistry analyses within the Malé
declaration, 2007) and majority followed this requirement. Dates of the events including the sample
sending and receiving are included in Appendix 4. Based on the follow-up analysis at AIT,
alteration of the parameter concentrations in the samples during the storage and shipment period of
2-3 weeks should not be the main cause of the large bias.
Table 5
Sample name
No.M11 (high concentration)
No.M12 (low concentration)
Outline of artificial rainwater samples
Amount of
sample
~ 800
mL/bottle
Container
Poly-propylene
bottle, 1000 mL
Number
of samples
1 bottle
for each
level
Note
Known amount of
reagents dissolved
in deionized water
3. RESULTS
AIT shipped the artificial rainwater samples to all 8 NIA laboratories of the Malé Declaration
Programme. However, only seven laboratories reported the results to AIT before the real
concentrations were informed to NIAs (at the Regional Refresher training workshop at AIT, March
2008). The Lab no.7 results were reported after the workshop, hence were not included in the data
evaluation. Thus, only the results of the 7 NIA laboratories were analyzed and are discussed in this
report. The received data are summarized in Table 6 and 7. Note that only 4 NIA laboratories
analyzed for all 10 parameters specified in the Malé monitoring protocol. Lab no.5 only measured
pH and EC, Lab no.2 analyzed 6 parameters while Lab no.1 did not analyze the polyatomic anions.
Lab no.2 reported zero values of NO3- and Lab no.4 reported zero values of Mg2+ for both samples
but did not specified the respective detection limits. These values as well as other below detection
limit values are considered as flagged data in this report. All seven NIAs reported pH and EC data
whereas many data points were missing for other parameters.
According to the Malé Inter-laboratory Comparison Protocol the NIAs would analyze each sample
3 times for all parameters and report results in the provided data template. However, not all NIAs
followed this requirement. For those NIAs that reported results of all 3 analyses for each parameter
in a sample the standard deviation of the data was calculated and presented in Table 6 and 7. For
those who did not report the repeated analysis results, only single values are presented (Lab no.2
and some parameters by Lab no.3).
8
Table 6 Summary of the analytical results of the high concentration artificial rainwater sample (M11) by NIAs as compared
to the prepared levels
NIA laboratories
Prepared
levels
Parameter
pH
5.08±0.02
Lab
no.2
7.07
EC (mS/m)
4.51±0.02
4.1
3.7±0.0
3.22±0.01
3.53±0.15
3.45±0.03
3.5±0
3.5
SO42-(mol/L)
na
na
44±3.86
67.03±1.37
na
69.73±2.95
55±1
39.0
NO3 (mol/L)
na
*
8.1±0.0
8.23±0.06
na
26.19±2.73
17.29±0.006
37.5
Cl- (mol/L)
118.44±1.84
na
172
300±0
na
Na+ (mol/L)
33.42±0.3
2.22
77±17.4
95±0
na
K+ (mol/L)
36.38±0.18
23.67
33±0.59
33.3±0
na
49.14±7.4
36±1
29.7
Ca (mol/L)
36.33±0.81
na
40
200±0
na
44.42±9.67
33±1
34.0
Mg2+(mol/L)
35.49±0.6
1.54
64
*
na
27.84±9.5
22.2±0.55
20.3
69.57±0.49
na
29.3±0.23
27.73±3.42
na
66.67±11.55 25.5±0.1
Lab no.1
-
2+
+
NH4 (mol/L)
Lab no.3
Lab no.4
Lab no.5
Lab no.6
Lab no.8
4.46±0.03
6.32±0.25
4.11±0.06
5.01±0.08
5.27±0.01
4.8
139.81±46.6
8.2±0.001
2
115.93±10.0
94.84±0.01
4
90.9
95.6
26.7
Note:
* Reported zero values without providing the detection limit. These are considered as flagged data
na: data not available(not analyzed)
9
Table 7
Summary of the analytical results of the low concentration artificial rainwater sample (M12) by NIAs as compared
to the prepared concentrations
NIA laboratories
Prepared
levels
Parameter
Lab no.1
Lab no.2
Lab no.3
Lab no.4
Lab no.5
5.5±0.05
7.07
5.43±0.02
6.00±0.12
5.73± 0.05 5.58±0.17
6.5±0.0
EC (mS/m)
1.3±0.016
0.4
0.4±0.0
0.55±0.01
0.35±0.01
0.34±0.01
0.4±0.0
SO42-(mol/L)
na
na
<40**
17.37±0.8
na
13.60±2.94
2.9±0.1
NO3- (mol/L)
na
*
<0.8**
0.2±0.1
na
6.95±1.82
1.58±0.00
6
Cl- (mol/L)
24±1.03
na
110
100±0
na
54.26±13.5
5.6±0.1
Na+ (mol/L)
4.59±0.08
1.99
<30**
4±0
na
26.08±7.53
7.4±0.1
K+ (mol/L)
5.74±0.18
1.94
<18**
0.8±0
na
13.87±1.85
2.63±0.01
Ca2+(mol/L)
7±0.6
na
<40**
41.67±2.89
na
22.25±9.53
3.52±0.01
Mg2+(mol/L)
6.33±0.5
0.10
<40**
*
na
16.60±0.24
2±0.1
NH4+(mol/L)
12.92±0.18
na
6.9
19.1±1.28
na
26.67±5.77
2±0.1
pH
Lab no.6
Lab no.8
5.8
0.4
3.1
2.0
9.3
5.2
2.0
2.1
1.6
3.0
Note:
* Reported zero values without providing the detection limit. These are considered as flagged data
** Below detection limit, the indicated values are the detection limits. These data are flagged.
na: data not available(not analyzed)
10
The statistics were calculated for the obtained data of each parameter such as Average, Minimum
(Min.), Maximum (Max.), Standard deviation (S.D.), and Number of data (N) and are presented in
Table 8. It is noted that there is a tendency to overestimate the levels in the low concentration
sample while for the high concentration sample the results vary with parameters. The relative
deviations between the average NIA results for each parameter against the prepared value [∆V/Vp]
are also shown in Table 8. The averages of the submitted data differ from the prepared
concentrations, for the low concentration sample (No.M12), within a range of 3% (pH) to almost
800% (Ca2+), and for the high concentration sample (No.M11) the relative deviation was from -60%
(NO3-) to 108% (Ca2+). Note that no outlier treatment was applied for this small data set and all the
received data were included in the analysis.
Table 8 Statistics of the NIA analytical results for the artificial rainwater samples
Parameter
Prepa
red
(Vp)
pH
EC (mS/m)
Average
S.D
N
Min
Max
(Va)
Sample No.M11 (high concentration)
5.3
1.0
7
4.1
7.1
3.7
0.4
7
3.2
4.5
4.8
3.5
12.0
6.0
SO42-(mol/L)
58.9
11.8
4
44.0
69.7
39.0
51.0
NO3- (mol/L)
15.0
8.6
4
8.1
26.2
37.5
-60.1
147.7
105.1
5
8.2
300.0
90.9
62.4
69.7
43.2
6
2.2
115.9
95.6
-27.0
35.2
8.2
6
23.7
49.1
29.7
18.7
Ca (mol/L)
70.7
72.4
5
33.0
200.0
34.0
108.1
Mg2+(mol/L)
30.2
22.7
5
1.5
64.0
20.3
48.9
22.3
5
25.5
69.6
Sample No.M12 (low concentration)
0.6
7
5.4
7.1
0.3
7
0.3
1.3
26.7
63.9
5.8
0.4
3.0
44.4
-
Cl (mol/L)
+
Na (mol/L)
+
K (mol/L)
2+
+
∆V/Vp
(%)
NH4 (mol/L)
43.8
pH
EC (mS/m)
6.0
0.5
SO42-(mol/L)
11.3
7.5
3
2.9
17.4
3.1
260.4
NO3 (mol/L)
2.9
3.6
4
0.2
7.0
2.0
44.9
Cl- (mol/L)
58.8
45.8
5
5.6
110.0
9.3
532.0
Na (mol/L)
8.8
9.8
5
2.0
26.1
5.2
71.1
K+ (mol/L)
5.0
5.3
5
0.8
13.9
2.0
148.8
18.6
17.4
4
3.5
41.7
2.1
797.0
6.3
7.4
5
0.1
16.6
1.6
286.4
5
2.0
26.7
3.0
346.5
-
+
2+
Ca (mol/L)
2+
Mg (mol/L)
9.8
NH4+(mol/L) 13.5
Note: ∆V = Average (Va) – Prepared (Vp)
11
The results of below detection limit by Lab no.3 (marked 781) and the zero values reported by Lab
no.2 and Lab no.4 (marked 781*) were not included in the statistics calculation.
The data obtained from NIAs were evaluated against the Data Quality Objectives (DQOs) of the
QA/QC for Malé Declaration Monitoring program, namely for every parameter the measured value
should be within ±15% of deviation from the prepared value. The bias (a measure of accuracy) of
the data was calculated for analytical results of each parameter of the artificial rainwater samples as
below:
Bias (%) =100 x (Analytical value – Prepared value)/(Prepared value)
Flag "E" was put to the data that exceed DQOs by a factor of 2, i.e between ±15% and ±30%.
Flag "X" was put to the data that exceed DQOs more than a factor of 2, i.e. beyond ±30%.
The results were evaluated from three aspects:
i) Sample-wise comparison to gain the concentration dependence assessment: separate
analysis for sample No.M11 (higher concentrations) and No.M12 (lower concentrations) and
compare the results
ii) Parameter-wise comparison to assess the data quality for individual parameters, and
iii) Comparison of circumstances of analysis in each participating laboratory.
Evaluation for each sample is presented in “3.1 Sample-wise comparison”, evaluation for each
parameter is presented in “3.2 Parameter-wise comparison” and evaluation of the data against the
circumstances in the analytical laboratories such as analytical methods used, number and
experiences of the personnel, and other analytical conditions are presented in “3.3 Circumstances of
sample analysis”.
12
3.1. Sample-wise comparison
Sample No. M11 (higher concentrations)
Table 9 presents the evaluation of NIA results for sample No.M11 (higher concentrations), which
shows 14 non-reported data points accounting for 20% of total commitment data (10
parameters/NIA x 7 NIA = 70 data points). The non-reported data points were assigned as 999.
There were 7 analytical data points out of reported 56 exceeded the DQOs by a factor of ≤2 and
were flagged by "E". There were 26 analytical data points out of 56 exceeded the DQOs by more
than a factor of 2 and were flagged by “X”. The total flagged data account for 62.5% of reported
analytical data for this sample, in which flagged “E” and “X” accounted for 13% and 46%,
respectively (Figure 1).
Table 9
Numbers of flagged data for the Sample No.M11 (higher concentrations)
pH
EC
SO42- NO3- Cl-
Na+
K+
Ca2+ Mg2+ NH4+ Total
Total available data points
7
7
4
5
5
6
6
5
6
5
56
999 (non-reported data), points
0
0
3
2
2
1
1
2
1
2
14
999 (non-reported data), %
0
0
42.8
28.6
28.6 14.3 14.3 28.6 14.3
28.6
20
Flag data (against the number reported data points)
781 (below detection limit) 0
0
0
1*
0
0
0
0
1*
0
2
Flag E 0
1
0
0
0
2
3
1
0
0
7
Flag X 2
1
3
4
5
2
1
2
4
2
26
Total flag data, points
2
2
3
5
5
4
4
3
5
2
35
Flagged data (%)
28.6 28.6 75
100
100
66.7 66.7 60
83.3
40
62.5
Data within the DQOs (against the number of reported data points)
Data within DQOs, points
5
5
1
0
0
2
2
2
1
3
21
Data within DQOs, %
71.4 71.4 25
0
0
33.3 33.3 40
16.7 60
Note:
Total available data: 56 (including below detection limit data, excluding the non-reported data)
781*- zero values reported, data are considered as below detection limit and flagged
37.5
13
Table 10
pH
EC
(mS/m)
Analytical results of sample No.M11 (higher concentrations)
SO42(mol/L)
NO3(mol/L)
Cl(mol/L)
Na+
(mol/L)
K+
(mol/L)
33.42
X
36.38 E 36.33
35.49 X 69.57
2.22
X
23.67 E
1.54
X
999
E
X
29.3
C
C
Lab no.1
5.08
4.51
X
999
999
118.44
Lab no.2
7.07 X
4.1
E
999
781*
999
Lab no.3
4.46
3.7
44
8.1
X
172
X
77
Lab no.4
6.32 X
3.22
67.03
8.23
X
300
X
Lab no.5
4.11
3.53
999
Lab no.6
5.01
3.45
69.73
X
26.19
X
139.81
X
115.93
Lab no.8
5.27
3.5
55
X
17.29
X
8.2
X
94.84
X
999
X
999
Ca2+
(mol/L)
999
Mg2+
(mol/L)
NH4+
(mol/L)
33
40
E
64
95
33.3
200
X
781*
27.73
999
999
999
999
999
E
49.14 X 44.42 X 27.84 X 66.67
36
E
33
22.2
R1 R2
X
-
-
-
-
X
25.5
E: value exceeds the DQO (±15%) by a factor of ≤2
X: value exceed the DQO (±15%) more than a factor of 2
999: missing measurement, reason not specified
781*: reported zero values without specifying the detection limit (they are considered as below detection limit)
I: poor ion balance agreement
C: poor conductivity agreement
(-) not enough data to calculate R1 and R2
14
C
The minimum number of flagged data points of 2 was recorded for pH and EC while for some ions
(NO3- and Cl-) all data points were flagged (Table 10). The evaluation against the criteria for ion
balance (R1) and electrical conductivity (R2) was possible only for the data from Lab no.6, Lab
no.8, Lab no.3 and Lab no.4 (the reported zero values for Mg2+ were used) because other NIAs did
not report the full composition data sets for all 10 parameters. Thus, all NIAs have the good ion
balance indicators while most NIAs have the “poor conductivity agreement”. Only Lab no.8 has
both R1 and R2 within the recommended ranges. However, due to overall low data quality, meeting
the R1 criteria would not guarantee for the good analytical data for ions due to the possible
compensation effects of the errors.
Flag E
13%
Data within
DQOs
38%
781*- below
detection limit
4%
Fig.1
Flag X
45%
Percentage of data meeting DQOs and flagged data for Sample No.M11 (higher
concentrations)
Sample M12 (lower concentrations)
Table 11 presents the evaluation of NIA results for sample No.M12 (lower concentrations), which
shows 14 non-reported data points accounting for 20% of total 70 committed data points. These
non-reported data points were assigned as 999. There were 4 analytical data points out of 56
exceeded the DQOs by a factor of ≤2 and were flagged by "E". There were 30 analytical data points
out of 56 exceeded the DQOs by more than a factor of 2 and were flagged by “X”. The total flagged
15
data account for 76.4% of analytical data points for this sample, in which E and X flag accounted
for 7.1% and 53.6%, respectively (Figure 2).
As presented in Tables 11 and 12, measured pH and EC values had less flagged data points (14%
and 29%, respectively). All the analytical results for ions have the flagged results of above 75%.
The evaluation against the criteria for ion balance (R1) and electrical conductivity (R2) was possible
only for the data from Lab no.6, Lab no.8 and Lab no.4 (zero value of Mg2+ was used). Lab no.3
reported many below detection limit (BDL) values while other NIAs did not report the complete
composition data sets. All the 3 NIAs have a poor conductivity agreement (flagged C). Similarly to
the discussion for sample M11 presented above, meeting the R1 criteria would not guarantee for the
good analytical data for ions.
Table 11
Numbers of flagged data for the Sample No.M12 (lower concentrations)
pH
EC
SO42- NO3- Cl-
Na+
K+
Ca2+ Mg2+ NH4+ Total
Total available data points
7
7
4
5
5
6
6
5
6
5
56
999 (non-reported data), points
0
0
3
2
2
1
1
2
1
2
14
999 (non-reported data), %
0
0
42.9
28.6
28.6 14.3 14.3 28.6 14.3
28.6
20
Flag data (against the number reported data points)
781 (below detection limit) 0
0
1
1
0
1
1
1
1
0
6
781* (Zero values reported) 0
0
0
1*
0
0
0
0
1*
0
2
Flag E 1
0
0
1
0
1
0
0
1
0
4
Flag X 0
2
2
2
5
3
4
4
3
5
30
Total flag data, points
1
2
3
5
5
5
5
5
6
5
42
Flagged data (%)
14.3 28.6 75
100
100
83.3 83.3 100
100
100
75
Data within the DQOs (against the number of reported data points)
Data within DQOs, points
6
5
1
Data within DQOs, %
85.7 71.4 25
0
0
1
1
0
0
0
14
0
0
16.7 0
0
0
0
25
Note:
Total available data:56 (including below detection limit data, excluding the non-reported data)
781: this flag is applied for values below detection limit
781*: this flag was applied for reported value of zero without specifying the detection limit (they
are considered as below detection limit)
16
Table 12
Analytical results of sample No.M12 (lower concentrations)
EC
(mS/m)
pH
Lab no.1
5.5
Lab no.2
7.07
Lab no.3
SO42(mol/L)
NO3(mol/L)
Cl(mol/L)
1.3
X 999
999
24
0.4
999
781*
999
5.43
0.4
<40
781 <0.8 781
110
Lab no.4
6
0.55
0.2
100
Lab no.5
5.73
0.35
999
Lab no.6
5.58
0.34
13.6
Lab no.8
6.55
0.4
2.9
E
X 17.37
X
X
999
X
X
Na+
(mol/L)
K+
(mol/L)
4.59
5.74
X
Ca2+
(mol/L)
7
X
Mg2+
(mol/L)
NH4+
(mol/L)
6.33
X
12.92 X
0.1
X
999
781
6.9
X
X
1.99
X
1.94
X
<30
781
<18
781
<40
781
<40
X
4
E
0.8
X
41.67
X
781*
19.1
999
999
999
999
999
999
999
6.95
X
54.26 X 26.08
X
13.87
X
22.25
X
16.60
X
1.58
E
5.60
X
2.63
X
3.52
X
2
E
X
7.4
-
-
-
-
-
C
-
26.67 X
2
R1 R 2
X
E: value exceeds the DQO (±15%) by a factor of ≤2
X: value exceed the DQO (±15%) more than a factor of 2
999: missing measurement, reason not specified
781: this flag is applied for values below detection limit
781*: reported zero values without specifying the detection limit (they are considered as below detection limit)
I: poor ion balance agreement
C: poor conductivity agreement
(-) not enough data to calculate R1 and R2
17
C
C
Data within
DQOs
25%
781- below
detection limit
14%
Fig.2
Flag E
7%
Flag X
54%
Percentage of data meeting DQOs and flagged data for Sample No.M12 (lower
concentrations)
Summary remarks
There were a large number of non-reported data. Only pH and EC were analyzed by all 7
considered NIA laboratories. The complete sets data of required 10 parameters, specified in the
Malé declaration monitoring protocol, were submitted only by 4 NIAs (Lab no.6, Lab no.3, Lab
no.4 and Lab no.8). Two NIAs, each reported zero values of a parameter, but did not provide the
detection limits (NO3- by Lab no.2 and Mg2+ by Lab no.4) hence these values were considered as
below detection limit and were flagged. Due to the incomplete data sets, the evaluation against the
criteria R1 and R2 was possible for the data of some NIAs. All datasets satisfied the R1 criteria and
only one data set satisfied both R1 and R2 criteria (Lab no.8, M11). However, due to overall low
data quality, meeting the R1 criteria would not guarantee for the good analytical data for ions due to
the possible compensation effects of the errors.
None of the NIAs submitted R1 and R2 calculation results though these are required in the protocol.
Checking these criteria would help the NIAs to quickly assess the overall data quality if these
criteria are not satisfied.
Overall, the percentages of flagged data points are high for both samples. The total data points
satisfying the DQOs for sample No.M11 (higher concentrations) account for 38% which is higher
than that for sample No.M12 (lower concentrations), which is 25%. Total number of flagged data as
well as the number of data points flagged “X” for sample No.M12 was significantly higher than for
sample No.M11. It indicates the difficulty of the analysis of the lower concentration sample. The
reported detection limits of the equipment appear to be too high for some NIAs indicating poor
sensitivity of the methods used which need improvement.
18
3.2
Parameter-wise evaluation
The results are analyzed and discussed for each analytical parameter separately as presented below.
1) pH
All of the participating laboratories reported pH results. All NIAs used pH meters for the
measurement (Table 13). There is no consistency in reporting the equipment names thus it is
assumed that the glass electrode was used as recommended by the Malé monitoring protocol. The
pH measurement was carried out at the temperature close to the recommended one (~25oC) except
for Lab no.2 NIA which measured pH at 9.8oC. Among all the parameters, pH has the smallest
flagged data points. The relative deviation of the average submitted pH data as compared to the
prepared was 12% for sample M11 and 3% for sample M12 (Table 8). Most of the data satisfied the
DQOs of the Malé declaration QA/QC program except for Lab no.2 data which were both flagged
(“X” and “E”) which may partly be due to the lower measurement temperature as compared to the
recommended as mentioned above. Lab no.4 has a flagged “X” (bias, 32%) for the high
concentration sample (Fig.3).
Bias, %
pH
high conc
60
45
30
15
0
-15
-30
-45
-60
Lab no.6
Fig.3
Table 13
low conc
Lab no.5
Lab no.2
Lab no.3
Lab no.8
Lab no.4
Lab no.1
Distribution of pH data normalized by prepared value
Analytical methods and flagged data of pH
Analytical methods
pH meters (glass electrode)
7/7
Non-reported data
0/7
Flagged data
E
X
999
Flagged %
Sample No.M11
0
2
0
28.6
Sample No.M12
1
0
0
14.3
19
2) EC
All participating laboratories used a conductivity meter to measure EC. There is inconsistency in
reporting the equipment names. It is assumed that the conductivity cell was used as recommended
by the Malé monitoring protocol (Table 14). Overall, the EC values mostly agreed with the prepared
values with the relative deviation between the average reported data and the prepared value of 6%
for sample M11 and 44% for sample M12. The later was mainly caused by the strong
overestimation by the Lab no.1 (bias of 251%). Note that the results submitted by Lab no.1 were
flagged “X” for both samples. The Lab no.4 data for sample No.M12 was flagged “X” (Fig.4) and
Lab no.2 data for sample M11 was flagged “E”. The Lab no.2 measured EC at a temperature of
9.8oC and Lab no.6 measured EC at 16-18oC while other NIAs measured EC at recommended
temperature of 25oC.
Fig.4
Table 14
Distribution of EC data normalized by prepared value (off-scale values are indicated)
Analytical methods and flagged data of EC
Analytical methods
Conductivity Cell
7/7
Non-reported data
0/7
Flagged data
E
X
999
Flagged %
Sample No.M11
1
1
0
28.6
Sample No.M12
0
2
0
28.6
20
3) SO42Four countries submitted SO42- analytical data (Lab no.6, Lab no.3, Lab no.8 and Lab no.4). Lab
no.8 laboratory employed Ion chromatograph whereas others used a Spectrophotometer for the
determination of SO42- (Table 15).
The results of 2 NIAs were flagged “X” for both high (M11) and low (M12) concentration samples
(Figure 5). Lab no.3 result for high concentration sample M11 was within the DQOs but the method
could not detect SO42- in sample M12 and a concentration below detection limit (BDL) was reported
with the detection limit of 40µmol/L. For the low concentration sample, only Lab no.8 result was
within the DQOs. Also, the result for sample M11 by this NIA was flagged “X” but with a smaller
bias than other NIA (41%).
Fig.5
Table 15
Distribution of SO42- data normalized by prepared value (off-scale values are indicated)
Analytical methods and flagged data of SO42-
Analytical methods
Spectrophotometry
3/7
Ion Chromatography
1/7
Non-reported data
3/7
Flagged data
E
X
999
781
Flagged %
Sample No.M11
0
3
3
0
75
Sample No.M12
0
2
3
1
75
21
4) NO3Five countries submitted NO3- analytical data (Lab no.6, Lab no.2, Lab no.3, Lab no.8 and Lab
no.4). Lab no.8 laboratory employed an Ion chromatograph (IC) whereas others used
Spectrophotometers for the determination of NO3- (Table 16). Lab no.2 reported zeros values for
both samples without providing the method used as well as the detection limit information hence the
data points were flagged and were not used in the min, max, etc. calculation.
All of non-zero data submitted by 4 NIAs were flagged by “E” or “X” for both high and low
concentration samples (Fig.6). Lab no.3 reported concentration below detection limit (0.8µmol/L)
for sample No. M12. The data produced by Lab no.8 using IC appear to be less biased though they
were also flagged.
Fig.6
Distribution of NO3- data normalized by prepared value (off-scale values are indicated)
Table 16 Analytical methods and flagged data of NO3Analytical methods
Spectrophotometry
3/7
Ion Chromatography
1/7
No specified method
1/7
Non-reported data or method
2/7
Flagged data
E
X
999
781*
781
Flagged %
Sample No.M11
0
4
2
1
0
100
Sample No.M12
1
2
2
1
1
100
22
5) ClFive NIAs submitted Cl- analytical data (Lab no.6, Lab no.3, Lab no.8, Lab no.1 and Lab no.4). Lab
no.8 NIA laboratory employed an Ion chromatograph while others applied the Argentrometric
method for the determination of Cl- (Table 17). The results by all NIAs for both sample M11 and
M12 are flagged “X” (Fig.7). The bias for Cl- was the most significant among all analyzed
parameters (more than for NO3-).
Fig.7
Table 17
Distribution of Cl- data normalized by prepared value (off-scale values are indicated)
Analytical methods and flagged data of Cl-
Analytical methods
Argentrometric - Titrimetry
4/7
Ion Chromatography
1/7
Non reported data
2/7
Flagged data
E
X
999
Flagged %
Sample No.M11
0
5
2
100
Sample No.M12
0
5
2
100
23
6) Na+
Six laboratories submitted the analytical results for Na+. Three of them (Lab no.6, Lab no.8 and Lab
no.1) used Atomic Absorption Spectrophotometry method, while Lab no.4 and Lab no.3 used Flame
emission spectrometry, Lab no.2 did not report the method used (Table 18). As seen in Figure 8, 4
data points are flagged for each sample M11 and M12. For sample M12, only the data point of Lab
no.1 is within DQOs while for M11 both Lab no.8 and Lab no.4 data are within the DQOs. The Lab
no.3 value was BDL (30µmol/L) for M12.
Fig.8
Table 18
Distribution of Na+ data normalized by prepared value (off-scale values are indicated)
Analytical methods and flagged data of Na+
Analytical methods
Atomic absorption spectrophotometry
3/7
Flame emission spectrometry
2/7
No method specified
1/7
Non-reported data
1/7
Flagged data
E
X
999
781
Flagged %
Sample No.M11
2
2
1
0
66.7
Sample No.M12
1
3
1
1
83.3
24
7) K+
Six laboratories submitted K+ analytical results. Lab no.6, Lab no.8 and Lab no.1 used Atomic
Absorption Spectrophotometry method, while Lab no.4 and Lab no.3 used Flame emission
spectrometry, Lab no.2 did not report the method used (Table 19). Results for sample M11 by Lab
no.3 and Lab no.4 are within the DQOs, the others are flagged “E” or “X”. For sample M12, only
Lab no.2 data is within DQOs while others are flagged “X”. Note though the data point of Lab no.8
was flagged “X” it has a bias of 30.8%. The result reported by Lab no.3 was below detection limit
(18µmol/L).
Fig.9
Table 19
Distribution of K+ data normalized by prepared value (off-scale values are indicated)
Analytical methods and flagged data of K+
Analytical methods
Atomic absorption spectrophotometry
3/7
Flame emission spectrometry
2/7
Not specified method
1/7
Non reported data
1/7
Flagged data
E
X
999
781
Flagged %
Sample No.M11
3
1
1
0
66.7
Sample No.M12
0
4
1
1
83.3
25
8) Ca2+
Five countries submitted data (Lab no.6, Lab no.3, Lab no.8, Lab no.4 and Lab no.1). Lab no.8
employed Atomic Absorption Spectrophotometry while other used the recommended Titrimetry
method to determine Ca2+ (Table 20). For sample M11, 2 data points were within the DQOs, the rest
3 were flagged “E” or “X”. For sample M12, Lab no.3 reported result below detection limit
(40µmol/L) while others had data flagged “X” with a very high bias (Fig. 10).
Distribution of Ca2+ data normalized by prepared value (off-scale values are indicated)
Fig.10
Table 20
Analytical methods and flagged data of Ca2+
Analytical methods
Titrimetry
3/7
Atomic absorption Spectrophotometry
1/7
Non-reported data
2/7
Flagged data
E
X
999
781
Flagged %
Sample No.M11
1
2
2
0
60
Sample No.M12
0
4
2
1
100
26
9) Mg2+
Six (6) NIAs submitted the analytical data for Mg2+. Four laboratories used the titrimetry method,
one laboratory used Atomic Absorption Spectrophotometry. Lab no.2 did not report the method
used. Lab no.4 reported zero values for both high and low concentration samples (by the titrimetry)
but the detection limits are not provided and the data are flagged. Most of the data points for sample
M11 flagged “X” except the data by Lab no.8. All data points for sample M12 are flagged including
the below detection limit (40µmol/L) result by Lab no.3.
Zero values
Fig.11
Table 21
Distribution of Mg2+ data normalized by prepared value (off-scale values are indicated)
Analytical methods and flagged data of Mg2+
Analytical methods
Titrimetry
4/7
Atomic absorption Spectrophotometry
1/7
Not specified method
1/7
Not reported data
1/7
Flagged data
E
X
999
781
781*
Flagged %
Sample No.M11
0
4
1
0
1
83.3
Sample No.M12
1
3
1
1
1
100
27
10) NH4+
Five NIAs submitted the analytical results. Lab no.3, Lab no.8, Lab no.4 and Lab no.1 laboratories
used the recommended Spectrophotometry (Idophenol) method while Lab no.6 applied Titrimetry
(Table 22). Three (3) data points of sample M11 were within the DQOs while other 2 were flagged
“X”. All results for sample M12 were flagged “X” with the one by Lab no.8 has the smallest bias
(Fig.12).
Fig.12
Distribution of NH4+ data normalized by prepared value (off-scale values are indicated)
Table 22 Analytical methods and flagged data of NH4+
Analytical methods
Spectrophotometry (Idophenol)
4/7
Titrimetry
1/7
Not reported data
2/7
Flagged data
Samples
E
X
999
Flagged %
Sample No.M11
0
2
2
40
Sample No.M12
0
5
2
100
28
Summary remarks
Among the analytical parameters, pH and EC results appeared to be more accurate with lower bias
by most of NIAs. Results by some NIAs were higher while others were lower than the prepared
values. The submitted analytical results for all specified anions and cations are in general highly
biased. Among the ions, two parameters Cl- and NO3- have 100% data points fagged for both
samples. In addition, for the low concentration sample (M12) all results for Ca2+, Mg2+ and NH4+
were flagged. Other ions also have large portions of the results flagged, above 40% for M11 and
above 83% reported data for M12. It is noted that the methods that involve intensive sample
treatment would result in more bias. For the simple measurements such as pH and EC the results are
better.
Among the parameters, the bias for Cl- was generally the highest. For all ions the bias of over 500%
was observed quite often. The relative deviation between the average submitted data and the
prepared value of each parameter (%) is presented in Figure 13 which shows high positive bias for
low concentration sample M12. For the high concentration sample the bias can both positive and
negative and in general the values are much lower than for M12. This again indicates the difficulty
in analyzing low levels of constituents in the sample. This is expected to be improved in the future
by accumulation of experience and strict implementation of the Malé Declaration QA/QC program
in each laboratory.
High conc.
∆V/Vp, %
Low conc.
800
750
700
650
600
550
500
450
400
350
300
250
200
150
100
50
0
-50
-100
pH
EC
SO42-
NO3-
Cl-
Na+
K+
Ca2+
Low conc.
High conc.
Mg2+
NH4+
Fig.13 Relative deviation between average submitted data and prepared value [∆V = Average
(Va) – Prepared (Vp)]
29
3.3. Circumstance of Sample Analysis
1) Measurement methods used
Not all NIAs used the recommended methods by the Malé Declaration Monitoring Protocol. A
summary of the methods used for each parameter is presented in Table 23. It is noted that some
NIAs did not report the specific name of the methods following the Malé protocol. Thus, the name
of the same method may be reported differently and also not precisely. For example, some NIAs
simply reported the conductivity meter or pH meter.
30
Table 23
Recommended methods and methods used by NIAs
Param
eter
Recommended
method
pH
Glass electrode
Lab no.1
Glass electrode
Lab
no.2
NR
Lab no.3
Lab no.4
Glass
electrode
Conductivity
Cell
Spectrophoto
metry
Cadmium
reduction
Spectrophoto
metry
Argentrometri
c
Flame
photometry
Flame
photometry
Titrimetry
(EDTA)
Glass
electrode
Conductivity
Cell
Spectrophoto
metry
Conductivity
Cell
Spectrophotome
try
Cadmium
reduction
Spectrophotome
try
Argentrometric
method
Flame
photometry
Flame
photometry
Titrimetry
(EDTA method)
Conductivity
Cell
NR
NA
NA
NA
NR
Argentrometric
NA
AAS
NR
AAS
NR
Titrimetric
(EDTA)
NA
Mg2+
Titrimetry
Titrimetry
NR
Titrimetry
NH4+
SpectrophotoSpectrophotome
meter
try (Indophenol)
(Indophenol)
NA
Spectrophoto
metry
(Indophenol)
EC
SO42NO3ClNa+
K+
Ca2+
Spectrophoto
metry
Lab no.5
pH meter
Conductiv
ity Cell
NA
Lab no.6
Lab no.8
Glass
electrode
Conductivit
y Cell
Spectrophot
ometry
Glass
electrode
Conductivit
y Cell
IC
NA
Spectrophot
ometry
IC
NA
Argentrome
tric
IC
NA
AAS
AAS
NA
AAS
AAS
Titrimetry
NA
Titrimetry
AAS
Titrimetry
NA
Titrimetry
AAS
Titrimetry
Spectrophot
o-meter
(Indophenol
)
Argentrometri
c
Flame
photometry
Flame
photometry
Spectrophoto
-meter
(Indophenol)
NA
Remark:
NR: not reported the method used
NA: no data (not analyzed)
IC: Ion Chromatograph
AAS: Atomic Absorption Spectrophotometry
31
2) Number of staff in charge of measurement and year of experience
The numbers of staff in charge of measurement and year of experience on rainwater samples are
shown in Table 24. Given the overall low accuracy of the data, there is no strong association
between the data quality and the number of years of experience or number of staff involved in the
sample analysis.
Table 24
Staff in charge of measurement and year of experience
Country
Number
of staff
Year of
experience
Lab no.6
1
4
Lab no.5
3
1; 1; 0.6
NA
Lab no.2*
NR
NR
NA
Lab no.3**
6
2; 19;17;17;20;3.5
Lab no.8
2
15;13
Lab no.4*
2
6;8
Lab no.1
2
2; 1.6
NR
NA
Dotted mesh: flagged data of “E” or “X” in sample No.M11 and/or sample No.M12.
Darked mesh: flagged (E or X) data of both sample No.M11 and No.M12
Not reported (no information provided)
No data (not analyzed)
reported zero values of NO3- (Lab no.2) and Mg2+ (Lab no.4) for both samples not providing
detection limits
reported data below detection limits for M12 samples (SO42-, NO3-, Na+, K+, Ca2+, Mg2+ )
*
**
pH
EC SO42- NO3- Cl-
NA
NA
NA
NA
Na+
K+
Ca2+
NA
NA
NA
Mg2+ NH4+
NA
NA
NA
NA
NA
32
3) Water temperature at measurement (pH and EC)
Most of the NIA laboratories measured pH and EC at rainwater temperature around 250C. However,
Lab no.2 measured these two parameters at temperature 9.80C and Lab no.6 measured EC at 1618oC. This may be a reason for the flagged data submitted by Lab no.2 for both parameters.
Water temperature at measurement for pH and EC (oC)
Table 14
Countries
pH
EC
No. M11
No. M12
No. M11
No. M12
Lab no.1
25
25
25
25
Lab no.2
9.8
9.8
9.8
9.8
Lab no.3
25
25
25
25
Lab no.4
25
25
25
25
Lab no.5
25
25
25
25
Lab no.6
23-25
23-25
16-18
16-18
Lab no.8
25
25
25
25
Blue (dark) background: Flagged data of “E” or “X”
33
4. Recommendation for improvement of measurement accuracy and precisions
The analytical results submitted by NIAs show strong bias from the prepared values for most of the
parameters, especially for the low concentrations in sample M12. Various factors may lead to the
low accuracy of the data. It is observed that not all NIAs follow the Malé QA/QC Monitoring
Protocol strictly in term of the equipment and methods. If NIAs have more advanced equipment
(IC) in place help it would be easier to do the repeated analyses hence to check the precision of the
data themselves. In general, the methods require intensive sample treatment provide lower accuracy.
The parameters that can be measured directly such as pH and EC produced much better accuracy
than the ions. The intensive treatment of samples may introduce errors from various dosing and
glassware as well as the purity of the chemicals used for the sample treatment. In this case, the
NIAs have to observe the standard operating procedures (SOP) of the analytical methods and the
QA/QC elements required by the Malé monitoring protocol.
The following fundamental recommendations matters should be taken into account in measurement,
analysis, and data control processes.
4.1 Fundamental factors to improve data quality
- Properly clean the apparatus/glassware
- Use the materials and reagents of required purity with as low as possible blank values of target
analytical substances.
- Measurement and analysis should be conducted by persons who are well trained and are
committed to produce high quality data. In house-expertise within each NIA laboratory should
be developed for this purpose. If NIAs have the samples analyzed by other institutions, the data
control and data quality check should be in place and should be done by in-house experts of the
NIAs.
- SOPs must be prepared for the management of apparatus, reagents, and procedure of operation.
The SOPs have to be followed strictly.
- A log book should be kept for the sampling and analysis in each NIA laboratory
- Details on measurement and analysis of samples are as follows.
1) Deionized water
Use only water with conductivity less than 0.15mS/m for dilution of samples and cleaning the
glassware for measurements and analyses. It was reported by one NIA that the water used was not
pure enough (high EC) while other NIAs did not mention about the EC of the waster used. This is a
simple check that may help much to improve data quality.
2) Use certified materials and certified samples (SRM) to standardize the used methods
- NIA laboratories should use the standard reference materials to evaluate their measurement
methods. These are samples with known concentrations to NIAs and they can compare the
measurement results with the certified values. Thus, repeated analyses can be made and the
NIA measurement procedures can be calibrated samples until the results are within the ranges
of the certified values.
34
-
The certified/standard reference materials (certified solutions and certified materials) should be
used periodically in each NIA laboratory as a QC element for their routine analysis. The Malé
Declaration Programmes can consider to purchase the SRM and distributed to NIAs at least
once per year.
3) Pretreatment of samples, storage and analysis time
- Conductivity and pH should be measured as soon as possible after sample receiving at the
temperature recommended by Malé QA/QC monitoring protocol of 25oC. Temperature of the
measurements should be recorded. In this inter-laboratory exercise 2 NIAs did not follow this
requirement.
- Other parameters should be analyzed within a week of sample receiving. The samples should
be capped and stored properly in refrigerators all the time before analysis. Care should be taken
to avoid the cross-contamination during sample transport and storage.
- It is noted in this exercise that the parameters that were analyzed by methods requiring
intensive sample treatment had the analytical results with strong biases. SOPs need to be
followed closely in this case. Hands-on trainings for the staff can be offered within each NIA
by more experiences staff or by Malé Declaration Programme.
- Repeated analyses should be made to ensure the data quality (precision). In this inter-laboratory
exercise, 3 analyses are required for each parameter. However, not all NIAs submitted the
results.
- A log book should be kept to record the timing (arrival in the laboratory, analysis etc.) and the
conditions of the samples, personnel involved, conditions of the equipment etc.
4) Calibration of analytical instruments
- Each analytical instrument must be calibrated when it is used. The appropriate adjustments
should be made. For sophisticated equipments, the calibration curves must be checked regularly
by a standard solution.
- Standard solutions and reference solutions must be prepared from different stock solutions to
ensure the independence (to eliminate the same systematic error in these solutions)
- New calibration and standard curves should be prepared if a new reagent bottle is used.
- Calibration should be done regularly, after 20-30 measurements, event though the same reagent
bottles are still used.
- The calibration curves have to be checked before each analysis by injecting a standard solution
(with known concentration)
5) Data quality checking and control by NIA laboratory
- When samples seem to be obviously contaminated, these data should be marked and treated as
unrecorded data. A log book record may be very useful for this track.
- In house experts should check for abnormal data points in the data series. A simple time series
plot may help to detect the abnormality. Appropriate reasons should be specified to explain the
situation.
- Incorrect data can corrupt the overall research results. Careful checks are needed to avoid
producing data of inadequate quality. When abnormal or unrecorded data appear, the process
should be carefully reviewed to prevent the occurrence of the same problem in the future.
35
-
-
The standard deviation of the repeated analyses should be as small as possible to ensure the
data precision. Highly precise data ensure that there are no random errors. The random errors
can be caused by human mistakes, ambient conditions (including contamination) as well as the
unstable instrument sensitivity. The random errors cause the results of repeated analyses or remeasurements to be significantly different. If the standard deviation of the repeated analyses is
small and the analytical methods are made following the SOP then the data quality is ensured.
Calculating the criteria for ion balance (R1) and for agreement between calculated and
measured electronic conductivity (R2) following the Male Protocol. Once these criteria are not
met then the measurement data quality should be reexamined. It is note that, however, meeting
these criteria is the necessary condition but not the enough condition.
Overall comment: “It’s better to have no data than to have wrong data. Wrong data will give
wrong information hence may be quite expensive if the actions are taken in the wrong
direction”.
36
5. REFERENCES
1. UNEP RRCAP, 2004: Technical Documents for Wet and Dry Deposition monitoring for Malé
Declaration. March 2004. Adopted from:
http://www.rrcap.unep.org/ew/air/male/manual/wetDry/03-chapter3.pdf.
2. Quality Assurance/Quality Control (QA/QC) Programme for Wet and Dry Deposition
Monitoring for Malé Declaration. March 2004. Adopted from:
http://www.rrcap.unep.org/ew/air/male/manual/wetDry/12-QAQC.pdf
3. Kim Oanh N. T. (2007). Protocol for inter – laboratory comparison of precipitation chemistry
analyses within the Malé declaration
4. Reports of the EANET Inter – laboratory comparison Project 2003 (Round robin analysis
survey, 6th Attempt) 2004.
5. Reports of the EANET Inter – laboratory comparison Project 2003 (Round robin analysis
survey, 7th Attempt) 2005.
6. Reports of the EANET Inter – laboratory comparison Project 2003 (Round robin analysis
survey, 8th Attempt) 2006.
7. Asian regional research network for improving air quality in developing countries (AIRPET),
http://www.serd.ait.ac.th/airpet
37
APPENDIX 1: Participating laboratories
Countries/Laboratories
1. Bangladesh
Khulna Divisional Laboratory, Department of Environment, Govt. of the People's Republic of
Bangladesh
2. Bhutan
National Environment Commission (NEC), Royal Government of Bhutan
3. Iran
Environmental Research Center, Air Pollution Research Office, Station directorate environment
4. India
Central Pollution Control Board, Ministry of Environment & Forests, Government of India
5. Maldives
Maldives Climate Observatory, Department of Meteorology
6. Nepal
Central Soil & Plant Analysis Laboratory, Institute of agriculture and Animal Science, Chitwan
7. Pakistan
Pakistan Environmental Protection Agency
8. Sri Lanka
Central Environmental Authority
38
Appendix 2: Results by Lab no.7
Organization Name
Department/Section
Number of staff in charge of measurement
Year of experience
08 years
(if more than 2 person, a row be added)
Name of contact person
Date of receiving samples
Samples conditions at received
Date of measurement of different parameters
(specify for each parameter)
Postal address
Contact address
Not
Parameter
pH
Temp*
EC
Temp*
SO42-
NO3ClNH4+
Na+
K+
Ca2+
Mg2+
Measurement/a
nalytical
method
Glass Electrode
Manufacturer/
Type of
equipment
WTW
Germany
made
Conductivity
cell
WTW
Germany
made
Anova_Spectroquant
(MERCK)
Anova_Spectroquant
(MERCK)
UV-1601
Schimadzu
Absorption
Method
Absorption
Method
Absorption
Method
Pakistan Environmental Protection Agency
Code
Islamabad
Central Laboratory for Environmental Analysis (CLEAN
LABORATORY)
01
Staff No. 1:
Sajjid Mehmood
Staff No. 2:
Sajjid Mehmood (Mr.)
31-03-2008
Sample leaked with some sample wasted.
07-04-2008
H #. 311, Margallah Road, F-11/3, Islamabad.
Tel: +92-51-9235142
Fax:
+92-51-9267622
Email: seachline2001@yahoo.com
Detection
limits
(umol/L)
Determinati
on limit
(umol/L)
4-5.5
at 25. oC
Concentration
(umol/L)
Sample 1
Sample 2
5.4
5.04
1-10ms/m
25. oC
20.20
3ms/m
25.6 oC
20.20
5.12ms/m
25.6 oC
- 0.003A to
0.002A
5 – 100
4.06
20.6
-
5 - 100
7.74
69.58
-
5 - 150
16.64
17.21
Note
**
**
**
Absorption
Method
Absorption
Method
Anova_Spectroquant
(MERCK
Anova_Spectroquant
(MERCK
-
1 - 50
179
188
1 - 50
7.81
56.2
(submitted on 14 Apr 2008 after the Male refresher training course on 27 March 2008)
*- Temperature reading of the pH and EC meters (recommended value ~250C)
**- Laboratory is under commissioning and most of instruments like AAS, IC are not proper
functioning.
39
Appendix 3: Calculation of R1 and R2 for artificial rain water sample
a. Calculation of R1 and R2 for low concentration artificial rain water sample
(1) Calculation of ion balance (R1)

Total anion (Aeq) of equivalent concentration (µeq/L) is calculated by summing the
concentration of all anions (C: µmol/L).
Aeq (µeq/L) = Σ n·CAi (µmol/L) = 2C(SO42-) + C(NO3-) + C(Cl-)
Where, n is electric charge and CAi = concentration (µmol/L) of anion ‘i’.

Total cation (Ceq) equivalent concentration (µeq/L) is calculated by summing the
concentration of all cations (C: µmol/L).
Ceq (µeq/L) = Σ n·CCi (µmol/L) = 10(6-pH) + C(NH4+) + C(Na+) + C(K+) + 2C(Ca2+)
+2C(Mg2+)
Where, n is electric charge and CAi = concentration (µmol/L) of cation ‘i’.

Calculation of ion balance (R1)
R1 (%) = 100 x (Ceq - Aeq)/(Ceq + Aeq)
(2) Calculation of R2 (calculated vs. measured EC)

Total electric conductivity (Λ calc) is calculated as follows:
Λ calc (mS/m) = {349.7 x 10 (6-pH) + 80.0 x 2C(SO42-) + 71.5 x C(NO3-) + 76.3 x C(Cl-) +
73.5 x C(NH4+) + 50.1 x C(Na+) + 73.5 x C(K+) + 59.8 x 2C(Ca2+) + 53.3 x 2C(Mg2+)}/
10,000
Where, C denotes the molar concentrations (µmol/L) of ions given in the parenthesis at
25°C. The constant value is ionic equivalent conductance at 25°C for each ion.

The agreement (ratio of R2) between calculated (Λ calc) and measured (Λ meas) electric
conductivity should be calculated as follows:
R2 = 100 x (Λ calc – Λ meas)/(Λ calc + Λ meas)
b. Calculation of R1 and R2 for the high concentration sample
(1) Calculation of ion balance (R1)

Total anion (Aeq) of equivalent concentration (µeq/L) is calculated by summing the
concentration of all anions (C: µmol/L).
Aeq (µeq/L) = Σ n·CAi (µmol/L) = 2C(SO42-) + C(NO3-) + C(Cl-) + 100*
40
Where, n is electric charge and CAi = concentration (µmol/L) of anion ‘i’.

Total cation (Ceq) equivalent concentration (µeq/L) is calculated by summing the
concentration of all cations (C: µmol/L).
Ceq (µeq/L) = Σ n·CCi (µmol/L) = 10(6-pH) + C(NH4+) + C(Na+) + C(K+) + 2C(Ca2+)
+2C(Mg2+)
Where, n is electric charge and CAi = concentration (µmol/L) of cation ‘i’.

Calculation of ion balance (R1)
R1 (%) = 100 x (Ceq - Aeq)/(Ceq + Aeq)
(2) Calculation of R2 (calculated vs. measured EC)

Total electric conductivity (Λ calc) is calculated as follows:
Λ calc (mS/m) = {349.7 x 10 (6-pH) + 80.0 x 2C(SO42-) + 71.5 x C(NO3-) + 76.3 x C(Cl-) +
73.5 x C(NH4+) + 50.1 x C(Na+) + 73.5 x C(K+) + 59.8 x 2C(Ca2+) + 53.3 x 2C(Mg2+)} /
10,000 + 0.4*
Where, C denotes the molar concentrations (µmol/L) of ions given in the parenthesis at
25°C. The constant value is ionic equivalent conductance at 25°C for each ion.

The agreement (ratio of R2) between calculated (Λ calc) and measured (Λ meas) electric
conductivity should be calculated as follows:
R2 = 100 x (Λ calc – Λ meas)/(Λ calc + Λ meas)
*Note: The added term of “100” to the right side of the equation for R 1 calculation and
“0.4” for R2 calculation is the contribution of another ion (than analytical parameters) used
in the preparation of the high concentration artificial rain water sample.
41
Appendix 4: Dates of Events
Sending samples:
Date of sending samples (#1) to all NIAs: 13-Nov-07
Date of sending samples to Lab no.6 (#2): 2-Mar-08
Date of sending samples to Lab no.4 (#2): 12-Mar-08
Note: samples were sent to Lab no.6 and Lab no.4 for the second time.
Dates of receiving samples and sample analysis
Date of
receiving
sample
Country
Lab no.1
Lab no.2
Lab no.3
Lab no.4
Lab no.5
pH
EC
SO4
NO3
Cl
Na
K
Ca
Mg
NH4
Date of
receiving
data
15-Nov07
21-Nov07
19-Nov07
19-Nov07
na
na
19-Nov07
21-Nov-07
21-Nov-07
20-Nov07
20-Nov-07
27-Nov-07
7-Feb-08
nr
nr
na
nr
na
nr
nr
na
nr
na
7-Dec-07
15-Nov07
13-Mar08
15-Nov07
16-Nov07
16-Nov07
16-Nov07
12-Mar08
19-Nov-07
16-Nov-07
20-Nov-07
13-Dec-07
9-Mar-08
17-Nov07
10-Mar08
19-Nov-07
9-Mar-08
16-Nov07
15-Mar08
13-Mar-08
13-Mar-08
16-Mar-08
11-Mar-08
25-Mar-08
26-Nov07
11-Mar08
14-Nov07
26-Nov07
11-Mar08
14-Nov07
na
na
na
na
na
na
na
8-Jan-08
12-Mar08
16-Nov07
12-Mar08
16-Nov07
11-Mar08
16-Nov07
13-Mar-08
13-Mar-08
11-Mar-08
12-Mar-08
20-Mar-08
17-Nov-07
nr
17-Nov-07
14-Nov-07
12-Dec-07
Date of measurement
Lab no.6
9-Mar-08
Lab no.8
15-Nov07
Lab no.7
Data received on 14 Apr 2008 ,
16-Nov07
16-Mar08
na
11-Mar08
17-Nov07
i.e. after the prepared concentrations were distributed at the training at AIT on 27 March
NA: sample not analyzed
NR: measurement done but date not reported
Dark background: date of measurement reported before sending date
42
Chloride, low concentration
Deviation from prepared value %
29 Oct 07 (0)
21 Nov 07 (23)
room temp
26 Nov 07 (28)
3 Dec 07 (35)
4oC
21 Dec 07 (53)
45
30
15
0
-15
-30
-45
Example of concentrations of Cl- measured at AIT as the follow-up for QA/QC until 53rd day after
sample preparation
43