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Quality Assurance program and interlaboratory comparisons within the UN/ECE ICP Forests Expert Panel on Soil and Soil Solution

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First meeting of the Global Soil Laboratory Network (GLOSOLAN), 1 - 2 Nov 2017 at FAO HQ in Rome. This network will be composed of national soil reference laboratories as a means to exchange resources, knowledge and experience. The goal of GLOSOLAN is to strengthen the performance of laboratories in support of the harmonization of soil data sets and information towards the development of standards. Indeed, the harmonization of soil analysis is a critical component of making soil information comparable and interpretable across laboratories, countries and regions. Presentations by Nils Koenig, Northwest German Forest Research Institute.

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Quality Assurance program and interlaboratory comparisons within the UN/ECE ICP Forests Expert Panel on Soil and Soil Solution

  1. 1. Quality Assurance Program and Interlaboratory Comparisons within the UN/ECE ICP Forests Expert Panel on Soil and Soil Solution Nils König Northwest German Forest Research Institut
  2. 2. Quality Assurance Program and Interlaboratory Comparisons within the UN/ECE ICP Forests Expert Panel on Soil and Soil Solution Content: 0. Introduction 1. The ICP Forests quality assurance program for labs 2. Harmonised and documented analytical methods for soil analysis 3. Internal quality control programs for all participating laboratories 4. Interlaboratory comparisons as basis of an external QC program 5. Exchange of analytical knowledge within the expert groups of ICP Forests 6. Conclusions
  3. 3. Quality Assurance Program and Interlaboratory Comparisons within the UN/ECE ICP Forests Expert Panel on Soil and Soil Solution Introduction0. - UN 1983: initiation of the Convention on Long-range Transboundary Air Pollution (CLRTAP) - One part of this convention is the Working Group of Effects (WGE): ICP Waters ICP Materials ICP Forests ICP Vegetation ICP Integrated Monitoring ICP Modelling and Mapping Task Force on Health 8 International Cooperating Programmes ICP Forests monitors forest condition in Europe at two monitoring intensity levels: the Level I monitoring is based on around 6000 observation plots on a systematic transnational grid to gain insight into the geographic and temporal variations in forest condition the Level II intensive monitoring comprises around 500 plots in selected forest ecosystems with the aim to clarify cause-effect relationships
  4. 4. Quality Assurance Program and Interlaboratory Comparisons within the UN/ECE ICP Forests Expert Panel on Soil and Soil Solution Introduction0. To detect changes in forest ecosystems at the European scale samplings and measurements in the field and in the laboratories have to be done in some homogeneous way over decades and across countries. In many of the surveys of the ICP Forests program samples are taken and analysed in laboratories: - measurement of atmospheric deposition - measurement of soil solution - measurement of changes in soil and humus layers - measurement of tree nutrition Therefore the evaluation and improvement of the quality in laboratories are a key issue. This presentation will show the structure and development of the quality control program for soil laboratories within the ICP Forests program and the improvement of the quality in these labs.
  5. 5. Quality Assurance Program and Interlaboratory Comparisons within the UN/ECE ICP Forests Expert Panel on Soil and Soil Solution Introduction0. Kind of laboratories (2009-2011) Number of Labs Labs for water analysis (deposition, soil solution) 41 Labs for plant analysis (foliage, litterfall, vegetation) 36 Labs for soil analysis (soil, humus layer) 38 Labs for soil physics analysis 25 Total number of Labs 63 Many laboratories from almost 30 different European countries are producing hundreds of thousands analytical results each year! To guarantee the comparability of the produced results a quality assurance program within each laboratory and between all laboratories is necessary.
  6. 6. Quality Assurance Program and Interlaboratory Comparisons within the UN/ECE ICP Forests Expert Panel on Soil and Soil Solution The ICP Forests Quality Assurance Program for Laboratories1. The program is based on 4 pillars: - The use of harmonized, well-defined and documented analytical methods - An internal quality control program within each laboratory - An external QC program with interlaboratory comparisons coordinated by the monitoring program organizers - Permanent exchange of analytical knownledge via ICP Forests website, the Working Group QA/QC in Labs and the Meeting of the heads of the labs
  7. 7. Quality Assurance Program and Interlaboratory Comparisons within the UN/ECE ICP Forests Expert Panel on Soil and Soil Solution Harmonised and documented analytical methods2. - For long time series and the comparability of data it is important to use harmonised methods (reference methods). - If new methods are introduced they have to be tested and compared with the reference method. The results must be comparable. - The documentation of the used methods is very important. - Therefore the ICP Forests Manual was developed. It is updated continuously (http://icp-forests.net/page/icp- forests-manual).
  8. 8. Quality Assurance Program and Interlaboratory Comparisons within the UN/ECE ICP Forests Expert Panel on Soil and Soil Solution Harmonised and documented analytical methods2. 0,00 0,50 1,00 1,50 2,00 2,50 1968 1973 1979 1983 1987 1990 1991 1995 g/kg year changing of element concentration over time in a humus layer (Solling spruce) P K Ca Mg Dry ashing Example: Changing of a method without testing the comparability acid digestion (HNO3) under pressure
  9. 9. Quality Assurance Program and Interlaboratory Comparisons within the UN/ECE ICP Forests Expert Panel on Soil and Soil Solution Harmonised and documented analytical methods2. Parameters and reference methods for forest soil analysis within the ICP Forests program (mostly ISO standard methods) - pH (in water and CaCl2) - elemental analysis für Carbon (Ctot, Corg C-CO3) and Nitrogen (Ntot) - exchangable cations (Na, K, Ca, Mg, Al, Fe, Mn, H+), and exchange capacity (ECE) – BaCl2-extrakt - Aqua regia extractable elements (K, Ca, Mg, Al, Fe, Mn, P, S, Cd, Cu, Pb, Cd, [Co, Cr, Hg]) - Reactive Iron (Fe) and Aluminum (Al) – Oxalate extract - Total elements (Na, K, Mg, Ca, Al, Fe, Mn) – digestion with HF/HNO3 - Particle size distribution - Bulk density - Soil water retention characteristic (pF analysis)
  10. 10. Quality Assurance Program and Interlaboratory Comparisons within the UN/ECE ICP Forests Expert Panel on Soil and Soil Solution Harmonised and documented analytical methods2. 0 10 20 30 40 50 60 range of the coefficients of variation (%) K Al Ca Comparison between Aqua Regia digestion (yellow) and routine digestion of each laboratory (red) for the elements Ca, Al, K (ringtest with 10 Humus samples; 16 paticipating laboratories) Example: Nonuse of the reference method (aqua regia)
  11. 11. Quality Assurance Program and Interlaboratory Comparisons within the UN/ECE ICP Forests Expert Panel on Soil and Soil Solution Harmonised and documented analytical methods2. 0 5 10 15 20 25 1 2 3 4 5 6 g/kg Aluminium 2 h 1 x acid 2 h 1,5 x acid 2 h 2 x acid 3 h 1 x acid 3 h 1,5 x acid 3 h 2 x acid (7 Samples) Method: Aqua regia digestion Instruction: 2 hours boiling with 21 ml acid (HNO3 + HCl) Higher amount with longer boiling Example : Nonobservance of method instructions Influence of time and amount of acid
  12. 12. Quality Assurance Program and Interlaboratory Comparisons within the UN/ECE ICP Forests Expert Panel on Soil and Soil Solution Internal quality control program for the participating laboratories3. Basics are: - the use of the reference methods of the ICP Forests program - different quality checks in the laboratory (18) - repeated measurement of standard material and use of control charts On basis of the manual each participating laboratory has developed its own quality control system.
  13. 13. Quality Assurance Program and Interlaboratory Comparisons within the UN/ECE ICP Forests Expert Panel on Soil and Soil Solution Internal quality control program for the participating laboratories3. Example: Control chart for standard material Parameter: K Mean control chart: 2,56 CV (%): 1,6
  14. 14. Quality Assurance Program and Interlaboratory Comparisons within the UN/ECE ICP Forests Expert Panel on Soil and Soil Solution Internal quality control program for the participating laboratories3. for soils and humic layers: - plausible range checks for mineral soil and humic layer - cross checks between soil variables: - total / extractable element check (total > extractable) - pH check (pH(H2O) > pH(CaCl2) - Ratio checks (C/N, C/P, C/S) - Carbon check (Ctot > Corg; Ctot > C-CO3) for soil solution: - ion balance (equivalent sum cations = equivalent sum anions) - Nitrogen-balance (N-NH4 + N-NO3 >/= Ntot) - comparison of measured and calculated conductivity Examples of quality checks in the laboratory:
  15. 15. Quality Assurance Program and Interlaboratory Comparisons within the UN/ECE ICP Forests Expert Panel on Soil and Soil Solution Interlaboratory comparisons as basis of an external QC program4. If the laboratories are checking their quality continuously and are using the reference methods the results of their analytical measurements should be comparable to other labs. This can be tested by interlaboratory comparisons, so called „ring tests“: 15 a c d b samples Lab 1 Lab 2 Lab 3 a1 digestion, 3 replicates a1 b1 c1 measurement of the digestion solutions c1b1 d1 a1 a1 b1 b1 c1 c1 d1 d1 a2 a2 a2 b2 b2 b2 c2 c2 c2 d2 d2 d2 a3 a3 a3 b3 b3 b3 c3 c3 c3 d3 d3 d3 a1 a1 b1 b1 c1 c1 d1 d1 d1 a2 a2 a2 b2 b2 b2 c2 c2 c2 d2 d2 d2 a3 a3 a3 b3 b3 b3 c3 c3 c3 d3 d3 d3
  16. 16. Quality Assurance Program and Interlaboratory Comparisons within the UN/ECE ICP Forests Expert Panel on Soil and Soil Solution Interlaboratory comparisons as basis of an external QC program4. 0 5 10 15 20 25 30 35 40 45 50 F04 F21 F26 S01 F03 F28 F05 S18 F15 F25 F24 F16 S05 F14 F12 S04 F06 A42 A39 A49 F18 F07 S22 F19 S13 A60 A85 g/kg) Corg (Sample 2, Soil ring test 2015) Rep1 Rep2 Rep3 MW Soll Parameter: Corg Tolerable Limit: +/- 15 % 3 from 27 labs out of the tolerable limit = 11 %
  17. 17. Quality Assurance Program and Interlaboratory Comparisons within the UN/ECE ICP Forests Expert Panel on Soil and Soil Solution Interlaboratory comparisons as basis of an external QC program4. Labs ParametersRing test evaluation: - Overview for all participating labs about the percentage of tolerable results for each parameter Ring test requalification: - If a lab has less than 50 % tolerable results for a parameter it has to requalify for this parameter - Requalification means that the lab has to find the reason for unacceptable results and to reanalyse the ring test samples. The results have to be send to the ring test organizers.
  18. 18. Quality Assurance Program and Interlaboratory Comparisons within the UN/ECE ICP Forests Expert Panel on Soil and Soil Solution Interlaboratory comparisons as basis of an external QC program4. The most important step to force quality assurance and control was the introduction of mandatory ring tests for water (each 2 year) and soil (each 3 year) samples. In the meantime 7 soil and 8 water ring tests have been organized within the ICP Forests program. All ring tests has been evaluated again on the basis of the latest tolerable limits. From the results of these ring tests the development of quality in the labs can be seen. Development of the ring test results in the ICP Forests monitoring program during the last 20 years
  19. 19. Quality Assurance Program and Interlaboratory Comparisons within the UN/ECE ICP Forests Expert Panel on Soil and Soil Solution Interlaboratory comparisons as basis of an external QC program4. soil ring tests: nontolerable results (%) 0 10 20 30 40 50 60 70 RT 1993 RT 2002 RT 2005 RT 2007 RT 2009 RT 2012 RT 2015 nontolerableresults(%) Extr. Al Extr. Ca Extr. Cd Extr. Cu Extr. Fe Extr. K Extr. Mg Extr. Mn Extr. Na Extr. P Extr. Pb Extr. S Extr. Zn Ring tests parameters: aqua regia extractable elements
  20. 20. Quality Assurance Program and Interlaboratory Comparisons within the UN/ECE ICP Forests Expert Panel on Soil and Soil Solution Interlaboratory comparisons as basis of an external QC program4. 0 10 20 30 40 50 60 RT1993 RT2002 RT2005 RT2007 RT2009 RT2012 RT2015 nontolerableresults(%) soil ring tests: nontolerable results (%) OC Total N pH CaCl2 pH H2O Ring tests parameters: total Nitrogen (TN), Organic Carbon (OC) and pH
  21. 21. Quality Assurance Program and Interlaboratory Comparisons within the UN/ECE ICP Forests Expert Panel on Soil and Soil Solution Interlaboratory comparisons as basis of an external QC program4. soil ring tests: nontolerable results (%) 0 10 20 30 40 50 60 70 RT 1993 RT 2002 RT 2005 RT 2007 RT 2009 RT 2012 RT 2015 nontolerableresults(% Exch. Ac Exch. Al Exch. Ca Exch. Fe Exch. K Exch. Mg Exch. Mn Exch. Na Ring tests parameters: exchangable cations
  22. 22. Quality Assurance Program and Interlaboratory Comparisons within the UN/ECE ICP Forests Expert Panel on Soil and Soil Solution Interlaboratory comparisons as basis of an external QC program4. Standard comparison in different labs over time: Another possibility for quality control between labs is the repeated measurement of the same standard material during a survey in all participating laboratories. This has been done within the BioSoil Project, organized by the FSCC (Forest Soil Coordinating Center of ICP Forests)
  23. 23. Quality Assurance Program and Interlaboratory Comparisons within the UN/ECE ICP Forests Expert Panel on Soil and Soil Solution Interlaboratory comparisons as basis of an external QC program4. 64 42 54 56 8 59 13 26 11 60 23 40 58 71 34 7 30 63 36 5 6 7 8 10.4;10.5;10.9;12.9 Location LaboratoryNumber OC - Sample FSCCref1 Parameter organic Carbon (Corg): dot plot per laboratory tolerable limit: +/- 15 % mean
  24. 24. Quality Assurance Program and Interlaboratory Comparisons within the UN/ECE ICP Forests Expert Panel on Soil and Soil Solution Exchange of analytical knowledge within the expert groups of ICP Forests5. In addition to the ring test program a Working Group QA/QC in Labs has been installed within the ICP Forests program. The aims of this group are: - organization, evaluation and discussion of the interlaboratory ring tests - definition of tolerable limits for these ring tests - continuous revision of the ICP Forests Manual (analytical part) in cooperation with other expert panels
  25. 25. Quality Assurance Program and Interlaboratory Comparisons within the UN/ECE ICP Forests Expert Panel on Soil and Soil Solution Exchange of analytical knowledge within the expert groups of ICP Forests5. The aims of this group are (2): - decisions about the inclusion of new methods into the ICP Forests Manual - organisation of biennial meetings of the heads of the labs - continuous exchange of analytical information during the meetings of the heads of the labs, especially about new analytical methods, method comparisons, new instruments and analytical problems - helping program for laboratories with unacceptable ring test results
  26. 26. Quality Assurance Program and Interlaboratory Comparisons within the UN/ECE ICP Forests Expert Panel on Soil and Soil Solution Exchange of analytical knowledge within the expert groups of ICP Forests5. These good labs can help those labs with problems ! Helping program:
  27. 27. Quality Assurance Program and Interlaboratory Comparisons within the UN/ECE ICP Forests Expert Panel on Soil and Soil Solution Conclusions6. 1. For a long time monitoring program like ICP Forests well defined methods and a permanent quality assurance and control are needed to get comparable results. 2. For chemical analyses within the program reference methods have to be defined and documented in the ICP Forests Manual. 3. A mandatory quality control program for the participating laboratories is important and has to be based on a quality manual. 4. With a ring test program the quality of the participating laboratories and the comparability of the data have to be tested continuously.
  28. 28. Quality Assurance Program and Interlaboratory Comparisons within the UN/ECE ICP Forests Expert Panel on Soil and Soil Solution Conclusions (2)6. 5. A continuous exchange of analytical knowledge via a Working Group QA/QC in Labs and other Expert Meetings is important to keep the quality high and to integrate new methods into the manual. 6. The results of the ring tests of the last 20 years within ICP Forests show the improvement of the quality of the laboratories over time.
  29. 29. Quality Assurance Program and Interlaboratory Comparisons within the UN/ECE ICP Forests Expert Panel on Soil and Soil Solution Conclusions6. Thank you for your attention!

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