47 laboratories in 23 countries participated in the 22nd Needle/Leaf Interlaboratory Test, but only 43 laboratories send their results in time.

The following test samples were submitted to the participants:

1. Spruce needles (France) - same sample like in the 18th Test (Sample 4)
2. Ash leaves (Austria)
3. Quercus robur (Austria)
4. Spruce needles (Germany)

Sample 1 was collected and prepared from INRA in France. Sample 2 and Sample 3 were collected from BFW in Austria. Sample 4 was collected from Saxon Public Enterprise-Sachsenforst in Germany. Special thank to all colleagues for collecting and preparing samples for this ringtest.

Figure 1: 22nd Interlaboratory Comparison Test - Percentage of correct results (mandatory and optional elements)

The following participating laboratories with a percentage of correct results below 80% have severe QC/QA-problems, miscalculation of the results and/or methodical problems: A85 (75.0%), A62 (62.5%), A88 (33.8%), A60 (18.5%) and A43 (8.3%).

Some of the ICP-Forests laboratories fail and have to do a re-qualification for certain parameters (A47: B; A60: S, P, Ca, Mg, K, Zn, Mn, Fe, Cu, Cd, B, As, Co, Ni; A62: Mg; F06: Cd; F07: B, As; F15: Cd, Pb). These (ICP-Forests) laboratories have to check and re-validate their method or employ a better method. FFCC offers old ringtest material if reference material is needed for this purpose.

The laboratories A60 (S, Ca, Zn) and F07 (As) failed with the same parameters in the last test(s). Therefore, their QC/QA-problem or their methodical problem is still not solved!

All interested laboratories are invited to take part in the re-qualification program up from now till 1st of September 2020.

Final report (4MB)