Atmospheric Deposition and Soil Solution Working Ring Test 2011. Laboratory ring test for deposition and soil solution sample analyses for the laboratories participating in the EU/Life+ FutMon Project

A third Working Ring Test (WRT) was organised within the framework of the EU/Life+ FutMon Project ("Further Development and Implementation of an EU-level Forest Monitoring System", LIFE07 ENV/D/000218), to evaluate the overall performance of the laboratories responsible for analysing atmospheric deposition and soil solution samples in European forests, and to verify improvements in the analytical quality resulting from the QA/QC work carried out in the laboratories which participated in previous WRTs organized in the framework of the UN/ECE International Cooperative Programme on Assessment and Monitoring of Air Pollution Effects on Forests (ICP-Forests) Monitoring Programme. Among the participants in the previous WRTs, 7 laboratories were also involved in the on ICP on Integrated Monitoring of Air Pollution Effects on Ecosystems (ICP-IM). Four new labs involved in the latter ICP were also invited at this third Working Ring Test. The WRT was carried out in accordance with International ISO and ILAG guide proficiency test both for sample preparation and numerical elaboration of the results. Four natural atmospheric deposition and soil solution samples and 2 synthetic solutions were distributed to 50 laboratories for analysis using their routine methods for the following variables: pH, conductivity, calcium, magnesium, sodium, potassium, ammonium, sulphate, nitrate, chloride, total alkalinity, total dissolved nitrogen (TDN), dissolved organic carbon (DOC). Two tolerable limits were defined for each variable on the basis of the measured value, the results of previous WRTs, a comparison with the Data Quality Objectives of other international networks, and the importance of the variable in deposition and soil solution monitoring.