Manual on methods and criteria for harmonized sampling, assessment, monitoring and analysis of the effects of air pollution on forests. Part XVI. Quality Assurance and Control in Laboratories

updated: 06/2020

Eberswalde

2020

48 S.

Bandaufführung

978-3-86576-162-0

40002276

Chemical analyses are an essential part of monitoring activities related to observations and measurements of nutrients and pollutants fluxes in forest ecosystems. The value of data collected under the framework of the ICP Forests programme depends to a great extent on the quality of the analytical work carried out in supporting laboratories across Europe. To gain full comparability of the spatial and temporal variability in the data, every effort must be taken to ensure accuracy of the analytical measurements. To that end, considerable efforts have been made over the last number of years to improve the quality of laboratory analyses in the various monitoring programmes within the framework of the ICP Forests programme. The Soil & Soil Solution, Deposition and Foliage & Litterfall expert panels and the Working Group on QA/QC in Laboratories have carried out a number of ring tests and held extensive discussions on harmonising analytical methodology, including the most appropriate quality control (QC) and quality assurance (QA) to be employed by participating laboratories. All ringtest results are stored in the PCC database and can be linked to the monitoring data. Presented quality assurance and control tools remain in line with the overall QA approach within the ICP Forests, as outlined in the Part III of the Manual.
This paper presents all the QC methods that have been devised for the relevant fields of analytical chemistry. The aim is to provide those laboratories carrying out analyses of deposition, soil solution, soil, foliage and litterfall within the ICP Forests programme with a complete overview of the QC options that can be applied in their laboratories. The QA programme in each laboratory should be based on both: internal and external quality control. Among the range of internal control methods that can be employed, the use of reference materials is highly recommended (Chapter 3.1) as an extremely valuable tool to ensure accuracy of analytical results. Although the use of Certified Reference Materials can be limited by expense and availability in large quantities alternative Reference Materials, such as National or Local Reference Materials can be used on a routine basis to confirm the analytical methods accuracy and precision over time. The variation and the quality of the analytical results can be controlled with the use of control charts. The different types of control charts available, their construction and application are described in Chapter 3.2. The determination of the detection- and quantification limits is described in Chapter 3.3.
Analytical data must be validated prior to data submission to confirm the correctness of analyses and reduce the risk of errors. A wide range of data consistency checks are detailed depending on the type of matrix analysed (Chapter 3.4, 3.4.1-3.4.3), based on the relationship between the chemical components and/or chemical and physical properties of the samples.