Ring tests as main parts of the quality assurance and control programme for the comparability of analytical data within the ICP Forests monitoring programme

Many laboratories from almost 30 different European countries are producing hundreds of thousands of analytical results each year within the ICP Forests monitoring programme. They are analyzing water, soil and foliage samples from Level I and Level Il plots all over Europe To guarantee the comparability of the analytical results between different laboratories in several countries and over time, a quality assurance (QA) programme is necessary with participation of all laboratories.