Representative sampling and sample preparation in biological environmental monitoring using spruce shoots

The design of sampling and sample processing has a tremendous effect on the analytical results from which conclusions are drawn with respect to the quality of the environment and any possible impact on human health. Large scale environmental surveys need rigorous planning and extensive screening experiments to evaluate their boundary conditions. Representativeness and sample homogeneity are highlighted here in the context of a long-term biological monitoring survey for trace elements using spruce shoots. Several aspects concerning the selection of samples, amount of material, material processing and sample preparation prior to chemical characterisation are illustrated by selected examples.