Spatial distribution of major, trace and ultra trace elements in three Norway spruce (Picea abies) stands in boreal forests, Forsmark, Sweden

The spatial distribution of 49 major, trace and ultra trace elements within a Norway spruce system was examined in three sites within the Forsmark area in central Sweden. The system included stemwood, roots, fresh green shoots, litterbags, humus, mineral soil, rhizosphere soil and moss. Based on Principal Component Analysis and manual plots the elements were grouped according to their distribution within the different compartments. One large group of elements occurring abundantly in the soil, and in much lower concentrations in the biota and litter was distinguished, containing mainly elements typically associated with soil minerals. A similar pattern was found for a second group of elements, but with higher concentrations in the biological samples and/or litter. In contrast, there was also one group of elements with high concentrations in biological samples and/or litter and low content in soil. This was mainly nutrients, but also the highly toxic Cd, Hg and Sb. This study is part of the site investigation programme, carried out by the Swedish Nuclear Fuel and Waste Management Company (SKB), in order to locate a suitable area for a deep repository for nuclear fuel waste.

Research Highlights
► Most elements can be grouped, but site specific features can dominate concentrations.
► Plant uptake and cycling of caesium is promoted by low soil clay content.
► Tl deposited from atmosphere on spruce needles is lost after 2 years of litter decay.
► Decaying spruce needles are substantially enriched in Zn during decay.