Results of Monitoring at Olkiluoto in 2006 - Environment (pdf) - Posiva

35FIP4 at all depths were very similar in all three years (Table F-17), and also similar tothe concentrations at the reference site.The Fe concentrations were higher at deeper depths than at the reference site, and FIP4.showed considerable year-to-year variation (Table F-17). The Si concentrations atdepths of 5 and 10 cm in 2005 and 2006 were considerably higher than the correspondingvalues in 2004 (Table F-19), and higher than the corresponding concentrations atthe reference site. The values in FIP10 at depths of 20 and 30 cm were also stronglyelevated (Table F-20). The high silicon values are undoubtedly due to the young age ofthe soil: silicon plays an important role in soil-forming processes (podzolisation) underconiferous tree species.The Cu concentrations at all depths of FIP10 and at the reference site, were below thelimit of quantification of the analytical instrument (Table F-22). The same was true forFIP4 and the reference site, except the depth of 10 cm in 2005 in Olkiluoto (Table F-21). In FIP4 the Zn concentrations were relatively constant, and higher than the referencevalues throughout the monitoring period. In FIP10, the Zn concentrations werealso slightly higher than the reference (Table F-22).The concentrations of heavy metals at all depths in FIP4 continued to be below the limitof quantification. In FIP10 the nickel concentrations at 20 and 30 cm were slightly elevatedin 2005 (Table F-22), which is a relatively common finding in soils that have developedfrom marine sediments. The Ni is derived from the bedrock in the region andnot a sign of pollution from industrial sources.Biomass and Carbon DistributionBiomass of different tree compartments on FIP plots was derived using tree-basedmodels, as presented above in the case of whole island. The results have been reportedin a memo by Lasse Aro and Timo Kareinen (Finnish Forest Research Institute). Meancarbon content in Scots pine stands of the FIP4 plot was 7.978 kg C m -2 (Table G-1).Mean carbon content in tree stands of the FIP10 plot was 16.946 kg C m -2 (from whichspruce counted 13.540 and birch 3.406 kg C m -2 , Table G-2).LitterfallLitterfall collection was started on the plot FIP4 in summer 2004 and on the plot FIP10in spring 2005, thus the results for litterfall production are incomplete for 2004 on FIP4and for 2005 on FIP10. The results have been reported in a memo by Lasse Aro andTimo Kareinen (Finnish Forest Research Institute). Annual total litterfall productionwas 293 g m -2 in the Scots pine stand FIP4 in 2005. This corresponded well with theresults from ICP Level II plot in Tammela (average 329 g m -2 during 1996-2003; Ukonmaanaho2007). Detailed results are presented in Appendix H. The nutrient contentof litter has also been analysed, but the reporting was underway.