Heavy metal distribution and chemical partitioning in Lake Saimaa (SE Finland) sediments and moss Pleurozium schreberi

This paper presents data on the concentration and chemical partitioning of four heavy metals, iron (Fe), copper (Cu), cadmium (Cd) and lead (Pb) in Great Lake Saimaa (Finland) sediments and moss (Pleurozium schreberi). Elemental analysis was performed by Flame Atomic Absorption Spectrometry and (FAAS) and anodic stripping voltammetry, using multi-element standard solutions. Results showed that the highest metal concentrations of Fe in sediments were recorded for Partakoski village, Mikkeli city and Ristiina with values of 86 mg/kg, 67.1 mg/kg and 63.8 mg/kg, respectively. The highest Cu concentration was observed in Anttola and Partakoski village sediments with values of 8.1 mg/kg and 7.3 mg/kg, respectively. On the contrary, the highest Cd concentration was found in Tetriniemi village and Puumala harbour sediments (0.6 mg/kg and 0.4 mg/kg, respectively) and the highest Pb concentrations were found in Puumala (2.2 mg/kg) and Ristiina (1.7 mg/kg) sediments. On average, the total metal contamination followed the order Partakoski > Mikkeli city-Ristiina > Anttola harbour > Imatra > Puumala harbour > Astuvansalmi > Tetriniemi. The highest amount of Fe was found in moss samples (85.4 mg/kg) from Ristiina and Cu was found to be the chiefly accumulated in moss (10.2 mg/kg) from Anttola. There was ineligible amount of Cd and Pb found in all the moss samples. Partitioning of Fe, Cu, Cd and Pb showed that more than 90% of metal was associated with residual fraction in sediments, with an exception of Cu that was significantly (20% of the total) associated with an organic/ sulfide fraction and Fe (22% of the total) was associated with exchangeable/carbonate fraction as well. On the other hand, chemical partitioning of metals in moss samples showed that Cu (up to 90%), Pb (up to 80%) and Fe (up to 60%) were strongly associated with extracellular fraction and Cd showed the highest affinity towards intracellular fraction (up to 70%). Statistical analyses carried out with principal component analysis and cluster analysis methods showed good correlation between Pb, Fe and Cu content and moss as well as sediments. Significant relationship (p>0.05) between different metals was observed for Cu-Cd (0.88), Fe-Pb (0.65), Fe-Cu (0.68), Cu-Pb (0.47) in sediments and moss samples. The metal content in exchangeable and extracellular fractions in sediments and moss samples showed that Cu, Pb and Fe were the most bioavailable elements.