Olli Järvinen

Trophodynamics of mercury and other trace elements in a pelagic food chain from the Baltic Sea.

Mercury (Hg) and 13 other trace elements (Al, Ti, V, Cr, Fe, Mn, Co, Ni, Cu, Zn, As, Cd, and Pb) were measured in phytoplankton, zooplankton, mysis and herring in order to examine the trophodynamics in a well-studied pelagic food chain in the Baltic Sea. The fractionation of nitrogen isotopes (delta(15)N) was used to evaluate food web structure and to estimate the extent of trophic biomagnification of the various trace elements. Trophic magnification factors (TMFs) for each trace element were determined from the slope of the regression between trace element concentrations and delta(15)N. Calculated TMFs showed fundamental differences in the trophodynamics of the trace elements in the pelagic food chain studied. Concentrations of Al, Fe, Ni, Zn, Pb and Cd showed statistically significant decreases (TMF<1) with increasing trophic levels and thus these trace elements tropically dilute or biodilute in this Baltic food chain. Cu, As, Cr, Mn, V, Ti and Co showed no significant relationships with trophic levels. Hg was unique among the trace elements studied in demonstrating a statistically significant increase (TMF>1) in concentration with trophic level i.e. Hg biomagnifies in this Baltic food chain. The estimated TMF for Hg in this food chain was comparable to TMFs observed elsewhere for diverse food chains and locations.

Trace Metals in Finnish Headwater Lakes — Effects of Acidification and Airborne Load

The study on the effects of acidification and airborne load on the concentrations of some trace metals (Al, Mn, Cd, Cu, Pb, Zn, Ni, Hg) in sediments (16 lakes), water (259 lakes) and aquatic fauna (14 lakes) of pristine Finnish headwater lakes was conducted in 1985–1989. Atmospheric trace metal load and concentrations in the water and in the sediments were higher in southern Finland than in central and northern Finland. The share of anthropogenic load according to sediments varied from 62 to 95% for Cd, Hg and Pb, was from 39 to 91% for Zn and varied from 0 to 84% for Ni and Cu in southern and central Finland. Anthropogenic load could be explained by atmospheric deposition. Acid conditions favoured high concentrations of Al, Mn, Zn, Pb and Cd in water and high concentrations of Pb, Cd, Zn, Cu and Ni in aquatic plants. Lead concentrations were usually one order of magnitude higher in liver and bones of fish from acidic lakes than in circumneutral lakes. Cadmium in liver, Hg in muscle and Al in gills also showed increased concentrations in several fish species in acidic lakes.

Trace metal concentrations in the water of small lakes, Finland

Abstract Concentrations of metals (Cd, Pb, Ni, Cu, Zn, Mn, Al and Fe) were measured in 256 lakes in 1987 as part of a nationwide acidification survey. Concentrations generally followed the pattern of atmospheric deposition observed in snowpack and moss chemistry. The lakes were separated into groups according to the same level of metal deposition using maps of metal concentration in forest moss. Metal concentrations in lakes were most significantly correlated to lakewater acidity and to the concentration of organic C. In a stepwise regression analysis, these two variables, together with a few catchment characteristics, accounted for ~70% of the variation of Fe and Al, and from 20 to 50% of the variation of the other metals. Copper concentration in lakes was significantly explained by the regional Cu concentration in the fine fraction of till.

Finnish experiences of QUASIMEME I

The authors outline the institutional benefits and improvements in analytical methodology arising as a result of their participation in the QUASIMEME project.