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Land-use history, soil ersosion, lake trophy and lake-level fluctuations during the last 3000 years were reconstructed through a multidisciplinary palaeolimnological study (pollen, plant macrofossils, diatoms, physical and chemical analysis, magnetic measurements and radiometric methods) of a small eutrophic lake in southern Sweden (Bj~resjOsjOn, Scania). There are striking responses in diatom, chemical, sediment yield and magnetic records to land-use changes documented by pollen analysis or historical sources, and to lake-level changes identified from sedimentary changes. Our multidisciplinary approach assists interpretation of the processes controlling long-term changes and separation of the effects of different factors (land-use changes, lake-level fluctuations) on individual biostratigraphical records. Climate has controlled processes in the lake indirectly, through lake-level fluctuations, from the Late Bronze Age to the Viking Age (700 BC-AD 800). Since the Viking Age, land-use controlled most of the changes observed in the lake's development and soil erosion processes. Major changes in lake development occurred during the last 200 years, due to a drastic increase in soil erosion and water eutrophication during a period of agricultural modernization.

Using analyses of lead concentrations, lead isotopes ( 206 Pb/ 207 Pb), and spheroidal carbonaceous flyash particles (SCP), we studied sediment accumulation patterns in the acidified lake Härsvatten in southwest Sweden. After determining the natural background 206 Pb/ 207 Pb ratio (1.5) in deeper sediments in long sediment cores from three basins in the lake, we applied an isotope mixing model to quantify pollution Pb accumulation in 46 gravity cores. The mean pollution Pb inventory in the cores was 2.6 g m Ϫ2 (range, 0.3-11 g m Ϫ2 ). Although some variation in Pb concentrations can be explained by loss on ignition (LOI) and water depth (together, R ϭ 0.33), there is no 2 adj relationship between pollution Pb inventories and these variables. Contrary to the traditional model of sediment focusing, where higher accumulations of pollutants are expected in deeper waters, the highest inventories for pollution Pb and SCP are generally found at shallow sites (Ͻ4 m water depth) and not in the three deep basins of the lake (10, 12, and 24 m deep). Furthermore, the model for sediment focusing, which may be appropriate for describing the physical building of sediments in a lake basin, may be inappropriate for describing the specific processes controlling the distribution of pollutants in a lake basin of this type.

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