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Fur die Untersuchung von Nadel-, Blatt-, Holz-, Rinden-, Wurzel-, Boden-und Gesteinsproben zur Klarung der Spurenstoffkreislaufe in Waldokosystemen wurde ein AufschluRsystem benotigt, das folgende Anforderungen erfiillt: a) einfache Handhabung b) geringe Kontaminationen c) Verwendbarkeit fiir unterschiedliche Probenmaterialien und Sauremischungen (HNO3, HNOdHF, HzSOdHF, HN03/H2SOdHF und unter ganz bestimmten Voraussetzungen HN03/HC104/HF und HClOdHF) d) geringe Kosten. Aufbauend auf einer uber zehnjahrigen Erfahrung mit einem DruckaufschluBsystem aus Aluminium (Wahler, 1964) wurde ein AufschluRsystem entwickelt, das von einer gut ausgeriisteten Werkstatt leicht nachgebaut werden kann. Das AufschluRsystem (s. Abb. 1) besteht aus einer Edelstahlhalterung (x 12 Cr Ni 18 8) und 6 aluminiumummantelten TeflongefaRen, die einzeln zwischen die Platten gestellt und arretiert werden. Die Edelstahlhalterung ist aus 3 verschraubten Teilen aufgebaut: einer runden Grundplatte rnit zentralem Gewinde, der Mittelsaule, die in die Grundplatte eingeschraubt wird, und der Deckplatte, die ebenfalls rnit der Saule verschraubt ist. In die Deckplatte sind kreisformig um das Zentralgewinde 6 Gewinde f i r M-10-Schrauben geschnitten. Mit diesen Schrauben werden Deckel und Becher der AufschluRgefaRe zusammengedriickt und gleichzeitig die 6 um den Mittelsteg angeordneten Becher arretiert. Die AufschluRbecher rnit einem Fassungsvermogen von ca. 30 ml und die Deckel sind aus gezogenem Teflon gedreht. Der Deckel hat eine PaRkante, die ein Verrutschen nach SchlieRen des Bechers verhindert. Der Becher ist rnit einem Aluminiumrohr ummantelt, wobei diese Ummantelung vom Rand des Teflonbechers uberlappt wird (Abb. 1). Wegen der Ausdehnung des Teflons beim Erwarmen ist zwischen Aluminiumummantelung und Teflonbecher in der Hohe und im Durchmesser ein Spiel von ca. 0.5 mm notig. Das Teflonmaterial muR vor der Verarbeitung uber eine langere Zeitspanne (ca. 10 Stunden) auf 200" C erhitzt werden, um spatere Verformungen zu vermeiden. Nach der 0044-3263/86/0306-0350 $ M.SO/O 0 VCH Verlagsgesellschaft mbH, D-6940 Wcinhcim, 1986

Concentration of the heavy metals Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, and Pb was measured in different compartments of vegetation and soil in a beech (Fagus silvatica) and a spruce (Picea abies) forest and the inventory of these elements was calculated. During a period of 3 years the heavy metal concentration in precipitation and soil water fluxes below tree root zone was determined and total element fluxes were calculated.Annual input from the atmosphere is small (≤30%) for the metals Cr, Mn, and Ni when compared to the amounts stored in the annual increment of biomass. The percentage is higher for Fe (40 to 60%). Uptake of these metals must be supplied partly by weathering of soil minerals. Accumulation of Cu in biomass is completely accounted for by atmospheric input. Total uptake of Co, Zn, Cd, and Pb into the cycling fraction (leaves, needles) and the noncycling fraction (wood) can be accounted for or is exceeded by atmospheric input. Air pollution from industry, home firing, and motor vehicles is the probable source.Biomass contained up to 27% of total Cd in the ecosystem, but only about 8% of Cu, 2 to 5% of Ni, Zn, and Mn, about 1% of Pb and Cr, and <0.3% of Fe and Co. Accumulation of Pb, Fe, and Co is very strong in the organic surface layer which contains up to 180 times the amount of metal reaching soil as annual litterfall, but only 3 times the amount of Mn, indicating a fast release of the metal by decomposition of organic matter.

Concentrations and annual fluxes of K, Na, Ca, Mg, Al, Fe, Mn, Zn, N, S, P, Cr, Cu, Ni, Pb, Sb, Bi, Cd, Hg, and Tl were measured in the precipitation input to the forest canopy, in precipitation beneath canopy, and in the seepage water below the humus layer and below the tree root zone (output) both in a Central European beech (Fagus silvatica) and in a spruce (Picea abies) forest. Concentrations were determined in an acid loess loam soil from the beech site and in a calcareous little‐weathered loess C‐horizon for the same elements plus Sr and V.When precipitation was passing through the forest canopy, some elements were partially retained (P, Cu, Fe, Zn, Hg, Cr). The flux of other elements increased during canopy passage.Strong retention of Pb and Ni in the organic surface layer (O‐horizon) was found when seepage water passed through it. Within the mineral soil, retention of dissolved elements from the seepage water is observed in the case of K, Ca, Fe, N, S, P, Cr, Pb, Sb, Hg, and Tl.Compared to the unweathered loess, the acid forest soil was nearly depleted of its Ca and carbonate‐C contents. A similar, but less distinct, decrease was found in the total profile (Na, Sr, V, Cr, Cu, Zn), or in the soil surface layer only (Mg, Al, Fe, Mn, Ni, Co). Carbon, N, P, S, Pb, Hg, Bi, and Tl accumulated in the soil surface layer.The input/output balance showed that both forest ecosystems accumulated all elements entering the system with atmospheric precipitation except Al and Mn. The elements Pb, Hg, Bi, and Tl accumulated mainly within the top soil.

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Abstract. A new plastic-lined high-pressure squeezing device has been developed for the extraction of soil pore solutions. At a maximum pressure of 1100 kg cm -~" the water recovery ranged between 30 and 55% of the total water content. Pressure dependent squeezing experiments showed a general increase in Si, Mn, Mg, Ca, K, Na, AI, Fe, Cd, and Zn concentrations with progressive pore water extraction and increasing pressure, indicating that micro pore solutes have the highest concentrations of solutes. Soil samples with moisture contents of more than about 15% generally provided enough water for major and trace element analyses. The data do not reveal any contamination of the pore fluids from the squeezing device. An advantage of this method is that the solution could be closely related to a specific soil horizon on a cm scale and also to the time of sampling. A further application of this squeezing method is the possibility of pressure dependent sequential squeezing to obtain fluids from different pore spaces.

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