No abstract

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.

In the absence of appreciable mass transfer due to water movement, diffusion processes in the soil account for the movement of pesticides to the soil surface to replace that lost by volatilization. Published solutions for heat flow equations have been applied to the volatilization of lindane and dieldrin from Gila silt loam for a number of different initial and boundary conditions. Predicted fluxes agreed well with experimental values. Five models have been proposed to describe various environmental conditions found in the field. Models I, II, and III assume pesticide concentration at the soil surface is maintained at zero concentration by air movement. Model IV assumes surface pesticide concentrations greater than zero with air turbulence sufficient to maintain zero pesticide concentration gradient in the air above the soil. Model V assumes a nonmoving air layer of various depths above the soil surface so that the pesticide concentration gradient in the air controls the rate of volatilization.

In the 1970s, acid sulfate soils (ASS) distributed within about 720 ha of predominantly mangrove and salt pan wetlands at East Trinity in north Queensland were developed after the area was isolated from tidal flooding by a surrounding seawall and the installation of tidal gates on major drainage creeks. Following drainage and oxidation of these estuarine acidic sediments, resultant acid leachate caused considerable, ongoing environmental problems including regular fish kills. A rehabilitation program covering much of these former tidal wetlands commenced in 2000 using a lime-assisted tidal exchange management regime. Changes in the established populations of estuarine fish and crustaceans were monitored in the two creeks (Firewood and Hills Creeks) where tidal flows were reinstated. In Firewood Creek between 2001 and 2005, there was a progressive increase in fish species richness, diversity and abundance. The penaeid prawn Fenneropenaeus merguiensis was a major component of the cast net catches in the lower sections of both Firewood and Hills Creeks but its relative abundance decreased upstream of the tidal gates on the seawall. Well established stocks of predominantly juvenile, male Scylla serrata resident upstream of the tidal gates indicated suitable habitats with acceptable water and sediment quality and adequate availability of food. The regular fish kills that occurred prior to the management regime abated and, overall, the implementation of the rehabilitation program is yielding positive benefits for the local fisheries.