Tiefengradienten der Bodenversauerung

Environmental risk of (heavy) metal release from urns into cemetery soils

Cremation of the deceased has become the most common funeral type in many countries in the world, including Germany. The ashes of the cremated human body (cremains) are transferred in an urn and most commonly buried in the soil. However, the possible environmental impacts of cremains on soils and groundwater have been rarely studied. In this context, it is still unclear whether or not the release of (heavy) metals like chromium, zinc, copper, nickel and lead from cremains and urns poses an environmental problem in urn grave soils. The aims of the study were to analyze the (heavy) metal content of two cremains from a 74-year-old male and 70-year-old female, and of soils in 6 cemeteries with urn graves in North and West Germany. Soil samples were taken from below the burial depth of 42 urns (upon expiry of the resting time) and from reference soils without urn burials (same cemetery site and depth). The two cremains differed significantly in their heavy metal content (zinc, nickel, copper, chromium), which originated from metal components of the deceased's clothing or burial objects or may have resulted from contrasting occupational exposure during the deceased's lives. Investigations at the cemetery sites revealed a high variability in (heavy) metal contents in the soil samples from below the buried urns. As expected, the accumulation of some element (e.g., lead and tin) in the soil increased with a higher degradation degree of the urns, but an enrichment in copper, chromium, nickel, and iron was also detected below only slightly corroded but not yet perforated urns, which were often made out of copper-bearing material and other alloying agents. This demonstrated that heavy metal releases into cemetery soils originated from both cremains and urn material.

Soil changes in forest ecosystems: evidence for and probable causes

A review of the literature on forest soil change in North America, Central Europe. Sweden, U.K., and Australia reveals that changes are occurring in both polluted and unpolluted sites at a greater rate than previously suspected. Acid deposition has played a major role in recent acidification in some areas of Europe and, to a more limited extent, in Sweden and eastern North America. However, rapid rates of soil acidification are occurring in western North America and Australia due to internal processes such as tree uptake and nitrification associated with excessive nitrogen fixation. The presence of extremely acid soils is not necessarily an indicator of significant acidic deposition, as evidenced by their presence in unpolluted, even pristine forests of the north-western U.S.A. and Alaska. Numerous studies in Sweden, Australia, and North America show the important effects of tree uptake and harvesting upon soil acidification in managed forests. Furthermore, arguments can be presented that harvesting takes a greater toll upon the pools of potentially limiting cations than leaching.

The rate at which soils are changing in some instances calls for a re-evaluation of the budget analyses used to predict soil change. Specifically, inter-horizon changes due to uptake and recycling by vegetation, the interactions of such changes with naturally- and anthropogenically-produced acids, and the effects of aluminium uptake and recycling need further evaluation and study.

Sulfate Reduction in a Forested Catchment as Indicated by δ(34)S Values of Sulfate in Soil Solutions and Runoff

Abstract In a forested catchment in the Fichtelgebirge mountains (NE-Bavaria, Germany) the long term SO(4) (2-) budget (average 1988-1994) indicated that about 40% of the input with throughfall (16.8 kg SO(4) (2-) S·ha(-1)·yr(-1)) was retained in the catchment. In order to identify processes acting as potential SO(4) (2-) sinks, δ(34)S values of SO(4) (2-) in soil solutions and runoff were measured between May and November 1994. δ(34)S values of the runoff and the fen were higher (5.8‰) than the δ(34)S values of the soil solution of the oxic soils in the terrestrial area (3.9‰). Because there is no lithogenic S source within the catchment, it can be assumed that SO(4) (2-) deposition is the only S source in the catchment. Thus the results were interpreted as a result of SO(4) (2-) reduction within the catchment, because the uptake of (32)S is favoured during the dissimilatory SO(4) (2-) reduction and (34)S is consequently enriched in the soil solution. To estimate the amount of SO(4) (2-) reduced isotopic fractionation factors between - 9‰ and -46‰ were considered, resulting in SO(4) (2-) reduction rates of 1.8-9.3 kg SO(4) (2)-S·ha(-1)yr(-1). It was concluded that besides dissimilatory SO(4) (2-) reduction another sink exists in the catchment (e.g. SO(4) (2-) sorption in deep soil layers).

Catchment acidification-from the top down

Three main factors define the speed of catchment acidification: the total input of pollutants; the thickness and character of soils, including the nature of the bedrock; and the size of subcatchments. The aerial input of pollutants in the Harz is among the highest in Central Europe (e.g. SO4-S: 22-70 kg (ha year)(-1); NO3-N: 9-10 kg (ha year)(-1); NH4-N: 10-15 kg (ha year)(-1) and Cd: 2.6-8.7 g (ha year)(-1); Cu: 34-125 g (ha year)(-1); Pb: 150-380 g (ha year)(-1); Zn: 105-560 g (ha year)(-1)). Thick soil profiles (2-4 m) acidify from the top down. Whether the soils will neutralize incoming acids depends on their buffering capacity. The small headwater subcatchments acidify first and subsequently release acidic water with pH values down to < or = 40. Four brook zones can be divided by the composition of their biocoenoses. The latter depend on the degree of acidification. These zones are also characterized by different hydrochemical conditions.