01.03.1 Lead in Soils /
01.03.2 Cadmium in Soils (Edition 1992)
Overview
Heavy Metals in the Environment
Heavy metals are natural components of soil. Most elements are only present in minimal, insignificant
eco-toxicological concentrations in undisturbed locations in the greater Berlin area. A few heavy metals
are important as trace elements for physiological processes in plants and animals.
Heavy metals are introduced into the eco-system by the manufacture and use of materials containing
heavy metals as well as the disposal of this waste. Soil is contaminated by material from the air and by
direct depositing of pollutants. The accumulation of contaminants is aided by the capability of soil to bind
them with clay minerals or organic substances, for example.
Lead and cadmium are widely distributed in the environment and are considered particularly toxic
elements. Their accumulation has multiple effects on the usability and functions of soil in the eco-system.
Effects of Cadmium
Cadmium is an especially toxic heavy metal that is very mobile in soil. Even minimal amounts in soil that
has a low pH or humus level will result in cadmium uptake into plants. Levels exceeding guidelines for
foodstuffs or feeds can result.
Effects of Lead
Lead is less mobile and is absorbed by plant roots only in exceptional cases. Contaminated soil can result
in pollution by both elements onto the surfaces of plants. Even minimal contents in soil can negatively
effect plant growth and damage soil organisms.
Very high lead or cadmium levels in playgrounds, allotment gardens and other areas can cause health
risks for small children by oral ingestion. If heavy metal contamination exceeds the binding capability of
the soil, there is a danger that heavy metal compounds can flow with percolation (seepage) into the
groundwater.
Heavy metal soil contamination is particularly problematic because they are not degraded in soil. Heavy
metals in soil cannot be permanently eliminated. At best they can be locally reduced by a redistribution in
the eco-system or removed from circulation by immobilization.
Statistical Base
Maps 01.03.1 and 01.03.2 were prepared by evaluating about 2,900 measuring points of the measuring
programs. The measuring programs were initiated to collect comprehensive data regarding heavy metal
contamination of specific area uses and to characterize the contamination of larger portions of the city and
its bordering areas.
Analyses were not taken into consideration which were made at individual locations for old contaminated
sites in the course of initial evaluations and preparations for restoration commissioned by the Berlin
Department of Urban Development and Environmental Protection or by borough environmental agencies.
Comprehensive heavy metal measurements were regularly conducted in this context, so the maps
presented here depict only part of the known soil pollution.
The map shows measurement data next to each other which were collected at different times at areas of
varying uses in Berlin and its bordering lands (see Table 1). A classification of the underlying studies, test
times and methodology is not possible on the map. The measurements are excerpts from the Heavy
Metal Data Base maintained by Department IIIA5 of the Berlin Department of Urban Development and
Environmental Protection. Complete information regarding depicted measurement points can be
accessed from this Data Base.
Methodology
Condition and Use of Tested Sites
The depicted measuring points show the location of each tested site. In the case of sewage farms in the
south of Berlin or agricultural areas, the middle point of these areas is marked. The use of each site at the
time of testing is given. Differentiated were allotment gardens, house yards, agricultural fields, horticulture,
current and former sewage farms, forests, green and open spaces, playgrounds, and miscellaneous
uses. Measurements for green and open spaces were taken both in larger parks and in incidental green
spaces in other use areas, such as schools.
Test Depth
The given measurement values document lead and cadmium only in the upper centimeters of soil.
Some measurement values of deeper soil layers were determined at some locations, but are not
considered here. The majority of values represent mixed tests of the upper 20 cm of soil; a portion of the
sewage farms in northeast Berlin were tested in the upper 30 cm.
The test depth in forests was between 5 and 35 cm. The heavy metal level listed here is for the upper
mineral soil horizon (layer). Heavy metal levels in organic horizon are not portrayed. Heavy metal levels in
playgrounds are documented for the uppermost soil horizon or the material used as a surface. All values
refer to materials found in the upper 10 cm of soil. Playground sand levels are not given. Allotment
gardens, house yards, horticultural and agricultural areas usually have several values dating from different
times, or because of differing methods of analysis. The highest levels for lead and cadmium are given
here because these values can be cause for considering amelioration (improvement) or restoration
programs.
Methods of Analysis
A direct comparison of measurement values should note that different extraction methods were employed
for an analysis of soil samples (see Tab. 1). Measurement values obtained by 1.5 NHNO3-, 2 M HCl- or
aqua regia (Königswasser) analysis register about 80-90% of total heavy metals. Total levels are given
(HF/HClO4-analysis) for a portion of tests in Berlin forests, the majority of values in green spaces, and
measurement points in Schönweide.
Index Values
Increasing knowledge about the extent and effects of heavy metal soil contamination shows that
measurement results can only be evaluated for specific protections and uses. Correspondingly
differentiated index value catalogs are currently in discussion (LAGA 1990, Eickmann & Kloke 1991,
LÖLF 1988).
Proceeding from these discussions, the Berlin Department of Urban Development and Environmental
Protection is working on index values for the evaluation of soil contamination levels in allotment gardens
and house yards (SenStadtUm 1991a) and for estimated contamination levels in agricultural and
horticultural soil (SenStadtUm 1991b). The Berlin Department of Health publishes evaluation criteria for
soil contamination in playgrounds (SenGes 1991). These index value catalogs evaluate possible dangers
in the use of contaminated surfaces and are oriented to the necessity of translating evaluation results into
concrete administrative action.
Value gradations (contamination levels) depicted in the maps correspond to index values in Table 2, so
that concrete recommendations for uses of specific locations can be derived, based on their contaminant
levels. Values given for other uses can be interpreted only in comparison to the natural heavy metal levels
of soil in Berlin.
Map Description
Lead and cadmium soil contamination in Berlin varies considerably, particularly in allotment garden,
agricultural, sewage farms, and forests. The number and distribution of measuring points for these areas
give representative values. Other areas were tested with a much lesser test density. These surveys give
only an initial overview of contamination degrees and distribution.
Allotment Gardens and Yards
The topsoil of allotment gardens everywhere is considerably contaminated with lead and cadmium. Both
the 50th percentile value as well as the average value exceed greatly natural soil values - and that in
areas where heavy metals can be absorbed by food crops. This was demonstrated by the Berlin Heavy
Metal Measurement Survey analysis of food crops (see 01.03.3). In some cases, both elements were
present at such levels that health risks incurred by direct contact with soil could not be ruled out.
Contaminated allotment gardens are found in all parts of the city, most heavily in the inner city. Lead
levels show a more clear gradient than cadmium levels. There are considerable contamination level
differences within a single area of gardens, sometimes even within a single garden.
The measurement values of differentiated follow-up tests of 1,600 allotment gardens conducted in 1989
and 1990 are not depicted in the map for graphic reasons. The values found at these sites are given in
Table 3.
House yards are less contaminated. Levels exceeding index values were determined at few locations.
Agriculture and Horticulture
The majority of tested agricultural areas are considered only slightly contaminated. More than 50% of
tested areas show levels within natural ranges for lead and cadmium. There is a clear regional
differentiation of contamination. Cadmium levels exceeding applicable index values were found almost
only in sites around the Gatow sewage farms. Lead levels are high here too, although few locations
exceeded the index values. Soil contamination correlated with contamination of food and feed crops, also
unusually high here (compare 01.03.3).
High heavy metal levels were also found in green spaces in northwest Berlin and in Lübars, due to larger
amounts of humus and its greater capability for binding heavy metals.
Horticultural businesses did not exceed soil index values. Determined lead and cadmium levels were in
the range of natural levels.
Sewage farms
Particularly high cadmium contamination was found in almost all soils of former or still functioning sewage
farms in Berlin and its vicinity (compare 01.10). The sewage farms in southern Berlin are more heavily
contaminated than those in Gatow or northeast Berlin. There are great pollution gradations within single
sewage farms. Soil contamination in the great majority of former sewage field areas, mainly used today
for agricultural purposes, lead to the expectation of disturbing cadmium levels in the crops cultivated here.
Contamination in crops cultivated on sewage farms have been determined. (cf. 03.03.3, Grün et al.
1990).
Lead is also accumulated in higher concentrations in sewage field soils, but concentrations remain under
applicable index values. The homogeneous pollution levels determined in the test areas indicate that
untested areas will have comparable heavy metal concentrations.
Forests and Green Spaces
High lead and cadmium levels were found in almost all forest topsoils. These values were, as a rule,
under those found in areas for heavier anthropogenic (human) use (cf. Table 3). Heavy metal
concentrations in organic horizon (not depicted) are usually higher than in mineral topsoil.
Contamination in depicted green spaces and other uses cannot be interpreted in context because of
their wide heterogeneity. The inner city again shows higher contamination. Contamination levels in
Schöneweide document the range of variation possible in inner-city areas.
Some playgrounds are contaminated with heavy metals. Some contamination levels were so high that
health risks caused by direct contact with the soil cannot be ruled out.
Causes of Pollution
Depositions
Causes of lead and cadmium soil contamination are mostly additives of contaminated materials
(building rubble, cinders) some of which come from refuse dumps or industrial sites.
Such land fill is especially practiced in allotment gardens and house yards, green spaces and
miscellaneous use areas. 115 allotment garden areas in West Berlin are on old deposit sites, old
industrial sites, or suspected old contaminated sites. Conspicuous are large areas on the edge of
West Berlin used today for allotment gardens (SenStadtUm 1991c). In the inner city there are large
deposits of debris.
The highest heavy metal values are regularly found at these locations and are usually due to
anthropogenic deposits. Significant contamination also appears in small areas, often from building activity
or land-fill in gardens.
Soil Conditioners
Considerable heavy metal deposits are also found in allotment gardens, house yards and green areas
because of the use of contaminated compost and soil conditioners, especially from regular and longterm use. Contaminated composts at many locations were confirmed by the Berlin Heavy Metal Program.
This is primarily caused by the composting of polluted waste (i.e., ash). The previously widely practiced
use of contaminated sewage sludge compost (fertilizer) in allotment gardens, house yards and green
spaces (used today only in small areas) contributed to soil contamination. Sewage farm sludge was
used as soil conditioner for agricultural areas around the Gatow sewage farms.
Waste Water
Soil contamination in current and former sewage farms is due to contaminants in their waste waters. The
contaminant spectrum of waste water is reflected in the soil. Variations in pollutant level between different
sewage farms and within individual sewage farms are due to the length and intensity of waste water flow
and origin. It is assumed that pollutants in waste water and treatment intensity were previously
significantly higher than at sewage farms in use today.
Variations of pollution within individual sewage farms are due to non-homogeneous use. Soil
contamination decreases with the distance from the waste water discharge pipes. Especially high values
are regularly found in sludge drying areas and sedimentation basins. These relationships are clearly seen
in comparing contamination levels in the 01.10 Map of Use of Sewage farms.
The lead and cadmium contamination around the Tiefwerder meadows exemplifies the effects of periodic
flooding by contaminated surface waters.
Contamination of playgrounds is due to the use of contaminated surfacing and building materials, such
as cinders and building rubble.
Inputs from the Air
Airborne heavy metals also contaminate the soil. This influence is more clear for lead than cadmium
because of the much greater amounts of lead. Soil in the inner city is more contaminated than soil at the
edge of the city. The highest contamination is found in the vicinity of commercial emitters, but also directly
next to heavily-traveled streets (see 01.03.3).
Forest contamination is almost entirely due to airborne pollutants. Pollutant sources cannot be clearly
determined in gardens and agricultural areas, because of regular supplements of soil conditioners and
other substances to the topsoil.
Overall View
The diversity of pollution and causes of contamination make it clear that the depicted lead and cadmium
levels in topsoils at many locations illustrate only part of the entire contamination present. Many sites
show contamination of other heavy metals, such as zinc, copper and chrome. The risk potential of soil is
clearly higher at these sites. Sewage farms and old contaminated sites often had organic pollutants in
relevant concentrations. It can be assumed that pollutants have been carried or washed into deeper soil
levels at landfill sites, sewage farms, and sites where topsoils have low binding capacities.
It can also be assumed that comparable contaminant levels are present at the many sites not yet tested,
particularly in East Berlin.
The Berlin Department of Urban Development and Environmental Protection is preparing possible action
plans for reducing risks arising from soil contamination (see Table 2). But these can only be sensibly
conceived after a thorough investigation of the causes of specific site contamination, and in consideration
of the total spectrum of pollution. Additional information about soil characteristics is needed in some
cases. This information would be given to users of those areas. Concrete safety or restoration measures
have been initiated for particularly highly-contaminated playgrounds.
Literature
[1]
Biologische Bundesanstalt für Land- und Forstwirtschaften 1982:
Schwermetalluntersuchungen zum Forschungsprojekt über die Ansiedlung landwirtschaftlicher
Betriebe im Bereich Karolinenhöhe und Gatow, not published.
[2]
Blumenstein, O., Grunewald, K., Schubert, R. 1991:
Das Altlastengebiet Rieselfelder Berlin-Süd - eine geoökologische Herausforderung, in:
Potsdamer Geographische Forschungen, Bd.1.
[3]
Bundesanstalt für Geowissenschaften und Rohstoffe 1991:
Umweltgeochemische Bestandsaufnahme des Stadtgebietes Berlin-Schöneweide, not published.
[4]
Ehrig, C., Stahr, K. 1988:
Untersuchung von Laubkompost, TU-Berlin, Institut für Ökologie - Fachgebiet Regionale
Bodenkunde, Gutachten im Auftrag der Senatsverwaltung für Stadtentwicklung und
Umweltschutz Berlin, Berlin.
[5]
Eickmann, T., Kloke, A. 1991:
Nutzungs- und schutzgutbezogene Orientierungsdaten für (Schad-) Stoffe in Böden,
Schriftenreihe des Verbands Deutscher Landwirtschaftlicher Untersuchungs- und
Forschungsanstalten, Bd.1.
[6]
Grün, M., Machelett, B., Metz, R., Kronemann, H., Podlesak, W., Schneider, J. 1990:
Schwermetallbelastung von Boden und Pflanze im Gebiet der Rieselfelder Berlins, in:
Exkursionsführer zum 102. VDLUFA-Kongress, Berlin, S.31-42.
[7]
LAGA (Länderarbeitsgemeinschaft Abfall) 1990:
Informationsschrift Altablagerungen und Altlasten. Abfallwirtschaft in Forschung und Praxis, 37,
1991.
[8]
Landesforstamt Berlin 1989:
Forstliche Standortserkundung, not published.
[9]
LÖLF (Landesanstalt für Ökologie, Landschaftsentwicklung und Forstplanung NordrheinWestfalen) (Hrsg.) 1988:
Mindestuntersuchungsprogramm Kulturböden, Recklinghausen.
[10] Metz, R., Herold, P. 1991:
Humboldt-Universität zu Berlin /Institut für Pflanzenernährung und Ökotoxikologie Jena,
Schwermetalluntersuchungen im Bereich der Rieselfelder im Norden und Süden Berlins, 19841987, not published.
[11] Niedersächsisches Landesamt für Bodenforschung (Hrsg.) 1988:
F&E-Vorhaben "Kennzeichnung der Empfindlichkeit von Böden gegenüber Schwermetallen",
Hannover.
[12] Salt, C. 1987:
Schwermetalle in einem Rieselfeldökosystem, Diss. TU-Berlin. Landschaftsentwicklung und
Umweltforschung, Schriftenreihe des Fachbereichs Landschaftsentwicklung der TU-Berlin, 53.
[13] SenGes (Senatsverwaltung für Gesundheit Berlin) 1991:
Bewertungskriterien für Bodenkontaminationen auf Spielplätzen, not published.
[14] SenStadtUm (Senatsverwaltung für Stadtentwicklung und Umweltschutz Berlin) 1990:
Berliner Schwermetalluntersuchungsprogramm für Klein- und Hausgärten, Landwirtschafts- und
Gartenbauflächen, 1979-1990, not published.
[15] SenStadtUm (Senatsverwaltung für Stadtentwicklung und Umweltschutz Berlin) 1991:
Ergebnisse der Schadstoffuntersuchungen auf Spiel- und Bolzplätzen, not published.
[16] SenStadtUm (Senatsverwaltung für Stadtentwicklung und Umweltschutz Berlin) 1991a:
Richtwerte zur nutzungsspezifischen Risikobeurteilung von Schwermetallgehalten in Böden bzw.
bodenartigen Materialien für Berlin, not published.
[17] SenStadtUm (Senatsverwaltung für Stadtentwicklung und Umweltschutz Berlin) 1991b:
Ergebnisse des Schwermetalluntersuchungsprogramms, not published.
[18] SenStadtUm (Senatsverwaltung für Stadtentwicklung und Umweltschutz Berlin) 1991c:
Kataster der Altlasten- und Altlastenverdachtsflächen, Abt.III.
[19] SenStadtUm (Senatsverwaltung für Stadtentwicklung und Umweltschutz Berlin) (Hrsg.)
1992:
Umweltatlas Berlin, aktualisierte und erweiterte Ausgabe 1992, Karte 01.03.3 Blei und Cadmium
in Pflanzen, 1:50 000.
[20] SenStadtUm (Senatsverwaltung für Stadtentwicklung und Umweltschutz Berlin) (Hrsg.)
1993:
Umweltatlas Berlin, aktualisierte und erweiterte Ausgabe 1993, Karte 01.10 Rieselfelder, 1:30
500.
[21] SenStadtUm (Senatsverwaltung für Stadtentwicklung und Umweltschutz Berlin) (Hrsg.)
1994:
Umweltatlas Berlin, aktualisierte und erweiterte Ausgabe 1994, Karte 03.03.3 Emissionen
Verkehr 1989, 1:200 000.
[22] Stahr, K. (Hrsg.) 1986:
Soilscapes of Berlin (West), in: Mitteilungen der Deutschen Bodenkundlichen Gesellschaft, 50,
S.1-204.
[23] TÜV (Technischer Überwachungsverein) (Hrsg.) 1989:
Abschlußbericht über die Messungen und Ergebnisse des Immissions-Meßprogramms Berlin
(West) 1988, Berlin.