Beurteilung der Lebensraumfunktion von Böden anhand von Bodenwerten und ökotoxikologischen Labortests
The goal of this work was the improvement of the assessment of the natural function of soils as a habitat for soil organisms. The first sub-goal was to derive soil values for the path ‘soil – soil organisms’. Using the DIBAEX-method soil values (HC5) were derived separately based on NOEC/EC0-20- and EC30-60-values for soil invertebrates, plants and microbial processes for 8 heavy metals and 4 organic compounds. The calculated values were checked for plausibility according to various parameters. For five of the heavy metals the calculated soil values were plausible for both effect levels, for another two metals the values were plausible with restrictions. For chrome the calculated values were regarded as not plausible and were not considered when further using the soil values in the course of the work. The soil values for the four organic compounds were all plausible with restrictions. The HC5 based on NOEC/EC0-20 data for BaP and the HC5 based on EC30-60 data for PAH were regarded as not plausible and were also not further considered. The second sub-goal was the application of ecotoxicological tests with earthworms and springtails as an example. First, dose-response tests were performed with zinc nitrate and tributyltin oxide in nine natural soils and OECD artificial soil and second, six contaminated soils from different legacy sites were assessed. Earthworm and springtail reproduction tests and earthworm avoidance tests were performed in the laboratory according to internationally standardized ISO guidelines. Additionally, in parallel and in comparison to the earthworm reproduction test the bait lamina method was used as a screening test. The results (e.g., EC50) of the dose-response tests differed between the different soils. The earthworm avoidance test was similar in sensitivity in the tests with zinc nitrate compared to the earthworm reproduction test while the latter was mostly more sensitive in the tests with TBT-O. The bait lamina test was comparable in sensitivity to the earthworm reproduction test and might be used as a future screening method in the laboratory. In the contaminated field soils the chronic earthworm and springtail tests showed clear effects in two of the six soils since no juveniles were produced by either species. Another two soils caused a strong effect in the earthworm tests as the reproduction was less than 50% of the control. For the remaining two soils no effects were observed. According to the results of the earthworm avoidance tests two soils showed an effect on the avoidance behaviour. The results were mostly confirmed by the bait lamina method. Based on these results the habitat function in three of the six soils was regarded as not fulfilled. Another soil was regarded as conspicuous. Finally, the third sub-goal was the application of the results and findings obtained so far on a total of 20 soils of different contamination from two remediation sites in Hamburg, Germany. These soils were assessed regarding exceeding of the previously derived soil values and the results of the practical testing in the laboratory. The comparison of both assessments showed that exceeding of soil values frequently predicted effects on soil animals. However, in many cases the results of the laboratory testing led to a different assessment than the exceeding of soil values. This could mean that despite low contamination the habitat function of the soil was still considered as not fulfilled. On the other hand strong nominal contamination in some cases did not necessarily lead to a toxic effect on soil organisms. The latter was a good example for results of ecotoxicological tests being also able to relieve a soil in its assessment. The combined assessment of the soils led to the conclusion that in 12 of 20 cases the habitat function was regarded as not fulfilled. In five cases the habitat function was considered to be fulfilled. In three cases no final assessment was possible and further investigations would be needed. In an outlook chapter precise recommendations could be given regarding a future concept for the chemical biological assessment of the habitat function of soils based on the TRIAD approach and need for further research and development efforts was identified. The combination of ecotoxicological testing and chemical-analytical investigations in comparison with soil values derived on the basis of ecotoxicological data may considerably improve the assessment of the habitat function of soils.
info:eu-repo/classification/ddc/570, Bodenmikrobiologie, Bodentiere, Bodenschutz, Deutschland / Bundes-Bodenschutzgesetz, Monitoring, Pflanzen, Umwelttoxikologie, Biowissenschaften, Biologie, Eisenia fetida, Folsomia candida, Köderstreifen, species sensitivity distributions
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