Testing and optimisation of ecotoxicological test methods for routine use (ERNTE)

Despite efforts to include ecotoxicological tests as an integral components of the assessment of contaminated land, most decisions regarding soil remediation or natural attenuation monitoring and/or assessment still rely on the results of chemical residue analyses. The German Federal Soil Protection Act (1998) stipulated the protection of natural soil functions, including the function as habitat for soil biota. As part of this requirement, a joint-research project was set up to address the main shortcomings of the existing battery of ecotoxicological tests. The aim of the project, which was coordinated by ECT, was to facilitate the use of ecotoxicological test methods for the site-specific risk assessment of contaminated soils. The influence of natural soil properties on the results of three chronic tests (earthworms, collembolans, and dicotyledonous plant tests) was studied and evaluated. Additionally, existing microbial and genotoxicity tests were optimised for use in on-site analysis of potentially contaminated field soils to ensure the availability of test results within 48 hours. To reach this goal, specific software was developed to automate sample handling and test performance. A new solid-phase miniaturised bacterial test kit for field soils was developed and its standardisation as an ISO guideline was started. It is expected that these improvements will facilitate the use of ecotoxicological test methods for assessing the quality of soils and, thus, complement residue analysis. Finally, recommendations concerning an ecotoxicological test battery as well as the evaluation of the test results results in conjunction with chemical data were put into practice at two contaminated sites in Hamburg (Northern Germany). Close cooperation with the local authorities provided valuable input for evaluating the pros and cons of including ecotoxicological tests in the routine assessment of contaminated sites.