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(78-02) Soil biological parameters and pollution-induced community tolerance (PICT) for risk assessment of large area metal contamination. Rutgers, Michiel*,1, Boivin, Marie-Elene1, Bogte, Jaap1, Van Beelen, Patrick1, Wouterse, Marja1, Breure, Anton1, 1 Laboratory for Ecotoxicology, Bitlhoven, The Netherlands ABSTRACT- In the Netherlands, large areas are contaminated with heavy metals, at concentrations in the range of the environmental quality criteria set for protecting the environment. Yet, it is extremely difficult to demonstrate adverse effects of these metals in the field on ecosystem structure and functioning. Emerging techniques like determination of pollution-induced community tolerance (PICT) with nematodes and bacteria, and community structure analysis of organisms in the soil food web might be sensitive and promising tools for risk assessment in such ecosystems. We set out field investigations in a contaminated peat area in the central western part of the Netherlands. From about the 14th to the 20th century, this area has been contaminated with heavy metals due to a specific agricultural practice called 'Toemaken', the application of sand and sediment together with domestic wastes from the towns to improve soil quality. In this way about 500 km2 have been contaminated, mostly with lead, copper and zinc. Since the majority of the soil is moderately contaminated, and gradients are relatively small, special empahsis is given to the sampling technique for finding significant gradients of pollution including reliable references in a patchy environment. The goal of the project is: 1. to demonstrate relationships between PICT and more 'classical' ecological observations, like abundancies, community structure and functioning, and 2. to demonstrate field effects at multiple trophic levels, i.e. bacteria and nematodes. In this presentation results of the field trials will be presented, comprising data of shifts in bacterial community structure from CLPP and DGGE analysis, and PICT. Key words: metals, PICT, microbial community shifts, tolerance |
