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(T/MF187) Earthworm bioassays for the Ecological Risk Assessment of potentially contaminated urban sites. Hankard, Peter1, Weeks, Jason2, Mann, Jayne1, 1 2 ABSTRACT- Five potentially contaminated urban sites have been investigated and characterised in terms of their soil type, contamination status and indigenous floral and faunal populations. In particular, the earthworm numbers biomass and diversity were assessed by formalin extraction and hand sorting of box cores. This poster reports the results of in-situ and laboratory earthworm bioassays for Ecological Risk Assessment of the sites. Soils were extracted from the sites and returned to the laboratory where an eight-week Earthworm Reproduction Test (OECD 2000) was carried out. Meanwhile, Adult Lumbricus rubellus were exposed to the soils in sealed mesh bags in-situ and their survival and weight change measured after four weeks exposure. The study demonstrated that such bioassays can be used to characterise the overall toxicity to earthworms of soils contaminated with a wide range of industrial pollutants. All parameters measured (indigenous earthworm populations, in-situ toxicity and reproduction effects in the laboratory study), varied considerably within sites as well as between sites. Earthworm Bioassays run in the laboratory using the field-collected soils resulted in considerably higher survival and growth than Assays run totally in the field. Reasons for this are discussed. Key words: contaminated land, earthworm bioassays |
