Measurement of Genotoxic Endpoints in Earthworms Exposed to Radioactive Wastes from an Abandoned Uranium Mine

The main objective of this study was to assess the sensitivity of genotoxic endpoints, to be considered in earthworm’s reproduction assays, performed under the evaluation of soils contaminated with radioactive wastes. Earthworms were exposed, under laboratorial conditions, to a contaminated soil from the Cunha Baixa uranium mine and to LUFA 2.2 soil (control soil). Earthworms (Eisenia andrei Bouché) were sampled from assay chambers after 0 h, 24 h, 48 h, 7 days, 14 days and 56 days of exposure. Some simple techniques like comet assay and flow cytometry were used to assess DNA damages and cytotoxicity in earthworm’s coelomocytes. Higher DNA damage was recorded in earthworms exposed to the contaminated soil when compared to the control. Flow cytometry revealed that earthworm’s coelomocytes were affected by the exposure to radioactive wastes, by causing depletion in cells responsible for the effector functions of the immune system of these organisms. These results suggest that DNA damages and cytotoxicity assessed by both techniques are sensitive endpoints for environmental risk assessment of radiological contaminated sites.