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(73-13) Assessing the Environmental Risk Assessment of oxytetracycline to soil organisms using MS3 resembling manure applications. Boleas, Sara*,1, Babin, Mar1, Alonso, Carmen1, Pro, Javier1, Garcia, Pilar1, Ortiz, Jose1, Fernandez, Carlos1, Carbonel, Gregoria1, Tarazona, Jose1, 1 Laboratory for Ecotoxicology, Madrid, SPAIN ABSTRACT- Multi-Species-Soil-Systems (MS3) consist of open PVC columns with embedded soil cores where terrestrial invertebrates and test plant species are added. They are kept under controlled light and temperature conditions and irrigated at prefixed intervals. Leachate can be collected for further testing. In this study, MS3 soil microcosms have been used for the assessment of ecotoxicological effects of veterinary pharmaceuticals on sieved agricultural soil. Several concentrations of the antimicrobial oxytetracycline, namely 0, 10 mg/kg soil, 1mg/kg soil and 100 mg/kg soil were added to the system. The product was distributed along the 20 cm-soil column (resembling arable land scenario). Microcosms were prepared in triplicates for each concentration. Seeds (Triticum aestivum. Brassica napus and Vicia sativa) and earthworms (Eisenia fetida) were introduced at the beginning of the experiment. Seed germination, biomass production, earthworm mortality, and several enzymatic activities (phosphatase, dehydrogenase, urease) of the microbial soil community (the latter assayed at two different depths) were used as toxicity endpoints. Effects were assessed after 7 days and 21 days of exposure. A parallel study was conducted where soil was amended with dung as organic N source. Chemical analysis of the compound in leachate was performed using SPE (solid phase extraction Oasis, Waters) followed by HPLCRP-DA (waters 2695-2696). Toxicity tests for aquatic organisms (Daphnia magna, Chlorella vulgaris) were performed in leachate from weeks 0,1,2 and 3. Toxicity of leachate was also tested on fish cell lines RTG-2 and RTH-W1 using EROD activity, b-Gal activity, neutral red viability assay and measurement of protein content as endpoints. The results of this work are compared with a similar study resembling grazing scenario application and with standardized toxicity tests. The suitability of this experimental approach as a cost-effective tool for risk assessment of veterinary medicines is discussed. This work is funded by the European Union Research Project ERAVMIS, EVK1-1999-00034P Key words: veterinary pharmaceuticals, soil microcosms |
