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(343) Environmental Fate and Behaviour of Veterinary Antibiotics in Clay Soils . Kay, Paul 1, Blackwell, Paul 1, Boxall, Alistair1, 1 ABSTRACT- Veterinary medicines may be released to the environment by grazing animals or the application of manure and slurry to land. Whilst a range of modelling approaches has been proposed for assessing the fate of veterinary medicines, very little data is available on their behaviour and concentrations in soil and water. This study was performed on heavy agricultural land which is likely to represent a 'worst-case' scenario for the transportation of veterinary drugs to surface waters, due to the presence of field drains and the impermeability of clay soils. Pig slurry containing the antibiotics oxytetracycline, sulphchloropyridazine and tylosin was applied to a 1.5 ha arable field. The movement of the drugs through the soil profile has been investigated as well as concentrations in drain flow from the field. Results obtained so far have indicated that components of the slurry percolated to depth rapidly and were discharged through the field drains into the receiving water. Other studies are investigating the transport of different manure and slurry types in overland flow whilst lysimeters are being used to investigate their potential to leach through the soil profile. Complementary studies will provide data on the persistence, mobility and ecotoxicity of the study compounds. Key words: antibiotics, clay soils, surface waters, drain flow |
