|
4D - Veterinary Medecine (MO13/12) The leaching potential of three veterinary antibiotics after manure application to a sandy loam soil. Blackwell, Paul1, Kay, Paul1, Boxall, Alistair1, 1 Cranfield Centre for EcoChemistry, Shardlow, Derby, UK ABSTRACT- Antibiotics are used in livestock production to prevent disease and treat sick animals, and thus, may be present in manure and slurry as the parent compound and/or metabolites. The environment may therefore be exposed to these substances following the application of organic fertilisers to agricultural land, deposition by grazing livestock, or direct runoff following topical application. The UK is the largest user in Europe, accounting for around 700 of the 5000 tonnes sold each year. There is increasing awareness and concern over the environmental effects of antibiotics e.g. increasing antibiotic resistance of pathogens, although very little information is available on environmental concentrations and the processes governing these. The antibiotics oxytetracycline, sulfachloropyridazine and tylosin were applied to sandy loam lysimeters in two separate experiments. In the first experiment slurry spiked with predicted environmental concentrations of OTC and SCP was applied to ten lysimeters and incorporated into the top 25 cm of half of these. Over a 120 day period the lysimeters received both natural rainfall and were irrigated, with leachate being collected on a per-volume basis. In the second experiment slurry spiked with OTC, SCP and also TYL was applied to the surface of 12 lysimeters and simulated intense rainfall (10 mm per day for 10 days) was applied to three sets of four replicate lysimeters after a delay of one, seven and ten days respectively with leachate collected daily. Results from the two leaching scenarios are presented and an assessment made of the potential environmental risks. Key words: antibiotic, veterinary medicine, leaching, lysimeter |
