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(03-07) Influence of manure on the mobility of tetracyclines and sulfonamides in two agricultural soils. ter Laak, Thomas*,1, Tolls, Johannes1, 1 University of Utrecht PO box 80176, Utrecht, Netherlands ABSTRACT- Tetracyclines and sulfonamides are two important groups of antibiotics. Their annual application rate in The Netherlands amounts to 220 tons, thereby accounting for more than 50% of the veterinary pharmaceuticals use. These compounds reach the soil environment, since the excreta of the treated animals are applied as fertilizer. Application of manure leads to changes of soil solution pH and dissolved organic matter content. Both changes are thought to influence sorption of these ionizable compounds. Solid phase micro-extraction (SPME) and equilibrium dialysis were applied to assess the distribution of these pharmaceuticals in a three phase system consisting of a freely dissolved, a dissolved organic carbon associated and soil-sorbed fraction. Two agricultural soils varying largely in clay and sand content were used in the sorption experiments. Influence of pH, application of manure and dissolved organic carbon (DOC) on the sorption of these compounds were examined in order to elucidate the functioning of this three-phase system. The effect of manure application on the mobility of the compounds will be discussed. In addition, the effect of manure amendment and the free concentration in the soil solution is reflected on with regards to the availability of these antibiotics to soil organisms, bacteria in particular. Key words: Soil sorption, Veterinary pharmaceuticals, Free dissolved concentration |
