PARENT SESSION
WP7 Human and Veterinary drugs in the environment
3:00 PM to 6:30 PM, Wednesday, 09 May 2001
Session Chair: D. Calamari
Room 7

(405) Oxolinic Acid in Freshwater Sediment - Extraction Method and Occurrence Due to Fish Farm Activities.

Holten Lützhøft, Hans-Christian¹, Halling-Sørensen, Bent¹, Guardabassi, Luca², Ingerslev, Flemming¹, Tjørnelund, Jette¹, ^{1 2}

ABSTRACT- A method was developed for extraction of oxolinic acid (OXA) from freshwater sediment. Sediment samples were collected from the inlet, a medicated pond, the outlet and 300 m downstream of a Danish freshwater trout farm undergoing treatment with OXA. Sediment packed solid phase extraction tubes were eluted with 20 % 10 mM H₃PO₄ pH 2.5 in tetrahydrofuran and extracts were concentrated under N₂. OXA was subsequently quantified using high performance liquid chromatography. OXA was detected in samples from the pond and from the outlet in concentrations up to 3.4 mg/kg and were higher than OXA detected in samples from the inlet (up to 0.8 mg/kg). Additionally, a sediment concentration of 1.6 mg/kg was found 300 m downstream the outlet 21 days after medication. In order to reduce the environmental impact of antimicrobial usage in land-based fish farms, the ability of different effluent treatments to detain antimicrobials should be investigated.

Key words: Oxolinic acid, Sediment extraction, Freshwater, Fish farm