Oxytetracycline assay in pond sediment

The fate of drug residues and their metabolites in the environment is relatively rarely investigated in the conditions of the Czech Republic, resulting in limited availability of scientific information. To demonstrate one example, we prepared a model study with medicated feedstuff containing oxytetracycline hydrochloride (OTC HCl), which was used in fish under normal conditions of use. The oxytetracycline (OTC) contents were determined in the sediments of the pond where the fish were treated. The ELISA method was used for OTC detection and the HPLC method was used for final quantification of OTC. The increasing contents of OTC in sediment depended on the repeated treatment and excretion of OTC by the fish. The concentration on Day 59 after the last administration was 1516 mu g.kg(-1) OTC in the sediment, which indicates a long-term persistence of the substance in the environment.