title: Degradation and dissipation of the veterinary ionophore lasalocid in manure and soil.
abstract: Lasalocid is a veterinary ionophore antibiotic used for prevention and treatment of coccidiosis in poultry. It is excreted from the treated animals mostly in its active form and enters the environment with the use of contaminated manure on agricultural land. To properly assess the risk that lasalocid poses to the environment, it is necessary to know its environmental concentrations as well as the rates of its degradation in manure and dissipation in soil. These values are still largely unknown. A research was undertaken to ascertain the rate of lasalocid degradation in manure under different storage conditions (aging in a pile or composting) and on agricultural soil after using lasalocid-contaminated manure. The results have shown that there is considerable difference in lasalocid degradation between aging manure with no treatment (t1/2=61.8±1.7 d) and composting (t1/2=17.5±0.8 d). Half-lives in soil are much shorter (on average 3.1±0.4 d). On the basis of the measured concentrations of lasalocid in soil after manure application, we can conclude that it can potentially be harmful to soil organisms (PEC/PNEC ratio of 1.18), but only in a worst-case scenario of using the maximum permissible amount of manure and immediately after application. To make certain that no harmful effects occur, composting is recommended.
authors.affiliation: Institute of Pathology, Foresnic and Administrative Veterinary Medicine, Veterinary Faculty, University of Ljubljana, Gerbičeva 60, SI-1000 Ljubljana, Slovenia. Electronic address: suzana.zizek@ung.si.
authors.forename: Suzana
authors.initials: S
authors.lastname: Žižek
authors.affiliation: Institute for Environmental and Animal Hygiene with Ethology, Veterinary Faculty, University of Ljubljana, Gerbičeva 60, SI-1000 Ljubljana, Slovenia.
authors.forename: Martin
authors.initials: M
authors.lastname: Dobeic
authors.affiliation: Institute for Environmental and Animal Hygiene with Ethology, Veterinary Faculty, University of Ljubljana, Gerbičeva 60, SI-1000 Ljubljana, Slovenia.
authors.forename: Štefan
authors.initials: Š
authors.lastname: Pintarič
authors.affiliation: Department of Biology, Biotechnical Faculty, University of Ljubljana, Večna pot 111, SI-1000 Ljubljana, Slovenia.
authors.forename: Primož
authors.initials: P
authors.lastname: Zidar
authors.affiliation: Institute for Physiology, Pharmacology and Toxicology, Veterinary Faculty, University of Ljubljana, Gerbičeva 60, SI-1000 Ljubljana, Slovenia.
authors.forename: Silvestra
authors.initials: S
authors.lastname: Kobal
authors.affiliation: Department of Agronomy, Biotechnial Faculty, University of Ljubljana, Jamnikarjeva 101, SI-1000 Ljubljana, Slovenia.
authors.forename: Matej
authors.initials: M
authors.lastname: Vidrih
mesh_terms: D000383:Agriculture; D000818:Animals; D000900:Anti-Bacterial Agents / Q000032:analysis*; D001673:Biodegradation, Environmental; D004784:Environmental Monitoring; D006207:Half-Life; D007476:Ionophores / Q000032:analysis*; D007832:Lasalocid / Q000032:analysis*; D008372:Manure / Q000032:analysis*; D011200:Poultry; D017524:Slovenia; D012987:Soil / Q000737:chemistry; D012989:Soil Pollutants / Q000032:analysis*; D019155:Veterinary Drugs / Q000032:analysis*
chemical_list: D000900:Anti-Bacterial Agents; D007476:Ionophores; D008372:Manure; D012987:Soil; D012989:Soil Pollutants; D019155:Veterinary Drugs; D007832:Lasalocid
keywords: Degradation; Dissipation; Environmental risk assessment; Lasalocid