Behaviour of (14)C-sulfadiazine and (14)C-difloxacin during manure storage.
The persistence of sulfadiazine, difloxacin, and their metabolites has been investigated in stored manure. The manure collected from sulfadiazine ((14)C-SDZ) and difloxacin ((14)C-DIF) treated pigs contained N-acetylsulfadiazine (Ac-SDZ), 4-hydroxy-SDZ (4-OH-SDZ), and sarafloxacin (SARA) as the main metabolites, respectively along with their parent compounds. Manures were stored separately at 10 degrees C and 20 degrees C at various moisture levels. About 96-99% of the radioactivity remained in extractable parent compounds and their metabolites after 150d of storage. The formation of non-extractable residue and the rate of mineralization were both negligible in manure containing SDZ and DIF. During storage SDZ concentration increased as a result of the deacetylation of Ac-SDZ, whose concentration decreased proportionally. Hence the environmental effects may be underestimated if the parent compound alone is considered for environmental risk assessment. About 11% and 14% of 4-OH-SDZ were lost after 20 and 40d of storage; thereafter its concentration increased relatively, highlighting hydroxylation of SDZ. DIF degraded very slowly (7% loss after 150d) during the storage of manure; in contrast the concentration of SARA decreased rapidly (72-90% loss after 150d). Dilution of manure and storage at higher temperatures for a reasonable period of time enhanced the rate of reactions of SDZ, DIF and their related metabolites.
Lamshöft
Marc
M
Institute of Environmental Research (INFU), TU Dortmund, Dortmund, Germany.
Sukul
Premasis
P
Zühlke
Sebastian
S
Spiteller
Michael
M
D000900:Anti-Bacterial Agents / Q000737:chemistry*; D002250:Carbon Radioisotopes / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D002939:Ciprofloxacin / Q000031:analogs & derivatives* / Q000737:chemistry; D008372:Manure; D013411:Sulfadiazine / Q000737:chemistry*; D053719:Tandem Mass Spectrometry
D000900:Anti-Bacterial Agents; D002250:Carbon Radioisotopes; D008372:Manure; D013411:Sulfadiazine; D002939:Ciprofloxacin; C047225:difloxacin