Determination Of Tetracyclines In Manure And Their Degradation During Manure Composting

In recent years, concern on antibiotics contamination has been raised because of its serious environmental impact. In this paper, firstly, the use and measurement methods of antibiotics, the fate of residual antibiotics in the environment, and the impact of residual antibiotics on the environment were reviewed and commented. The possible solution and future researches were also prospected in this paper.Secondly, a SPE-HPLC method was developed to analyze oxytetracycline (OTC), tetracycline (TC)and chlortetracycline (CTC)in animal manure. The results showed that the recoveries of OTC, TC and CTC in manure were between 51.3%-93.7%. the lowest-limits detected of OTC, TC and CTC were 0.029mg kg-1, 0.055mg kg-1 and 0.073mg kg-1, respectively. This method was further applied for the analysis of manures collected from the animal farms in Hefei. OTC, TC and CTC were detected in hen manure, pig manure and partly in dairy manure, respectively.Lastly, the degradation of tetracyclines(OTC, TC, CTC)in manure was investigated during composting. Composting is a common disposal method in animal manure management. During composting, the degradation of tetracyclines followed first-order dynamics equation. The relative coefficient r2 of the euqation was >0.9 for tetracyclines. The half-lives for OTC, TC, and CTC were 5, 4-7, and 3-4 days, respectively. At the end of the composting (38-45d)), the concentrations of tetracyclines was < 3 mg/kg DW, which corresponded to > 95% reduction in OTC, TC, and CTC. These results suggest that composting is an effective option for the removal of residual tetracyclines in animal manure.