Wang Q-Q, Bradford S A, Zheng W, Yates S R
USDA-ARS, U.S. Salinity Lab., 450 W. Big Springs Rd., Riverside, CA 92507, USA.
J Environ Qual. 2006 Oct 27;35(6):2162-9. doi: 10.2134/jeq2006.0178. Print 2006 Nov-Dec.
Sulfadimethoxine is a widely used sulfonamide veterinary antibiotic and could be a source of agricultural contamination. Therefore, information is needed about its degradation kinetics in manure under aerobic conditions. Based on the analysis of first-order kinetics and the assumption that sulfadimethoxine availability for degradation in manure could be limiting, a new kinetic model was developed and was found to fit the degradation kinetics well. The degradation rate in sterile manure was found to be much lower than in nonsterile manure, indicating that biodegradation was significant. In biologically active manure, the degradation rate constant decreased with increasing initial concentration of sulfadimethoxine, implying that the activity of the degrading microorganisms was inhibited. Increasing moisture or temperature was found to increase sulfadimethoxine degradation in manure. Mixing manure containing high levels of sulfadimethoxine with manure containing lower levels may result in more rapid degradation, thus greatly diminishing sulfadimethoxine contamination in manure and significantly reducing sulfadimethoxine inputs into the environment. During treatment, keeping the manure moist and storing in a moderately warm place under aerobic conditions may also help to diminish sulfadimethoxine contamination.
磺胺二甲氧嘧啶是一种广泛使用的磺胺类兽用抗生素，可能是农业污染的一个来源。因此，需要了解其在有氧条件下在粪便中的降解动力学信息。基于一级动力学分析以及粪便中可用于降解的磺胺二甲氧嘧啶可用性可能受到限制的假设，开发了一种新的动力学模型，发现该模型能很好地拟合降解动力学。结果发现，无菌粪便中的降解速率远低于非无菌粪便，这表明生物降解作用显著。在具有生物活性的粪便中，降解速率常数随磺胺二甲氧嘧啶初始浓度的增加而降低，这意味着降解微生物的活性受到了抑制。研究发现，增加湿度或温度会加快粪便中磺胺二甲氧嘧啶的降解。将含有高浓度磺胺二甲氧嘧啶的粪便与低浓度的粪便混合，可能会导致更快的降解，从而大大减少粪便中磺胺二甲氧嘧啶的污染，并显著减少其向环境中的输入。在处理过程中，保持粪便湿润并在有氧条件下储存在适度温暖的地方，也可能有助于减少磺胺二甲氧嘧啶的污染。
