Assessing the influence of pig slurry pH on the degradation of selected antibiotic compounds.
Assessing the influence of pig slurry pH on the degradation of selected antibiotic compounds.
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DOI：
10.1016/j.chemosphere.2021.133191
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发表时间：
2021-12
期刊：
影响因子：
8.8
通讯作者：
J. Nightingale;L. Carter;C. Sinclair;Phil Rooney;M. Dickinson;J. Tarbin;P. Kay
中科院分区：
文献类型：
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作者：
J. Nightingale;L. Carter;C. Sinclair;Phil Rooney;M. Dickinson;J. Tarbin;P. Kay
畜牧业中经常使用兽药，因此，环境可能会通过施用粪便而暴露于兽药。这带来了潜在的环境和社会风险，如对水生/陆地生物的毒理影响和抗菌素耐药性的传播。评估兽用抗生素在粪便储存期间的降解性的监管研究目前允许每种动物类型只使用一种粪便，尽管我们推测pH等异质性可能会导致降解率的显着变化。为了弥合这一认识差距，并评估降解与pH的变异性，在三个不同的环境相关pH水平(5.5、7和8.5)下，对多种抗生素(头孢硫呋喃、氟苯尼考、土霉素、磺胺甲恶唑和泰乐菌素)进行了实验室降解研究。猪浆pH值对降解率的影响是显著的，而且是化合物特有的。通常，与中性pH相比，酸性浆液对氟苯尼考、泰乐菌素和头孢硫呋喃的降解有抑制作用；相关的DT50(半衰期)值变化分别为2-209小时、35.28-234小时和0.98-2.13小时。在某些情况下，与中性pH相比，碱性浆液对泰乐菌素的降解率有所提高，其DT50值的变化范围为3.52~35.28小时。相比之下，磺胺甲恶唑在酸性条件下的降解率高于中性条件下的降解率(DT5020.6~31.6小时)。首次在猪浆中初步鉴定出磺胺甲恶唑和氟苯尼考的未知转化产物(TPS)。这些结果揭示了在评估抗生素化合物的降解时考虑泥浆pH的重要性，这对粪便的酸化和兽药的环境风险评估具有影响。环境相关性和意义：鉴于猪浆pH对降解率的显著影响，粪便降解研究需要协调和标准化，考虑到pH的影响。
Veterinary medicines are routinely used in animal husbandry and the environment may consequently be exposed to them via manure applications. This presents potential environmental and societal risks such as toxicological effects to aquatic/terrestrial organisms and the spread of antimicrobial resistance. Regulatory studies that assess the degradability of veterinary antibiotics during manure storage currently permit the use of just one manure per animal type although we speculate that heterogenic properties such as pH could be driving significant variability within degradation rates. To bridge this knowledge gap and assess degradation variability with pH, laboratory degradation studies were performed on a broad range of antibiotics (ceftiofur, florfenicol, oxytetracycline, sulfamethoxazole and tylosin) at three different environmentally relevant pH levels (5.5, 7, and 8.5). The effect of pig slurry pH on degradation rates was found to be significant and compound specific. Usually, acidic slurries were found to inhibit degradation when compared to neutral pH, for florfenicol, tylosin, and ceftiofur; the associated changes in DT50(half-life) values were 2–209 h, 35.28–234 h, and 0.98–2.13 h, respectively. In some circumstances alkaline slurries were observed to enhance the degradation rate when compared to those for neutral pH, for tylosin, the respective changes in DT50values were from 3.52 to 35.28 h. Comparatively, the degradation of sulfamethoxazole was enhanced by acidic conditions compared to neutral (DT5020.6–31.6 h). Tentative identification of unknown transformation products (TPs) was achieved for sulfamethoxazole and florfenicol for the first time in pig slurries. These results reveal the importance of considering slurry pH when assessing the degradation of antibiotic compounds, which has implications for the acidification of manures and the environmental risk assessment for veterinary medicines.Environmental relevance and significance: Given the significant effect of pig slurry pH on degradation rates, manure degradation studies need to be harmonised and standardized, taking into account the influence of pH.