Department of Environmental Toxicology, Texas Tech University, Lubbock, TX, USA.
Department of Environmental Toxicology, Texas Tech University, Lubbock, TX, USA.
Environ Pollut. 2019 Apr;247:467-473. doi: 10.1016/j.envpol.2018.12.047. Epub 2018 Dec 24.
Beef cattle feedyards have been identified as sources of large amounts of particulate matter (PM) which may transport affiliated chemicals including steroids, beta agonists, and antibiotics from feedyards into the environment. This study is the first to examine persistence of PM-affiliated pharmaceuticals downwind of feedyards using multiple downwind samples collected at increasing distances from feedyard boundaries (n = 5). Concentrations of antibiotics and ractopamine per gram of PM remained consistent at all downwind locations (out to 4.8 km) whereas concentrations per m air decreased significantly at distances between 0.1 and 0.7 km downwind, corresponding to significant decreases in mass of PM. Monensin was present in the highest concentrations of any measured pharmaceutical, with concentrations of 37 μg/g PM (376 ng/m) air in samples collected within 0.1 km downwind of feedyards. Total copy count of tetracycline resistance genes (tetW, tetQ, tetO, tetM, tetL, and tetB) were also significantly increased in samples collected within 0.1 km downwind of feedyards (10 copies) as compared to samples collected upwind (10 copies) and farther downwind (10 copies) of feedyard boundaries. These results suggest that transport of pharmaceutical-laden PM into the terrestrial environment is occurring primarily via PM deposition within 0.7 km of the feedyard, while aerial transport persists over longer distances (>4.8 km).
肉牛养殖场已被确定为大量颗粒物 (PM) 的来源，这些颗粒物可能会将与饲料有关的化学物质（包括类固醇、β 激动剂和抗生素）从养殖场输送到环境中。本研究首次使用从养殖场边界以递增距离收集的多个下风样本（n=5），检测下风处与 PM 相关的药物的持久性。在所有下风位置（最远 4.8 公里），每克 PM 中的抗生素和莱克多巴胺浓度保持一致，而在 0.1 至 0.7 公里下风距离的空气中，每立方米的浓度显著下降，这与 PM 质量的显著下降相对应。莫能菌素是所有测量药物中浓度最高的，下风 0.1 公里处采集的样本中 PM 的浓度为 37μg/g（376ng/m）空气。在距养殖场下风 0.1 公里处采集的样本中，四环素抗性基因（tetW、tetQ、tetO、tetM、tetL 和 tetB）的总拷贝数也显著增加（10 拷贝），而在上风向（10 拷贝）和更远的下风（10 拷贝）处采集的样本则没有增加。这些结果表明，载药 PM 向陆地环境的输送主要通过 PM 在距养殖场 0.7 公里内的沉积来实现，而在较长距离（>4.8 公里）上则通过空气输送来实现。
