Abstract：
Didecyldimethylammonium chloride (DDAC), a toxic quaternary ammonium compound (QAC) linked to multidrug resistance, is used widely in households and hospitals and on swine farms to prevent disease transmission. However, little is known about its occurrence in watersheds receiving livestock wastewaters or manure. We monitored DDAC and tracers (veterinary and human drugs) once a season over a year at 14 sites in a Japanese watershed where swine outnumbered humans 1.2 to 1 and where both swine and human wastewaters were largely treated on site. DDAC concentrations in sewage-treatment-plant effluent (33-52 ng/L) were close to, whereas those in river waters (3.6-16,672 ng/L) far exceeded, those reported worldwide. DDAC mass flows at the catchment outlet (1692-3816 μg/s) were higher than those of any of the drugs. DDAC concentrations were significantly correlated with total concentrations of veterinary drugs (Spearman\'s correlation coefficient, 0.95, P < 0.01), indicating that the major pathway of DDAC entry to surface waters was via effluent discharge from swine farms. Comparison of observed and predicted mass flows implied that a substantial percentage of DDAC was washed from the barn floor into swine excrement. To our knowledge, this is the first study to demonstrate QAC hotspots attributable to animal husbandry.
摘要：
二酰基二甲基氯化铵（DDAC），一种与多药耐药性相关的有毒季铵化合物(QAC)，广泛用于家庭和医院以及猪场，以防止疾病传播。然而,人们对它在接受牲畜废水或粪便的流域中的发生知之甚少。我们每年在日本分水岭的14个地点监测一次DDAC和示踪剂（兽药和人类药物），那里的猪数量超过人类1.2到1，并且在现场对猪和人类废水进行了大量处理。污水处理厂废水中的DDAC浓度（33-52ng/L）接近，而河水(3.6-16,672纳克/升)远远超过，那些在世界范围内报道的。集水区出口处的DDAC质量流量（1692-3816μg/s）高于任何药物。DDAC浓度与兽药总浓度显著相关(Spearman相关系数，0.95,P<0.01),这表明DDAC进入地表水的主要途径是通过猪场的废水排放。观察到的质量流和预测的质量流的比较表明，很大一部分的DDAC从谷仓地板冲入了猪排泄物。据我们所知,这是第一项证明QAC热点归因于畜牧业的研究。
