In April 2016, a series of earthquakes (M 7.3 on the Japan Meteorological Agency scale) occurred in Kumamoto, Japan causing serious damage to underground sewerage networks. In this study, we evaluated sewer exfiltration in groundwater in the Kumamoto area after the earthquakes by using multiple tracers. We used 14 pharmaceuticals, including carbamazepine and crotamiton, and anthropogenic Gd as tracers, and we measured concentrations of these tracers from September 2016 to November 2017 seasonally. The detection frequency of caffeine, carbamazepine, crotamiton, ibuprofen, and anthropogenic Gd ranged from 29% to 45%, and the concentrations of the pharmaceuticals in the groundwater were lower than those in previous studies. The median of all pharmaceutical concentrations did not decrease, whereas the median of the sum of crotamiton and carbamazepine concentrations, which are quantitative sewage markers, decreased with time. The sewer exfiltration rates in September 2016 estimated using carbamazepine, crotamiton, and anthropogenic Gd were 0.59 ± 0.27%, 0.66 ± 0.47%, and 0.11 ± 0.18% of sewage dry weather flow, respectively, indicating that the effect of the earthquakes on sewer exfiltration was small, probably because the damaged sewers were quickly repaired. This study demonstrated that a multiple-tracer approach is useful for evaluating sewer exfiltration after major earthquakes.

2016年4月，日本熊本县发生了一系列地震（日本气象厅等级为M 7.3），对地下污水管网造成了严重破坏。在这项研究中，我们使用多个示踪剂评估了地震后熊本地区地下水的下水道渗漏情况。我们使用了包括卡马西平和克罗米通在内的14种药物以及人为的Gd作为示踪剂，并从2016年9月至2017年11月季节性测量了这些示踪剂的浓度。咖啡因，卡马西平，克罗米通，布洛芬和人为引起的Gd的检出频率在29％至45％之间，地下水中的药物浓度低于以前的研究。所有药物浓度的中位数均未降低，而克罗他通和卡马西平浓度之和的总和（这是定量的排污指标）随时间下降。使用卡马西平，克罗米通和人为Gd估算的2016年9月的下水道渗漏率分别为污水干燥天气流量的0.59±0.27％，0.66±0.47％和0.11±0.18％，表明地震对下水道渗漏的影响很小，可能是因为损坏的下水道得以迅速修复。这项研究表明，多示踪法可用于评估大地震后下水道的渗漏。污水干燥天气的流量分别为18％，这表明地震对下水道渗漏的影响很小，这可能是因为受损的下水道得以迅速修复。这项研究表明，多示踪法可用于评估大地震后下水道的渗漏。污水干燥天气的流量分别为18％，这表明地震对下水道渗漏的影响很小，这可能是因为受损的下水道得以迅速修复。这项研究表明，多示踪法可用于评估大地震后下水道的渗漏。