Curtis Kyle, Jahne Michael, Keeling David, Gonzalez Raul
Hampton Roads Sanitation District, Virginia Beach, VA 23455, United States.
United States Environmental Protection Agency, Office of Research and Development, 26W. Martin Luther King Dr., MS 689, Cincinnati, OH 45268, United States.
Microb Risk Anal. 2024 Dec;27-28:100315. doi: 10.1016/j.mran.2024.100315.
Host-associated fecal indicator measurements can be coupled with quantitative microbial risk assessment to develop risk-based thresholds for recreational use of potential sewage-contaminated waters. These assessments require information on the relative concentrations of indicators and pathogens in discharged sewage, typically based on data collected from wastewater treatment plant influent samples. However, most untreated sewage releases occur from within the collection system itself (i.e. compromised sewer laterals, compromised gravity and force mains, sanitary sewer overflows), where these relationships may differ. This study therefore analyzed the concentrations of a selected reference pathogen (norovirus) and fecal indicator (HF183) in sewage samples from upper and lower segments of gravity sewage collection systems, wastewater pumpstations, and the influent and effluent of treatment plants, to characterize variability in their relative concentrations. Norovirus detection rates were lower and more variable in upper collection system samples due to the smaller population represented; whereas, HF183 was routinely detected at all sites with higher concentrations in the collection system compared to treatment plant influent, resulting in variable comparative relationships across sample locations (types). Mean HF183:NoV ratios ranged from 1.0 × 10 for sewer lateral samples to 7 × 10° for force main samples. Results were used to develop risk-based thresholds for HF183 based on estimated recreational exposure to norovirus following a release from each potential sewage source, with higher thresholds for treatment facility influent compared to forced mains, or effluent. Consequently, this approach can allow for the rapid application of potential risk-based thresholds for recreational water quality applications based on different types of sewage discharge events.
与宿主相关的粪便指示物测量可与定量微生物风险评估相结合，以制定基于风险的潜在污水污染水体娱乐用水阈值。这些评估需要有关排放污水中指示物和病原体相对浓度的信息，通常基于从污水处理厂进水样本收集的数据。然而，大多数未经处理的污水排放发生在收集系统本身内部（即受损的下水道支管、受损的重力和压力主管、生活污水溢流），而这些关系可能有所不同。因此，本研究分析了重力污水收集系统上下段、污水泵站以及处理厂进水和出水的污水样本中选定的参考病原体（诺如病毒）和粪便指示物（HF183）的浓度，以表征它们相对浓度的变异性。由于上段收集系统样本所代表的人群较少，诺如病毒的检测率较低且更具变异性；而HF183在所有地点均能常规检测到，与处理厂进水相比，其在收集系统中的浓度更高，导致不同样本位置（类型）的比较关系各不相同。HF183与诺如病毒的平均比值范围从下水道支管样本的1.0×10到压力主管样本的7×10°。研究结果用于根据每次潜在污水源排放后诺如病毒的估计娱乐暴露量，制定基于风险的HF183阈值，与压力主管或出水相比，处理设施进水的阈值更高。因此，这种方法可以根据不同类型的污水排放事件，快速应用基于潜在风险的娱乐用水质量阈值。
