CSIRO Land and Water, Ecosciences Precinct, 41 Boggo Road, QLD 4102, Australia.
Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104, USA.
Environ Int. 2018 Aug;117:243-249. doi: 10.1016/j.envint.2018.05.012. Epub 2018 May 15.
Microbial source tracking (MST) methods have provided the means to identify sewage contamination in recreational waters, but the risk associated with elevated levels of MST targets such as sewage-associated Bacteroides HF183 and other markers is uncertain. Quantitative microbial risk assessment (QMRA) modeling allows interpretation of MST data in the context of the risk of gastrointestinal (GI) illness caused by exposure to pathogens. In this study, five sewage-associated, quantitative PCR (qPCR) MST markers [Bacteroides HF183 (HF183), Methanobrevibacter smithii nifH (nifH), human adenovirus (HAdV), human polyomavirus (HPyV) and pepper mild mottle virus (PMMoV)] were evaluated to determine at what concentration these nucleic acid markers reflected a significant health risk from exposure to fresh untreated or secondary treated sewage in beach water. The QMRA models were evaluated for a target probability of illness of 36 GI illnesses/1000 swimming events (i.e., risk benchmark 0.036) for the reference pathogens norovirus (NoV) and human adenovirus 40/41 (HAdV 40/41). Sewage markers at several dilutions exceeded the risk benchmark for reference pathogens NoV and HAdV 40/41. HF183 concentrations 3.22 × 10 (for both NoV and HAdV 40/41) gene copies (GC)/100 mL of water contaminated with fresh untreated sewage represented risk >0.036. Similarly, HF183 concentrations 3.66 × 10 (for NoV and HAdV 40/41) GC/100 mL of water contaminated with secondary treated sewage represented risk >0.036. HAdV concentration as low as 4.11 × 10 GC/100 mL of water represented risk >0.036 when water was contaminated with secondary treated sewage. Results of this study provide a valuable context for water quality managers to evaluate human health risks associated with contamination from fresh sewage. The approach described here may also be useful in the future for evaluating health risks from contamination with aged or treated sewage or feces from other animal sources as more data are made available.
微生物源追踪 (MST) 方法为识别娱乐水中的污水污染提供了手段，但与 MST 目标（如与污水相关的拟杆菌 HF183 和其他标记物）水平升高相关的风险尚不确定。定量微生物风险评估 (QMRA) 模型允许在接触病原体引起的胃肠道 (GI) 疾病风险的背景下解释 MST 数据。在这项研究中，评估了五种与污水相关的定量 PCR (qPCR) MST 标记物 [拟杆菌 HF183 (HF183)、甲烷杆菌 nifH (nifH)、人腺病毒 (HAdV)、人多瘤病毒 (HPyV) 和胡椒轻斑驳病毒 (PMMoV)]，以确定在何种浓度下，这些核酸标记物反映了在海滩水中接触未经处理或二级处理的新鲜污水的健康风险。QMRA 模型针对目标疾病发生率为 36 例 GI 疾病/1000 次游泳事件（即风险基准 0.036）进行了评估，针对参考病原体诺如病毒 (NoV) 和人腺病毒 40/41 (HAdV 40/41)。在几个稀释度下，污水标记物超过了参考病原体诺如病毒和人腺病毒 40/41 的风险基准。HF183 浓度为 3.22×10（用于诺如病毒和 HAdV 40/41）基因拷贝数 (GC)/100 mL 受未经处理的新鲜污水污染的水代表风险 >0.036。类似地，HF183 浓度为 3.66×10（用于诺如病毒和 HAdV 40/41）GC/100 mL 受二级处理污水污染的水代表风险 >0.036。当水受到二级处理污水污染时，HAdV 浓度低至 4.11×10 GC/100 mL 也代表风险 >0.036。本研究的结果为水质管理者评估与新鲜污水污染相关的人类健康风险提供了有价值的背景。随着更多数据的可用，这里描述的方法将来也可能用于评估与老化污水或其他动物来源的粪便污染相关的健康风险。
