Institute of Environmental Science and Research Limited, Christchurch Science Centre, PO Box 29-181, Christchurch, New Zealand.
Institute of Environmental Science and Research Limited, Christchurch Science Centre, PO Box 29-181, Christchurch, New Zealand.
Sci Total Environ. 2019 Feb 15;651(Pt 1):1588-1604. doi: 10.1016/j.scitotenv.2018.09.258. Epub 2018 Sep 21.
This study explores the relationships between faecal source tracking (FST) markers (quantitative Polymerase Chain Reaction (qPCR) markers and steroids), microbial indicators, the faecal ageing ratio of atypical colonies/total coliforms (AC/TC) and potential human pathogens (Giardia, Cryptosporidium and Campylobacter). Faecal source PCR markers tested were GenBac3, HumM3, HumBac (HF183-Bac708R); Bifidobacterium adolescentis, wildfowl and canine-associated markers. Sediment and water samples from the Avon River were collected during and post-discharge of untreated human sewage inputs, following a series of earthquakes, which severely damaged the Christchurch sewerage system. Significant, positive Spearman Ranks (r) correlations were observed between human-associated qPCR markers and steroid FST markers and Escherichia coli and F-specific RNA bacteriophage (r 0.57 to 0.84, p < 0.001) in water samples. These human source indicative FST markers demonstrated that they were also effective predictors of potentially pathogenic protozoa in water (r 0.43-0.74, p ≤ 0.002), but correlated less well with Campylobacter. Human-associated qPCR and steroid markers showed significant, substantial agreement between the two FST methods (Cohen's kappa, 0.78, p = 0.023), suggesting that water managers could be confident in the results using either method under these contamination conditions. Low levels of fluorescent whitening agents (FWA) (mean 0.06 μg/L, range 0.01-0.40 μg/L) were observed in water throughout the study, but steroids and FWA appeared to be retained in river sediments, months after continuous sewage discharges had ceased. No relationship was observed between chemical FST markers in sediments and the overlying water, and few correlations in sediment between chemical FST markers and target microorganisms. The low values observed for the faecal ageing ratio, AC/TC in water, were significantly, negatively correlated with increasing pathogen detection. This study provides support for the use of the AC/TC ratio, and qPCR and steroid FST markers as indicators of health risks associated with the discharge of raw human sewage into a freshwater system.
本研究探讨了粪便源追踪（FST）标志物（定量聚合酶链反应（qPCR）标志物和类固醇）、微生物指标、非典型菌落/总大肠菌群（AC/TC）的粪便老化比和潜在的人类病原体（贾第虫、隐孢子虫和弯曲菌）之间的关系。测试的粪便源 PCR 标志物包括 GenBac3、HumM3、HumBac（HF183-Bac708R）；双歧杆菌、野生鸟类和犬科相关标志物。地震严重破坏了基督城的污水系统后，在未经处理的人类污水输入期间和之后，从雅芳河采集了沉积物和水样。在水样中，与人类相关的 qPCR 标志物和类固醇 FST 标志物与大肠杆菌和 F 特异性 RNA 噬菌体呈显著正 Spearman 秩相关（r 0.57 至 0.84，p < 0.001）。这些指示人类来源的 FST 标志物表明，它们也是水中潜在致病原生动物的有效预测因子（r 0.43-0.74，p ≤ 0.002），但与弯曲菌的相关性较差。与人类相关的 qPCR 和类固醇标志物在两种 FST 方法之间显示出显著的实质性一致性（Cohen's kappa，0.78，p = 0.023），这表明在这些污染条件下，水管理者可以对使用任何一种方法的结果充满信心。在整个研究过程中，水中都观察到低水平的荧光增白剂（FWA）（平均值 0.06μg/L，范围 0.01-0.40μg/L），但类固醇和 FWA 似乎在连续污水排放停止数月后仍保留在河沉积物中。沉积物中的化学 FST 标志物与上覆水之间没有观察到关系，沉积物中化学 FST 标志物与目标微生物之间的相关性也很少。水中粪便老化比 AC/TC 的低值与病原体检测的增加呈显著负相关。本研究支持使用 AC/TC 比、qPCR 和类固醇 FST 标志物作为指示与向淡水系统排放未经处理的人类污水相关的健康风险的指标。
