Kongprajug Akechai, Denpetkul Thammanitchpol, Chyerochana Natcha, Mongkolsuk Skorn, Sirikanchana Kwanrawee
Research Laboratory of Biotechnology, Chulabhorn Research Institute, Bangkok, Thailand.
Department of Social and Environmental Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
Front Microbiol. 2021 Apr 20;12:647602. doi: 10.3389/fmicb.2021.647602. eCollection 2021.
Rapid economic development has caused industrial expansion into residential communities, leading to higher fecal pollution loads that could be discharged into aquatic environments. However, little is known regarding the potential microbial impact on human health. This study investigated microbial contamination from coastal industrial-residential community areas in nine sampling sites in waterways during three dry events. A general microbial source tracking (MST) marker, GenBac3, was detected in all samples from all three events, indicating continuing fecal pollution in the area, mostly from human sewage contamination. This was shown by the human-specific genetic marker crAssphage (88.9%) and human polyomavirus (HPyVs; 92.6%) detection. Enteric human adenovirus (HAdV40/41) showed three positive results only from residential sites in the first event. No spatial difference was observed for MST markers and traditional fecal indicators (total coliforms and ) in each event. Still, a significantly lower abundance of GenBac3, HPyVs, and total coliforms in the first sampling event was detected. Spearman's rho analysis indicated a strong correlation among certain pairs of microbial parameters. Multivariate analysis revealed two clusters of samples separated by land use type (industrial vs. residential). According to factor analysis of mixed data, the land use parameter was more associated with physicochemical parameters (i.e., salinity, conductivity, water temperature, and dissolved oxygen). A Quantitative Microbial Risk Assessment (QMRA) was then conducted to estimate the annual infection risks of HAdV40/41 for non-potable water reuse purposes using predicted concentrations from crAssphage and HPyVs. The highest risks (95th percentiles) were ranked by food crop irrigation, aquaculture, and toilet flushing, at 10, 10, and 10 per person per year (pppy). Required treatment levels to achieve a 10 pppy annual infection risk were estimated. QMRA-based water treatment scenarios were suggested, including chlorination for toilet flushing reuse and depth filtration prior to chlorination for aquaculture and food crop irrigation. Microbial monitoring combined with a QMRA could provide better insights into fecal pollution patterns and the associated risks, facilitating effective water quality management and appropriate prior treatments for water reuse.
经济的快速发展导致工业扩张至居民区，使得排入水环境的粪便污染负荷增加。然而，对于其潜在的微生物对人类健康的影响却知之甚少。本研究调查了三个干旱期内九个航道采样点的沿海工业 - 居民区的微生物污染情况。在所有三个时期的所有样本中均检测到一种通用的微生物源追踪（MST）标记GenBac3，表明该地区存在持续的粪便污染，主要源于人类污水污染。这通过人类特异性基因标记crAssphage（88.9%）和人类多瘤病毒（HPyVs；92.6%）的检测得到证实。肠道人类腺病毒（HAdV40/41）仅在第一个时期的居民区样本中出现了三个阳性结果。在每个时期，MST标记和传统粪便指标（总大肠菌群和）均未观察到空间差异。不过，在第一次采样时期检测到GenBac3、HPyVs和总大肠菌群的丰度显著较低。Spearman秩相关分析表明某些微生物参数对之间存在强相关性。多变量分析揭示了按土地利用类型（工业与住宅）划分的两个样本聚类。根据混合数据的因子分析，土地利用参数与理化参数（即盐度、电导率、水温及溶解氧）的相关性更强。随后进行了定量微生物风险评估（QMRA），以利用来自crAssphage和HPyVs的预测浓度估计非饮用水回用目的下HAdV40/41的年度感染风险。最高风险（第95百分位数）按粮食作物灌溉、水产养殖和冲厕排序，分别为每人每年10、10和10（pppy）。估计了实现每年10 pppy感染风险所需的处理水平。提出了基于QMRA的水处理方案，包括用于冲厕回用的氯化处理以及用于水产养殖和粮食作物灌溉的氯化前深度过滤。微生物监测与QMRA相结合可以更好地洞察粪便污染模式及其相关风险，有助于有效的水质管理和适当的水回用预处理。
