Stanford University, Department of Civil & Environmental Engineering, 473 Via Ortega, Stanford, CA 94305, USA.
Water Res. 2011 May;45(11):3279-90. doi: 10.1016/j.watres.2011.03.033. Epub 2011 Apr 12.
This work aimed to understand the distribution of five bacterial pathogens in O'ahu coastal streams and relate their presence to microbial indicator concentrations, land cover of the surrounding watersheds, and physical-chemical measures of stream water quality. Twenty-two streams were sampled four times (in December and March, before sunrise and at high noon) to capture seasonal and time of day variation. Salmonella, Campylobacter, Staphylococcus aureus, Vibrio vulnificus, and V. parahaemolyticus were widespread -12 of 22 O'ahu streams had all five pathogens. All stream waters also had detectable concentrations of four fecal indicators and total vibrio with log mean ± standard deviation densities of 2.2 ± 0.8 enterococci, 2.7 ± 0.7 Escherichia coli, 1.1 ± 0.7 Clostridium perfringens, 1.2 ± 0.8 F(+) coliphages, and 3.6 ± 0.7 total vibrio per 100 ml. Bivariate associations between pathogens and indicators showed enterococci positively associated with the greatest number of bacterial pathogens. Higher concentrations of enterococci and higher incidence of Campylobacter were found in stream waters collected before sunrise, suggesting these organisms are sensitive to sunlight. Multivariate regression models of microbes as a function of land cover and physical-chemical water quality showed positive associations between Salmonella and agricultural and forested land covers, and between S. aureus and urban and agricultural land covers; these results suggested that sources specific to those land covers may contribute these pathogens to streams. Further, significant associations between some microbial targets and physical-chemical stream water quality (i.e., temperature, nutrients, turbidity) suggested that organism persistence may be affected by stream characteristics. Results implicate streams as a source of pathogens to coastal waters. Future work is recommended to determine infectious risks of recreational waterborne illness related to O'ahu stream exposures and to mitigate these risks through control of land-based runoff sources.
本研究旨在了解瓦胡岛沿海溪流中五种细菌病原体的分布情况，并将其存在与微生物指示物浓度、周围流域的土地覆盖以及溪流水质的理化指标联系起来。22 条溪流在四个季节（12 月和 3 月，日出前和中午）进行了四次采样，以捕捉季节性和时间变化。沙门氏菌、弯曲杆菌、金黄色葡萄球菌、创伤弧菌和副溶血性弧菌广泛存在——22 条瓦胡岛溪流中有 12 条溪流中存在所有这五种病原体。所有溪流水中还检测到四种粪便指示物和总弧菌的可检出浓度，其对数平均值±标准偏差密度分别为 2.2±0.8 肠球菌、2.7±0.7 大肠杆菌、1.1±0.7 产气荚膜梭菌、1.2±0.8 F(+)噬菌体和 3.6±0.7 总弧菌/100ml。病原体与指示物之间的二元关联表明，肠球菌与数量最多的细菌病原体呈正相关。在日出前采集的溪流水中发现肠球菌浓度较高，且弯曲杆菌的检出率较高，表明这些生物对阳光敏感。作为土地覆盖和理化水质函数的微生物多元回归模型显示，沙门氏菌与农业和森林土地覆盖呈正相关，金黄色葡萄球菌与城市和农业土地覆盖呈正相关；这些结果表明，这些土地覆盖物特有的来源可能会将这些病原体带入溪流。此外，一些微生物靶标与溪流理化水质（即温度、营养物、浊度）之间存在显著关联，表明生物体的持久性可能受到溪流特征的影响。结果表明溪流是沿海水域病原体的来源。建议开展进一步研究，以确定与瓦胡岛溪流暴露相关的娱乐性水传播疾病的感染风险，并通过控制基于土地的径流源来降低这些风险。
