Department of Biology, Memorial University of Newfoundland, St. John's, NL, Canada.
Département de Géomatique Appliquée, Université de Sherbrooke, Sherbrooke, QC, Canada.
Front Public Health. 2020 Nov 25;8:607997. doi: 10.3389/fpubh.2020.607997. eCollection 2020.
Performing microbiological assays on environmental samples in field settings poses logistical challenges with respect to the availability of suitable equipment or the ability to get samples to the laboratory in a timely fashion. For example, the viability of some bacteria can decrease greatly between sampling and arrival to the laboratory for processing. We developed and constructed rugged, reliable, and cost-effective portable incubators that were used by 10 independent field teams to perform microbiological assays on surface water samples from lakes across Canada. Rigorous testing and validation of our incubators ensured that incubation conditions were consistent within and across all 10 field teams and 2 sampling years. Samples from all sites were processed in duplicate and bacterial counts were highly repeatable within and across sampling teams. Bacterial counts were also found to be statistically equivalent to counts obtained with standard laboratory techniques using a conventional incubator. Using this method, thermotolerant coliforms (TTCs) and were quantified from 432 lakes, allowing comparison to both historical datasets that relied on TTCs and those following current guidelines that use counts. We found higher loads at the shoreline than the middle of lakes and different patterns between ecozones. was not frequently detected, but many lakes exceeded Canadian guideline values for activities such as swimming and some even exceeded the guideline value for secondary recreational activities such as boating. To the best of our knowledge, this is the largest bacteriological water quality assessment of freshwater lakes to date in terms of both spatial scale and the number of lakes sampled. Our incubator design can be easily adapted for a wide variety of researcher goals and represents a robust platform for field studies and other applications, including those in remote or low-resources settings.
在野外环境中对环境样本进行微生物检测存在一些后勤方面的挑战，例如设备是否可用，或者能否及时将样本送到实验室。例如，有些细菌的存活率在采样和到达实验室进行处理之间会大大降低。我们开发并构建了坚固、可靠且具有成本效益的便携式培养箱，由 10 个独立的野外团队使用，对来自加拿大各地湖泊的地表水样本进行微生物检测。我们对培养箱进行了严格的测试和验证，以确保所有 10 个野外团队和 2 个采样年份的孵育条件保持一致。所有站点的样本均进行了重复处理，并且细菌计数在采样团队内部和之间具有高度可重复性。还发现，使用这种方法获得的细菌计数与使用传统培养箱的标准实验室技术获得的计数在统计学上是等效的。使用这种方法，从 432 个湖泊中定量了耐热大肠菌群（TTC）和 ，并与依赖 TTC 的历史数据集以及当前使用 计数的指南进行了比较。我们发现，在湖边的负荷比在湖中心的负荷高，而且在生态区之间存在不同的模式。 虽然不常被检测到，但许多湖泊的活动水平（如游泳）超过了加拿大的指导值，有些甚至超过了划船等二级娱乐活动的指导值。据我们所知，就空间尺度和采样湖泊数量而言，这是迄今为止对淡水湖泊进行的最大规模的细菌水质评估。我们的培养箱设计可以轻松适应各种研究人员的目标，是野外研究和其他应用（包括在偏远或资源匮乏地区的应用）的强大平台。
