Integrating running water monitoring tools with the Micro Biological Survey (MBS) method to improve water quality assessment

Running water habitats are among the most altered aquatic systems by human activities driving an increase in the organic components and the associated bacterial load as well. To contribute in improving the monitoring activities in running waters, here we tested the validity of the new Micro Biological Survey (MBS) method to specifically assess the bacterial load in running waters focusing on Total Viable Counts (at 22°C and 37°C) and Escherichia coli (at 44°C) in order to propose a new prognostic tool for watercourses. MBS method is an alternative colorimetric method for counting bacterial load in water and food samples that is easy to use and leads to a reliable and simple interpretation of results, being also faster and less expensive than traditional methods. Then, we compared MBS with the traditionally used reference method for the bacterial load, and with the most used biotic index for Italian watercourses based on the benthic invertebrates: the Extended Biotic Index (EBI). The last comparison was performed to validate the use of MBS in biomonitoring activities since the benthic invertebrate multi-species assemblage (and then EBI) alter own structure mainly depending on the organic component variation. During the first part of the study, the assessment of both linearity (regressions among bacterial concentrations) and accuracy (significant correlation between a measured value and a value used as reference) confirmed the validity of the MBS method. Second, the linear regressions between the three investigated microbial parameters vs. both physical-chemical descriptors and EBI, revealed the usefulness of MBS as a valid tool for routine microbiological analyses involved in rapid and easy field monitoring activities. This represents the first attempt to evaluate the river microbial status by exploiting the innovative MBS on running waters to propose it as new valuable monitoring tool in the biomonitoring field.

流水生境是受人类活动干扰最为显著的水生生态系统之一，人类活动同时引发了水体有机质组分与关联细菌负荷的上升。为改进流水生态系统的监测工作，本研究聚焦总活菌计数（22℃与37℃培养条件下）与大肠杆菌（44℃培养条件下）的检测，验证了新型微生物学调查（Micro Biological Survey, MBS）方法在流水生境细菌负荷评估中的有效性，以期为河道监测提供一种新型预测工具。
MBS方法是一种用于水体与食品样本细菌负荷计数的替代比色检测技术，操作简便、结果解读可靠直观，相较传统检测方法更为快捷且成本更低。随后，本研究将MBS方法与传统细菌负荷检测参考方法，以及意大利河道最常用的基于底栖无脊椎动物的扩展生物指数（Extended Biotic Index, EBI）进行了对比。开展此项对比的原因在于，底栖无脊椎动物的多物种群落（及其对应的EBI）的结构变化主要取决于有机质组分的波动，因此可通过该对比验证MBS方法在生物监测中的应用价值。
研究的第一阶段中，对线性关系（细菌浓度间的回归分析）与准确度（实测值与参考标准值间的显著相关性）的评估均证实了MBS方法的有效性。
第二阶段中，针对三项研究微生物参数与理化指标、EBI分别开展的线性回归分析，揭示了MBS方法作为常规微生物分析工具的实用性，可应用于快速便捷的野外现场监测工作。本研究首次尝试将创新型MBS方法应用于流水生境的微生物状态评估，以期将其推广为生物监测领域中极具应用价值的新型监测工具。