USDA-ARS, Environmental Microbial and Food Safety Laboratory, 10300 Baltimore Avenue, Building 173, BARC-East, Beltsville, MD, 20705, USA.
School of Urban and Environmental Engineering, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea.
Sci Total Environ. 2019 Mar 25;658:753-762. doi: 10.1016/j.scitotenv.2018.12.213. Epub 2018 Dec 14.
Fecal coliform bacteria (FCB) contamination of natural waters is a serious public health issue. Therefore, understanding and anticipating the fate and transport of FCB are important for reducing the risk of contracting diseases. The objective of this study was to analyze the impacts of climate change on the fate and transport of FCB. We modified both the soil and the in-stream bacteria modules in the soil and water assessment tool (SWAT) model and verified the prediction accuracy of seasonal variability of FCB loads using observations. Forty bias-correcting GCM-RCM projections were applied in the modified SWAT model to examine various future climate conditions at the end of this century (2076-2100). Lastly, we also compared the variability of FCB loads under current and future weather conditions using multi-model ensemble simulations (MMES). The modified SWAT model yielded a satisfactory performance with regard to the seasonal variability of FCB amounts in the soil and FCB loading to water bodies. The modified SWAT model presented substantial proliferation of FCB in the soil (30.1%-147.5%) due to an increase in temperature (25.1%). Also, increase in precipitation (53.3%) led to an increase in FCB loads (96.0%-115.5%) from the soil to water body. In the in-stream environment, resuspension from the stream bed was the dominant process affecting the amount of FCB in stream. Therefore, the final FCB loads increased by 71.2% because of the growing peak channel velocity and volume of water used due to an increase in precipitation. Based on the results of MMES, we concluded that the level of FCB would increase simultaneously in the soil as well as in stream by the end of this century. This study will aid in understanding the future variability of FCB loads as well as in preparing an effective management plan for FCB levels in natural waters.
粪大肠菌群（FCB）对天然水体的污染是一个严重的公共卫生问题。因此，了解和预测 FCB 的归宿和迁移对于降低患病风险非常重要。本研究旨在分析气候变化对 FCB 归宿和迁移的影响。我们修改了土壤和水评估工具（SWAT）模型中的土壤和溪流细菌模块，并使用观测结果验证了 FCB 负荷季节性变化的预测精度。将 40 个偏差校正的 GCM-RCM 预测应用于修改后的 SWAT 模型中，以检查本世纪末（2076-2100 年）各种未来气候条件。最后，我们还使用多模型集合模拟（MMES）比较了当前和未来天气条件下 FCB 负荷的变异性。修改后的 SWAT 模型在土壤中 FCB 数量的季节性变化和 FCB 向水体的负荷方面表现出令人满意的性能。由于温度升高（25.1%），修改后的 SWAT 模型导致土壤中 FCB 大量繁殖（30.1%-147.5%）。此外，降水增加（53.3%）导致土壤向水体的 FCB 负荷增加（96.0%-115.5%）。在溪流环境中，溪流床的再悬浮是影响溪流中 FCB 数量的主要过程。因此，由于降水增加导致峰值渠道速度和水量增加，最终 FCB 负荷增加了 71.2%。基于 MMES 的结果，我们得出结论，到本世纪末，土壤和溪流中的 FCB 水平将同时增加。本研究将有助于了解 FCB 负荷的未来变异性，并为自然水中 FCB 水平的有效管理计划做好准备。
