After a biological terrorist attack, understanding the migration of agents such as Bacillus anthracis is critical due to their deadly nature. This is important in urban settings with higher likelihood of human exposure and a large fraction of impervious materials contributing to pollutant washoff. The study goals were to understand the removal of spores from urban surfaces under different rainfall conditions, to compare washoff of two B. anthracis surrogate spores, and to compare two empirical fits for the first flush of spores from small areas. Concrete and asphalt were inoculated with either Bacillus atrophaeus or Bacillus thuringiensis kurstaki spores and exposed to simulated rainfall. The study assessed goodness‐of‐fit for the Storm Water Management Model (SWMM)'s exponential washoff function compared to an alternative two‐stage exponential function. The highest average washoff of spores was 15% for an hour‐long experiment. Spore washoff was not significantly different for the two spore types, but there were significant differences in washoff from asphalt versus concrete with more occurring from asphalt. Average kinetic energy of the storm event impacted washoff from asphalt, but not concrete. The two‐stage function had a better goodness‐of‐fit than the SWMM exponential function. As such, emergency responders should be aware that the spread of contamination is impacted by the droplet characteristics of the storm event and the surface material type in the contaminated area; modelers should be aware that different data‐fitting approaches may be more appropriate for first‐flush calculations of small washoff areas than those used for continuous long‐term simulation of large subcatchments.

中文翻译：

---

雨水冲刷掉混凝土和沥青表面的孢子

在生物恐怖袭击之后，了解炭疽杆菌等病原体的迁移至关重要，因为它们具有致命性。这在城市环境中非常重要，因为城市环境中人类暴露的可能性更高，并且大部分不透水材料会导致污染物冲刷。研究目标是了解不同降雨条件下城市表面孢子的去除情况，比较两种炭疽芽孢杆菌替代孢子的冲刷情况，并比较小区域孢子首次冲洗的两种经验拟合。用萎缩芽孢杆菌或苏云金芽孢杆菌 kurstaki接种混凝土和沥青孢子并暴露于模拟降雨中。该研究评估了雨水管理模型 (SWMM) 的指数冲刷函数与替代的两阶段指数函数相比的拟合优度。在长达一小时的实验中，孢子的最高平均冲刷率为 15%。两种孢子类型的孢子冲刷没有显着差异，但沥青与混凝土的冲刷存在显着差异，沥青的冲刷更多。风暴事件的平均动能影响了沥青的冲刷，但不影响混凝土。两阶段函数比 SWMM 指数函数具有更好的拟合优度。因此，应急响应人员应该意识到污染的传播受到风暴事件的液滴特征和污染区域的表面材料类型的影响；