USDA-Agricultural Research Service , Northwest Irrigation and Soils Research Laboratory, 3793 North 3600 East, Kimberly, Idaho 83341, United States.
Environ Sci Technol. 2014 May 6;48(9):5033-42. doi: 10.1021/es405693v. Epub 2014 Apr 16.
In the western United States where dairy wastewaters are commonly land applied, there are concerns over individuals being exposed to airborne pathogens. In response, a quantitative microbial risk assessment (QMRA) was performed to estimate infectious risks after inhalation exposure of pathogens aerosolized during center pivot irrigation of diluted dairy wastewaters. The dispersion of pathogens (Campylobacter jejuni, Escherichia coli O157:H7, non-O157 E. coli, Listeria monocytogenes, and Salmonella spp.) was modeled using the atmospheric dispersion model, AERMOD. Pathogen concentrations at downwind receptors were used to calculate infectious risks during one-time (1, 8, and 24 h) and multiday (7 d at 1 h d(-1)) exposure events using a β-Poisson dose-response model. This assessment considered risk of infection in residential populations that were 1 to 10 km from a center pivot operation. In the simulations, infectious risks were estimated to be the greatest in individuals closest to the center pivot, as a result of a higher pathogen dose. On the basis of the results from this QMRA, it is recommended that wastewaters only be applied during daylight hours when inactivation and dilution of airborne pathogens is highest. Further refinement of the dispersion and dose-response models should be considered to increase the utility of this QMRA.
在美国西部，奶制品废水通常被土地利用，人们担心个体暴露于空气中的病原体。因此，进行了定量微生物风险评估（QMRA），以估计在中心枢轴灌溉稀释奶制品废水中雾化的病原体吸入暴露后感染的风险。使用大气扩散模型 AERMOD 对病原体（空肠弯曲菌、大肠杆菌 O157:H7、非 O157 大肠杆菌、单核细胞增生李斯特菌和沙门氏菌）的扩散进行建模。利用β-泊松剂量反应模型，根据下风接受器处的病原体浓度，计算单次（1、8 和 24 小时）和多日（7 天，每天 1 小时）暴露事件期间的感染风险。这项评估考虑了距中心枢轴操作 1 至 10 公里范围内的居住人群的感染风险。在模拟中，由于较高的病原体剂量，最接近中心枢轴的个体感染风险估计最大。根据这项 QMRA 的结果，建议仅在白天进行废水处理，此时空气中病原体的失活和稀释效果最佳。应考虑进一步细化扩散和剂量反应模型，以提高该 QMRA 的实用性。
