Citation:

Hook, D., J. Gilberry, C. Johnson, R. Yaga, AND J. Archer. Evaluation of Water Treatments on Surfaces to Inhibit Bacterial Spore Resuspension. Remediation Journal. John Wiley & Sons, Inc., Hoboken, NJ, 34(3):e21779, (2024). https://doi.org/10.1002/rem.21779

Impact/Purpose:

Prior to and following the 2001 anthrax attack on the Hart Senate Office building, significant research has been conducted into the ability of surrogates of Bacillus anthracis spore resuspension and transport. These studies have highlighted that particle resuspension occurs readily with normal human activities and wind shear stresses, and includes the potential for particle movement during the decontamination process. Humidity and wet-dry cycles are known to increase the adhesion levels of microparticles to surfaces. Inhibiting toxic or pathogenic microparticle resuspension has the potential to reduce the risk of infiltration of material into buildings prior to or during decontamination. This, in turn, would protect the evacuating public and reduce the risk of first responder exposure by reducing the overall air concentration of particles and prevent the spread of material to areas not directly affected by the initial release event both indoors and outdoors. The purpose of this study was to evaluate the degree to which a thin water treatment reduces resuspension of a B. anthracis spore simulant, B. thuringiensis var kurstaki (Btk), from concrete surfaces.

Description:

The impact of water and the wet-dry cycle was examined as a potential mitigation solution to pathogenic bacterial spore transport and inhalation risk via resuspension of spores from surfaces due to human activities. The natural occurrence of wet-dry cycles and the ease of application make a study of the water’s potential resuspension inhibition important for two reasons; 1) active suppression to reduce the risk of inhalation exposure and 2) understanding the impact on spore transport after a natural weather event in determining the effectiveness of decontamination efforts. This study distributed a fine mist of water onto a hydrophilic surface to represent conditions during a dew cycle or fog. Resuspension experiments were conducted on clean and dusty surfaces while they were wet and after drying. These resuspension studies were directly compared to surfaces that had not undergone any surface water treatment to determine an absolute resuspension rate reduction ratio that could be treated as independent of resuspension technique. A minimum of a 3-log reduction in resuspension was observed for dusty wet coupons and a maximum reduction of 4-logs was observed after the clean coupons had dried.

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