Laboratory evaluation of largeâscale decontamination approaches
2012
Calfee, M.W. | Ryan, S.P. | Wood, J.P. | Mickelsen, L. | Kempter, C. | Miller, L. | Colby, M. | Touati, A. | Clayton, M. | GriffinâGatchalian, N. | McDonald, S. | Delafield, R.
Aims: To evaluate the effectiveness of two sprayâbased decontamination methods for surface contamination reduction and to determine the potential for contamination spread by these methods. Methods and Results: Material coupons (treated plywood and concrete) were contaminated with c. 1â×â107 spores of Bacillus atrophaeus by aerosol deposition. Decontaminants (pHâadjusted bleach or SporâKlenz® RTU) were applied to coupons by either backpack sprayer or gasâpowered sprayer. Contact time, reapplication frequency and rinse method were also varied. In addition to surface removal efficacy, partitioning of contamination between the rinsate and aerosol fractions was determined. Results indicated that pHâadjusted bleach was effective (≥6 logs reduction) when two applications and a 30âmin contact time were administered, regardless of the decontaminant application method or material. SporâKlenz® RTU was effective on wood, but achieved ≤3 logs reduction on concrete. A shortened application procedure with pHâadjusted bleach resulted in lower efficacy on wood, and a greater apparent potential for contamination spread. Conclusions: Consideration of material surface type is important when selecting a decontaminant. Also, achieving conditions that effectively inactivate surface biological contamination are critical to preventing the spread of contamination. Significance and Impact of the Study: Results presented here are intended to help development of remediation plans following a biological contamination incident.
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