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Abstract

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. MATERIALS AND METHODS
  5. RESULTS AND DISCUSSION
  6. ACKNOWLEDGMENTS
  7. REFERENCES
  8. Biographies

The cleaning robots, a vacuum-based robot (R2) and a wetted-wipe-based robot (R4), were evaluated in this study to determine their effectiveness for sampling Bacillus atrophaeus spores. The tests were designed to evaluate the benefit of robot sampling on large areas with two different contamination scenarios: a high-concentration, low spatial extent contamination (hot spot) and a low concentration, high spatial extent contamination (widely dispersed). The hot spot tests were conducted with the high spore contamination (approximately 107 colony forming units [CFUs]) on a limited area (30.5 cm × 30.5 cm), 2 percent of the entire test. The widely dispersed tests were conducted with approximately 0.1 CFUs/cm2 for floor laminate and approximately 10 CFUs/cm2 for carpet surfaces. The widely dispersed tests distributed spores across the test surface and covered approximately 40 percent of the entire test area. The test results showed that both robots successfully sampled a large quantity of spores from carpet and floor laminate surfaces for both test scenarios. Robot performance is discussed in the context of currently used surface sampling methods. © 2014 Wiley Periodicals, Inc.*


INTRODUCTION

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. MATERIALS AND METHODS
  5. RESULTS AND DISCUSSION
  6. ACKNOWLEDGMENTS
  7. REFERENCES
  8. Biographies

Following the 2001 Bacillus anthracis letter attacks, sampling methods such as the wetted gauze wipe, vacuum sock, swab, and air filtration were used to determine the presence, magnitude, and spatial extent of contamination (Small et al., 2001). More recent efforts have focused on the validation of these methodologies, as recommended by a U.S. Government review panel (GAO, 2005a; Hodges et al., 2010; Krauter et al., 2012; Rose et al., 2011). However, sample collection and analysis remains a significant bottle-neck for response to a large-scale biological contamination incident, potentially requiring thousands of samples using the current sampling techniques (Buttner et al., 2004; Franco & Bouri, 2010). Recently, the utility of commercially available robotic floor cleaning devices for collection of Bacillus spores was demonstrated by Lee et al. (2013). Autonomous collection of samples over large spatial scales (as compared to the area covered using the current sampling methods) could reduce sampling personnel, sampling time, exposure risk, and analytical laboratory workload, without reducing the total area sampled. In the current study, a scenario-based evaluation was set-up to determine the effectiveness of two robotic floor cleaning devices at collecting spores from surfaces in areas with widely dispersed contamination or hot spots. A wetted-wipe-based robot was evaluated on laminate flooring (nonporous) and a vacuum-based robot was evaluated on carpet (porous). The robots were each challenged with two contamination scenarios: a low level, large spatial extent of contamination (widely dispersed) scenario in which approximately 40 percent of the total area sampled was inoculated with spores (approximately 0.1 colony forming units [CFUs] per square centimeter [cm2] and 10 CFUs/cm2) and a high level, small spatial extent of contamination (hot spot) scenario in which approximately 2 percent of the test area was loaded with spores (approximately 104 CFUs/cm2).

MATERIALS AND METHODS

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. MATERIALS AND METHODS
  5. RESULTS AND DISCUSSION
  6. ACKNOWLEDGMENTS
  7. REFERENCES
  8. Biographies

In this study, two cleaning robots were selected from the previous experiments described in Lee et al. (2013). Aerosol deposited B. atrophaeus spores were used as a surrogate of B. anthracis spores. Robotic cleaners were evaluated for their performance when challenged with two different contamination scenarios: hot spot and widely dispersed contamination in the test chamber. Test results were compared to currently used surface sampling methods (vacuum sock and sponge wipe).

Cleaning Robots

Two types of commercially available cleaning robots, a vacuum-based robot (R2 from the previous study, XV-11, Neato robotics®, Newark, CA) and a wetted-wipe-based robot (R4 from the previous study, Mint 4200, Evolution Robotics, Inc. Pasadena, CA), were selected from the previous study results and purchased from an internet retail store. R2 and R4 were tested for sampling efficiency on carpet and floor laminate surfaces, respectively, by following the factory manuals procedures for use. The sterilization procedure and sterility checks of test robots are addressed in the previous paper in detail (Lee et al., 2013). In brief, all tested robots were sterilized with vaporized hydrogen peroxide (H2O2; VHP®, 1000ED, Steris, Mentor, OH) before testing and the sterility of robots was confirmed by sampling at least one robot per sterilization batch by swabbing the robot surfaces. Test robots retained their factory settings during testing, and each robot was used only once before being discarded. The R4 wipe material was soaked with sterile phosphate buffered saline with 0.05 weight percent Tween 20 (PBST) before testing.

Test Materials

Robot sampling tests were conducted with two floor surface types: carpet (Model 6666-01-1200-AB, Beaulieu Laredo Sagebrush loop carpet) and floor laminate (PE-191113, Pergo Estate Oak). These materials were purchased from a local retail store (Home Depot, Durham, NC). Coupons were fabricated into 107 cm × 107 cm and 71 cm × 71 cm size pieces for robot sampling tests and 36 cm × 36 cm for vacuum or sponge wipe sampling tests to fit into the Consequence Management and Decontamination Evaluation Room (COMMANDER; Exhibit 1; Wood et al., 2013). Both coupon types were backed with an equal-sized piece of 1.1 cm thick Oriented Strand Board (OSB) plywood. Test coupons were treated before testing to remove the detachable foreign debris and particles. This entailed vacuuming the carpet coupons and the laminate coupons were cleaned with a dry wipe (SIMWyPE tack cloth, Babcock & Wilcox Technical Services Y-12 L.L.C., Oak Ridge, TN). After surface cleaning, all test coupons were sterilized by exposure to 250 ppm of H2O2 for 4 hr inside the COMMANDER. The sterilized coupons were stored in sterilization bags (P/N 63636TW, General Econopak, Inc., Philadelphia, PA) until tested. All fumigated coupons and apparatus were degassed for at least 3 days and their sterility was confirmed by sampling at least one coupon and one deposition apparatus per sterilization batch by swabbing (P/N R12100, Remel Products, Lenexa, KS) their respective surfaces. Sterility check and coupon preparation procedures were described previously (Lee et al., 2013).

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Exhibit 1. COMMANDER floor test setup

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Spore Deposition

The B. anthracis surrogate used for this study was a powdered spore preparation of B. atrophaeus (ATCC 9372, Manassas, VA) and silicon dioxide particles. The preparation procedure is reported in Brown et al. (2007). The powdered preparation was loaded into metered dose inhalers (MDIs). The MDI preparation and characteristics have been reported (Calfee et al., 2013; Carrera et al., 2005; Lee et al., 2011). The sterilized coupons were inoculated using the MDI following the method described in the study by Calfee et al. (2013). Coupons were inoculated with between 10−1 CFUs/cm2 and 104 CFUs/cm2, depending on defined target inoculum levels (Exhibit 2). The consistency and loading levels of inoculums were verified using four stainless steel control coupons during each inoculation event. Test coupons used for robot sampling tests were inoculated in the centermost 30.5 cm × 30.5 cm area of the coupon (36 cm × 36 cm). The same size area was inoculated on the comparative surface sampling method coupons. All test coupons underwent the same inoculation procedures, and were stored (less than 24 hr) together until used in testing. Each coupon was inoculated independently using separate dosing chambers, originally designed for inoculation of the centermost 30.5 cm × 30.5 cm areas of 36 cm × 36 cm coupons. Following a metered dissemination, spores were allowed to settle onto the coupons for a minimum period of 18 hr.

Exhibit 2. Test matrix for two scenarios: Hot spot and widely dispersed contamination

Scenario TypeSurfaceRobotTarget Spore Loading (CFUs/cm2)
Hot spotCarpetR2104
Hot spotCarpetR2104
Widely dispersed contaminationCarpetR2101
Widely dispersed contaminationCarpetR2101
Hot spotLaminateR4104
Hot spotLaminateR4104
Widely dispersed contaminationLaminateR410−1
Widely dispersed contaminationLaminateR410−1

Robot Testing Procedure

All Robot sampling tests were conducted inside COMMANDER and the test environment was controlled for the temperature (22 ± 0.7 °C) and relative humidity (57 ± 5 percent). More detailed information about the COMMANDER can be found in a prior publication (Wood et al., 2013). The test initiated with a blank robot sampling. After the blank sampling, B. atrophaeus spore-inoculated test coupons were sampled with robots. After the completion of sampling, the robots were powered off, removed from the testing chamber one at a time, and disassembled for retrieval of the sample. The robot components were placed in a sterilized plastic bag. Each bag was then secondarily contained in another bag and transported to another laboratory for processing.

To evaluate R2 and R4 in the two scenarios, hot spot and widely dispersed contamination, subsections of the floor were inoculated using the method described in the previous section. COMMANDER was fitted with pre-sterilized coupons as shown in Exhibit 1. The set-up consisted of two 107 cm × 107 cm coupons, four 71 cm × 71 cm coupons, and a single 36 cm × 36 cm coupon in the center. The spore inoculation was performed at the center of the room for the hot spot. Approximately 1.7 m2 from two 107 cm × 107 cm coupons and the center coupon (36 cm × 36 cm) were inoculated for the widely dispersed scenario (Exhibit 1).

Surface Sampling Procedure

The number of spores CFUs sampled using test robots was compared to the CFUs obtained by currently used surface sampling methods. Control coupons of carpet and laminate were sampled using currently used surface sampling methods (Brown et al., 2007; GAO, 2005b; Krauter et al., 2012; Rose et al., 2011; Valiante et al., 2003). Floor laminate surfaces were sampled with a sponge wipe sampling method and carpet surfaces with a vacuum sock method. An area of 34 cm × 34 cm, delineated with a sterile stainless steel template placed over the target area was sampled with the sponge wipe. Sponge wipe samples were collected using the following five steps: (1) the surface was sampled using horizontal S-strokes using one flat side of the sponge wipe, covering the entire template area; (2) the sponge wipe was then flipped over to the opposite flat side to sample the surface in a vertical S-stroke pattern, covering the entire template area; (3) using the narrow edges of the sponge wipe, the surface was sampled using the same S-strokes but applied diagonally across the template, (4) rotating the sponge to use the opposite narrow edge at the midway point of the coupon; and (5) the tip of the sponge wipe was then used to sample the perimeter of the sampling area. During vacuum sampling, a 34 cm × 34 cm sterile stainless steel template and a sterile sock/nozzle attachment to a vacuum were used to collect the sample. Holding the nozzle at a 45 degree angle on the sample area, samples were taken using horizontal and vertical S-strokes. The sponge wipe sampling method is described in detail in the study by Rose et al. (2011), and the vacuum sock method is a modified version of the method detailed in the study by Brown et al. (2007).

Sampling Extraction and Spore Recovery

Sponge wipe (PN SSL10NB, 3M Inc., St. Paul, MN) samples were extracted by stomaching (1 min, 260 rpm) in 90 mL of PBST using a Seward® Model 400 circulator (Seward® Laboratory Systems, Inc, Port Saint Lucie, FL). Vacuum sock samples were extracted by first wetting the collection (white) portion of the filter in PBST, then cutting it with sterile scissors (vertically and horizontally) into small pieces (approximately 1 cm × 4 cm). As the filter was fractioned, the resulting pieces were allowed to fall into a 120 mL sterile specimen cup (Starplex Scientific LeakBuster Specimen Containers, Fisher Scientific, Pittsburgh, PA) containing 20 mL sterile PBST. The cups were then agitated (30 min, 300 rpm, ambient temperature) using an orbital platform shaker incubator (Model 3625, Lab-Line Instruments, Inc., Melrose Park, IL). Spores collected by R4 were recovered from the mopping cloth by stomaching the cloth (2 min, 230 rpm) in 133 mL PBST using a Seward® Model 400 circulator (Seward Laboratory Systems, Inc., Bohemia, NY).

Two extraction procedures were required for R2 as collected spores could have partitioned to either the collection bin or the filter. Recovery from the filters proceeded by placing each filter into two 14 cm × 23 cm sterile sample bags (Fisher Scientific, Pittsburgh, PA), one inside the other for double containment. A total of 180 mL of sterile PBST was then added to the innermost bag, and the samples were agitated (30 min, 300 rpm) on an orbital platform shaker incubator (Model 3625, Lab-Line Instruments, Inc., Melrose Park, IL). Spore recovery from the particle bins was accomplished by placing the bins into double layer of 25 cm × 38 cm sterile sample bags, aseptically adding 180 mL of PBST to each bag containing the bin, and then agitating (30 minutes, 300 rpm, ambient temperature) on an orbital platform shaker incubator (Model 3625, Lab-Line Instruments, Inc., Melrose Park, Illinois).

The resulting liquid extracts from the robots and all fractions were individually concentrated by centrifugation where, briefly, each sample was retrieved from its respective extraction bag or cup, and dispensed equally into four 50 mL conical tubes (approximately 45 mL for each tube). The samples were then centrifuged (3,500 × g, 15 min, 4 °C) to sediment the collected spores. All but 5 mL of the supernatant was carefully removed via 50 mL sterile serological pipette. Each spore pellet was resuspended in the remaining 5 mL by three cycles of alternating vortex mixing (30 sec) and sonication (30 sec, 40 kHz, Model 8510, Branson, Rochester, NY).

Following resuspension, the four fractions per sample were recombined into one approximately 20 mL sample extract. All sample extracts (robot, vacuum sock, and sponge wipe) were then subjected to a series of ten-fold dilutions, as necessary, by adding 0.1 mL of the sample to 0.9 mL of PBST using a micropipette. Appropriate dilutions were spread in triplicate (0.1 mL each) onto trypticase soy agar (BD™; Becton, Dickinson, and Company, Franklin Lakes, NJ) plates and incubated at 35 ± 2 °C. Resulting CFUs were counted manually after approximately 18 hr. The recovery for each sample was determined by averaging the observed CFUs from triplicate plates (subsamples), multiplying by the inverse of the dilution factor, dividing by the volume plated (typically 0.1 mL), and multiplying by the total volume of the sample extract. Total recoveries from each of the replicate samples were then averaged to determine mean recovery for each device and material type.

RESULTS AND DISCUSSION

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. MATERIALS AND METHODS
  5. RESULTS AND DISCUSSION
  6. ACKNOWLEDGMENTS
  7. REFERENCES
  8. Biographies

Hot Spot Tests

For hot spot tests, approximately 104 CFUs/cm2 were inoculated on the area (30.5 cm × 30.5 cm) in the center of the test area (approximately 4.4 m2) as shown in Exhibit 1. The results are shown in Exhibit 3. The average CFUs obtained with currently used surface sampling methods were obtained by sampling separately inoculated surfaces with the vacuum sock method for carpet and the sponge wipe method for laminate flooring. These results represent the recoveries when the currently used method was used to sample the exact hot spot area (e.g., sampling only the inoculated 30.5 cm × 30.5 cm area), i.e., the sampler had knowledge of the location of the hot spot. The CFUs recovered from R2 (Exhibit 3) were approximately 5 to 10 times less than those achieved by the vacuum sock method. In the case of the laminate surfaces, the spores recovered by R4 were similar in quantity to recoveries achieved by the sponge wipe method.

Exhibit 3. Hot spot test results

Surface TypeRobotAverage Currently Used Surface Sampling Recovery (CFUs/929 cm2), n = 3Robot Sampling Recovery (CFUs)
CarpetR21.6 × 106 ± 6.1 × 1051.4 × 105
CarpetR21.9 × 106 ± 1.7 × 1065.8 × 105
LaminateR41.6 × 107 ± 3.9 × 1061.2 × 107
LaminateR41.7 × 106 ± 1.4 × 1062.1 × 106

Widely Dispersed Contamination Tests

Surface spore loadings were approximately 0.1 CFUs/cm2 and 10 CFUs/cm2 on laminate and carpet surfaces, respectively. The inoculated area (1.8 m2) was approximately 40 percent of the entire test surface (approximately 4.4 m2) for each test. The results from the widely dispersed contamination tests are shown in Exhibit 4. As explained in the previous section, the average recoveries of currently used surface sampling methods were obtained by sampling separately inoculated surfaces (area of approximately 1,000 cm2). Therefore, these results represent the CFUs recovered for these methods when used to sample only an inoculated area. The quantification limit of the extraction and analysis method used in this study for B. atrophaeus is approximately 100 CFUs/sample (Lee et al., 2013). Since the sampling efficacies are approximately 1 to 10 percent and 60 to 100 percent for R2 and R4 on carpet and laminate surfaces, respectively, the spore surface loadings were targeted as 102 and 104 CFUs for laminate and carpet surface tests, respectively. These loading levels represented a near quantification limit challenge. The total CFUs recovered from R2 sampling tests (sampling area of approximately 4.4 m2) on carpet were all higher by a factor of 5.2 and 1.4 compared to the vacuum sock sampling results (sampling area of 1,000 cm2). For laminate surface, the total CFUs recovered from R4 were 6.2, and 7.4 times higher than the ones recovered from the sponge wipe sampling.

Exhibit 4. Widely dispersed contamination test results

Surface TypeRobotAverage Currently Used Surface Sampling Recovery (CFUs/929 cm2), n = 3Robot Sampling Recovery (CFUs)
CarpetR29.6 × 102 ± 5.2 × 1025.0 × 103
CarpetR22.3 × 102 ± 4.2 × 1013.2 × 102
LaminateR44.5 × 102 ± 4.5 × 1022.8 × 103
LaminateR46.6 × 101 ± 3.8 × 1014.9 × 102

Implications

Robots were challenged for their sampling capability with two different scenarios (hot spot and widely dispersed contamination). The currently used sampling methods use a discrete sampling area. The sampling areas are about 3,716 cm2 for the vacuum sock method and 929 cm2 for the sponge wipe method (CDC, 2013; Rose et al., 2011). One sample of the currently used methods covers approximately 8 percent and 2 percent of the entire floor (approximately 4.4 m2) for the vacuum sock and the sponge wipe methods, respectively. The hot spot area (30.5 cm × 30.5 cm) in the test scenario was about 2 percent of the entire floor. Using these methods, the detection capability depends on the choice of sample location. Without prior knowledge of contaminant location, increasing the probability of detection by discreet sampling methods requires an increase in the amount of area sampled.

The visual observation of robots’ operation during tests confirmed that the test robots sampled more than 90 percent of the test area. Test results also showed that the robots afforded a detection rate of 100 percent during the hot spot scenario (Exhibit 3). This clearly demonstrates that the wide area sampling capability of robots can increase the probability to detect the sparsely distributed contaminants compared to the currently used sampling methods.

During hot spot tests, some contamination was relocated to previously non-inoculated areas by the robots (data not shown). Contaminant relocation can increase the spatial extent of contamination in a hot spot scenario; however, the extent is confined to the area sampled and is not likely to change the decontamination approach. In addition, the increased probability of contaminant detection, in the hot spot scenario, significantly outweighs the potential for contaminant spread.

The widely dispersed contamination test was designed to assess the composite sampling capability of robots on areas with low level widely dispersed contamination. For comparison, if the test area was sampled once with currently used methods with a randomized (statistical) sampling approach, the probability of sampling the contaminated area would be 40 percent since only 40 percent of the test area was contaminated. According to the study by Krauter et al., the limit of detection using the sponge wipe sampling method was between 0.015 CFUs/cm2 and 0.039 CFUs/cm2 for six different nonporous surfaces (Krauter et al., 2012). In this study, the currently used methods (laminate surfaces) yielded 66 CFUs/sample and 450 CFUs/sample, which were near the detection limit (0.07–0.48 CFUs/cm2, respectively). The robots demonstrated recoveries of 490 CFUs/sample and 2,800 CFUs/sample. Using sampling approaches near or below the detection limit increases the likelihood of false negative results.

The previous studies demonstrated the potential use of commercially available cleaning robots as spore sampling tools by testing the various robots in a limited area (71 cm × 71 cm with 102 CFUs/cm2). The current study evaluated the robots’ performance when challenged with different spore loading levels. The results showed that the robots sample as effectively as the currently used surface sampling methods for various spore loadings. The robots were further challenged by two contamination scenarios: a low level, large spatial extent of contamination (widely dispersed) and a high level, low spatial extent of contamination (hot spot). The test results confirmed the potential that the composite sampling capability of robots can improve the detection capability in a wide area, whether hot spot or widely dispersed, over the currently used sampling methods.

As shown in the current and previous studies, cleaning robots have various benefits for wide area sampling over the currently used sampling methods: fewer numbers of samples via one sample per deployment, composite samples, less risk of personnel exposure, etc. Future studies will focus on evaluating cleaning robots for their effectiveness at sampling in a real world scenario.

ACKNOWLEDGMENTS

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. MATERIALS AND METHODS
  5. RESULTS AND DISCUSSION
  6. ACKNOWLEDGMENTS
  7. REFERENCES
  8. Biographies

The U.S. Environmental Protection Agency, through its Office of Research and Development, completed the research described here under ARCADIS G&M contract #EP-C-09-027. This study was funded through the Wide Area Recovery and Resiliency Program by the Department of Homeland Security (DHS) Science and Technology Directorate under interagency agreement (# RW-70-95812401). The authors acknowledge Jayson Griffin (EPA), Stephen Wolfe (EPA), Chris Russell (formerly of DHS), and Lori Miller (DHS) for their support of this work. The views expressed in this article are those of the authors and do not necessarily reflect the views of the Agency. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.

REFERENCES

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. MATERIALS AND METHODS
  5. RESULTS AND DISCUSSION
  6. ACKNOWLEDGMENTS
  7. REFERENCES
  8. Biographies
  • Brown, G. S., Betty, R. G., Brockmann, J. E., Lucero, D. A ., Souza, C. A., Walsh, K. S., Boucher, R. M., Tezak, M. S., & Wilson, M. C. (2007). Evaluation of vacuum filter sock surface sample collection method for Bacillus spores from porous and non-porous surfaces. Journal of Environmental Monitoring, 9, 666671.
  • Buttner, M. P., Cruz, P., Stetzenbach, L. D., Klima-Comba, A. K., Stevens, V. L., & Emanuel, P. A. (2004). Evaluation of the Biological Sampling Kit (BiSKit) for large-area surface sampling. Applied Environmental Microbiology, 70, 70407045.
  • Calfee, M. W., Lee, S. D., & Ryan, S. P. (2013). A rapid and repeatable method to deposit bioaerosols on material surfaces. Journal of Microbiological Methods, 92, 375380.
  • Carrera, M. K. J., Zandomeni, R., & Sagripanti, J. L. (2005). Method to determine the number of bacterial spores within aerosol particles. Aerosol Science and Technology, 39, 960965.
  • Franco, C., & Bouri, N. (2010). Environmental decontamination following a large-scale bioterrorism attack: Federal progress and remaining gaps. Biosecurity and Bioterrorism: Biodefense Strategy, Practice, and Science, 8, 107117.
  • Hodges, L. R., Rose, L. J., O'Connell, H., & Arduino, M. J. (2010). National validation study of a swab protocol for the recovery of Bacillus anthracis spores from surfaces. Journal of Microbiological Methods, 81, 141146.
  • Krauter, P. A., Piepel, G. F., Boucher, R., Tezak, M., Amidan, B. G., & Einfeld, W. (2012). False-negative rate and recovery efficiency performance of a validated sponge wipe sampling method. Applied Environmental Microbiology, 78, 846854.
  • Lee, S. D., Calfee, M. W., Mickelsen, L., Wolfe, S., Griffin, J., Clayton, M., Griffin-Gatchalian, N., & Touati, A. (2013). Evaluation of surface sampling for Bacillus spores using commercially available cleaning robots. Environmental Science and Technology, 45, 25952601.
  • Lee, S. D., Ryan, S. P., & Snyder, E. G. (2011). Development of an aerosol surface inoculation method for Bacillus spores. Applied Environmental Microbiology, 77, 16381645.
  • Rose, L. J., Hodges, L., O'Connell, H., & Noble-Wang, J. (2011). National validation study of a cellulose sponge wipe-processing method for use after sampling Bacillus anthracis spores from surfaces. Applied Environmental Microbiology, 77, 83558359.
  • Small, D., Klusaritz, B., & Muller, P. (2001). Evaluation of Bacillus anthracis contamination inside the Brentwood mail processing and distribution center—District of Columbia, October 2001. Morbidity and Mortality Weekly Report, 50, 11291133.
  • U.S. Centers for Disease Control and Prevention (CDC). (2013). Comprehensive procedures for collecting environmental samples for culturing Bacillus anthracis. Retrieved from http://emergency.cdc.gov/agent/anthrax/environmental-sampling-apr2002.asp
  • U.S. Government Accountability Office (GAO). (2005a). Anthrax detection: Agencies need to validate sampling activities in order to increase confidence in negative results. GAO-05-493T. Washington, DC: Author.
  • U.S. Government Accountability Office (GAO). (2005b). Anthrax detection: Agencies need to validate sampling activities in order to increase confidence in negative results. GAO-05-251. Washington, DC: Author.
  • Valiante, D. J., Schill, D. P., Bresnitz, E. A., Burr, G. A., & Mead, K. R. (2003). Responding to a bioterrorist attack: Environmental investigation of anthrax in New Jersey. Applied Occupational and Environmental Hygene, 18, 780785.
  • Wood, J. P., Calfee, M. W., Clayton, M., Griffin-Gatchalian, N., Touati, A., & Egler, K. (2013). Evaluation of peracetic acid fog for the inactivation of Bacillus anthracis spore surrogates in a large decontamination chamber. Journal of Hazardous Materials, 250–251C, 6167.

Biographies

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. MATERIALS AND METHODS
  5. RESULTS AND DISCUSSION
  6. ACKNOWLEDGMENTS
  7. REFERENCES
  8. Biographies
  • Sang Don Lee, PhD, is an environmental research scientist for the United States Environmental Protection Agency's Office of Research and Development. He has 9 years of experience at the EPA in decontamination and consequence management. His expertise includes material engineering, aerosol science, and environmental science, and much of his research at the EPA has focused on the fate and transport of radionuclides in the urban environment. Dr. Lee received his PhD in environmental sciences and engineering in 2004 from the University of North Carolina at Chapel Hill after earning his master's degree in environmental engineering from Korea University in 1998.

  • M. Worth Calfee, PhD, is a microbiologist with the National Homeland Security Research Center within the United States Environmental Protection Agency's Office of Research and Development. He earned his PhD at East Carolina University while studying bacterial communities in estuarine environments. He has over 15 years of bacteriology research experience, investigating topics such as carbohydrate metabolism, quorum sensing, virulence gene regulation, and microbial decontamination. Currently, his research focuses on improving sampling and decontamination methods following biological terror incidents.

  • Leroy Mickelsen received a BS chemical engineering degree from the University of Iowa and MS chemical engineering degree from North Carolina State University and is a licensed professional engineer in the state of Ohio. Leroy worked for the Centers for Disease Control and Prevention (CDC), National Institute for Occupational Safety and Health (NIOSH) for 25 years. Leroy joined the United States Environmental Protection Agency in 2005 to work on decontamination related issues and responses at cleanup sites.

  • Matt Clayton has been with ARCADIS since 1998 and has a wide range of experiences with environmental sampling, from gaseous and particulate emissions to specialized sampling of fumigant atmospheres. He is experienced with particle sampling, operating and troubleshooting a wide variety of environmental measurement instruments. Mr. Clayton is currently responsible for the operation of a lab researching effects of using fumigation for decontamination after a biological attack.

  • Abderrahmane Touati, PhD, is a senior research scientist with ARCADIS-US Corporation since 1995. He earned an engineering degree in chemical and petrochemical engineering from the Algerian Institute of Petroleum in 1980, and MS (1983) and PhD (1987) degrees in mechanical engineering from the University of Florida. Prior to his tenure with ARCADIS, Dr. Touati was an associate professor (1988–1995) and dean of the graduate school at the University of Blida (Algeria). Dr. Touati has an extensive range of experience in the field of environmental emissions from combustion sources and in bio-chemical research defense with emphasis on sampling and decontamination methods following biological terror incidents. Dr. Touati is currently a certified ARCADIS project manager for the Research Triangle Park (RTP) United States Environmental Protection Agency's Office of Research and Development Onsite Laboratory Support (OLS) contract.