title: Considerations for estimating microbial environmental data concentrations collected from a field setting.
abstract: In the event of an indoor release of an environmentally persistent microbial pathogen such as Bacillus anthracis, the potential for human exposure will be considered when remedial decisions are made. Microbial site characterization and clearance sampling data collected in the field might be used to estimate exposure. However, there are many challenges associated with estimating environmental concentrations of B. anthracis or other spore-forming organisms after such an event before being able to estimate exposure. These challenges include: (1) collecting environmental field samples that are adequate for the intended purpose, (2) conducting laboratory analyses and selecting the reporting format needed for the laboratory data, and (3) analyzing and interpreting the data using appropriate statistical techniques. This paper summarizes some key challenges faced in collecting, analyzing, and interpreting microbial field data from a contaminated site. Although the paper was written with considerations for B. anthracis contamination, it may also be applicable to other bacterial agents. It explores the implications and limitations of using field data for determining environmental concentrations both before and after decontamination. Several findings were of interest. First, to date, the only validated surface/sampling device combinations are swabs and sponge-sticks on stainless steel surfaces, thus limiting availability of quantitative analytical results which could be used for statistical analysis. Second, agreement needs to be reached with the analytical laboratory on the definition of the countable range and on reporting of data below the limit of quantitation. Finally, the distribution of the microbial field data and statistical methods needed for a particular data set could vary depending on these data that were collected, and guidance is needed on appropriate statistical software for handling microbial data. Further, research is needed to develop better methods to estimate human exposure from pathogens using environmental data collected from a field setting.
authors.affiliation: United States Environmental Protection Agency, National Homeland Security Research Center, Threat Consequence Assessment Division, Cincinnati, Ohio, USA.
authors.forename: Erin E
authors.initials: EE
authors.lastname: Silvestri
authors.affiliation: United States Environmental Protection Agency, National Homeland Security Research Center, Threat Consequence Assessment Division, Cincinnati, Ohio, USA.
authors.forename: Cynthia
authors.initials: C
authors.lastname: Yund
authors.affiliation: United States Environmental Protection Agency, National Homeland Security Research Center, Threat Consequence Assessment Division, Cincinnati, Ohio, USA.
authors.forename: Sarah
authors.initials: S
authors.lastname: Taft
authors.affiliation: United States Environmental Protection Agency, National Homeland Security Research Center, Threat Consequence Assessment Division, Cincinnati, Ohio, USA.
authors.forename: Charlena Yoder
authors.initials: CY
authors.lastname: Bowling
authors.affiliation: Battelle Memorial Institute, Columbus, Ohio, USA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Chappie
authors.affiliation: Battelle Memorial Institute, Columbus, Ohio, USA.
authors.forename: Kevin
authors.initials: K
authors.lastname: Garrahan
authors.affiliation: United States Environmental Protection Agency, National Homeland Security Research Center, Threat Consequence Assessment Division, Cincinnati, Ohio, USA.
authors.forename: Eletha
authors.initials: E
authors.lastname: Brady-Roberts
authors.affiliation: Battelle Memorial Institute, Columbus, Ohio, USA.
authors.forename: Harry
authors.initials: H
authors.lastname: Stone
authors.affiliation: United States Environmental Protection Agency, National Homeland Security Research Center, Threat Consequence Assessment Division, Washington DC, USA.
authors.forename: Tonya L
authors.initials: TL
authors.lastname: Nichols
mesh_terms: D001408:Bacillus anthracis / Q000302:isolation & purification*; D023482:Bioterrorism; D003627:Data Interpretation, Statistical; D004781:Environmental Exposure / Q000032:analysis*; D004784:Environmental Monitoring; D052918:Environmental Restoration and Remediation / Q000379:methods; D006801:Humans; D008828:Microbiological Techniques / Q000379:methods / Q000592:standards; D011786:Quality Control; D013048:Specimen Handling / Q000379:methods / Q000592:standards; D013171:Spores, Bacterial / Q000302:isolation & purification