FEMA letter wipe sampling methodology corrections, August 2003

NYC 9/11 Public Portal Document

City of New York that require the determination of the presence and quantity of ACM prior to alteration, renovation, modification, or demolition activities.

It should also be noted that several errors were detected in the calculation of sample concentrations. Two samples had incorrect concentrations reported, samples 221160-02 and 221160-03 (reported on page 6 of the report) should have reported concentrations of 1,471,401 and 432,765 s/cm^, respectively.

Mold and Bacteria Data

Based upon the results that were received, it appears that one wip^sample was collected for mold and bacteria from a kitchen floor and counter on the third floor of the building. The sample was analyzed by P&K Microbiology Services, Inc. with the number and type of fungi and bacteria being counted and identified. Seven fungi species were identified with the highest count for any one species being 900 colony forming units/square inch (CFU/in^-) and a total sum of 2,200 CFU/in^, while six bacteria I species were identified with the highest count for any one species being 500 CFU/in^ and a total sum of 1,600 CFU/in^.

Mold

Interpretation of these results cannot be completed using standard practices. The standard practice for determining if an indoor-environment is being impacted by mold is to compare the species and concentration of indoor mold samples to outdoor mold samples that were collected during the same sampling event. However, based on the data received, it appears that there were no outdoor samples collected for comparison. Using an approach that is less desired than the standard practice, the following conclusions can be drawn from the data. Although there are no specific standards, the a general rule of thumb for interpreting mold data usually considers concentrations lessgreater than 10,000 CFU/in^ to be the-low and typical of background levels end of the spectrum for beginning additional mold investigation,- and concentrations greater than-100,000 to signify “mold contamination”. The concentrations for each individual species, as saa well as the total sum for all species was well below 10,000 CFUrin^^ should be considered background levels.;—fit In addition, the dominant fungi speeies-that were observed are the most-freq uent speciescommonlv identified species and are ubiquitous in the environment, both indoors and outdoors and indoors. This leads to an overall conclusion that the concentration and species of mold present are typical of on indoor environment. More information can be obtained from the American Industrial Hygiene Association at http.//www-.aiha.-ofg/(.ioveinmentAffairs PR/'html/oomold.htm.

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