NYC-WTC_000195194

NYC 9/11 Public Portal Document

wipe samples indicate that asbestos was present in three of the five samples. Two of the three samples in which asbestos was detected were below the detection limit.

Dimdn Before Cleaning Samples - Three pre-cleaning wipe samples were collected and analyzed for dioxin. The results indicate that dioxin was present, however, the TEQ concentration for each sample was below the primary clearance criterion of 4 ng/m^.

Post Cleaning Samples - Four post-cleaning wipe samples were collected and analyzed for dioxin. The results indicate that the TEQ concentration for each sample was below the primary clearance criterion of 4 ng/m^.

Gypsum Before Cleaning Samples - Pre-cleaning air samples were not collected.

Post P‘ Cleaning Samples - Two air samples were collected after the first cleaning. Gypsum was not detected in either sample.

Lead Before Cleaning Samples - Three micro vacuum samples and three wipe samples were collected. Lead was detected in one of the three micro vacuum samples at a concentration below the comparison value of 25 pg/ft^. Two of the three wipe samples had detectable concentrations of lead; one sample was above the primary clearance criterion of 25 pg/ft^. The third sample was below the detection limit.

Post f‘ Cleaning Samples - Two air samples, four micro vacuum samples and four wipe samples were collected after the first cleaning. The two air samples were below the primary clearance criterion. The four micro vacuum samples and one of the four wipe samples, were below the detection limit. Three of the four wipe samples were above the detection limit, but below the primary clearance criterion of 25 pg/ft". The results from the first cleaning indicate that the cleaning technique was effective in removing the elevated concentrations of lead that were observed prior to the first cleaning.

Post 2nd Cleaning Sampling - Because the cleaning was conducted prior to the establishment of a risk-based cleanup level for lead in air, this unit was re-cleaned in an effort to meet the established primary clearance criterion. Sampling results following the second cleaning indicate levels below the primary clearance criterion.

Alpha-Quartz Before Cleaning Samples - Pre-cleaning air samples were not collected.

Post P* Cleaning Samples - Two air samples were collected after the first cleaning. All of the samples were below the detection limit.

Calcite Before Cleaning Samples - Pre-cleaning air samples were not collected.

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