NYC-WTC_000195194

NYC 9/11 Public Portal Document

and analyzed for dioxin. The concentrations of dioxin were slightly higher than the pre­ cleaning samples. The TEQ concentration for each sample was below the primary •r clearance criterion of 4 ng/m^.

Post P* Cleaning Samples (Test 4E) - Two post-cleaning wipe samples and two pre-water wipe samples were collected and analyzed for dioxin. The results indicate that the concentrations of dioxin were similar to the pre-cleaning samples. TEQ concentrations were below the primary clearance criterion of 4 ng/m^.

* Gypsum «r Before Cleaning Samples - Pre-cleaning air samples were not collected. * Post P' Cleaning Samples (Test 4A) - Two air samples were collected. Gypsum was not detected in the air samples above the detection limit.

Post P‘ Cleaning Samples, (Test 4B) - Two air samples were collected. Gypsum was not detected in the air samples above the detection limit.

Post P‘ Cleaning Samples, (Test 4C) - Two air samples were collected. Gypsum was not detected in the air samples above the detection limit.

Lead Before Cleaning Samples - Seven micro vacuum samples and three wipe samples were collected. All seven micro vacuum samples were below the comparison value of 25 pg/ft^. Two of the three wipe samples were above the primary clearance criterion of 25 pg/ft^. The third was below the detection limit. Concentrations of lead in the two wipe samples, which exceeded the primary clearance criterion of 25 pg/ft^, were 38.9 pg/ft" and 77 pg/ft^. «» Post P^ Cleaning Samples (Test 4A) - Two air samples, seven micro vacuum samples, and four wipe samples were collected after the first cleaning. The two air samples were below <• the primary clearance criterion of 1.0 pg/m^. Five of the seven micro vacuum samples 41 were below the detection limit. All seven samples were below the comparison value. Two of the four wipe samples exceeded the primary clearance criterion with concentrations of 42.2 pg/ft^ and 43.9 pg/ft^. Of the remaining two samples, one was below the primary clearance criterion and both were below the detection limit and below the primary clearance criterion.

w Post P' Cleaning Samples (Test 4B) - Two air samples and four wipe samples were collected. The two air samples were below the primary clearance criterion of 1.0 pg/m^. Two of the four wipe samples exceeded the primary clearance criterion with concentrations of 91.5 pg/ft^ and 79.3 pg/ft^. Of the remaining two, one was below the primary clearance criterion and the other was below the detection limit.

Post P‘ Cleaning Samples (Test 4C) - Two air samples and seven micro vacuum samples were collected. The two air samples were below the primary clearance criterion of 1.0 pg/m^. All seven micro vacuum samples were below the comparison value of 25 pg/ft^.

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