DEP Cleanup Completion Letter, 125 Liberty Street, Nov 2002

NYC 9/11 Public Portal Document - - -- . ---- •• •.. ' "I r, UFc. iu y1'( 4544 P.04/O5

relative potency compared to benzo[a]pyrene, which is the most toxic of the PAHs. The TEF procedure generally uses Y of the detection limit in the; calculations when the reported value is below the detection limit. As the results from 125 Cedar Street were all non-detect, the TEF calculations yield a value of 580 µg/m2 when calculated using %2 the detection limit. The PAH data set would have been more robust had the detection limit been set at 2.5 µg. If a detection limit of 2.5 µg would have been used, the TEF calculations would have yielded a value of 290 µg/m2, assuming that the samples remained as non-detect. This distinction is important because the numeric criteria presented in the COPC document is 300 µg/m2. In an attempt to make an informed evaluation of the PAH data from 125 Cedar Street, a comparison was made to PAH data which USEPA collected from 110 Liberty Street. The PAR data from 110 Liberty indicated that the concentration of the seven PAHs used in the TEF calculations were primarily non- detect at a detection limit of 2.5 µg. This indicates that even if a lower detection limit was used at 125 Cedar Street, the results would likely indicate non-detect for the PAHs, similar to what was observed at 110 Liberty Street. In addition, some of the PARs that are not included in the calculation of TEFs (i.e., non-carcinogenic PAIIs) were the most frequently detected PAHs at 110 Liberty and were detected at concentrations above S µg. The non-carcinogenic PAHs are not included in the TEF calculations because they arc less toxic than the carcinogenic PAHs, therefore identification of a non-carcinogenic PAH would not increase the TEF value. Thus, it would be expected that some of the non-carcinogenic PAHs would have been detected above 5µg if they were present at 125 Cedar Street. The combination of these two factors provides evidence that the data collected at 125 Cedar Street can be accepted even though the detection limit was not as low as it could have been. In addition, the pre-cleaning PAH results are similar to the results observed at 110 Liberty Street. The post-cleaning PAH samples at 110 Liberty Street were all below the numeric criteria as well. Therefore, even though the post-cleaning samples from 125 Cedar Street were not evaluated, it is expected that the samples will all be below the numeric criteria based on the pre-cleaning samples being below the criteria and the similarity to what was observed at 110 Liberty Street. Thus, for PAHs, the data we reviewed indicates that PAHs are not a hazard at 125 Cedar Street.

Dioxin — The analytical data for dioxin that was reviewed consisted only of pre-cleaning samples. Post- cleaning samples were also collected, however the analytical results are not available at this date. When the analysis is completed for the post-cleaning samples, USEPA will review the data. We reviewed 66 wipe results which were analyzed for dioxin. Evaluation of dioxin results is similar to that reported above for PAHs in that the results for individual congener groups arc adjusted and summed to provide toxic equivalency for 2,3,7,8-TCDD, the most toxic dioxin congener, using a process called toxic equivalents (TEQs). Similar to the PAH data the TEQ calculations use 2 of the detection limit in the TEQ calculations. The detection limit was acceptable and all of the samples met the numeric criteria of 4 ng/m2. The pre-cleaning dioxin results are similar to the results observed at 110 Liberty Street. The post- cleaning dioxin samples at 110 Liberty Street were all below the numeric criteria as well. Therefore, even though the post-cleaning samples from 125 Cedar Street were not evaluated, it is expected that the samples will all be below the numeric criteria based on the pre-cleaning samples being below the criteria and the similarity to what was observed at 110 Liberty Street. Thus, for dioxin, the data we reviewed indicates that dioxin is not a hazard at 125 Cedar Street.

Lead — We reviewed approximately 72 wipe sample results which were analyzed for lead. There were 10 samples that were above the numeric criteria, of 25 µg/ft2, listed in the COPC document. The apartments which exceeded the numeric criteria were 12N, IIN, 10S, ION, 9N, 8S, 8N, 3S, and 2S. These apartments were recleaned and retested (14 samples). Six units met the numeric criteria, however three units (12N, 11N, and 1 OS) did not meet the numeric criteria. These three units were recleaned and retested. Apartment 12N and lOS met the numeric criteria after the second cleaning. Apartment 11N did not meet the numeric criteria and required a third cleaning. The results for apartment 11N after the third cleaning were below the numeric criteria. Thus, for lead, the data we reviewed indicates that lead is not a hazard at 125 Cedar Street.

NYC-WTC 000107521