Environmental assessment report, 100 Church Street, April 2002

NYC 9/11 Public Portal Document

Sampling Methodology Sampling and analysis for PCBs on surfaces was conducted utilizing sterile wipes impregnated with hexane. A known surface area (10cm x 10cm) is wiped and the wipe sample submitted to the lab and analyzed.

4.4.3 Lead fLipe Sampling and Results TRC collected lead wipe samples from surfaces in the NYCLD office space, from materials, such as papers, books, and files, which were placed in boxes, and from the HVAC system. Lead wipe results are presented in the following tables in Appendix A: Table 5a - Office Area Table 5b - Boxed Items

Table 6a - HVAC Supply Ducts Table 6b - HVAC Return Ducts table 6c - HVAC Air Handling Units Table 6d - HVAC Induction Units Table 6e - HVAC Return Plenum Table 6f - Field Blanks

Table 7a - Post Re-Cleaning Office Table 7b - Post Re-Cleaning HVAC

Lead Wipe Results for NYCLD Space Table 5 presents the fifty eight (58) lead wipe samples that were collected and analyzed within the NYCLD spaces. TRC collected the samples listed on Table 5 after ZAR’s cleaning contractors (Branch and Miho) cleaned the NYCLD space. Table 5a in Appendix A, presents the results for lead wipe samples collected on surfaces in the office area. Of the twenty-five (25) samples collected on surfaces in the NYCLD offices, seven (7) samples slightly exceeded the office area target post-cleaning concentration of forty (40) micrograms per square foot (ug/f?). Utilizing specific wet wiping techniques, the entire NYCLD space has been re-cleaned twice, once during placement of furniture on newly installed carpet and once as part of capital cleaning just prior to re-occupancy. All samples collected following re-cleaning activities were found to be less than 25 ug/ftv These results are presented in Table 7a.

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