Northeast Analytical, Inc., 2190 Technology Dr., Schenectady, NY

The evaluation of extraction and cleanup methods for the determination of PCB aroclors in caulking and sealing material

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Courtesy of Northeast Analytical, Inc., 2190 Technology Dr., Schenectady, NY

Buildings that were built and/or refurbished before 1977 may well have caulking used to seal masonry joints and windows that contain PCB Aroclor 1254 and/or 1260. The Aroclors were used as a plasticzier and were added to the material to ease application and improve resiliency. The caulking material has been mainly used when there are dissimilar materials, like brick next to concrete, metal window framings, and roofing joints.

Several investigations took place in the 1990’s in Germany, Sweden, and Finland. The studies established relationships between PCBs in caulking and levels in indoor air as well as in soil around the foundations of buildings containing these materials (Balfanz et al. 1993; Burkhardt et al. 1990; Pyy and Lyly 1998). This same relationship has been demonstrated here in the US by R.F. Herrick (2004) and his team at the Department of Environmental Health, Harvard School of Public Health, Boston, MA. This study surveyed the PCB content of caulking from 24 buildings in the Boston Area. Of the 24 buildings sampled, 13 contained caulking with detectable PCBs. Of these, 8 buildings contained caulking that exceeded the USEPA’s hazardous waste standard of 50 ppm. The laboratory identified the PCB as Aroclor 1254 and Aroclor 1260.

Commercial laboratories, like NEA, are put to the test when analyzing caulk matrix. Caulking material itself is made of several different polymer components, many of which can interfere with the extraction and detection of PCBs. Typically, results are requested on a quick turnaround basis. So, the challenge is to optimize extraction and cleanup methods for this matrix. NEA has evaluated 4 extraction methods for processing caulk. The extraction methods are soxhlet, sonication, accelerated solvent extraction (ASE) and polytron homogenization. All extractions used 1:1 Hexane/Acetone. Several cleanup methods were also employed on the sample extracts including: acid wash, Florisil slurry, Florisil columns, and ultrasonication. NEA analyzed the samples by USEPA Method 8082 Aroclor analysis by GC/ECD. We will present an optimized method that is rugged, fast, cost effective, and has reproducible results.

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