How to Test for PCBs and Characterize Suspect Materials
This information applies if you would like to test for the presence of PCBs in a building. Once you have made the decision to test, EPA recommends that you first test the air to determine if building occupants may be exposed to PCBs in the indoor air. This initial step may help prioritize the steps and/or approaches for the renovation or repair work. If you have identified a PCB problem, you will need to characterize it and determine the extent of PCB contamination. It is important to note that even if PCBs are not present in the air, they still may be present in building materials.
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A sampling plan should be developed to characterize the caulk and other potential building materials that might either contain PCBs or be contaminated through contact with PCB-containing caulk, such as wood, masonry, or brick. The sampling plan should consider the following steps:
- Test indoor air to determine if PCBs are present. If your building is a school, you can compare the test results to the the Exposure Levels for Evaluating PCBs in Indoor School Air.
If PCBs in indoor school air are above the exposure levels, determine the extent of the problem by:
- Test suspect building material to determine PCB sources. Building material that is removed and contains 50 ppm PCBs or greater is regulated for disposal (see Abatement Step 3)
- Evaluate building material sample results and determine if surrounding materials warrant testing.
- Outline areas requiring corrective action and prioritize contaminated building materials for removal based on their PCB-concentration levels, potential accessibility, and building occupancy (see Abatement Step 1 for more details).
For various sample types listed below, a sufficient sample size should be collected to ensure the laboratory can measure the concentrations of PCBs at levels required by the PCB cleanup and disposal regulations at 40 CFR part 761.61. It is recommended that you contact the analytical laboratory or your Regional PCB Coordinator to discuss the necessary requirements for each sample type.
- Bulk solid samples - Bulk solid samples include such materials as caulk, soil, and sand. Bulk solid sampling typically includes removing a small portion of the potentially contaminated material for analytical testing. For example, a caulk sample would be the quantity of caulk needed by the laboratory for analytical testing, removed directly from the suspect area. Take care to ensure that only the caulk is included in the final sample and not other adjacent materials, such as wood or concrete that may skew the sample analysis results. When soil or sand samples are collected, you should consider whether the PCBs are on the soil surface or if they could be located deeper in the soil. An example of when PCBs might be on the soil surface would be if fragments of weathered caulking were deposited on undisturbed soil surfaces. Alternatively, PCBs could be located deeper in the soil, in locations such as landscaping areas where the soil surface has been disturbed or where new soil has been added.
- Porous surface samples - Because PCBs can migrate into porous surfaces (e.g., brick, masonry, concrete or wood) surface wipe sampling is not adequate to characterize the PCB concentration of porous surfaces. Instead, core samples should be collected on a bulk basis (i.e., mg/kg) to collect the top 0.5 to 2 cm of the porous surface. For these porous surface samples, an adequate sample (as determined by the analytical laboratory) should be removed for analysis. Tools such as chisels, drills, and saws can be used to collect the sample, taking care to minimize dust generation. The samples should be collected from the top 0.5 cm to 2 cm of the surface closest to the likely source of PCB contamination.
- Non-porous surface samples - If the surface being sampled is smooth and impervious (e.g., unpainted metal surfaces), a wipe sample can be collected to determine if the surface is contaminated with PCBs. A standard wipe test, as specified in 40 CFR 761.123, uses a 10 cm by 10 cm (or equivalent that equals 100 cm2) template to outline the sample area and a gauze pad or glass wool that has been saturated with hexane to collect the sample. The hexane-saturated wipe is used to thoroughly swab the area inside the 100 cm2 template. Care must be taken to assure proper use of the sampling template, as the sample results will be based on the 100 cm2 sample area (i.e., μg per 100 cm2).
- Indoor air samples - You should collect indoor air samples in accordance with EPA Methods TO-10A, TO-4A, or equivalent. Sufficient sample volumes, as referenced in the EPA Methods, should be collected to prove a minimum laboratory reporting limit of less than 0.1 μg/m3. Consult with your PCB Regional Coordinator for the number of samples to be taken and the type of sampling method to be used.
You or your supervisor should maintain a field log book that contains all information pertinent to the site inspection and sampling activities. The person making the entry should sign and date all entries in the log book. Entries into the log book should include the following types of information:
- Site and location of the sample extraction
- Date on each page
- Exact times of sampling events or visual observations
- Types of samples collected and sample identification numbers
- Number of samples collected
- Specific description of sample locations
- Description of sampling methods
- Field observations
- Name of all field personnel