PLACERVILLE . INFO

Summary -- Intro -- Data Source -- Analysis of El Dorado Hills Air Samples -- Analysis of El Dorado Hills Soil Samples

2. Data Source _____________________________________

2.1 Laboratory Data for Air Filters

The analytical laboratory for the EPA project is Lab/Cor, Inc., located at 7619 6th Ave. NW, Seattle, WA 98117. The laboratory has various accreditations to perform asbestos testing, including the National Voluntary Laboratory Accreditation Program (NVLAP) as laboratory 10192-0. According to its web site (www.labcor.net, accessed August 13, 2005), the laboratory director is John Harris and there is one transmission electron microscopy (TEM) analyst, Dirk Wipprecht. The laboratory operates a Philips 410 transmission electron microscope (TEM).

The laboratory data was produced as a series of Adobe™ (pdf) files on two compact disks (labeled "Raw Data Summaries Group by Activity" and "Raw Data Summaries Plus Detail Grouped by Activity") sent to RJ Lee Group by Ecology and Environment, Inc. (the prime contractor on the El Dorado Hills project). The data appeared on one of two forms (shown in Figures 2-1 and 2-2), with Figure 2-1 being a summary of the sample analysis and Figure 2-2 showing the count sheet for the sample.

Each sample has three sample identifications, two of which are shown on Figures 2-1 and 2-2. The first identification is the field sample number or client sample number (AAMS-D01-092704, e.g.). The second identification is listed as the "Lab/Cor Sample No." (B 4762 S20 A1, e.g.). The third number appears on quality assurance analyses sheets and is a combination of the "Report #" (041174R5, Figure 2-1) and a portion of the Lab/Cor number. The third number is created by combining the portion of the report number before the "R" ("041174") and the numerical value after the "S" in the Lab/Cor sample number ("20"), creating "041174-20".

There were two versions of Figure 2-1 in the data set. The difference in the two versions is the classifications "PCM Equivalent Structures – US" (Figure 2-1) and "PCM Equivalent Structures – ISO" (such as in sample SFBA-H2-2FD-100504). It was assumed that these two classifications are equivalent. No explanation for this difference could be found in the May report.

Table 2-1 shows the number of samples collected (collated according to the Tables contained in the EPA's May report) and analyzed as part of this project. In addition to the two analysts identified in the Lab/Cor web site, two other analysts were identified on the laboratory data sheets – KM and TM. The total number of analyses performed by each person (including quality assurance analyses) was: DW – 94, JH – 119, KM – 152, and TM – 47.

On September 6, 2005, two additional disks were received which contained the same information as was previously received, as well as copies of recorded energy dispersive X-ray spectra (EDXA, chemical signatures of the particles) and selected area electron diffraction pattern analyses (SAED, information on the crystal structure of the particle).

The air samples collected by the EPA during the activity based testing were reportedly analyzed using the ISO 10312 analytical procedure. This procedure is applicable to the determination of airborne asbestos and for detailed evaluation of any atmosphere in which asbestos structures are likely to be the predominant particle present. Most countable particles in ambient atmospheres are not asbestos, and therefore there is a requirement for fibers to be identified. The ISO 10312 procedure uses a transmission electron microscope and counts as asbestos fibers all mineral particles from the six regulated asbestos minerals that have a minimum length of 0.5 µm and a minimum aspect ratio (the ratio of length to width) of 5:1. The analytical method does not differentiate the amphibole asbestos fibers from their non-asbestos polymorphs. This is clearly noted in the method by: "The method cannot discriminate between individual fibres of asbestos and non-asbestos analogues of the same amphibole minerals." (Section 1.1 of ISO 10312).

Lab/Cor modified the ISO 10312 analytical procedure to count mineral particles with an aspect ratio of 3:1 and greater and did not report this modification on its laboratory reports. Because of this change, a third of all amphibole particles in this study have aspect ratios less than 5:1, particles that were counted but should not have been counted by the ISO method. There is no indication of this modification to the analytical procedure on any of the produced Lab/Cor analytical reports. The May 2005 EPA report also does not mention the analytical procedure used for these studies, but does show that "AHERA-like" structures were counted that have an aspect ratio of 3:1 (see, for example, the comments on the bottom of EPA Table 5-1 on page 5-8 of the May 2005 report).

Soil samples were collected at the test site concurrently with the air samples. Splits of these samples were analyzed using polarized light microscopy (PLM) by Asbestos TEM Laboratories, Inc. (http://www.asbestostemlabs.com/, accessed September 21, 2005). Asbestos TEM Laboratories is accredited by the NVLAP to perform asbestos analyses on bulk building materials (laboratory # 101891-0). There are two PLM microscopes at the laboratory (models Olympus BH and BH-2). The majority of the PLM analyses were performed by Steve Flexser (SF) who performed 215 analyses. A second microscopist (Mark Bailey, MB) performed 38 PLM analyses.

The air sample pdf files were converted to an Excel™ format using a program called Able2Extract Professional© which performed optical character recognition on the scanned images in the provided pdf files. After conversion, the data were reviewed to correct errors in conversion and to create a consistent file format. There are a total of 317 samples, 57 quality assurance (QA) analyses, and 65 pending samples. [Note: these numbers may not match those shown in Table 2-1 due to duplication of samples in the various report tables.] The EDXA and SAED data were entered into spreadsheets for later evaluation.

Summary -- Intro -- Data Source -- Analysis of El Dorado Hills Air Samples -- Analysis of El Dorado Hills Soil Samples