Summary -- Intro -- Data Source -- Analysis of El Dorado Hills Air Samples -- Analysis of El Dorado Hills Soil Samples
4. Analysis of El Dorado Hills Soil Samples_____________
Soil samples were collected in the locations where test activities were performed.
These samples were analyzed by TEM Asbestos Laboratories, Inc. in April-May, 2005; the data from these analyses were received on September 21, 2005.4.1 Soil Sample Results
[29]The analytical data incorrectly reports the amphibole content of the soil samples as
actinolite asbestos. Asbestos TEM Laboratories analyzed the samples reportedly in accordance with the polarized light microscopy (PLM) method NIOSH 9002. 30 The data are internally consistent – all field samples were determined to contain some amount of actinolite (either "<1%" or "1 – 5%") and no chrysotile. The reported actinolite in all samples had the following optical properties: green color; green/dark green pleochroism; parallel refractive index – 1.672; perpendicular refractive index – 1.652; moderate birefringence; positive sign of elongation; and a 12° extinction angle 31 . All of the actinolite was described as having a morphology of "needles".The reported optical properties are descriptive of non-asbestos minerals ("Needles" and inclined extinction). As noted in Campbell et al 32 , needles are acicular structures from single crystals, not asbestos.
Parallel extinction is a primary indicator in the polarized light microscope that the observed fiber may be asbestos. The NIOSH method indicates that tremolite/actinolite fragments (not asbestos fibers) have inclined extinction (Table 1 in method). OSHA 33 indicates tremolite and actinolite non-asbestos particles "show inclined extinction under cross polars with no compensator. Asbestos fibers usually show extinction at zero degrees or ambiguous extinction if any at all." Figure 4-1 illustrates the extinction of the amphibole particle from El Dorado Hills and compares it to the extinction of a tremolite asbestos from Korea and an asbestos amphibole from Jamestown.
4.2 Split Soil Samples
RJ Lee Group received 23 soil samples from Youngdahl Consulting Group on Friday,
August 26, 2005. These samples were split samples, collected by Ecology & Environment during their September/October 2004 testing at El Dorado Hills. The samples analyzed by RJ Lee Group were collected near areas where the EPA activity-based sampling had reported high airborne particle concentrations. All of the samples were analyzed using standard optical microscopy techniques; seven of the samples were selected by RJ Lee Group for additional analyses. These seven represent the various types of soil expected to be found in the test locale: the nature trail (three samples), a baseball infield sample (one), and grass-covered fields (three samples). Table 4-1 lists the samples that were received, their general location, the analyses performed on the samples by RJ Lee Group, as well as the analytical results for those samples determined by TEM Asbestos Laboratories (see Section 4.1 of this report). Aerial photographs of the samples locations that were published on the Internet are included in Appendix 2.The samples contained no asbestiform amphibole minerals when analyzed by polarized
light microscopy (PLM). One sample (EDH-ZP-3-100704) contained non-asbestiform tremolite (extinction angles approximately 20°) as well as some chrysotile. Hornblende was observed by PLM in the remaining samples. The hornblende was observed at varying concentrations as short, blocky particles (low aspect ratio) with no striations along the long particle axis (striations are used to optically differentiate actinolite from hornblende). The hornblende was observed to have inclined extinction angles (10 - 20°), indicative of a non-asbestiform crystal.Several of the samples were examined using X-ray powder diffraction (XRD). These
analyses confirmed the presence of amphibole particles in the samples at concentrations ranging from one to three percent (1-3%: JSS-S04-101004-FG2), three to five percent (3-5%: CPS-S05-100804-FG2, NYT-SF1-100804-FG2), five to ten percent (5-10%: NYT-SA1-100804-FG2, NFB-SS04-100804-FG2), and ten to fifteen percent (10-15%: NYT-SJ3-100804-FG2). XRD does not differentiate between hornblende and actinolite.No asbestiform amphibole particles were observed during RJ Lee Group's analyses.
The soil samples were examined in a scanning electron microscope to evaluate general particle morphology and to determine the range of EDXA chemistries observed on suspected amphibole particles. Examples of the particles observed in these analyses are shown in Figures 4-2 and 4-3. Each of these samples shows an elongated amphibole particle that is non-asbestiform. These Figures are typical of the amphibole particles observed in the soil samples.As noted in Table 4-1, several samples were examined using transmission electron
microscopy (TEM). These analyses indicate the samples contained both hornblende and actinolite, all in non-asbestos habit.[29]
The soil sample data reviewed by RJ Lee Group are data from TEM Asbestos Laboratories, Inc. There is a report from Ecology and Environment (dated July 20, 2005) indicating an earlier set of analyses on the samples was performed by EMSL, Inc. The EMSL data was not available for review. 30 The method can be found at http://www.cdc.gov/niosh/nmam/pdfs/9002.pdf. 31 Extinction – in the polarized light microscope with crossed polarizing filters, a particle will appear to go "extinct" or black (no light passes through the particle) when the optical axes of the particle are parallel to those of the polarizing filters. Asbestos fibers will have parallel extinction. 32 W. J. Campbell, et al (1977). "Selected Silicate Minerals and Their Asbestiform Varieties", U.S. Department of the Interior, Bureau of Mines, Information Circular 8751. 33 OSHA (1992). "Polarized Light Microscopy of Asbestos", Method ID-191.Summary -- Intro -- Data Source -- Analysis of El Dorado Hills Air Samples -- Analysis of El Dorado Hills Soil Samples
