Summary -- Intro -- Data Source -- Analysis of El Dorado Hills Air Samples -- Analysis of El Dorado Hills Soil Samples
Prepared by: RJ LeeGroup, Inc. 350 Hochberg Road Monroeville, PA 15146
Prepared for: National Stone, Sand & Gravel Association 1605 King Street Alexandria, VA 22314
Report Date: November 2005 Project: LSH306975
Abstract
In October 2004, the U.S. Environmental Protection Agency (EPA) Region IX conducted a series of tests in and around El Dorado Hills, California, to assess the potential exposure of residents to naturally occurring asbestos fibers. An EPA contracted laboratory, Lab/Cor, evaluated air samples collected during these tests to determine the presence and concentrations of asbestos fibers. The ISO 10312 analytical method was used. Another EPA contracted laboratory, TEM Asbestos Laboratory, evaluated soil samples for asbestos content. EPA released a report summarizing the results of this testing to the general public in May 2005. The study, El Dorado Hills, Naturally Occurring Asbestos Multimedia Exposure Assessment Preliminary Assessment and Site Inspection Report Interim Final ("El Dorado Hills Study"), concludes that asbestos fibers are present in both the soil and background air and notes exposure to elevated concentrations of asbestos fibers in connection with activity-based monitoring.
In September 2005, RJ Lee Group was contracted to conduct a peer review of the El Dorado Hills Study. Specifically, the RJ Lee Group was asked to evaluate whether the air and soil data gathered and analyzed by EPA and the contracted laboratories support the published findings, and to assess the data collected using the latest science concerning asbestos fiber definition as associated with potential health risk. As set forth fully in the attached evaluation, the RJ Lee Group makes the following findings:
1. Based on Mineralogy, Sixty-Three Percent (63%) of the Amphibole Particles Identified as Asbestos Fibers can not be Asbestos.
The EPA performed electron dispersive x-ray analyses (EDXAs) on a representative sampling of amphibole (actinolite) particles. It is well-established that particles classified as asbestiform amphiboles contain only trace quantities of aluminum. Detailed mineralogical analyses have shown that the aluminum content of asbestiform actinolite is less than 0.3 aluminum atoms per formula unit (pfu). Particles with more than 0.3 aluminum atoms pfu or about 1.5 percent Al2O3 cannot form in the asbestos habit due to crystal lattice constraints.
Based on a review of the EDXAs, sixty-three percent (63%) of the reported amphibole actinolite particles the El Dorado Hills Study identified as asbestos fibers contain sufficient aluminum to prevent the development of asbestiform habit (i.e., they contain more than 1.5 percent Al2O3). The remaining thirty-seven percent (37%) are, by virtue of their particle dimensions, also non-asbestos particles.
The selected area electron diffraction (SAED) pattern analyses performed by the EPA laboratory further corroborates that the amphibole particles collected for the El Dorado Hills study are non-asbestiform minerals. SAED data provides information on a mineral’s atomic structure.
2. The Laboratory Procedures did not Comply With the NVLAP Quality Assurance Standard.
Accredited laboratories must comply with the quality assurance standard promulgated by the National Voluntary Laboratory Accreditation Program (NVLAP). The NVLAP standard limits acceptable false positives to ten percent (10%). The false positive percentage for Lab/Cor’s data analyses was thirty-five percent (35%).
3. The Soil Samples do not Demonstrate the Presence of Amphibole Asbestiform Minerals.
As part of the El Dorado Hills Study, the EPA also collected soil samples in the locations where airborne testing activities were performed. TEM Asbestos Laboratories, an EPA subcontractor, analyzed the soil samples using polarized light microscopy (PLM) and concluded that the amphibole content was consistent with actinolite asbestos.
The amphibole actinolite particles reported as asbestos in the soil samples had a reported extinction angle of 12 degrees. Non-zero extinction angles are an intrinsic property of monoclinic amphibole rock fragments (non-asbestos cleavage fragments), and zero-degree extinction angles are a property of amphibole asbestos. Consequently, the amphibole particles reported in the soil samples cannot be asbestiform.
RJ Lee Group obtained splits of 23 soil samples collected from areas where the EPA activity-based sampling had indicated elevated fiber concentrations. The analyses completed by RJ Lee Group confirm that the amphibole minerals present in the soil contain elevated levels of aluminum indicative of hornblende and non-asbestos actinolite. All of the amphibole particles detected were non-fibrous cleavage fragments.
4. The ISO 10312 Analytical Method can not Distinguish Between Asbestos Fibers and Non-Asbestos Cleavage Fragments.
The El Dorado Hills Study’s analytical method used to count airborne asbestos fibers, ISO 10312, cannot differentiate between asbestos fibers and non-asbestos cleavage fragments. ISO 10312 states, "The method cannot discriminate between individual fibers of asbestos and non-asbestos analogues of the sample amphibole material." As a result, EPA methodically inflated the reported asbestos concentrations with non-asbestos cleavage fragments that are not known to produce asbestos-like disease.
Furthermore, analysis of the laboratory data shows that thirty-five percent (35%) of all amphibole particles that the El Dorado Hills Study identified as amphibole asbestos fibers have aspect ratios of less than 5:1 and do not, even under the general ISO 10312 standard, meet the definition of an "asbestos fiber".
5. Applying the Latest Science And Definitional Techniques, the El Dorado Hills Study Shows no Significant Exposure to the Type of Amphibole Asbestos Fiber Connected to Health Risk.
The latest science for measuring the risk posed by asbestos is the Berman-Crump Asbestos Risk Assessment Protocol (Berman-Crump Protocol) as referenced by the Agency for Toxic Substances and Disease Registry. This protocol is the result of an EPA funded, multi-year study (revised in 2003) that demonstrates airborne amphibole asbestos fibers that are long and thin (longer than 10 micrometers (µm) and having widths that are less than 0.5 micrometers) are understood to be of most concern with respect to health risk.
In the El Dorado Hills study, EPA’s contract laboratory identified 2,386 amphibole particles as amphibole asbestos fibers. Based on a review of the data, only 42 of these reported "fibers" were less than 0.5 micrometers in width and longer than 5 micrometers. Only 7 of these reported fibers were longer than 10 micrometers and less than 0.5 micrometers in width.
Summary -- Intro -- Data Source -- Analysis of El Dorado Hills Air Samples -- Analysis of El Dorado Hills Soil Samples
