Phase Contrast Microscopy (PCM)
Phase contrast microscopy (PCM) is used to determine fiber concentrations in air. All asbestos analyses are performed in strict compliance with the NIOSH 7400 Method, counting rules A. Fiber glass is determined using the same method and counting rules B. The PCM laboratory is AIHA accredited and a successful participant in the Proficiency Analytical Testing program.
Polarized Light Microscopy (PLM)
Polarized light microscopy (PLM) is used to determine asbestos fiber concentrations in bulk building materials. PLM is applicable to the analysis of building survey submissions and other bulk materials. In addition, it is used to determine asbestos concentrations in soil by California Method 435 and in building materials by NESHAP methods. The laboratory is accredited by the National Voluntary Laboratory Accreditation Program (NVLAP) and the State of California Department of Health Services for the analysis of hazardous waste.
Particle Identification Services
Particle identification and trace particle analysis projects are performed on an unlimited variety of materials. The primary tools used for particle identification are optical microscopy and scanning electron microscopy. Particle identification is useful for comparisons of specific particles, determination of sources of particles, percent of respirable particles, product evaluations and forensic investigations. Particles can be sized and characterized by elemental composition and the distribution of sizes documented.
Gravimetry, which quantitatively removes organic and acid-soluble binder components (typically found in building materials) by ashing or acid-washing samples, is an ideal preparation technique when low level asbestos concentrations need to be determined. Once the gravimetric weight loss is established, the sample residue can be analyzed by PLM (visual estimate or point counting) or TEM. If over 90% of the original sample is removed gravimetrically, detection limits below 0.1% can be achieved by PLM; less than 90% weight reduction requires TEM analysis to attain this sensitivity.
Electron Microscopy Services
The analysis of mineral fibers and particulates by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) provide absolute mineral identification and low method sensitivity. Our electron microscopes include Phillips CM12 and Hitachi 600AB TEMs equipped with energy dispersive spectrometers (EDX) and a RJ Lee Personal SEM with EDX. Air sample preparation is carried out in class 100 HEPA-filtered clean benches to prevent contamination.
AHERA and Yamate Analyses
A variety of analytical protocols are available for determining the concentrations of asbestos fibers in air samples. The AHERA protocol is the industry standard for clearance sample analysis and is mandatory for primary and secondary schools in the U.S. The protocol calls for the collection and submission of sets of 13 samples, the counting of fibers and structures greater than or equal to 0.5 micrometers in length and the counting of fibers with aspect ratios greater than 5 to 1. The Yamate protocols, while similar in sample preparation techniques, count all structures with aspect ratios greater than 3 to 1. The TEM laboratory is accredited by NVLAP for the analysis of asbestos in air samples.
Water samples are analyzed for asbestos under a protocol which conforms to that detailed in EPA's National Primary and Secondary Drinking Water Regulations and EPA Method 600. Special sampling containers and sampling instructions are provided to clients. The TEM laboratory is accredited by the State of California for the analysis of asbestos in drinking water and wastewater.
Bulk Material Analyses
Building materials including floor tiles and roofing tars and dust samples are analyzed by TEM. Analyses may be qualitative, semi-quantitative or quantitative and involve a variety of sample preparation techniques including gravimetry. "Microvac" samples are analyzed quantitatively to determine surface contamination resulting from settling asbestos dust. TEM is an excellent alternative to the exclusive reliance on PLM and may be used when resolution is required to identify ACM to under 1%.
Consultation and Special Projects
A wide range of experience and training provides a team of microscopy experts who are available to supplement investigative teams in the field of forensics, geochemistry, product identification, particle sizing and size distribution, and contamination sources. Recent projects include studies to analyze dusts for various inorganic materials and pharmaceutical products for asbestos.
Forensic Analytical, 3777 Deport Road Suite 409, Hayward, CA 94545. Tel: 800-827-3274; Fax: 510-887-4218.