Transmission Electron Microscopy Methods
Transmission electron microscopy is used to identify asbestos fibers in air and bulk samples. The TEM is capable of analyzing samples at high magnification (20,000X and higher) and identifies asbestos fibers by morphology, crystalline structure and elemental analysis.
The heart of our laboratory is a JEOL 1200EX transmission electron microscope capable of achieving magnifications in excess of 200,000X. The 1200EX is equipped with a Kevex Sigma Gold Energy Dispersive X-ray analyzer (EDAX) which is used to obtain information on the chemical composition of samples. The 1200EX is also capable of performing Selected Area Electron Diffraction (SAED) analysis which provides information on the crystalline structure of particles.
TEM Environmental is accredited by the National Voluntary Laboratory Accreditation Program (NVLAP) for the analysis of airborne asbestos fibers. Our Lab Code is 101130-0
AHERA Appendix A Analysis of airborne fibers greater than 0.5 microns in length on 0.45 micron mixed cellulose ester (MCE) filters. Typical sample set consists of thirteen samples, five inside the work area, five outside the work area and three blanks. Outside samples and blanks are not analyzed without prior approval by client.
NIOSH 7402 Analysis of "phase contrast microscopy equivalent" (PCME) fiber. Fibers greater than five microns in length and greater than 0.25 microns in width are included in the analysis. Results are reported in one of two ways depending on clients needs: 1) PCME asbestos fiber concentration in asbestos fibers per cubic centimeter, or 2) Percent PCME asbestos fibers and percent PCME non-asbestos fibers. This result can be used to "correct" other similar PCM sample results to estimate asbestos fibers in each sample.
ISO 10312 Analysis of airborne asbestos fibers meeting a complex set of counting rules. Samples are typically collected on 0.45 micron mixed cellulose ester filters (AHERA cassettes) during activity based sampling (ABS) programs as part of a site hazard assessment. Report includes detailed information on types of "asbestos structures" found in the sample including fibers, matrix, bundles and clusters along with detailed information on the number and size of "fibers" in each complex structure.
TEM Gravimetric (Chatfield or NYS NOB) The analysis includes a detailed and very labor-intensive testing of bulk building materials for its organic components, inorganic acid-soluble and insoluble components. Residue from gravimetric reduction process is analyzed on the transmission electron microscope at magnifications ranging from 1000 to 20,000X. Percent asbestos in sample is based on visual estimate of fibers observed during the analysis. Currently the New York State Department of Public Health Laboratory Method 198.4 Transmission Electron Microscopy Method for the Identification and Quantification of Asbestos in Non-Friable Organically Bound Samples" is the preferred method.
Soil and Sand Samples
Soil and sand samples present a unique challenge to the laboratory because the standard PLM methods are based on homogeneous samples and soil and sand samples tend to be non-homogeneous samples not suitable to the standard EPA 600/R-93/116 method. The exact test method applied to soil and sand samples depends upon whether the aim is to determine whether the sample contains asbestos containing material (ACM) debris, to determine if any asbestos fibers are present in the sample, or if asbestos present in the sample in quantities greater than one percent. Please contact our lab to discuss your needs so that we can work together as a team to meet your client needs.