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Crystal Clear Windows a JLC Project# 02-2349 page 2 lk uifdin ate ' Is Ana nd Procedure

Polarized light microscopy with dispersion introduction asbestos in bulk samples, it is this staining (PLM-DS) is the most efficient method for method that the JLC lab uses during bulk detecting building material analyses.

Methodology A chain of custody is kept for each sample to ensure proper handling and delivery to analysis. To avoid any possible the JLC lab prior to contamination, all sample and slide preparation is ventilated, HEPA-filter hood with continuous carried out in a airflow, Sample analysis is performed using accordance with the USEPA , "Method for the PLM-DS in EPA 600 R-93 116, July 1993, and Determination of Asbestos in Bulk Building Materials," NYDOH-ELAP certification manual, "Polarized Light Methods for identifying and Quantitating Microscope Asbestos in Bulk Samples," ELAP 198.1, October 1993.

Analytical Procedures All samples are subject to preliminary visual fiber identification, and semi- quantitation stereomicroscopic examination, Observation of of constituents can be made at this point. Samples homogeneity, uniformity of composition and/or distribution of lacking non-friable organically bound (NOB) samples component materials then undergo homogenization, Some such as floor tiles and roofing materials may require steps to dislodge problem matrices (i.e. ashing, additional extractions, and TEM). Identification of suspect fibers is made by PLM analysis of subsamples. A microscope equipped with dual polarizing filters enables us to observe specific of asbestos requires determination of the optical characteristics of each sample. Positive identification following optical properties: morphology, color and refractive indices, birefringence, extinction pleochroism, characteristics, and signs of elongation. Asbestos quantitation Is performed by point-counting procedure, a standard technique in petrography for determining the relative areas occupied by separate or points over the microscope's field of minerals in rock. An ocular reticle superimposes a point view. The number of points positioned directly above particle or fiber is recorded. A total of 400 points each kind of must be counted over at least eight different representative subsamples to complete analysis.

Polarized Light Microscopy JLC uses an Olympus BHT-P Polarizing Microscope complete with polarizer, analyzer, port for retardation plate, 360 degree graduated rotating wave stage, substage condenser, lamp and lamp iris, reticle, and 25 point Chalkley Point Array. eyepiece Plane polarized light allows for the determination of indices relative to specific crystallographic refraction orientations. Morphology and color can also be plane polarized light. Observation of particles observed under or fibers while oriented between polarizing privileged vibration directions are perpendicular filters whose allows for determination of isotropisml anistropism, extinction characterisitcs of anisotropic particles, be placed in the polarized light path for and calculation of birefringence. A retardation plate may verification of signs of elongation.

Analytical Results The "Summary of Analytical Results" represents the results of analysis. is asbestos or contains more Positive results mean the sample than one percent asbestos by weight. identification and quantitation of major The results are generally sufficient for additional techniques may be necessary. concentrations of asbestos. However, it may be found that Please be aware that PLM is not consistenly detecting asbestos in floor coverings and reliable in similar NOR materials. Before the material treated as non-asbestos containing, can be considered or confirmation must be made by quantitative Microscopy (TEM), Transmission Electron

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