2017-00293 - demo - Laserfiche WebLink

Home Browse Search

I 5001 Cedar Lake Rd. ngStrom St.Louis Park,MN 55416 952-252-0405 office nalytical 952-252-0407 fax Inc. Analysis of Bulk Samples for Asbestos Using Polarized Light Microscopy(PLM) Steve Burns Excavating 3470 Co.Rd 21 Mayer,MN 55360 Re: 426 Old Crysatl Bay Number of Samples: 54 Methods and Definitions The submitted samples were analyzed using the EPA interim Method #600/M4-82-020 (polarized light microscopy with dispersion staining). The method defines 1 an asbestos containing material as one that contains grater than 1% asbestos by weight and asbestos is defined as the fibrous forms of serpentine and certain amphiboles. While the fibrous and non-fibrous forms of minerals are discernible microscopically in hand specimens, the distinction between them is not clear on a microscopic level, especially after processing or manufacturing. Fibrous amphiboles are generally those whose mean aspect ratios (length over width) under the microscope are approximately >10; non-fibrous amphiboles are generally those whose mean aspect ratios are approximately <6. During analysis, morphology and an estimate of mean aspect ratio are used to assign a given mineral fiber population to fibrous and non-fibrous categories. That non-fibrous amphiboles are not reported as asbestos is consistent with mineralogical definitions, but does not imply that non-fibrous amphiboles are not hazardous. Airborne concentrations of them may be regulated by OSHA under certain circumstances. The type of dispersion staining used It generally phase contrast, although central stop dispersion staining may also be used. Percentage Reporting The percentage of each fiber type present was determined using volume percents estimated from stereoscopic examination, projected area percents from mounted slide examination and percents from pomparison to weight percent standards. Such estimations are suitable for most sarhpies, but do have large error ranges. Errors are estimated to be 100 relative percent uncertainty for percentage estimates under 10% ranging down to as little as 10 relative percent uncertainty for percentage estimates greater than 50%. Friable samples which have been estimated by the above methods to contain less than 10% asestos can be point counted, according to the EPA EPA Interim Methods, as required by NESHAPS. In low per ntage samples, point counting may produce false negatives or positives, due to the small number of points counted. For samples consisting of more that one apparent type of material or layer, the percentage of each fiber type of material of layer is determined and reported separately; an overall average for the sample of eachlfiber type is then calculated. The reported friability of a sample refers to that friability observed in the condition) analyzed (broken, crushed, etc.), and is not to be substituted for an on-site assessment of friability. Each Angstrom Analytical lab report relates only to the sample tested and may not, •ue to the sampling process be representative of the material sampled. March 24,2017 Kevin Hagen, • :s.-; • - &cal,Inc. Full Service Laboratory and on-site Industrial HygienelServices for the Hazardous Materials Abatement Industry