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Environmental Asbestos Assessment Manual: Superfund Method for the Determination of Asbestos in Ambient Air, Part 1: Method
Citation:
Chatfield, E. J. AND D. W. Berman. Environmental Asbestos Assessment Manual: Superfund Method for the Determination of Asbestos in Ambient Air, Part 1: Method. U.S. Environmental Protection Agency, Washington, DC, EPA/540/2-90/005a (NTIS 90-274283), 1990.
Impact/Purpose:
to inform the public
Description:
This is a sampling and analysis method for the determination of asbestos in air. Samples are analyzed by transmission electron microscopy (TEM). Although a small subset of samples are to be prepared using a direct procedure, the majority of samples analyzed using this method will be prepared using an indirect technique. The method allows for the determination of the mineralogical type(s) of asbestos present and for distinguishing asbestos from non-asbestos minerals. In the method, asbestos structures are characterized as fibers, bundles, clusters, or matrices and the length and width of each asbestos structure are measured. Although the method Is designed specifically to provide results suitable for supporting risk assessments at Superfund sites, it is applicable to a wide range of ambient air situations. To support a risk assessment, this method addresses two objectives: (a) to provide increased precision at the low concentrations of asbestos typically found in the environment; (b) to provide measurements that can be compared with risk factors derived from existing epidemiology studies. An additional consideration addressed in this method is the need to control sampling and analysis costs. The method focuses on sampling requirements for individual sampling stations and the analysis of sample filters collected at such stations. During a site investigation, sampling stations would be arranged in an array designed to distinguish spatial trends in airborne asbestos concentrations. Sampling schedules would be fashioned to establish temporal trends. Thus proper design of a comprehensive sampling strategy, detailing the design of the array of sampling locations and the schedule for sample collection, is also critical to the success of an investigation. However, design of a sampling strategy is necessarily site specific and site-specific considerations are beyond the scope of this document. Satisfying the two method objectives listed above requires innovations that tax the limits of available technology. Consequently, several variations were considered during development and this method represents a workable compromise among several technical constraints. Although the method has not been validated as a whole and the feasibility of a few procedures needs to be better documented, many of the component procedures of this method have been performed in the laboratory. Thus, the principle features of the method are well enough established that the method can be profitably employed in current field investigations. There is no better way to acquire the necessary experience and data for completing method validation. At the same time, until a validation study and appropriate pilot studies are completed, this should be considered an interim method.