What analytical techniques does EPA recommend for use at Superfund sites?
There are a wide variety of analytical methods for asbestos, each with some advantages and limitations. For air, the most common methods are PCM (phase contrast microscopy) and transmission electron microscopy (TEM). PCM cannot distinguish asbestos fibers from other fibers. TEM is slower and more costly, but can distinguish asbestos types and can see fibers too small to be seen by PCM. TEM is the method required by Asbestos Hazard Emergency Response Act (AHERA) and International Organization for Standardization (ISO) Method 10312. For soil, methods that can detect asbestos at levels in the range of 1% or less are limited. The most common method is polarized light microscopy (PLM), which can be used either quantitatively (point counting mode) or semi-quantitatively (visual area estimation mode). Other techniques such as scanning electron microscopy (SEM) can also be used, but standardized approaches for quantification of low levels of asbestos are not yet well established.
