Development of Improved Analytical Techniques for Determination of Asbestos in Water Samples

摘要

Sample preparation techniques were examined for the analysis of asbestos fiber concentrations in water. The carbon-coated Nuclepore technique using a polycarbonate filter proved to be superior to either the 'drop' or the collapsed membrane filter technique. Compared with plasma ashing, ozone-ultraviolet light oxidation of water samples was found to be a simpler and superior technique for removal of organic materials. Experiments revealed that large proportions of the suspended asbestos fibers could become attached to the inside surfaces of sample containers. This effect was caused by trace organic materials of bacterial origin. Ozone oxidation, carried out inside the collection container, released the attached fibers into the water again. If bacteria and their products were excluded initially, and if absolute sterility was maintained thereafter, suspensions of both chrysotile and crocidolite appeared to be stable for long periods of time. Tests of reference suspensions in sealed glass ampoules stored for almost two years produced fiber concentration values statistically compatible with those obtained at the time of sample preparation.