On the problem of milling and ultrasonic treatment of asbestos and glass fibers in biological and analytical applications

Abstract

In preparing fiber suspensions for biological applications, as well as in many analytical procedures, the fibers--e.g. asbestos and glass--often have to be mechanically diminished and ultrasonically treated. Such treatments may sometimes produce changes in the physical and chemical properties of the original fiber samples. Measurements have been made to estimate the changes in fiber shape, size, and structure after milling and ultrasonic treatment. The results have shown that milling procedures not only change the size distribution, but also the particle shape and crystal structure of asbestos fibers. Ultrasonic energy (50 kHz) had practically no influence on the crystal structure, but in long-term applications it produces changes in fiber size and fiber concentration.

New Detoxification Processes for Asbestos Fibers in the Environment

“…Following power US for 21 h in pure Milli-Q water ( Figure 2C), the long fibers of chrysotile were strongly reduced in length, but fibrous habit was largely preserved and fiber lengths remained within the micrometric range. Consistent with previous reports (Spurny et al, 1979(Spurny et al, , 1980, the effect of US on asbestos fibers in pure water was mechanical in nature. Ultrasound in heterogeneous systems may act on suspended particles, i.e., asbestos fibers, through two different cavitation mechanisms, microjet impact and shock-wave damage, depending on US resonance frequency and particle size (Suslick, 1990).…”

Analysis of inorganic fiber concentrations in biological samples by scanning electron microscopy.

“…There are two mai'n features, a homogeneous dispersion ,and a rapid dissolution of the tissue salits. Our data, along with those (jf Ohatfield et al (2) and Spumy et al (9), show that homogenization of fiber suspensions may well be performed !by ultrasonics if a sufficiently low power input is used (ie, 0.2 W/rdl or less). High-power sonication may significantly increase fiber number.…”

Asbestos fibers in human pulmonary and extrapulmonary tissues

“…Low plasma energy LTA method has proven to have the least influence on fiber count and fiber length, compared with other methods such as wet digestion, high-temperature ashing, and high plasma energy LTA (e.g., energy input 150 W) [Gylseth et al, 19811. A certain weight of tissue residue (0.5-1.5 mg for lung and 4.5-10 mg for other tissues) was suspended in 30 ml isopropyl alcohol and then treated in an ultrasonic bath (B-220J model, 45 KHz, power density 0.02 W/ml) for 5 min. According to the research of Spurny et al (1980), low ultrasonic energy (0.1 W/ml) and short-term sonication treatment had little influence on fiber count and fiber size.…”