A Biopersistence Study following Exposure to Chrysotile Asbestos Alone or in Combination with Fine Particles

D. M. Bernstein, K. Donaldson, U. Decker, S. Gaering, P. Kunzendorf, J. Chevalier, S. E. Holm

Research output: Contribution to journalArticlepeer-review

Abstract

In designing a study to evaluate the inhalation biopersistence of a chrysotile asbestos that was used as a component of a joint-compound, a feasibility study was initiated to evaluate the short-term biopersistence of the chrysotile alone and of the chrysotile in combination witht the sanded reformulated joint-compound.

Two groups of Wistar rats were exposed to either 7RF3 chrysotile ( Group 2) or to 7RF3 chrysotile combined with aerosolized sanded joint-compound ( Group 3). In addition, a control group was exposed to filtered-air. The chrysotile used in the Ready Mix joint compound is rapidly removed from the lung.

The chrysotile alone exposure group had a clearance half-time of fibers L>20 mu m of 2.2 days; in the chrysotile plus sanded exposure group the clearance half-time of fibers L > 20 mu m was 2.8 days. However, across all size ranges there was approximately an order of magnitude decrease in the mean number of fibers remaining in the lungs of Group 3 as compared to Group 2 despite similiar aerosol exposures.

Histopathological examination showed that the chrysotile exposed lungs had the same appearance as the filtered-air controls.

This study uniquely illustrates that additional concurrent exposure to an aerosol of the sanded joint-compound, with large numbers of fine-particles depositing in the lungs, accelerates the recruitment of macrophages, resulting in a tenfold decrease in the number of fibers remaining in the lung. The increased number of macrophages in the chrysotile/sanded joint exposure group was confirmed histologically, with this being the only exposure-related histological finding reported.

Original languageEnglish
Pages (from-to)1009-1028
Number of pages20
JournalInhalation Toxicology
Volume20
Issue number11
DOIs
Publication statusPublished - 2008

Cite this