Studies on surface properties of asbestos. II. Role of dimensional characteristics and surface properties of mineral fibers in the induction of pleural tumors.

In animal experiments, the probability that pleural tumors will develop after mineral fiber implantation is dependent upon the fiber's size. This was originally analyzed in relation to the number of injected fibers with specific dimensional characteristics and, more recently, in relation to average aspect ratio (average length/diameter ratio). New experimental data on various mineral fibers suggest that the carcinogenic potency of a solid particle depends on two parameters: the nature of the mineral and therefore the nature of active surface sites, and the aspect ratio of the particle. These two parameters can intervene in a mechanism of model reaction involving the basic properties of lateral faces of fibers.

Studies on surface properties of asbestos. I. Active sites on surface of chrysotile and amphiboles.

The study of the acid-base properties of asbestos reveals a striking analogy between amphiboles and chrysotile. The high sites' density with basic character, evidenced by use of various probe molecules, is very similar for the two asbestos types (chrysotile and crocidolite) and on the same order as the density encountered in some catalysts. Discussion of the surface structure reveals that it is the noncrypting lateral surfaces which possess an electron donor character while the surfaces of the extremities of the fibers with crypting character possess a null or very weakly positive charge.