ABSTRACT
Toxicology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 465 11.3 Biopersistence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 466
11.3.1 The Macrophage as a Mediator of Biopersistence. . . . 467 11.3.2 Short Fiber Clearance. . . . . . . . . . . . . . . . . . . . . . . . . 469
11.4 Chronic Inhalation Toxicology Studies . . . . . . . . . . . . . . . . . . 470 11.4.1 The Difficulty of Designing Chronic Inhalation
Toxicology Studies with Fibers. . . . . . . . . . . . . . . . . . 470 11.5 Intraperitoneal Injection Studies . . . . . . . . . . . . . . . . . . . . . . . 484 11.6 The Importance of Fiber Length . . . . . . . . . . . . . . . . . . . . . . . 485 11.7 Relationship of Biopersistence to Chronic Toxicity . . . . . . . . . 490 11.8 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 492 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 494
Fibers, due to their unique characteristics and effects, have prompted extensive scientific research over the years. The emphasis was initially on asbestos after the discovery of the association of asbestos exposure with mesothelioma and lung cancer. Subsequently, as interest in synthetic mineral fibers (SMFs) developed, these fibers were investigated using more advanced techniques that incorporated not only our understanding of the physical and chemical properties of fibers but also the limitations imposed by the test system used for these toxicological investigations. It is largely
through these studies that a more complete understanding of the factors influencing fiber toxicology has developed.
