ABSTRACT
There is a large body of data relating to the biological effects of inhaled particulates. Two sets of parameters appear to stand out from the experimental data: physical parameters, such as size and geometry, and chemical parameters such as surface charge and surface chemistry. The use of condensed silica fume in concrete is rather recent, the first reported experiment dating back to the early 1950s. There are significant differences in the fibrogenic potential of different types of free silica, the severity and speed of fibrosis being greatest due to tridymite, then in descending order, to cristobalite, quartz, and least of all to vitreous silica. There are other indications that chemical surface characteristics also contribute to the overall pathogenic potential of respirable particles. Some materials display very strong chemical affinity toward well-known organic carcinogens, such as some polyaromatic hydrocarbons.
