It is well known that freshly fractured silica sand resulting from sandblasting operations causes pulmonary toxicity and inflammation. However, it is unclear what contribution, if any, the material that is blasted may have upon the toxicity of silica sand. Two alternative hypotheses were proposed: 1) that the addition of freshly fractured metals, such as iron, would make the metal/sand mix more potent via the Fenton reaction, or 2) that metal, such as aluminum, would coat the silica particles, mask reactive sites on the silica surface and attenuate the toxicity. In this study, plates of several pure metals (iron, aluminum, copper, tungsten, titanium, chromium, tin or nickel) were blasted with silica sand using an automated sandblasting apparatus. The resulting aerosolized silica sand/metal dust mixture was collected on filters, then characterized by ESR, chemical analysis and microscopy. Additional samples of the dust (1.0 mg) were instilled intratracheally into Sprague Dawley rats, followed by lavage at either one or three days post instillation. The resulting studies of inflammatory indices indicate that the addition of metal does not make the dust mix more toxic than the silica sand alone, rather, toxicity is depressed.
The Toxicologist. Society of Toxicology 45th Annual Meeting and ToxExpo, March 5-9, 2006, San Diego, California