Comparative pulmonary toxicity of 6 abrasive blasting agents

Inhalation of silica dust is associated with pulmonary fibrosis, Therefore, substitute abrasive materials have been suggested for use in abrasive blas ting operations. To date, toxicological evaluation of most substitute abras ives has been incomplete, Therefore, the objective of this study was to com pare the pulmonary toxicity of a set of substitute abrasives (garnet, staur olite, coal slag, specular hematite, and treated sand) to that of blasting sand. Rats were exposed to blasting sand or an abrasive substitute by intra tracheal instillation and pulmonary responses to exposure were monitored 4 weeks postexposure. Pulmonary damage was monitored as lactate dehydrogenase (LDH) in the acellular lavage fluid. Pulmonary inflammation was evaluated from the yield of polymorphonuclear leukocytes (PMN) obtained by bronchoalv eolar lavage, The activity of alveolar macrophages was determined by measur ing: zymosan-stimulated chemiluminescence. Blasting sand caused lung damage and showed histologic evidence for inflammation and fibrosis, Garnet, stau rolite, and treated sand exhibited toxicity and inflammation that were simi lar to blasting sand, while coal slag caused greater pulmonary damage and i nflammation than blasting sand, In contrast, specular hematite did not sign ificantly elevate LDH or PMN levels and did not stimulate macrophage activi ty 4 weeks postexposure.