In vitro and in vivo tests for determination of the pathogenicity of quartz, diatomaceous earth, mordenite and clinoptilolite

The effects of samples of crystalline quartz, diatomaceous earth, mordenite and clinoptilolite were investigated in vitro (as concerns erythrocyte hae molysis and lactate dehydrogenase (LDH) release from peritoneal macrophages ) and in vivo (on LDH, protein and phospholipids in rat bronchoalveolar lav age (BAL), and phospholipids in rat lung tissue). The respirable mineral sa mples were instilled intratracheally, Determinations in the BAL were carrie d out after 15, 60 and 180 days, and in the lung tissue after 90, 180 and 3 60 days. Quartz DQ and quartz FQ induced acute, subacute and chronic inflam mation and progressive fibrosis, However, due to the Al2O3 contamination on the surface of the particles quartz FQ caused a delayed response in vivo. Diatomaceous earth produced acute/subacute inflammation that gradually beca me more moderate after 60 days. Clinoptilolite was inert, whereas the other zeolite sample, mordenite, was cytotoxic in vivo. The reason far this was presumably the needle and rod-shaped particles in the mordenite samples. Th e investigation revealed that different in vitro and in vivo methods can pr ovide valuable data concerning the pulmonary toxicity of minerals. (C) 2000 British Occupational Hygiene Society. Published by Elsevier Science Ltd, A ll rights reserved.