The potential of Gol-e-Gohar iron ore mine airborne dust to induce toxicity in human lung A549 cells

Abstract

Airborne particulates in iron ore mining are a risk factor for adverse human lung effects. In this study, fine particulates deposited on surfaces of about 1.5 m above the ground and 6 meters from a milling unit of the Gol-e-Gohar iron ore mine were collected through wipe sampling. Dust particles less than 5 µm in diameter were separated with an electronic sieve. Aliquots were prepared from the sieved iron ore dust estimated to be equivalent to respiratory exposure in the iron ore mill in the concentrations of 1, 5, 10, 50, 100, and 250 µg/mL, which were intended to represent equivalent inhaled doses from working one month to a working life (25 years) in the mine. The airborne concentration of respirable particles was about five times the threshold limit value given (TLV^®) for iron oxide published by the American Conference of Governmental Industrial Hygienists. The in vitro toxicity range was estimated to be equivalent to an accumulated dose associated with working from one month to a working life in the mine. Treatment of the A549 cells resulted in decreased dehydrogenase activity and cell glutathione content and increased reactive oxygen species (ROS) generation, mitochondrial membrane permeability, and cell apoptosis-necrosis rates. The results of this study revealed the possibility of lung damage at cell doses for respirable airborne iron oxide particles estimated to be equivalent to accumulated lifetime exposures among Gol-e-Gohar miners. Further studies are recommended to investigate the effect of actual contaminants in the workplace on the occurrence of health effects on workers.