Concentrations of Metal Elements in Mouse Lung After Intratracheal Administration of Coal Fly Ash

Abstract

Coal fly ash particles, 1-5 μm in diameter and 2.4-2.8 g/cm³ in density, were administered to mouse lungs intratracheally at doses of 0.8-1.9 mg/mouse, and the concentrations of Al, Ca, Fe, Mg, Mn, Ni, and Ti in the lungs were measured by inductively coupled plasma emission spectroscopy and atomic absorption spectroscopy up to 16 wk after administration. The increase in concentration of these elements in the lungs administered fly ash was calculated by subtracting the background levels of untreated control mice from the measured values. The increase in concentration of Al in the lungs varied with individual animals; it was 980 ≥ 495 μg/g tissue at 16 wk after administration, and decreased there after to 519 ± 244 μg/g tissue at 16 wk after administration. Of the metal elements assayed, the ratios of the concentrations of Fe, Mg, and Ti to that of Al were relatively constant throughout the experimental period, suggesting that these elements were cleared from the lung at a rate similar to the clearance of Al. On the other hand, the concentration ratios of Ca, Ni, and Mn to Al appeared to decrease during the 16 wk following administration. When the lung tissues administered fly ash were homogenized and separated into insoluble and soluble (cytosol) fractions by ultracentrifugation, significant increases in all these metal elements were observed in the insoluble fractions. In addition, Ca, Ni, and Mn concentrations increased in the cytosol at 2, 4, or 8 wk after administration.