SILICATE AND METAL DUST IN LUNGS OF GREYHOUNDS

Objectives-To determine whether the amount of opaque dust in lung spec imens increases with age, the composition of that dust, and whether th e composition is similar for Greyhounds and pet dogs. Design-Quantific ation of lung particulate dust burdens. Animals-192 Greyhounds and 5 p et dogs. Procedure-Lung specimens of 192 Greyhounds and 5 pet dogs wer e examined for dust accumulation, using light microscopy. Lung specime ns from 20 Greyhounds and the 5 pet dogs were analyzed, using scanning electron microscopy and energy dispersive x-ray spectroscopy to quant ify the lung burden of inorganic particles. Results-Lung dust burden i ncreased linearly with age. Pulmonary dust was composed oi aluminum si licates, silica, and 18 metals. Silicate and metal particulate burdens were higher in Greyhounds than in the pet dogs. The 3 most common met als were iron, titanium, and chromium. Conclusions and Clinical Releva nce-Amount of opaque dust increased with age. The higher pulmonary dus t burden in Greyhounds than in pet dogs suggests that environmental ex posure is important.