Lung clearance, translocation, and acute toxicity of arsenic, beryllium, cadmium, cobalt, lead, selenium, vanadium, and ytterbium oxides following deposition in rat lung.

Young adult rats were exposed via inhalation or intratracheal instillation to oxides of arsenic, beryllium, cadmium, cobalt, lead, selenium, vanadium, and ytterbium. Serial necropsies were performed to assess the metal content in organs at times up to several weeks after exposure. The lung clearance varied widely for these compounds, and the times to remove 50% of the initial burden ranged from 18 min for vanadium to 400 days for beryllium. Arsenic, cadmium, lead, selenium, and vanadium were initially soluble in lung, but a small fraction (1-20%) remained there over the long term. Extrapulmonary tissues often accumulated substantial amounts of the soluble oxides, and whole-body retention was often greater for compounds that were more soluble in lung. Arsenic, selenium, and vanadium translocated to carcass and bone. Arsenic, cadmium, lead, and selenium accumulated in the liver, and the kidney retained cadmium and lead. Beryllium, cobalt and ytterbium did not deposit at any extrapulmonary site in significant amounts. In general, the aqueous solubility of these compounds was a poor predictor for behavior in vivo because of their interaction with metabolic processes. Of the metal oxides tested for acute lethality following pulmonary deposition, cadmium was most toxic, followed by selenium, vanadium, and arsenic.