Cadmium solubility in suspension during long-term generation of CdS aerosols

Our recent long-term inhalation study with rats resulted in high lung tumor rates either after exposure of water soluble (CdC12, CdSO4) or water insoluble (CdS, CdO dust and fume) cadmium compounds. These results suggested that all Cd compounds are highly carcinogenic in rats after inhalation exposure. However, since the CdS aerosols in that study had been generated from aqueous suspensions, a suggested possibility of dissolution of CdS and subsequent formation of soluble CdSO4 prior to inhalation might have occurred which needed to be investigated. We conclude that instability of CdS suspensions during the aerosolization procedure and subsequent solubilization due to photo-oxidation may have contributed to the high lung tumor incidence in rats during long-term exposure to CdS.