The inhalative toxicity of different cadmium compounds in rats.

In a long-term inhalation study, male and female Wistar rats were continuously exposed to submicron aerosols of CdO, CdCl2, CdSO4, CdS and a CdO/ZnO combination. For chronic exposures it was shown that at aerosol levels equal to and above 90 myg/cbm Cd, even the less soluble cadmium compounds (CdO and CdS) were toxic and lethal, especially to male rats. No mortality was seen in the group exposed to the ZnO/CdO combination. Our study suggests that inhalative toxicity of cadmium compounds may be related to lung retention of bioavailable cadmium. In a short-term inhalation study we found that the lung retention of cadmium was two times higher after exposure to CdO than to CdCl2. The lung and body burden of cadmium differed by a factor of ten between CdO and CdS. The reasons behind these results are not yet fully understood.