The clearance of cadmium aerosols after inhalation exposure.

CdO and CdCl2 aerosols were inhaled by two groups of rats and their subsequent clearance behaviour was studied. The half-life of the long term lung clearance rates was identical for both compounds, namely 67 days. For CdO, an initial faster clearance was observed, whereas the initial clearance of CdCl2 did not differ from its long term clearance rate, resulting in a relatively higher Cd burden of the lung in the CdCl2 study. Cd liver and kidney concentrations were also higher in the CdCl2 study, originating from a high resorption rate duringthe time of the exposure.

Effects of lead inhalation exposures alone and in combination with carbon monoxide in nonpregnant and pregnant rats and fetuses. I. Distribution of lead in blood and liver.

Nonpregnant and pregnant rats were continuously exposed for 3 weeks to an aerosol containing 1, 3 and 10 mg lead/m3 air and to a combination of 3 mg Pb/m3 and 500 ppm carbon monoxide. At the two lower lead doses, fetal blood lead levels exceeded those of the mothers. Active transport mechanisms were discussed to be responsible for these differences. A decrease of the fetal blood lead level below the maternal level in the high exposure group was explained by an increasing storage capacity of the fetal livers with increasing lead doses. Lead concentrations of the maternal livers exceeded the nonpregnant values at all 3 doses, probably caused by a higher ventilation and altered pharmacokinetics of lead in pregnancy. Additional CO-inhalation lowered the storage capacity of the livers of the adult animals and raised the blood concentration. In the fetuses additional CO-inhalation raised liver lead concentrations.

[Investigations on the carcinogenic burden by air pollution in man. XVI. Formation of combined carbon black and benzo(a)pyrene aerosol (author's transl)]. / Untersuchungen über die karzinogene Belastung des Menschen durch Luftverunreinigungen. XVI. Herstellung von Mischaerosolen aus Russ und 3,4-Benzpyren.

Two methods for the preparation of carbon black aerosols have been investigated: incomplete combustion of acetylene, acetylene + benzene and other hydrocarbons as well as a "resublimation" of amorphous carbon. The first method was developed for generating soot aerosols in animal experiments, but the latter method needs more basic investigation. Using radioactive acetylene and benzene the produced soot aerosol could be labelled by 14C. Benzo(a)pyrene aerosol was prepared by means of a vapour condensation and was also radioactive labelled. With a combination of both generators, a combined carbon black and benzo(a)pyrene aerosol was prepared. The benzo(a)pyrene amounts bound to the soot were in the range of from 1 ng to 50 microgram per 1 mg soot. Experiments dealing with adsorption and desorbtion of benzo(a)pyrene on soot in the gas phase have shown, that benzo(a)pyrene is relatively tightly adsorbed and cannot be easily or completely desorbed.