THE ABSORPTION, DISTRIBUTION AND ELIMINATION OF RADIOACTIVE CARBON TETRACHLORIDE BY MONKEYS UPON EXPOSURE TO LOW VAPOR CONCENTRATIONS

¹ Biochemical Research and Spectroscopy Laboratories of The Dow Chemical Company, Midland, Michigan

1. Experiments were carried out in which monkeys inhaled a vapor concentration of 46 ppm (0.290 mgm./l.) C¹⁴-labeled carbon tetrachloride through a mask and respiratory valve system for periods of 139, 344 and 300 minutes.

2. The radioactive carbon tetrachloride was absorbed at an average rate of 0.022 mgm./kgm./minute. Of the total amount inhaled, an average of 30 per cent was absorbed by the monkeys.

3. The highest concentration of radioactive material deposited in the monkey tissues was found in the fat which had a distribution ratio of 7.94 (blood = 1).

4. Radioactive carbon was found in the blood carbonate, exhaled carbon dioxide and in urinary urea and carbonate. However, most of the radioactivity in the urine appeared to be present in some nonvolatile fraction other than urea, carbonate or amino acids. This material was retained on anion exchange resin and was converted to another substance by acid hydrolysis.

5. The equivalent of at least 51 per cent of the carbon tetrachloride absorbed during an inhalation period was estimated to have been eliminated in the expired air of a monkey within 1800 hours following the end of the exposure. The remainder evidently was excreted to a large extent in the urine and feces.

6. Other experiments were carried out in which monkeys received skin exposures to 485 ppm (3.06 mgm./l.) and 1150 ppm (7.24 mgm./l.) of radioactive carbon tetrachloride vapor for periods of 240 and 270 minutes, respectively. Negligible amounts of radioactive material were found in samples of blood and expired air.