Toxicokinetics of cobalt and the problems of biological monitoring.

Toxicokinetics of cobalt was studied on rats by the method of radioactive isotopes using single or repeated administrations. Co was used in the form of sulphate in doses of 0.1 and 0.2 mg/kg administered by 4 different routes (intragastric, intraperitoneal, intratracheal, subcutaneous). Good absorption was established in the parenteral routes of administration, the regularities of absorption, retention in the internal organs and elimination of cobalt were determined and mathematically expressed. Clear dependence was established between the doses administered and the content in biomedia. The liver and the kidneys were found to be the organs of highest accumulation of cobalt. Elimination half-lives and the time of establishment of a constant level during long-term exposure were determined. It is proposed to carry out diagnostic examination in the course of a few hours after the work shift. Urine and blood are the test objects in which direct correlation has been established. Delayed elimination of cobalt from the organism under protracted exposure may be the essential cause of increased hazard for man, which conditions the necessity of determining maximum acceptable concentration for this substance.