Results obtained in short-term experiments and their application prospects in prognosticating threshold levels of chronic exposure to chemical compounds.

Joint studies carried out by toxicologists of CMEA countries have led to the development of new ways of approach to the problem of rapid establishment of toxicometric parameters and hygienic standards (TSEL, MAC) for the working-zone atmosphere. One of the most promising approaches is the rapid establishment of MAC from the threshold of acute specific effect. Upon this principle, methodical directives for determining MAC values for specifically active irritants were elaborated. A study of the quantitative relations between toxicometric parameters and the physicochemical properties of substances in the working-zone atmosphere furnished methods for calculating TSEL values for noxious substances in this atmosphere. The essential possibility was confirmed of using isolated mitochondria as a model for preliminarily estimating the toxicity and establishing safe concentration levels of noxious substances in the working-zone atmosphere. The application of a complex of functional, biochemical and morphometric indices made it possible to foretell from short-term experiments minimal effective concentrations of a substance on chronic exposure. Ways of further research in the field of prognosticating toxicometric parameters and hygienic regulations for chemical compounds are outlined.

Development of methodological approaches to the determination of safe levels of activity of harmful substances in the air of the working environment.

1. An experiment study was carried out to substantiate fundamental approaches to the determination of shift-average and maximum instantaneous concentration of highly cumulative substances in the air of the working environment. 2. The determination of maximum instantaneous concentrations in the air of the working environment is maintained for some groups of chemical compounds (irritant poisons, substances having acute effect, etc). An express, method of determining MAC in the air of the working environment has been developed for the purpose of hygienic norm-setting for irritant substances.