[The criteria of threshold effects of environmental pollutants]

A set of criteria, indices and methods applicable to determining the threshold doses and concentrations of chemical substances was critically examined, analyzed and summarized. A differentiated notion for the hazard effect threshold and for threshold effects, with due respect for which the daily doses and norms are substantiated for various environmental objects, is described. An original interpretation of the hygienic evaluation of an enhanced enzyme activity, mainly of the microsomal hepatic enzymes, is suggested; it is noteworthy, that this aspect was often regarded as a physiological response to the detoxication of chemicals. An advantage of calculating the reference doses as compared to other mathematical methods of determining the threshold values is demonstrated. The article is intended to promote and enhance the safety of hygienic regulation, which is a basis for the state environmental monitoring.