The retrospective study evolution of trends in concentrations of Cd, Pb, Cu and Se in the po pulation of the Czech Republic over 30 years period could be useful in design of regulations concerning health protection, prevention of dise ases caused by deficiency of trace elements and have considerable economic importance. Concentrations of the named elements in the serum were determined by means of atomic absorption spectrometry (AAS) after mineralisation in a microwave digestion system. The 1433 samples of serum (730 males and 703 females, average age 48.7 and 49.1 years respectively) from a time period 1970 – 1995 were obtained from the Serum bank of National Institute of Public Health and volunteers (1999). Serum samples from the years 1970, 1975, 1980, 1985, 1990, 1995 and 1999 were examined. The accuracy of the results was checked by means of the Control material Seronorm Whole Blood 404107 and Seronorm Serum 704121, Nycomed. The concentration of Cd had a decreasing trend for the years 1975 – 1999 (0.82 mg Cd.l –1 vs 0.47 mg Cd.l –1 ). The levels of Pb are falling in the interval 1970–1980 (15.6 mg Pb.l -1 vs. 6.6 mg Pb.l –1 ). In year 1985 concentration of Pb increased (10.7 mg Pb.l -1 ) but subsequently decreased again (1995 – 6.4 mg Pb.l –1 ). In year 1999, it was 8.9 mg.l –1 . The concentration of Cu decreased in period 1970 – 1990 (1525 mg Cu.l –1 vs. 990 mg Cu.l –1 ). From 1990 to 1999 the levels of Cu had an increasing tendency (1999 – 1060 mg Cu.l –1 ). Levels of Se in the interval 1970 – 1985 were surprisingly equal (58.1 mg Se.l –1 – 54.4 mg Se.l –1 ). However in the interval 1986 – 1990 the level of Se sharp declined (38.3 mg Se.l –1 ). Since 1990 levels of Se in serum increased again, up to 67.1 mg Se.l –1 in 1999. Statistically significant differences between men and women were found only in Cu and Pb concentrations. Concentrations of under study elements corresponded to the published values concerning unexposed population.

        Key words: trace elements, serum, retrospective study