RESUMO
Liver, kidney, muscle and hair samples from newborn, born-dead or found-dead calves were collected within 10 days after parturition, for the determination of Pb, Cd and Hg levels. Differential pulse anodic stripping voltammetry at the static mercury dropping electrode was used for Pb and Cd determination after dry ashing of the samples. Cold-vapour atomic absorption spectrometry was used for direct Hg determination. The aim of the study was to monitor background Pb, Cd and Hg levels in vital and important tissues of newborn calves in which nutritional influence was negligible. Three geographic areas in Czechoslovakia were monitored (A, B and C). The following ranges of mean values for all animals were obtained (mg kg-1, wet wt): Pb--muscle (0.04-0.25), liver (0.10-0.29), kidney (0.05-0.43), hair (0.11-0.55); Cd--muscle (0.007-0.038), liver (0.008-0.073), kidney (0.007-0.062), hair (0.009-0.074); Hg--muscle (0.002-0.071), liver (0.005-0.18), kidney (0.004-0.50), hair (0.07-0.77). The value obtained for heavy-metal levels (Pb, Cd, Hg) indicated that there is a significant difference between the groups of found-dead and slaughtered calves from the Nymburk region (muscle--Pb, Cd; liver--Pb; kidney--Pb, Cd). Unexplained high Hg levels in hair samples were measured in the Hradec Králové region.
