CONTENTS AND LOCALIZATION OF HEAVY-METALS IN HUMAN PLACENTAE

The placenta was used as an exposure index for the risk evaluation of prenatal fetal chemical exposure. Full-term placenta samples collected at maternity hospitals in 4 regions of different environmental pollut ants and traffic density were examined for lead and cadmium contents u sing atomic absorption spectrometry (AAS). The results showed similar lead contents in placental samples from all selected regions, except f or a small town with a lower traffic density. The findings may implica te traffic-related environmental lead pollution, rather than industria l sources. The highest concentration of cadmium was shown to be in the samples collected from the region with the highest proportion of smok ing mothers (including passive smoking). Simultaneously, the placental samples were processed histochemically to determine the location of l ead in the placental tissue (using light microscopy). The degree of pl acental metal contamination was done semiquantitatively, and the diffe rence between the rural and industrial region was statistically compar ed. Parallel quantitative AAS analyses and semiquantitative histochemi cal lead analyses of human placental samples revealed analogous result s regarding the level of placental contamination with metals.