Review of the Developmental Toxicity and Teratogenicity of Three Environmental Contaminants (Cadmium, Lead and Mercury)

Heavy metals are among a large number of substances that exert adverse effects on embryonic
development and human health. The large amount of heavy metals recently employed by modern
industry produces a gradual increase of their concentrations in water, soils, and food. Embryos and
fetuses are exposed every day to such toxic chemicals and other harmful substances in the air their
mothers breathe, the food their mothers eat, the water their mothers drink, even in their mothers’ milk.
Exposure to these health hazards is putting embryos and newborns at risk for dangerous diseases and
abnormal development. Even infant death and sudden infant death syndrome have been linked to toxic
air. Therefore, the objective of this article was to illustrate the spectrum of developmental toxicity and
teratogenicity (in experimental animals and human) resulting from exposure to cadmium, lead and
mercury. A bibliography of many papers from different journals was generated from which appropriate
data were presented. These data should provide a basis for predictions about types of malformations
that might be expected in further studies and for judging postulated heavy metal-induced human birth
defects. The following parameters were listed: 1) the developmental toxicity and teratogenicity of the
chosen heavy metals (cadmium, lead and mercury) in experimental animal and human embryos, fetuses
and newborns, 2) the mode of action and mechanism of their teratogenicity as well as the antagonism
of their-induced teratogenic effects, 3) their transfer through placenta and breast milk, and 4) their
bioaccumulation and toxicity in different body organs of vertebrates.