Lead and mercury have been the most extensively studied reproductive and developmental toxicants. They are widely dispersed throughout the environment, and everyone is exposed to them. Three other common metals—cadmium, arsenic, and manganese—are also likely reproductive toxicants, and some animal studies suggest that chromium and nickel damage fetal development. 1 Other metals, such as tellurium, gallium, and indium, which only recently have come into widespread use as a result of high-tech applications, have some early indications of reproductive and developmental toxicity. These metals pose a potential hazard for future generations that cannot yet be quantified. Here we will concentrate on the effects of lead, mercury, cadmium, arsenic, and manganese.
Lead causes infertility in exposed males and spontaneous abortion in women exposed at high levels. Strong evidence suggests that lead exposure also leads to subtle neurological effects, developmental delays, and behavioral abnormalities in otherwise normal-appearing children. Mercury has been responsible for two major epidemics of spontaneous abortion and birth defects in human populations. Organic mercury compounds cause brain damage to the developing fetus and result in microencephaly (small brain), cerebral palsy, and mental retardation.
The reproductive effects of cadmium, arsenic, and manganese, by contrast, have not been well studied in humans. In animals, cadmium damages the testes and interferes with sperm production, and it may interfere with normal lung development and predispose to respiratory