Review of the multiple chemical exposure factors which may disturb human behavioral development.

Previous research both in humans and laboratory animals provides evidence that prenatal exposure to metals, pollutants and drugs may impair the neurobehavioral development of the offspring. This may induce mental and psychomotor disturbances as well as learning, behavioral and sensory disorders. However, proof for a strict causality between some low-level exposures to chemicals and behavioral developmental dysfunctions, is often considered still not to be established. The pertinent studies on neurobehavioral developmental toxicity of individual substances (lead, cadmium, organic solvents, PCBs, alcohol, nicotine, diazepam) are reviewed, and the methodologies and conclusions, the missing aspects and the existing problems which still need to be solved in further studies, are discussed. In addition, the necessity of undertaking a broad prospective cohort study on multifactorial influences on the behavioral development of children is emphasized.