Risk assessment for children and other sensitive populations.

Children form a unique subgroup within the population who require special consideration in risk assessment. Children are not little adults. Their tissues and organs grow rapidly, developing and differentiating. These development processes create windows of great vulnerability to environmental toxicants. Furthermore, the exposure patterns of children to environmental chemicals are very different from those of adults. Traditional risk assessment has generally failed to consider the special exposures and the unique susceptibilities of infants and children. Adoption of a new child-centered agenda for research and risk assessment is necessary if disease in children of toxic environmental origin is to be identified, understood, controlled, and prevented. This agenda needs to be multidisciplinary. Specific requirements within the agenda include: (1) exploration and quantification of unique patterns of exposure for children; (2) adoption of new, more sensitive approaches to testing chemicals that can recognize the consequences of exposure during early development; (3) identification, through clinical and epidemiologic studies, of etiologic associations between environmental exposures and pediatric diseases; and (4) elucidation, at the cellular and molecular levels, of the pathogenetic mechanisms of pediatric environmental illness. In the United States, an important start toward adoption of this new agenda has occurred since passage of the Food Quality Protection Act in 1996. A Presidential Executive Order on Children's Health and the Environment has been promulgated. This Order requires all federal agencies to make protecting the health of children against environmental hazards a high priority. A new Office of Children's Health Protection has been established at the U.S. Environmental Protection Agency. Programs in children's environmental health have been created at the Centers for Disease Control and Prevention, the Agency for Toxic Substances and Disease Registry, and the National Institute of Environmental Health Sciences. A national network of eight new Children's Environmental Health Research and Disease Prevention Centers has been formed. These developments will enhance research on previously understudied issues in the environmental health of children and will provide a scientific basis for child-centered risk assessment.