Children's Health and the Environment: Public Health Issues and Challenges for Risk Assessment

Article excerpt

Infants and children are not little adults. They are uniquely vulnerable to environmental toxicants. To protect infants and children against toxicants, the National Research Council in 1993 called for development of an approach to risk assessment that considers children's unique patterns of exposure and their special vulnerabilities to pesticides. Many aspects of that call were codified into federal law in the Food Quality Protection Act (FQPA) of 1996. This report highlights the central elements needed for development of a child-protective approach to risk assessment: a) improved quantitative assessment of children's exposures at different life stages, from fetal life through adolescence, including acute and chronic exposures, exposures via multiple routes, and exposures to multiple agents; b) development of new approaches to toxicity testing of chemicals that can detect unanticipated and subtle outcomes and that evaluate experimental subjects over the entire life span from early exposure to natural death to replicate the human experience; c) development of new toxicodynamic and toxicokinetic models that account for the unique physiologic characteristics of infants and children; d) development of new approaches to assessment of outcomes, functional, organ, cellular and molecular, over the entire life span; these measures need to be incorporated into toxicity testing and into long-term prospective epidemiologic studies of children; and e) application of uncertainty and safety factors in risk assessment that specifically consider children's risks. Under FQPA, children are presumed more vulnerable to pesticides than adults unless evidence exists to the contrary. Uncertainty and safety factors that are protective of children must therefore be incorporated into risk assessment when data on developmental toxicity are lacking or when there is evidence of developmental toxicity. The adequate protection of children against toxic agents in the environment will require fundamental and far-reaching revisions of current approaches to toxicity testing and risk assessment. Key words: children's environmental health, developmental toxicology, risk assessment, safety factors, toxicity testing. Environ Health Perspect 112:257-265 (2003). doi:10.1289/ehp.6115 available via http://dx.doi.org/[Online 25 November 2003]

Protection of human health against disease and injury caused by toxic chemicals in the environment is the ultimate goal of risk assessment and risk management. Historically, risk assessment focused on adult exposures and toxicities and gave little consideration to vulnerable life stages such as fetal development and early childhood. An emphasis on adult cancer risk and the evolution of methodologies for estimating cancer risks that are different from the methods used to assess other health effects tended to further diminish the importance for risk assessment of children's exposures and outcomes. In addition, the use of default factors based on the healthy young adult did not account adequately for the unique exposures and sensitivities of fetuses, infants, and children (Landrigan and Carlson 1995).

In the past decade, stimulated especially by the 1993 National Research Council (NRC) report on Pesticides in the Diets of Infants and Children [NAS (National Academy of Sciences) 19931, recognition has grown that children are a group within the population who have unique exposures and special vulnerabilities to environmental toxicants. It is now understood that children require an approach to risk assessment that considers their particular characteristics. The present report, developed by the International Life Sciences Institute (ILSI) with support from the U.S. Environmental Protection Agency (U.S. EPA), is intended to consider the elements and structure of a child-protective approach to risk assessment.

The purpose of this article is to introduce a series of reports from an ILSI Workshop on Risk Assessment and Children's Health held in July 2001. …