Assessing children's exposure to hazardous environmental chemicals: an overview of selected research challenges and complexities.

There is renewed interest in the United States regarding characterization of children's exposures to hazardous environmental chemicals. Many studies are currently underway that use novel and innovative approaches to assess childhood exposures to a variety of toxic chemicals, including both persistent and nonpersistent compounds. This article reviews some of the critical challenges that can impede scientifically rigorous studies designed to measure children's environmental exposures. The discussion briefly examines three topical areas: administrative issues (IRB approval, participant incentives, community involvement, and communication of results to research participants and stakeholders); data-collection issues (identifying and recruiting children/families, measuring actual exposures/doses); and issues related to chemical analysis of biological samples (examples of chemicals and chemical classes that can be measured in human tissue and excreta, effects of a child's age on the type and amount of biological samples available for analysis). These research complexities are discussed in the context of developing more effective and efficient exposure assessment methods.