New Arrival: CERHR Monograph Series on Reproductive Toxicants

Article excerpt

The sheer number of environmental chemicals known or suspected to be reproductive toxicants--from the ingredients in paints and organic solvents to lead, pesticides, plastics, tobacco smoke, alcohol, and even hair treatments--can puzzle, frighten, and overwhelm the average parent. Their apprehensions reflect widespread concern among health professionals, scientists, and advocacy groups that exposure to some environmental agents may contribute to human reproductive and developmental disorders.

These are not idle concerns. According to the American Society for Reproductive Medicine, nearly 10% of couples desiring children have difficulty achieving pregnancy, and studies suggest that 35-50% of pregnancies do not reach successful completion. The American College of Obstetricians and Gynecologists reports that about 3% of babies are born with major birth defects.

Where can both the public and the experts go for trustworthy information on reproductive toxicants? One source is the Center for the Evaluation of Risks to Human Reproduction (CERHR). Established in 1998 by the National Toxicology Program (NTP) and the NIEHS, the center serves as a clearinghouse for reputable, up-to-date scientific information on environmental agents that could affect human reproduction and development. According to center director Michael Shelby, good, reliable information is the first line of defense against harm: "The more complete and accurate the information you have, the better decisions you can make," he says.

The center is charged with compiling and evaluating data on chemicals to assess their potential reproductive health hazards, and with making these assessments available to the public. With that driving purpose, the center recently announced the publication of new monographs on each of six phthalate esters, chemicals selected in part because of their widespread occurrence in the environment and resultant substantial potential for human exposure.

Good Information Takes Time

Anyone--from members of the scientific community, academia, government, industry, environmental, and public interest groups to individual citizens themselves--may nominate a chemical for review by the CERHR. Nomination of a chemical does not automatically lead to evaluation, however. The center may defer reviewing a nominated chemical, choosing instead to focus efforts on higher-priority chemicals or to wait until more reproductive and developmental toxicity data are available.

From the nominations tendered, selected chemicals are recommended for review by the CERHR's Core Committee, an advisory group of representatives from agencies including the NIEHS, the Centers for Disease Control and Prevention, the National Institute for Occupational Safety and Health, the Food and Drug Administration, the Environmental Protection Agency, and the Consumer Product Safety Commission. The committee bases its recommendations on several criteria, including extent of public concern, availability of research data for review, and extent of human exposure.

For each chemical or group of chemicals, the center recruits an independent panel of scientists and health experts from academia, industry, and government agencies representing wide-ranging expertise. This panel conducts a rigorous and critical review of all currently available scientific data and published literature on a particular chemical--anything that would illuminate understanding of a chemical's potential to cause developmental or reproductive toxicity in humans. The panel then meets in a public forum to draft the summary and conclusions of their deliberations. Producing an expert panel report is a laborious process that can take as long as 12 months to complete, once the initial decision to evaluate the chemical is made.

In evaluating all the evidence, the panel considers a number of potential health effects, including impaired fertility in males and/or females, adverse pregnancy outcomes, birth defects, and deficits in postnatal function. …