Sponsor: U.S. Environmental Protection Agency

We are exposed continually to a wide range of chemical substances. Some are known to be toxic at common exposure levels, and others might be toxic. We have special concern about man-made chemicals, which often move readily from place to place—for example, from factory smokestack to air to rain to groundwater to household water supply—and can enter our food supply, air, and soil. Data on the movement and present location of specific chemicals are remarkably sparse, but even extensive monitoring of the concentrations of chemicals in various exposure media often can fail to detect or define human health risks. There are too many chemicals, too many sources, and too many routes of exposure to rely solely on environmental monitoring. Additional problems arise when a chemical is newly recognized as important but was not included in past programs to monitor human exposure, and still other problems arise when the relationships between exposure levels and concentrations in the human body are unknown.

Those concerns make it important to determine the concentrations of specific chemicals in human tissues. The National Human Monitoring Program (NHMP) was established in 1967 by the U.S. Public Health Service and since 1970 has been housed in the Environmental Protection Agency. In response to a request from EPA, this report of the National Research Council’s Committee on National Monitoring of Human Tissues evaluates the current program; identifies important scientific, technical, and programmatic issues; and makes recommendations regarding the design of the program and use of its products. The program had not been reviewed in this way at any earlier time, and we believe that it had become a textbook example of a program that was well intentioned, was focused on a critical issue, was managed by staff competent in their disciplines, but was in need of a hard look by external peer review. The program was not large in the overall scheme of

things, and peer review would not have been difficult; but by the time our committee was asked to undertake this review, the accumulated problems in the program had reached a stage of crisis, even to the point of doubt about whether the NHMP should be continued. One is moved to wonder how many other small, critically important scientific programs might profit from peer review, and not just at EPA.

The members of our committee were expert, in various combinations, in biostatistics, toxicology, exposure assessment and epidemiology, chemistry, pharmacokinetics, risk assessment, public policy, survey statistics, data base management and tissue archiving, and biologic markers. Before writing this report, the committee convened a workshop in January 1989 to obtain the opinions of program officials and experts in fields relevant to tissue monitoring, environmental monitoring, and risk assessment. These officials and experts helped our committee identify the potential goals and uses of a national program and study in detail the operations and technical methods of the NHMP. Users and potential users of tissue monitoring data also made important contributions to the workshop.

During our work, the committee was repeatedly surprised by the gaps between the needs for data from human tissue monitoring and the limited scope of current activities to fill those needs. Other countries, most notably Germany, have far more extensive human tissue monitoring activities, and the data are used widely for many purposes. In the United States, the right kind of program could generate data of great value to numerous and diverse users. Thus, our main conclusion is that a substantially new program, designed with an appreciation of the strengths and weaknesses of the old, should be implemented forthwith.

The typical committee process often is criticized, but in this case, things worked very well indeed. The members of our committee, all strong and independent professionals, rolled up their sleeves and settled down to work together at our very first meeting. The National Research Council staff were fully effective members of the team. We could not have produced this report without the support of Lee Paulson and Carolyn Fulco; our efforts and deliberations were greatly aided by Jim Reisa, director of the Board on Environmental Studies and Toxicology; and others, especially Karen Hulebak and Shelley Nurse, helped in critical ways. We also profited from the continuing interest and cooperation of present NHMP staff at EPA, its contractors, and many potential users of the data.

John C.Bailar, III

Chairman