Toxic Substances and Human Risk: Principles of Data Interpretation. Robert G. Tardiff and Joseph Y Rodricks, Eds. Plenum Publishing, 233 Spring St., New York, NY 100131578. 1988. xiii + 4.45 pages. $65.00, cloth.
Reviewed by Robin K. White and Curtis C. Travis, Oak Ridge National Laboratory, Oak Ridge, l" 3 7831, Toxic Substances and Human Risk: Principles of Data Interpretation attempts two difficult but useful tasks: providing a comprehensive overview of the relationship between toxicology and risk assessment and identifying the principles that should be used to evaluate toxicological data for human risk assessment. The book opens by distinguishing between the practice of toxicology as a science (observational and data-gathering activities) and its practice as an art (predictive or risk-estimating activities). This dichotomous nature produces the two elemental problems with which users of toxicological data must grapple. First, how relevant are data provided by the science of toxicology to assessment of human health risks? Second, what methods of data interpretation should be used to formulate hypotheses or predictions regarding human health risk? Toxic Substances and Human Risk: Principles of Data Interpretation is designed to facilitate a better understanding of these two essential problems. Because the volume is addressed to a wide-ranging audience (professional toxicologists, toxicology students, regulators) the editors begin with a series of essays on the historical perspectives of toxicology and its fundamental concepts. Then, to address the question of the quality and relevance of scientific toxicological data to risk assessment, the editors turn to a series of essays organized around the three principle sources of risk assessment data: epidemiology studies, in vivo experimental data, and in vitro experimental studies. The volume closes with a section on the principles used in exposure and risk as1006 Environ. Sci. Technol., Vol. 22, No. 9, 1988
sessment to extrapolate toxicological data for human risk assessment. The opening unit on general toxicology concepts provides an articulate introduction to elementary toxicological measurements and factors modifying toxicity and is coupled with a helpful discussion of various statistical models used in dose-response curve fitting. The explanations of statistical concepts and techniques used in interpreting experimental results are especially helpful for students of the science or regulators who must understand the limits of the data used for risk management. The second unit concentrates on generalized principles of human data interpretation-the ideal source of data for human health risk assessment. The essays define basic types of epidemiology studies and the essential criteria used to evaluate them. Case studies illustrate the various concepts in practice. Because the ideal data sources often are unavailable, the editors turn next to the best reasonable substitute: in vivo animal studies. The essays cover the range of salient points: criteria for selection of models, the complexities of toxicokinetics, and data extrapolation. The two most complex discussions of the volume cover toxicokinetics and extrapolation of dose; nonetheless, these topics are presented cogently with numerous graphical illustrations. The unit closes with a presentation of statistical estimators of various types of toxicity, but fails to mention newer approaches involving physiologically based pharmacokinetic models or pharmacodynamic models being developed. Discussions of in vitro data (another substitute for actual human toxicity data) likewise begin with fundamental explanations of genetic toxicity, shortterm tests, and xenobiotic metabolism. The unit closes with a cursory discussion of how in vitro results may be extrapolated to humans. Given the uncertainties involved with these techniques, the brevity here is understandable, although it glosses over the possibility that these tests eventually may be developed as predictors of the relative po-
tency of various compounds. The final unit is perhaps the most disappointing, both for its brevity and for its superficiality. Still, it presents clearly the basic elements of exposure and risk assessment and the critical points of data interpretation. Although experienced scientists and researchers may not find the overview useful, students and risk managers should find the final chapter enlightening, adding to their basic understanding of a very complex relationship. The editors of and contributors to Toxic Substances and Human Risk: Principles of Data Interpretation represent a body of well-known scientists and researchers in toxicology and risk assessment, and their considerable expertise and experience contribute to a thorough overview of the field. The book does not present new approaches or innovations to the problems of human health risk assessment; rather, it is an excellent primer that clarifies concepts and issues. At the same time it avoids meaningless oversimplification and confusing technicalities. For example, the volume presents both the basic concepts of toxicology and toxicokinetics along with detailed, specific discussions on dose-response curve fitting and first-order toxicokinetics under chronic toxicant administration. Although the substance of the study may fail to reach a part of its intended audience (professional, experienced researchers), it does achieve a helpful balance between elementary explanations and technical expertise that must appeal to students, risk managers, and other users of risk information. Further, despite the book's laudable effort to review and clarify essential toxicological and risk assessment issues, perhaps its weakest point is its failure to identify those areas in which new approaches to data analyses and interpretation are being explored and developed. In final consideration, however, the editors do achieve a notable objective here: They clarify the essential issues of data interpretation for human risk assessment, and that alone makes the study a useful addition to the field.
0013-936X/88/0922-1006$01.50/0 0 1988 American Chemical Society
