Asbestos: Risk Assessment,Epidemiology,and Health Effects Edited by Ronald F. Dodson and Samuel P. Hammar Publisher: Taylor and Francis Group,Boca Raton,London,New York ISBN: 10: 0-8493-2829-2. 425 pages;Price: $159.95.

The rear cover of this book claims the following:

“While there are hundreds of books available on the many different aspects of asbestos, none contain the encyclopedic, comprehensive coverage you will find here. Edited by leading authorities, with contributions from specialists and leaders in their respective fields, Asbestos: Risk Assessment, Epidemiology, and Health Effects provides a cross-disciplinary approach and an authoritative review of asbestos research. The breadth and depth of coverage spans history, pathology, epidemiology, as well as sampling, analysis, and regulatory issues.”

And many (but not all) of these promises are fulfilled. The authors are highly qualified and many are active in relevant research, teaching, and/or litigation. A claim that these are leading authorities in the field is not mere hyperbole.

The scope of the book is wide-ranging. It includes chapters on history, asbestos analysis methods, analysis and relevance of asbestos burden in tissue, molecular and cellular responses to asbestos exposure, pathologic features of asbestos induced disease, epidemiology, clinical diagnosis of asbestos-related disease, core curriculum for practicing physicians, and asbestos regulations.

I am not a physician, much less a pulmonary specialist. Therefore, it would be inappropriate for me to comment on the accuracy of the medical information (e.g., much of the material on Chapter 7) given in this book.

There are additional sources (see below) that should have been included, but the book does provide a large number of references, which are useful for the novice and specialist alike. For example, Chapter 6 contains 681 numbered references as well as a shipyard bibliography.

Nearly all of the chapters deal with highly technical material, but the majority of the writing is workmanlike and readable. Some of the chapters, such as the chapter on epidemiology, are particularly well written (whether or not you agree completely with the content). This is a strong and welcome feature of the book.

There are no equations in this text. No doubt some readers will find this feature attractive, but the omission of any equation is curious, particularly for a book that purportedly discusses risk analysis. Likewise, although photographs are numerous and well chosen, there are very few figures on which quantitative information is displayed. Again, for a book that discusses complicated and fundamentally quantitative concepts such as dosimetry (fiber deposition, clearance, and retention) and potency, the omission of equations and graphs is problematic.

The editing is uneven, and there are both gaps and redundancies in coverage. For example, the introduction of Chapter 6 overlaps considerably with the material presented in Chapter 1 and also the first few pages of Chapter 8.1,2 Chapter 1 (very much shorter than the others) is the logical place to include all relevant history. Careful cross-referencing would eliminate the need to duplicate coverage. As a second example, there is information on epidemiology in both Chapters 6 and 7. All of this should be consolidated into Chapter 6.

The chapter titles are not fully descriptive, which should have been caught in the editing process. Chapter 1 (the history of the extraction and uses of asbestos), for example, includes information on public health issues. Certainly, such material is relevant—and, indeed, more should have been included—but the link is not made between these public health issues and “extraction and uses.” All in all, Chapter 1 is disappointing; there are substantial data on country-by-country asbestos production and consumption levels (readily available from the USGS or Canadian Minerals Yearbook), uses, and health-related and regulatory developments. These data could have been woven into the narrative and included in tables or figures to give the reader a clear understanding of asbestos markets and how these have evolved as knowledge of health effects emerged and laws and regulations were put in place in many countries of the world.

It is a personal choice, certainly, but the overall organization used in the International Agency for Research on Cancer (IARC) cancer monographs would have been more logical than that used in this book—and might have highlighted some of the gaps in coverage.

As a final comment on editorial matters, the index at the end of the book is not useful. For example, fiber length is an important determinant of potency and there is a substantial body of literature that discusses this point for fibers generally and for asbestos in particular. The effect of fiber is discussed (albeit incompletely) in several places in the book, including Chapters 3 and 6. The index, however, has no entries under fiber or length. The reader has to hunt for entries such as “pathogenicity, fiber lengths relationship” and “short fiber toxicity” to find relevant information. Biopersistence is not listed at all in the index, although the concept is included in the text. This may seem a minor point, but a good index greatly enhances the utility of a reference book. The lack of a good index (coupled with some of the editorial decisions as to what goes where) means that one has to read the book cover to cover to discover its contents.

As noted, both redundancies and gaps survived the editing process. For a book that purports to provide “encyclopedic, comprehensive coverage,” there are a surprising number of gaps. Here are a few illustrations:

Chapter 2 provides an excellent discussion of asbestos analysis methods. However, there is very little discussion of the relationship between fiber concentrations derived from phase-contrast optical microscopy (PCOM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The diameter distribution of various types of asbestos is such that PCOM is likely to miss a substantial number of fibers—so fiber concentrations determined by different methods will not agree unless a conversion factor is employed. Moreover, much of the early industrial hygiene work (prior to 1970) measured asbestos concentrations in either gravimetric units or in millions of particles per cubic foot (mppcf). The conversion factors from these earlier units to fibers per milliliter (f/ml) are uncertain and still complicate interpretation of epidemiological studies. Several studies and surveys (see e.g., HEI-AR [1991] and Hodgson and Darnton [2000] and contained references) address these topics and should have been included in this chapter.

There is no chapter that adequately covers asbestos mineralogy and physicochemical properties. (Section 3.5 contains some relevant information and there are other bits and pieces scattered through the text.) Such topics as fiber size distributions, breakage modes (longitudinal versus transverse), and biopersistence are potentially important determinants of dosimetry, toxicology, and the correct interpretation of lung burden data. Useful general discussions (Eastern Research Group [ATSDR] 2003; Lippmann 1990, 1992, 2000; Virta 2002), new estimates of chrysotile biopersistence (Bernstein et al. 2003a, 2003b, 2004), specific deposition-clearance models (see e.g., Asgharian and Yu, cited in Eastern Research Group 2003), and statistical analyses of the effect of fiber size, shape, and mineralogy on potency (e.g., Berman et al. 1995; Berman and Crump 2003) are available and ought to be included. The authors may challenge some of the findings or interpretations contained in these references, but these should be addressed in any book that purports to be “encyclopedic and comprehensive.”

Considering that the phrase “risk analysis” is used in the title, the book contains relatively little discussion of this topic—being limited chiefly to material in Chapter 6. As stated above, Chapter 6 is very well written—interesting and easy to follow—but there is almost no discussion of analytical risk models—and (as noted above) no equations. As these are central to an understanding of how risk is estimated, their omission is surprising. I also found it curious that one of the major epidemiology review papers (Hodgson and Darnton 2000) was not discussed or even cited. The Hodgson and Darnton paper is generally regarded as objective, authoritative, and comprehensive. And many important issues, such as whether or not linear models3 are appropriate or whether or not there is a threshold exposure for tumors are dismissed with a brief comment and citation, rather than a careful discussion. The author undoubtedly believes that linear nonthreshold models are scientifically valid. Fair enough, but the reader deserves a careful examination of these points as risk estimates are sensitive to these assumptions. Likewise, the author provides an excellent discussion supporting the hypothesis that “pure” chrysotile is capable of causing lung cancer and mesothelioma.4 But he omits discussion of quantitative potency estimates that indicate that chrysotile has lower potency than amphiboles (see, e.g., Hodgson and Darnton 2000). Again, the author may believe that the evidence to support differences in potency among asbestos types is weak or flawed, or alternatively that such differences are unimportant. But, if so, he should state this explicitly along with his reasons for these views.

The discussion of environmental asbestos exposure is limited and incomplete. Some of the newest material (e.g., Pan et al. 2005) may be too recent to have been included, but other studies are available.

Despite the critical comments ventured above, I found the book interesting, readable, and potentially useful. It is likely to be primarily of interest to specialists, but is well enough written to be accessible to a more general (but still technical) audience. The text certainly deserves a place on the specialist’s bookshelf. Though useful and interesting, it cannot serve as a single source-book on the topic—“encyclopedic, comprehensive coverage” is an overstatement.