Published in collaboration with the University of Bergen and the Institute of Marine Research, Norway, and the Marine Biological Laboratory, University of Copenhagen, Denmark
The Toxicology of Fishes
Edited by Richard T. Di Giulio and David E. Hinton
Boca Raton, Taylor & Francis, 2008
1071 pp., ISBN 978-0415248686. US$149.95/£83.00 (hardback)
The research areas ‘toxicology’ and ‘ecotoxicology’ have most commonly been separated in that ‘toxicology’ has been used to describe the science that characterizes the influence of xenobiotics and natural toxins on mammals (including humans), whereas ‘ecotoxicology’ has concerned itself with all other organisms. Although initially derived from ecology with a resulting focus on populations and communities, ecotoxicology has increasingly adopted and adapted theory and techniques from (mammalian) toxicology. While most volumes on the ecotoxicology of organisms leans heavily on fundamental concepts described in books in classical toxicology, this book contains it all, but from a fish perspective. This does of course imply that there is a substantial degree of overlap with books on mammalian toxicology, especially in the initial chapters, but it also provides simultaneous access to both fundamental principles and specific processes relevant to fish. As a lecturer in both toxicology and ecotoxicology I certainly found this refreshing. The focus of this volume is how xenobiotics affects individual fish and not population or community impacts. This is an impressive book, not merely for the number of pages, but more so for the depth of knowledge conveyed in many of the chapters. The structure of the book is logical and most relevant areas are well covered, but some additional topics could have been included, e.g. metal toxicity, DNA damage and membrane transport/pumps in unit I (General Principles), other tissues such as gills, kidney, gastrointestinal tract (all discussed briefly in chapter 8 on osmoregulation) or olfaction in unit II (Key Target Systems and Organismal Effects) and microarray/proteomics/metabolomics and in vitro techniques in unit III (Methodologies and Applications). Still, with the size of the current book it is easy to see why some topics had to be left out.
The most important weakness of this book to readers of Marine Biology Research would be a general lack of information about processes specific to marine environments and species. One obvious reason for this situation is the larger volume of studies available for freshwater species than for marine species, but there is no excuse to omit a discussion of how seawater affects e.g. bioavailability of metals and ionized substances. There is a short discussion on differences between freshwater and marine fish in the chapter on osmoregulation, but this topic would require more. As is often the case, books with a broad range of topics tend to rely heavily on either European or American contributors (in this case the latter), resulting in a bias in terms of examples, species and references used. Some of the chapters of the book fall into that trap and there is a predominance of American species and case studies. The best chapters of the book have a good coverage of relevant scientific work from different parts of the globe. As will often be the case for volumes with many contributors there are some chapters which provide high quality reviews while other chapters remain close to textbook level.
In addition to the introduction, the first part of the book (unit I) comprises chapters on bioavailability, toxicokinetics, biotransformation, receptor-mediated responses and oxidative stress. While the other three chapters provide good overviews in their respective areas, the chapters on toxicokinetics and biotransformation are particularly extensive and really give the reader a comprehensive insight into the current state of knowledge for the two topics.
Unit II concerns target tissues or systems and includes chapters on liver toxicity, osmoregulation, neurotoxicity, immunotoxicity, toxicity of the endocrine system, chemical carcinogenesis and pre-exposure processes. The chapter on liver toxicity gives an in-depth review of hepatic morphology, processes and although less extensive, consequences of toxic insult. If the chapter were to be expanded it would have been interesting to see even more discussion of links between environmental pollutants and liver function and disease. The chapter on osmoregulation is well written, but too short to communicate the different aspects of osmoregulation relevant to toxicology. The three chapters on neurotoxicity, immunotoxicity and toxicity of the endocrine systems provide good overviews of the respective systems and how xenobiotics may affect them. Chemical carcinogenesis is a process which receives much attention in human toxicology and this chapter gives a comprehensive review from a fish perspective. The final chapter of the unit concerns how pre-exposure to contaminants may or may not provide protection if exposed to the same or related substances later. This is still an area that needs further research, but the chapter reviews both physiological and genetic mechanisms that may explain tolerance in natural populations.
Topics covered in unit III include exposure assessment, toxicity testing, biomarkers, mesocosm studies and risk assessment. While the first three chapters provide good overviews of the respective research areas at an introductory level, it is not clear why the two last chapters were included in the volume. Although of course relevant to ecotoxicology in a wider sense, none of them focus particularly on fish and do not link well up with the other chapters in the volume.
The final unit (IV) describes seven case studies, two of which are marine. The chapters includes ‘classical’ ecotoxicological case studies such as dioxin effects in the Great Lakes, effects of polycyclic aromatic hydrocarbons on flatfish in Puget Sound and oestrogen effects on fish in UK rivers. All three chapters are eminently readable and certainly show the resources required to unravel pollution impacts in aquatic ecosystems. In addition, there are two good reviews, one concerns an area affected by mining over a long period, the other recounts decades of experience with pulp and paper mill effects and monitoring. Finally, this unit ends with a straightforward review of pyrethroid toxicity and a (disappointingly) brief chapter on impacts of Exxon Valdez oil on Pacific herring.
As mentioned initially, this is an impressive book which works both as an introduction to general toxicology and as a resource for in-depth topics in fish ecotoxicology. I would recommend it to anyone in need of a comprehensive introduction to fish toxicology or an update on state-of-the-art for specific topics such as e.g. fish toxicokinetics, biotransformation, liver toxicology or chemical carcinogenesis. The book is more a reference than a book to read from start to end. The Toxicology of Fishes clearly aims at researchers in ecotoxicology, but should also be useful as a reference to postgraduate students in aquatic ecotoxicology.
Ketil Hylland
Professor, Department of Biology
University of Oslo
and
Senior Researcher
Norwegian Institute for Water Research
E-mail: [email protected]
© 2009 Ketil Hylland
Metal Contamination in Aquatic Environments – Science and Lateral Management
Samuel N. Luoma and Philip S. Rainbow
Cambridge, Cambridge University Press, 2008
573 pp., ISBN 978-0521860574. US$87/£60/ €62 (hardcover)
Over the past couple of decades there has been such a focus on environmental impacts caused by organic contaminants that it would be easy to forget that metal contamination is still a major problem in both terrestrial and aquatic ecosystems worldwide. In contrast to most organic contaminants, although with some exceptions, e.g. polycyclic aromatic hydrocarbons, metals are naturally present in the biosphere. Human activities may increase or decrease the levels of environmentally relevant metals in ecosystems or change their speciation, but they will of course not be synthesised or degraded.
This book is a true tour-de-force written by two of the most senior researchers in the world in the field of metal ecotoxicology. Although the title alludes to a management perspective, the chapters of the book bring the reader through extensive and well-written reviews of most aspects of the ecotoxicology of both essential and toxic metals. That said, management perspectives are integrated in all chapters, thereby keeping the focus on ‘lateral thinking’ throughout. Each section begins with a ‘prologue’ that briefly states the concept of that section. While this is a bit disturbing at first, it is quickly appreciated by the reader (at least this reader) and actually helps to keep a focus on the issues under discussion. The conclusion at the end of each chapter may therefore be somewhat superfluous, at least for some of the topics discussed. The authors have supplied a limited number of references for further reading at the end of each chapter, some of which are reviews and some of which delve more deeply into one or more of the topics discussed in the chapter. The text is complemented by good graphics that contribute well in illustrating relationships that at times are rather complex. One would sometimes wish for somewhat larger figures and there does appear to have been a few minor slip-ups in proof-reading for some figures (‘omissions’ rather than ‘emissions’, ‘atomsphere’ rather than ‘atmosphere’, etc.), but none which detracts from its understanding.
As within any field of research, concepts and definitions are under continuous debate in metal biogeochemistry and ecotoxicology. To the non-expert there will be a confusing wealth of more or less useful definitions available in the general literature, and it is difficult to know which is correct. The boxes range from the clarification of simple concepts such as ‘heavy metals’ to a case example of how aquatic toxicity criteria may be developed for cadmium (Cd). Through text boxes with definitions and cases, Luoma & Rainbow share from their extensive experience in the relevant disciplines to clearly and succinctly define and clarify concepts and provide highly relevant examples. The book could be recommended for these text boxes alone.
The first three chapters, although brief, provide the required background for readers unfamiliar with basic concepts or indeed the history of metal ecotoxicology. As mentioned above, definitions are clear and such chapters are useful as a quick reference to students, managers and researchers alike. Chapter 4 on sources and biogeochemical cycles focuses on processes and managerial issues and less on the actual sources. Examples are given for environmentally relevant metals such as mercury (Hg), lead (Pb) and zinc (Zn). As mentioned above, on a slightly negative note, the chapter provides limited quantitative information about sources for different metals and the references for e.g. atmospheric inputs of different metals are old (from the 80s). It would have been interesting if the authors had developed the discussion on life-cycle assessment of environmental sources for some selected metals.
Speciation is crucial to understand metal partitioning and bioavailability in aquatic ecosystems and this is the topic of Chapter 5. The chapter covers the subject well, at least for the marine environment, although perhaps leaning a bit too heavily on classical studies in marine chemistry. The section on new methods by which to identify different metal species in a water body could possibly have been expanded and there should have been some discussion on freshwater issues, e.g. aluminium (Al) speciation and toxicity in acidified rivers. This observation leads back to the introduction and the list of metals of ecotoxicological interest, in which Al is absent, but selenium (Se) present. As the authors say ‘This example further typifies the general problem of fitting all metals of ecotoxicological significance into any objective chemical definition’.
Metal biogeochemistry, bioavailability and physiological processes are key research areas for the authors of this book and the two chapters 6 and 7 clearly reflect their overview in these fields. Chapter 6 provides a very useful review of trace metal dynamics in freshwater and marine particulate material and sediments, indicating the most important processes and providing quantitative state-of-the-art partitioning estimates for different metals between sediment components. Chapter 7 on bioaccumulation provides an excellent review of bioavailability and physiological processes associated with transport, accumulation/storage and excretion of metals in aquatic organisms. In addition to providing the required basis to understand relevant processes, the chapter includes useful discussions on metal-specific assimilation efficiency and trophic transfer, consequences of pre-exposure, biodynamic modelling and interactions between factors in determining bioaccumulation.
The chapters of the book follow a logical order from the environmental basis (Chapters 1–6), through accumulation in the individual (Chapter 7), on to how to select species for monitoring (Chapter 8), how to measure biological effects (Chapter 9), toxicity testing (Chapter 10), metal effects in natural habitats (Chapter 11), effects of mining (Chapter 12), two specific cases, Se and organometals (Chapters 13 and 14), risk assessment issues for water (Chapter 15) and sediment (Chapter 16) and finally two chapters of synthesis (17 and 18).
The chapters that directly address how metals affect organisms (9, 10, and 11) are surprisingly comprehensive in their coverage of the topics, including the most pertinent areas. Although one would not really expect it, the authors have found the space to explain the basic concepts of toxicity testing in that chapter and have provided a good overview of confounding factors such as seasonal variability in Chapter 11. Mining activities are probably the single largest anthropogenic source of metal inputs in a global context and clearly deserves a chapter in a volume on metal contamination. Again, a good introduction as well as clear and useful definitions put the reader on the track and the chapter provides both a general overview and some interesting specific examples.
The authors make a strong case for why Se should be included and it has resulted in a very interesting chapter that gives a good overview of environmental issues with this element. Perhaps more fitting (in my opinion) is the chapter on organometals, commonly overlooked in volumes on metal toxicity. Despite the amount of scientific literature on the subject, the section on tributyltin (TBT) accumulation is well put and clearly phrases some of the issues of e.g. bioaccumulation that are commonly overlooked for this organometal.
As mentioned earlier, one of the concepts of this book was to integrate issues relevant to society with the science. This book has succeeded to a large extent towards that objective, but the authors have also wished to include some chapters relevant to environmental monitoring and risk assessment, i.e. selection of biomonitors (Chapter 8), water quality guidelines (Chapter 15) and sediment quality guidelines (Chapter 16). Although this is obviously not a textbook on risk assessment, the chapters still cover relevant aspects such as the biotic ligand model (BLM), species sensitivity curves and issues relevant to the use of acid-volatile sulphide (AVS) in the assessment of sediment metal toxicity.
The authors correctly state that there exist no guidelines by which metals in different matrices can be assessed and managed in a holistic manner. In Chapter 17 they raise some interesting thoughts and perspectives on how such a holistic assessment may be developed and implemented, but they also display some of the problems involved.
As a lecturer in ecotoxicology, I should add that reading this book has given me inspiration to consider developing a course in metal ecotoxicology. This book covers all relevant aspects of aquatic metal ecotoxicology. Although some sections may be omitted from the curriculum of such a course (e.g. some of the aspects of risk assessment), the other topics needed are well covered.
As should be apparent from the above, I wholeheartedly recommend this book for anyone interested in metal ecotoxicology. It reads well and builds progressively on preceding chapters, so it is even appropriate for readers new to the subject (although some background in ecotoxicology would be required), but at the same time useful to managers and experts in the field and, not least, to lecturers.
Ketil Hylland
Professor, Department of Biology
University of Oslo
and
Senior Researcher
Norwegian Institute for Water Research
E-mail: [email protected]
© 2009 Ketil Hylland
Notes
Published in collaboration with the University of Bergen and the Institute of Marine Research, Norway, and the Marine Biological Laboratory, University of Copenhagen, Denmark