Nondestructive biomarkers in vertebrates

In the last twenty years, ecotoxicology has been increasingly concerned with the use of biomarkers to evaluate the biological hazard of toxic chemicals and, as an integrated approach, in the assessment of environmental health. The concept of biomarkers in the evaluation of environmental risk has captured the attention of regulatory agencies and is currently being assessed by several research commissions. This interest is confirmed by the increasing number of specialist manuals (see other publications by McCarthy and Shugart, Huggett et al., PeakaIl, and Shugart and Peakal). The central feature of this methodological approach is to "quantify exposure and its potential impact by monitoring biological end-points (biomarkers) in feral animals and plants as indicators of exposure to and the effects of environmental contaminants". Sometimes, however, in environmental contamination problems, the terms of investigation may shift from evaluation of environmental health, using sentinel species as bioindicators, to a more specific investigation of the "health" of a population or an endangered species in a situation of already-ascertained environmental poIlution. This inversion of terms inevitably leads to a demand for analytical and sampling methods that are compatible with the protection and conservation of the organism to be studied. In light of this increasingly important requirement, this book focuses on the use of nondestructive biomarkers (NDB) in the hazard assessment of vertebrate populations. The choice of nondestructive biomarkers over destructive biomarkers is not only an ethical one. The editors do not whoIly agree with the ideology of certain radical environmental movements in which the animal organism, as an individual, must be saved at all costs. From the ecological point of view, the value of a population or a community is greater than that of an individual. With this in mind, the loss of a few individuals for research purposes is permissible if the data obtained contribute to the conservation of the population or community studied. On the other side of the scale, there is the problem of the "ethic of the researcher". One may often ask whether the researcher is more harmful to the population than the contaminants studied. Several examples exist of "case studies" in which populations of protected species, already heavily stressed by anthropogenic disturbance and contaminants, have been further reduced in number by "wildcat" sampling on the part of shortsighted ecotoxicologists. Apart from ethical considerations, destructive testing in vertebrates may be unacceptable under many conditions, for example, in the hazard assessment of protected or threatened species, or when the number of animals available at a site is limited, or when sequential samples from the same individual are required for time-course studies. The use of noninvasive methods of monitoring the health of species and populations at risk has rarely been the subject of investigation by the "biomarker scientific community”. In this book we present an alternative approach for hazard assessment in high vertebrates based on nondestructive, rather than destructive, methods. World experts in the biomarker field have been co-opted in this "editorial adventure" in which we attempt to review the state of the art and to define the development and validation procedures of this new strategy. In November 1991, after a stimulating discussion with John McCarthy and Lee Shugart at Oak Ridge National Laboratory (U.S.), we conceived the idea of organizing an international workshop to discuss the current state of the nondestructive biomarker approach with the main experts in the sector, many of whom are authors of chapters in this book. In the winter of 1992, an application was made to the U.S. Department of Energy (USDOE) to hold an International Workshop on "Nondestructive Biomarkers in Vertebrates". The Organizing Committee consisted of M. Cristina Fossi and Claudio Leonzio, as directors, together with Lee Shugart, John McCarthy, David Peakall, Colin Walker, Silvano Focardi, and Aristeo Renzoni. The application was approved in the spring of 1992 and additional financial support to supplement the USDOE award was obtained from the Consiglio Nazionale delle Ricerche (Italy) and the Italian bank, Monte dei Paschi di Siena (MPS). On May 25 through 27, 19 scientists from six countries - United States, 6; United Kingdom, 6; Italy, 4; Spain, 2; Denmark, 1 - met in a medieval monastery, the Certosa di Pontignano, now owned by the University of Siena, for high-level scientific discussions on a new strategy for hazard assessment in vertebrates based on nondestructive biomarkers. This workshop provided a forum for the comprehensive review of the state of the art and for establishing an international consensus on the most useful and sensitive nondestructive biomarkers. Research priorities for the development and validation of this promising new method were also defined. This book makes the results of the workshop available to the international scientific community. The chapters in this volume describe different types of nondestructive biomarkers for hazard assessment in vertebrate species. The biomarkers are classified according to the nature of the toxic endpoint being probed. Particular attention is paid to the study of endangered species such as marine mammals. Each chapter contains an introduction in which the scientific basis and rationale for the endpoint being used as biomarker is explained, followed by a brief history of its application to environmental problems, together with available analytical techniques and possible destructive and nondestructive uses. The book is organized in eight sections: Overview (Chapter 1), Enzymatic Biomarkers (Chapters 2 and 3), Metabolic Products as Biomarkers (Chapter 4), Genotoxic Responses (Chapters 5, 6, and 7), Cellular Biomarkers (Chapter 8), Biomarkers in Eggs (Chapter 9), Biomarkers in Studies of Endangered Species (Chapters 10 and 1 ]), and Remarks on Nondestructive Biomarker Strategy (Chapters 12, 13, and 14).