Toxicity testing in laboratory animals provides much of the information used by the Environmental Protection Agency (EPA) to assess the hazards and risks associated with exposure to environmental agents that might harm public health or the environment. The data are used to establish maximum acceptable concentrations of environmental agents in drinking water, set permissible limits of exposure of workers, define labeling requirements, establish tolerances for pesticides residues on food, and set other kinds of limits on the basis of risk assessment. Because the number of regulations that require toxicity testing is growing, EPA called for a comprehensive review of established and emerging toxicity-testing methods and strategies. This interim report reviews current toxicity-testing methods and strategies and near-term improvements in toxicity-testing approaches proposed by EPA and others. It identifies several recurring themes and questions in the various reports reviewed. The final report will present a long-range vision and strategic plan to advance the practices of toxicity testing and human health assessment of environmental contaminants.

Advances in molecular biology and toxicology are paving the way for major improvements in the evaluation of the hazards posed by the large number of chemicals found at low levels in the environment. The National Research Council was asked by the U.S. Environmental Protection Agency to review the state of the science and create a far-reaching vision for the future of toxicity testing. The book finds that developing, improving, and validating new laboratory tools based on recent scientific advances could significantly improve our ability to understand the hazards and risks posed by chemicals. This new knowledge would lead to much more informed environmental regulations and dramatically reduce the need for animal testing because the new tests would be based on human cells and cell components. Substantial scientific efforts and resources will be required to leverage these new technologies to realize the vision, but the result will be a more efficient, informative and less costly system for assessing the hazards posed by industrial chemicals and pesticides.

The public depends on competent risk assessment from the federal government and the scientific community to grapple with the threat of pollution. When risk reports turn out to be overblownâ€"or when risks are overlookedâ€"public skepticism abounds. This comprehensive and readable book explores how the U.S. Environmental Protection Agency (EPA) can improve its risk assessment practices, with a focus on implementation of the 1990 Clean Air Act Amendments. With a wealth of detailed information, pertinent examples, and revealing analysis, the volume explores the "default option" and other basic concepts. It offers two views of EPA operations: The first examines how EPA currently assesses exposure to hazardous air pollutants, evaluates the toxicity of a substance, and characterizes the risk to the public. The second, more holistic, view explores how EPA can improve in several critical areas of risk assessment by focusing on cross-cutting themes and incorporating more scientific judgment. This comprehensive volume will be important to the EPA and other agencies, risk managers, environmental advocates, scientists, faculty, students, and concerned individuals.

Nationally, toxicology programs have evolved from a traditional exploration of the chemistry and applied toxicity of chemicals and drugs to a more comprehensive study of toxicology and toxicology testing as independent entities. Consequently, the second edition of Principles of Toxicology Testing starts with basic toxicological principles, including absorption, distribution, metabolism, and elimination of toxins, including chemicals and drugs. The book then continues with animal (in vivo) and in vitro toxicology testing methods associated with toxicological analysis and preclinical drug development. As in the first edition, the book begins with an introduction into the fundamentals of toxicology (Section I) to prepare readers for the subsequent topics and continues through with a discussion of toxicokinetics and human risk assessment. This introductory material is useful in understanding the applications of toxicology testing. Section II describes the fundamental principles of toxicology testing in animals in greater detail. This section describes acute toxicity studies as well as subchronic and chronic studies performed on animals. Special emphasis is placed on study design and determination of classical indicators for acute and chronic testing, such as the LD50. The book examines other short- and long-term animal toxicity testing methodologies, including dermal, ocular, and reproductive toxicity testing. In addition, mutagenicity and carcinogenicity studies are also discussed in separate chapters. Section III introduces and discusses in vitro alternatives to animal toxicology tests. This section emphasizes cell culture methodology and cellular methods for acute systemic toxicity, target organ toxicity, and local toxicity. The contributors present the advantages and disadvantages of alternative methods. They also describe the use of high-throughput screening and its applications, the concepts of standardization and validation of in vitro techniques (especially large, organized validation efforts currently supported by US and EU regulatory agencies), and the theories supporting the development of in vitro methodologies. This second edition is a must-read for undergraduate and graduate toxicology students. Industrial and academic research centers will also find the text useful for establishing a toxicology testing laboratory.

The test substance is administered in graduated doses to several groups of males and females. Males should be dosed for a minimum of four weeks; females should be dosed throughout the study (approximately 54 days). Normally, matings “one male to one ...

Acute toxicity tests are an area of focus for developing alternative assays and approaches to address animal welfare concerns. In the context of this document, acute toxicity studies refer to studies involving a single exposure to a test chemical and include those assessing systemic toxicity as ...

This updated and revised edition delineates the basic concepts and fundamental principles needed to grasp current issues in modern toxicology. In addition, new contributions help to redefine the book's scope and coverage, and illuminate new and emerging areas of toxicologic interest.