****NOTE: The newer FIFTH EDITION, released 8 April 2022 with more up-to-date materials, is currently in stock at https: //www.amazon.com/dp/B09X3Z5WN3****. The core content difference between this Fourth and the Third Edition is minimal. In addition to the correction of the typos found in the Third Edition, this Fourth Edition has made minor refinements but updated substantially the status and the discussion of numerous contemporary issues covered in this book. In particular, this Fourth Edition has highlighted a number of recent public health and regulatory concerns, including the global concerns with the recent pandemics of Zika as well as Ebola and the U.S. Food and Drug Administration's ban on trans fats in all American processed foods by 2018. Moreover, it has updated the five persistent organic pollutants that the Stockholm Convention has added to its action list since the publication of this book's Third Edition in 2014. As three more update examples, this book is now current with the latest estimate data available concerning the annual amounts of pesticide active ingredients used in the United States and worldwide. It is now consistent with the International Agency for Research on Cancer's latest determinations made on the human carcinogenicity potential of the biological, physical, and chemical agents that the agency has analyzed. Furthermore, it is now up to date with the chemical elements included in the current periodic table.As with the earlier editions, this Fourth Edition offers an introductory text on the scope and principles for as well as the relevant topics of environmental toxicology. To this end, the book is organized into 23 chapters under four parts (sections) as listed below. PART I. TOXICOLOGIC CONCEPTS AND ENVIRONMENTAL ISSUES: (1) Scope and Principles for/of Environmental Toxicology; (2) Environmental Changes and Environmental Health; (3) Environmental Pollution and Regulatory Agencies; (4) Occurrence and Types of Environmental Toxicants; and (5) Fate and Transport of Toxicants in the Environment. PART II. BIOACCUMULATION AND BIODISPOSITION OF TOXICANTS: (6) Bioaccumulation of Persistent Environmental Toxicants; (7) Uptake, Distribution, and Excretion of Toxicants; (8) Metabolism/Biotransformation of Xenobiotics; (9) Adverse Action/Toxic Response; and(10) Factors and Conditions Affecting Toxicity. PART III. NATURE AND EFFECTS OF ENVIRONMENTAL TOXICANTS: (11) Air Pollutants - I: Inorganic Gases;(12) Air Pollutants - II: Particulate Matter;(13) Volatile Organic Compounds;(14) Toxic and Radioactive Metals;(15) Pesticides and Pesticide Residues;(16) Persistent Toxic Substances; and(17) Biological and Underrated Physical Toxic Agents. PART IV. SPECIAL TOPICS, ISSUES, CONSIDERATIONS, AND FOCI: (18) Environmental Mutagenesis/Carcinogenesis;(19) Reproductive Toxicity and Endocrine Disruption;(20) Occupational Toxicology/Workplace Hazards;(21) Food Toxicants and Toxic Household Substances;(22) Human Health Aspects of Ecotoxicology; and(23) Environmental Health Risk Assessment.