Environmental toxicology, also known as entox, is a multidisciplinary field of science concerned with the study of the harmful effects of various chemical, biological and physical agents on living organisms. Ecotoxicology is a subdiscipline of environmental toxicology concerned with studying the harmful effects of toxicants at the population and ecosystem levels. Environmental toxicology is the study of the nature, properties, effects and detection of toxic substances in the environment and in any environmentally exposed species, including humans. This book will provides significant advances and discoveries in the field of environmental toxicology, air, soil, water and food contamination and pollution, toxicants in the total environment, public health, environmental health, pollution and remediation as well as other research subjects closely related to the book. This book will also provide a general understanding of toxicology related to the environment. Fundamental concepts will be covered including dose-response relationships, absorption of toxicants, distribution and storage of toxicants, biotransformation and elimination of toxicants, target organ toxicity, teratogenesis, mutagenesis, carcinogenesis and risk assessment. In the second part of the course, we will study the chemodynamics of contaminants in the environment including fate and transport.