This contributed volume brings out a comprehensive collection of information on environmental toxicology, its impact on living organisms in general and human health in particular. The main focus of this book is to address human health issues and risk assessment.   Toxicological studies help in understanding the impact of harmful substances including both natural and synthetic chemicals on organisms and their environment. Contributions in the title include both laboratory and field based studies with a focus on human health. Moreover, day by day, there is an increase in the range of chemicals from pharmaceutical and other industries, agricultural runoffs, medicine, and many other sources which continuously contribute to the earths chemical load. Almost all the countries are facing great difficulties in responding to the crucial and immediate need for effective management of such contaminants. The title compiles studies in regards to environmental toxicology and itseffect on human health.  This book provides critical information and knowledge that can be used by regulatory agencies, decision-makers, policy makers, graduate and post-graduate students, researchers, environmental toxicologists, etc, and others to put programs and policies in place to limit our exposures to these substances thereby preventing or reducing the likelihood that a disease or other negative health outcomes would occur.