Trace metals are necessary for the proper functioning of living organisms and are absorbed by the body through diet or environmental exposure. However, excessive intake of trace metals can cause health problems. As such, the study of the presence of trace metals in the environment and their effects on health is important. This volume includes four chapters that provide details about trace metals in various contexts. Chapter One explains the nutritional zinc requirements of humans and discusses the usefulness of different supplements in various applications. Chapter Two addresses the different aspects of metal-microbial interactions, focusing on soil and sediment ecosystems. Chapter Three addresses pollution of heavy metals, emission sources, health implications, and commonly used methods for assessment of pollution. Lastly, Chapter Four assesses possible changes in the geochemical behaviour of chromium caused by sediment resuspension in a hypereutrophic estuary that receives domestic and industrial effluents daily.