Preface

Urbanization and industrialization are producing large amounts of heavy metals, which are toxic to humans and the environment. These metals are commonly used for applications such as protecting surfaces, building, painting, in the food industry, and more. In addition to natural sources, these anthropogenic activities introduce heavy metals such as titanium (Ti), cadmium (Cd), chromium (Cr), arsenic (As), mercury (Hg), lead (Pd), nickel (Ni), copper (Cu), zinc (Zn), and others into the environment. In addition, rare earth elements such as neodymium (Nd), europium (Eu), terbium (Tb), dysprosium (Dy), and ytterbium (Yb) are being introduced into our ecosystem including the air, water, soil and sediment, and biological species. These elements are hazardous, toxic, and carcinogenic and they have a negative impact on the ecosystem and human health. Although minute quantities of some metals are required for the physiological processes in the body, excessive amounts can lead to a number of disorders. This book includes fifteen chapters and presents a comprehensive overview of heavy metals including their physiochemical properties, toxicity, transfer in the environment, legislation, environmental impacts, and mitigation measures. Chapters include scientific research and studies. This book provides insight into the available techniques for removing heavy metals, such as adsorption, their qualitative and quantitative analysis, and future prospects for these removal methods.

> **Mazen Khaled Nazal** Center for Environment and Marine Studies (CEMS), Research Institute (RI), King Fahd University for Petroleum and Minerals (KFUPM), Dhahran, Saudi Arabia
