High levels of toxic elements have harmful effects on all aspects of the environment (water, air, plants, etc.). Trace elements, many of which are heavy metals, can compromise soil quality, cause toxicity to plants, and ultimately contaminate the food chain. This book summarizes the effects of trace elements in the environment. Section 1 discusses the influence of trace elements on soil and the ecosystem and Section 2 examines the influence of trace elements on water. The book also discusses microplastics, which accumulate trace elements and pollute the oceans, harming both aquatic and human life.