Contaminants are substances that make something impure or unclean. They can be found in air, water, soil, and food, and can come from various sources, such as industrial processes, agricultural practices, or household products. Common examples include chemicals, heavy metals, and microorganisms that can harm human health and the environment. Contaminants can affect ecosystems and biodiversity. For instance, when pollutants enter water bodies, they can disrupt aquatic life and contaminate drinking water sources. Efforts to reduce contaminants often involve regulations, clean-up initiatives, and public awareness campaigns to protect both people and the planet from harmful effects.