The contamination of the air, water, or soil with potentially harmful substances can affect any person or community. Contaminants are often chemicals found in the environment in amounts higher than what would be there naturally. We can be exposed to these contaminants from a variety of residential, commercial, and industrial sources. Sometimes harmful environmental contaminants occur biologically, such as mold or a toxic algae bloom. The following are some environmental contaminants that can affect a community or an individual's health.