The document discusses various forms of pollution and methods of pollutant biodegradation. It focuses on biodegradation, the process by which microorganisms break down pollutants for energy. Specific examples discussed include biodegradation of hydrocarbons in oil spills by hydrocarbon-degrading bacteria. While many pollutants can be broken down biologically, some like heavy metals require additional remediation methods. Overall the document provides an overview of pollution types and how bioremediation can help reduce environmental contamination.