Watershed Pollutants: Risk Assessment and Management of Chemicals and Hazardous Substances

Watersheds provide ecological services that benefit flora and fauna, and people are also benefited from the ecological services, particularly for living and development purposes. Hence, watersheds must be managed in holistic and integrated manners to ensure their sustainability. Nonetheless, rapid development has polluted watersheds, and some of the watershed pollutants are chemicals and hazardous substances. This chapter explains the concept of chemical risk and introduces a framework for chemical risk assessment and management that takes into account the importance of human and environmental health. The chapter also discusses chemicals that cause air pollution (such as ground-level ozone and asbestos) and water pollution (such as different types of heavy metals). In the conclusion, this chapter highlights that we cannot avoid dealing with chemicals in our daily life but we can reduce the risks associated with them.