The Clean Water Act is a comprehensive federal law that aims to restore and maintain the chemical, physical, and biological integrity of the nation's waters. It regulates the discharge of pollutants into navigable waters, sets water quality standards, and provides funding for wastewater treatment facilities.

Agricultural runoff is the leading source of water pollution in the United States. It contains fertilizers, pesticides, and animal waste, which can contaminate surface water and groundwater. Industrial wastewater and municipal wastewater are also significant sources of pollution, but they are typically treated before being discharged into the environment.

Water treatment is the process of removing pollutants from water to make it safe for drinking, industrial use, or other purposes. It can involve a variety of processes, including filtration, disinfection, and chemical treatment.

The maximum contaminant level (MCL) for lead in drinking water is 15 ppb (parts per billion). This means that public water systems cannot exceed this level in their treated water.

The Resource Conservation and Recovery Act (RCRA) is the federal law that regulates the disposal of hazardous waste. It sets standards for the treatment, storage, and disposal of hazardous waste, and it requires businesses to obtain permits before they can dispose of hazardous waste.

Remediation is the process of removing pollutants from soil and groundwater. It can involve a variety of techniques, such as excavation, pumping, and chemical treatment.

The Montreal Protocol is an international treaty that aims to protect the ozone layer. It was signed in 1987 and has been ratified by over 190 countries. The treaty has been successful in reducing the production and consumption of ozone-depleting substances, and it has helped to protect the ozone layer.

The Clean Air Act is the federal law that regulates air pollution. It sets standards for air quality, and it requires businesses to obtain permits before they can emit air pollutants.

Waste reduction is the process of reducing the amount of waste produced. It can involve a variety of techniques, such as using less packaging, reusing materials, and composting organic waste.

The Resource Conservation and Recovery Act (RCRA) is the federal law that regulates the disposal of solid waste. It sets standards for the treatment, storage, and disposal of solid waste, and it requires businesses to obtain permits before they can dispose of solid waste.

Waste-to-energy is the process of converting waste into energy. It can involve a variety of technologies, such as incineration, gasification, and pyrolysis.

The Hazardous Materials Transportation Act (HMTA) is the federal law that regulates the transportation of hazardous materials. It sets standards for the packaging, labeling, and transportation of hazardous materials, and it requires businesses to obtain permits before they can transport hazardous materials.

Ecological restoration is the process of protecting and restoring natural ecosystems. It can involve a variety of techniques, such as planting native vegetation, removing invasive species, and restoring natural hydrology.

The Federal Land Policy and Management Act (FLPMA) is the federal law that regulates the management of public lands. It sets standards for the use and disposal of public lands, and it requires federal agencies to consider the environmental impacts of their actions on public lands.

Energy conservation is the process of reducing the use of energy. It can involve a variety of techniques, such as using more efficient appliances, turning off lights when they are not needed, and weatherizing homes and businesses.