Aquifers are areas of soil or rock that contain large amounts of water. Aquifers may be specifically defined as those areas from which we can obtain and use the water.

Arsenic is a chemical that occurs naturally and can also be made in industry. Too much arsenic in your drinking water can lead to serious health effects, such as depression and loss of energy. Arsenic is also toxic to your nervous system.

EPA stands for the Environmental Protection Agency, which is a United States government agency. The EPA's purpose is to help protect the health of the people by protecting the health of the environment. The EPA sets and enforces limits of chemicals that industry can put into the air, the water and the land. The EPA also regulates waste disposal.

The hydrologic cycle involves the movement of water throughout the earth and atmosphere.

A soil or rock layer which is impermeable does not permit water, or contaminants in the water, to pass through the layer.

Pathogens are bacteria and viruses that cause disease.

Usually found in hazardous waste sites, PCB's can cause liver damage and cancer.

TCE is a material used in cleaning. It can cause cancer.

A gasoline additive that can cause liver, kidney, and nervous system damage.