The effects, intentional or unintentional, beneficial or harmful, direct or indirect, which human activities have upon the environment and living things.
- Water science for schools: land subsidence [More info]
- Site for elementary school studies on land subsidence with links to land subsidence in California, wells, ground water quality, sinkholes, glossary, and a random link.
- Water science for schools: water quality [More info]
- Educational site for elementary school students on water quality with links to related topics including pesticides in ground water, kid's view, urbanization and water and others.