Region
- United States 60 results
- India 10 results
- California 8 results
- Great Britain 8 results
- OECD countries 6 results
- Africa 4 results
- Carlsbad Region 4 results
- New Mexico 4 results
- Africa, Sub-Saharan 2 results
- Atlanta 2 results
- Atlanta (Ga.) 2 results
- Caribbean Area 2 results
- Delta Region 2 results
- Delta Region (Calif.) 2 results
- Egypt 2 results
- England 2 results
- Europe 2 results
- Everglades National Park (Fla.) 2 results
- Florida 2 results
- Georgia 2 results
- Great Lakes (North America) 2 results
- Greece 2 results
- Greenland 2 results
- Gulf States 2 results
- Idaho 2 results
- Idaho National Engineering and Environmental Laboratory Region 2 results
- Japan 2 results
- Kurdistan 2 results
- London 2 results
- Mexico, Gulf of 2 results
- Nile River Watershed 2 results
- Scandinavia 2 results
- Soutthern States 2 results