Region
United States
549
Florida
10
New Jersey
8
Great Lakes (North America)
6
Massachusetts
6
California
5
New York (State)
5
Chesapeake Bay (Md. and Va.)
4
Louisiana
4
Alaska
3
Maine
3
Mexican-American Border Region
3
Montana
3
Nevada
3
Tennessee
3
Texas
3
West (U.S.)
3
Wisconsin
3
Arkansas
2
Atlanta
2
Brazoria County
2
Chesapeake Bay Watershed
2
Colorado
2
Connecticut
2
Developing countries
2
East (U.S.)
2
Europe
2
Georgia
2
Hialeah
2
Idaho
2
Illinois
2
Kansas
2
Lake Charles
2
Maryland
2
Mexico
2
Mexico, Gulf of
2
Michigan
2
Naval Station Newport (R.I.)
2
Oklahoma
2
Pennsylvania
2
Washington (D.C.)
2
Washington (State)
2
Yucca Mountain
2
Aberdeen Proving Ground
1
Adams County
1
Alabama
1
Albuquerque
1
Arizona
1
Assateague Island (Md. and Va.)
1
Bartlesville
1
more ...