Region
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Kentucky
13
Montana
13
Utah
13
Australia
12
Iowa
12
Los Angeles
12
Russia (Federation)
12
Mexican-American Border Region
11
New York
11
Prince William Sound
11
Puget Sound
11
Appalachian Region
10
Developing countries
10
England
10
European Union countries
10
Great Lakes Region (North America)
10
Louisiana
10
Mississippi
10
France
9
Gulf of Mexico
9
Maine
9
Navajo Nation, Arizona, New Mexico & Utah
9
New England
9
New Mexico
9
Washington (D.C.)
9
West (U.S.)
9
Antarctica
8
Fukushima-ken
8
Missouri
8
Nebraska
8
North Dakota
8
Oahu
8
Europe, Eastern
7
Germany
7
London
7
Puerto Rico
7
Snake River Plain (Idaho and Or.)
7
Snake River Plain Aquifer
7
Susquehanna River Watershed
7
Animas River Watershed (Colo. and N.M.)
6
Camp Lejeune
6
Erie, Lake
6
Fort Gordon
6
Fort Gordon (Ga.)
6
Gulf Coast (U.S.)
6
Hudson River (N.Y. and N.J.)
6
Long Island Sound (N.Y. and Conn.)
6
Mississippi River
6
Morris County
6
Ontario
6
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