Percentage of population using improved drinking-water
sources and sanitation facilities in 2008 by World Health
Organization (WHO) region and country-income group
AfricaNorth and South America
Europe
Southeast Asia
Eastern Mediterranean
Western PacificGlobal0 10203040
Percentage of population50 60 70 80 90 100Water
SanitationThe World’s 10 Largest Watersheds
Area of watershed
Watershed Region (thousand km^2 )
Amazon South America 6145
Congo Africa 3731
Nile Africa 3255
Mississippi North America 3202
Ob Asia 2972
Paraná South America 2583
Yenisey Asia 2554
Lena Asia 2307
Niger Africa 2262
Yangtze Asia 1722
Source: Water Resources of the World, World Resources Institute (2010).PRIMARY WATERSHEDS AND CRITICAL AREAS
Earth’s bodies of fresh water can cover enormous
areas and cross many political boundaries.
Watersheds are Earth’s rain barrels. They collect
precipitation and filter it as they channel it
to streams, rivers, lakes, and aquifers. Many
watersheds are stressed by human activities.ACCESS TO CLEAN FRESH WATER
Access to clean fresh water is critical for human health.
Yet in many regions, potable water is becoming scarce
because of heavy demands and pollution. Especially
worrisome is the poisoning of aquifers—a primary source
of water for nearly one-third of the world—by sewage,
pesticides, and heavy metals.WHO 2011
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Ü>ÌiÀÊÀiÃÕÀViÃÊUÊ}ÕÀiʣ䰣£ÊInterpreting Data
Which continent appears to have
the best access to fresh water?
the poorest access?