Water is integral to ecological and human health.
The Earth’s Water
- One billion cubic kilometers of water covers approximately 70% of the Earth’s surface.
- Only 2.5% of the world’s water is freshwater.
- Only 0.83% of the world’s water is fresh and accessible to humans. 97% of this water is groundwater – water found in the rock and soil pores underground. Groundwater is replenished by rainwater, snowmelt and seepage from the bottoms of some lakes and rivers.
- About 2 billion people, in both urban and rural areas worldwide, depend on groundwater for their needs.
- The longest river in the world is the Amazon, which is 4,225 miles (6,800 kilometers) long. The Nile River is a close second at 4,160 miles (6,695 kilometers) long.
- The deepest fresh water lake in the world is Lake Baikal in Russia at 5,369 feet (1,636 kilometers). It contains about 5,521 cubic miles of water (23,012 cubic kilometers), approximately 20 percent of the Earth’s total fresh surface water. This volume is nearly equivalent to the water contained by all five of the Great Lakes in North America combined.
- The Caspian Sea holds the title of the largest landlocked body of water, in terms of surface area. The Caspian Sea is 143,200 square miles (370,886 square kilometers) in size.
- Lake Superior, on the United States – Canadian border, is the largest freshwater body of water, in terms of surface area. Lake Superior is 31,700 square miles (82,103 square kilometers) in size.
- The highest river is the Yarlung Tsangpo, with an average elevation of 13,123 feet (4,000 meters). The Yarlung Tsangpo originates in Tibet, crossing the Himalayas and into India where it is known as the Brahmaputra. The Brahmaputra then merges with the Ganges in Bangladesh, forming the world’s largest delta, before emptying into the Bay of Bengal.
- The Challenger Deep, in the Mariana Trench of the North Pacific Ocean, is the deepest point in the Earth’s oceans. The Challenger Deep is 35,840 feet (10,924 meters) below sea level.
Water Use & Pollution
- India withdraws the greatest amount of freshwater of all the world’s nations, 154.95 cubic miles (645.84 cubic kilometers) per year. China withdraws the next largest volume, 131.89 cubic miles (549.76 cubic kilometers) per year. The United States is third in water withdrawals, 114 cubic miles (477 cubic kilometers) per year.
- Globally, 68.5% of freshwater withdrawals are used in agriculture, 18.1% are used in the industrial and energy sectors and 13.3% are devoted to municipal and household uses.
- Water is integral to the production of most everything we eat, drink or use:
- 2,400 liters of water going into producing a hamburger, an egg is produced with 135 liters of water and an apple requires 70 liters of water.
- It takes 140 liters of water to make a single cup of coffee, 75 liters to make a glass of beer and 35 liters to make a cup of tea.
- 8,000 liters of water go into producing a pair of leather shoes, 2,000 liters for a cotton t-shirt and 10 liters for a single letter-sized piece of paper.
- Water pollution comes in many forms – chemical contaminants, disease-causing pathogens and thermal pollution. Agriculture, dams, industry, invasive species, sewage, polluted runoff and water diversions are sources of water pollution and ecological harm.
- The Blacksmith Institute’s Top 10 list of the World’s Worst Pollution Problems contains 8 issues that are directly related to water pollution – artisanal gold mining, contaminated surface water, industrial mining activities, groundwater contamination, metals smelting and processing, radioactive waste and uranium mining, untreated sewage, and used lead acid battery recycling.
- Pharmaceuticals and personal care products can be found in the rivers, lakes and coastal waters of any place humans live or even visit – they have been detected in wastewater effluents, surface waters, groundwater, and drinking water supplies around the world.
- The Ganges River, sacred to Hindis and important to Buddhists, is among the most polluted due to mills and tanneries, chemical and energy industries and untreated sewage.
- Areas of the Baltic Sea, Chesapeake Bay, Gulf of Mexico and Sea of Marmara are so polluted from agricultural and urban runoff that fish and other aquatic life passing through can die from lack of oxygen.
- In the U.S., 44% of assessed river miles, 64% of assessed lake acres and 30% of estuarine square miles are considered impaired due to agriculture, atmospheric deposition, hydromodification, municipal discharges and “unknown/unspecified.”
- Water pollution is the leading worldwide cause of diseases and deaths.
Water & Human Heath
- The human body is mostly water, approximately 55 to 80%, depending on your age and gender.
- The daily requirement of water for survival, sanitation, bathing and cooking is between 5 and 13 gallons (20 and 50 liters).
- Millions of women and children spend several hours each day collecting water from distant and often polluted sources.
- 884 million people, or approximately 1 in 8 people, lack access to safe water supplies.
- At any given time, half of the world’s hospital beds are filled with patients suffering from water-related disease.
- More than 3.6 million people die each year from water-related diseases; 98% of these deaths occur in developing nations and 43% of water-related deaths are due to diarrhea.
- Every 15 seconds a child dies from water-related disease; 84% of the water-related deaths are in children under 15 years old.
Learn more about the world water crisis by visiting these online resources.
Blacksmith Institute. 2008. World’s Worst Pollution Problems of 2008. Last visited 21 April 2009.
Daughton, C.G. and T.A. Ternes. 1999. Special report: pharmaceuticals and personal care products in the environment: agents of subtle change? Environmental Health Perspectives. 107. Supp. 6.
Geology.com. 2009. Earth Science World Records. Last visited 21 April 2009.
Gleick, P.H., H. Cooley, M. Cohen, M. Morikawa, J. Morrison, M. Palaniappan. 2009. The World’s Water 2008-2009. Last visited 21 April 2009.
Hoekstra, A.Y. and A.K. Chapagain. 2007. Water footprints of nations: Water use by people as a function of their consumption pattern. Water Resources Management. 21(35-48).
Jackson, R.B., S.R. Carpenter, C.N. Dahm, D.M. McKnight, R.J. Naiman, S.L. Postel, S.W. Running. 2001. Water in a Changing World. Ecological Society of America. Last visited 5 December 2005.
National Aeronautics and Space Administration. 2003. Weighing Earth’s Water from Space. Last visited 20 April 2009.
National Parks Service. 2001. The World’s Deepest Lakes. United States Department of Interior. Last visited 21 April 2009.
People’s Daily Online. 2009. World’s Highest River May Power China. China-Tibet Online. Last visited 21 April 2009.
Roach, J. 2007. Amazon Longer than Nile River, Scientists Say. National Geographic News. Last visited 21 April 2009.
UN-Water. 2009. Statistics: Graphs & Maps. Last visited 21 April 2009.
UNICEF/WHO. 2008. Progress on Drinking Water and Sanitation: Special Focus on Sanitation. Last visited 21 April 2009.
United Nations Development Programme. 2006. Human Development Report 2006, Beyond Scarcity: Power, poverty and the global water crisis. Last visited 21 April 2009.
United States Environmental Protection Agency. 2009. The National Water Quality Inventory: Report to Congress for the 2004 Reporting Cycle – A Profile. Last visited 28 May 2009.
Westerhoff, P., Y. Yoon, S. Snyder, E. Wert. 2005. Fate of endocrine-disrupter, pharmaceutical, and personal care product chemicals during simulated drinking water treatment processes. Environmental Science and Technology. 39(17).
The World Bank. 2009. Water Resources Management: Groundwater. Last visited 21 April 2009.
World Health Organization. 2008. Safer Water, Better Health: Costs, benefits, and sustainability of interventions to protect and promote health. Last visited 21 April 2009.