Figure 2. Percent Water Consumption click for copyright

• Average North American uses 300 liters of water per day (see Figure 2).
• A dripping faucet that leaks just one drop of water every second will waste 4 gallons of water a day (1,400 gallons in a year). Yet, it usually only costs a few dollars to repair.
• Irrigation has played a roll in human lives for nearly 5,000 years. The Pharaohs in ancient Egypt ordered people build channels to carry water to dry fields. In about 1,000 B.C., a farmer with a bucket and a pole could irrigate about ¼ acre a day. Then, in about 1,000 A.D., a farmer using a buffalo to turn a wheel could irrigate about 5 acres a day. Today, in industrialized countries using advanced technology, a farmer can pump 1,000 gallons of water per minute over a 160-acre area. On average, crops require about 2,200 lbs of water to produce 2.2 lbs of food.
• The Exxon Valdez, carrying millions of gallons of crude oil, ran aground in Prince William Sound, Alaska, in March 1989. Over 11 million gallons of oil spilled into the sea. It eventually spread over 1,100 miles of coastline and killed as many as 100,000 birds and 1,000 sea otters as well as other shore life.
• During the Gulf War in 1991, Iraq deliberately dumped 240 million gallons of crude oil from Kuwaiti oil reserves in an attempt to halt U.S. marine operations. Reports estimate that 8 million gallons ran directly into the Persian Gulf.
• Safe and abundant water is listed as fourth of the 20 greatest engineering achievements of the 20th century (according to NAE, the National Academy of Engineers).
• Typhoid fever, cholera, dysentery and diarrhea killed many people in the early 1900s. Because of water treatment systems created by engineers starting in the 1940s in the United Stated, these diseases were almost eradicated. Furthermore, water was moved into areas that were previously inhabitable.

Point source pollution is the leading cause of water pollution. Point source pollution is pollution that comes from a definite source, such as: direct industrial discharge and dumping, accidents, deep-well injection, leaky landfills, leaking underground storage tanks, abandoned hazardous waste sites, septic tanks, etc. Point source pollution can usually be measured and there is strict government regulations on its discharge (i.e., permits must be obtained from the local government for permission to discharge such pollutants into the environment). Following are some examples of how point source pollution exists today.

Figure 3. Sources of Pollution click for copyright

• City and Industrial Waste - Such waste includes chemical waste produced by factories, raw/partly treated sewage from cities (that contains dangerous, sometimes deadly, bacteria), and garbage that is irresponsibly dumped straight into water. This type of water pollution is the most heavily regulated today.
• Deep Well Injection - Industrial liquid waste is injected into porous areas that are sealed off from the aquifers above and below by a layer of impermeable rock. The rock can develop cracks, and sometimes the chemical wastes corrode through the impermeable rock. Also, the lining of the well can leak.
• Landfills - Leachate is a liquid that is produced when rainwater mixes with the substances that are buried in a landfill. This liquid leaks from the landfill and often seeps into the groundwater.
• Heat - Some industrial companies use water to cool their equipment (like nuclear power plants). The water is heated up above its normal temperature and is drained back into the original water source. This results in animals dying (when the temperature is outside their range of tolerance) and an increase in algae growth — eutrophication — of the types that grow more quickly in warmer water.
• Saltwater Infiltration - occurs when too much water is taken from a freshwater aquifer near the ocean, allowing salt water to infiltrate, and contaminate, the aquifer.
• Natural - This type of water pollution occurs in many ways including: blue-green algae that can poison fresh-water ponds, rapid algae growth called "red tides," dust/ash/heat from erupting volcanoes, germs (bacteria), and floods.

Nonpoint source pollution follows point source pollution in terms of its cause for polluting our waters, but is still a major contributing factor. Nonpoint source pollution is described as water that runs over the ground and picks up — and then carries away — natural and human-made pollutants. This water is then deposited into our lakes, streams, coastal waters and even underground sources of drinking water, resulting in harmful effects on drinking water supplies, recreation and wildlife. Sources for nonpoint source pollution include: agricultural runoff, urban runoff, mining, logging, grazing, etc.

Figure 4. A coastal oil spill. click for copyright

• Farmland Runoff - Irrigation runoff carries nitrates/phosphates (from fertilizer) and pesticide/insecticides to water sources. Runoff water also carries large quantities of soil which settle on the bottom of lakes and rivers.
• Transportation - This includes the use of waterways for industrial shipping (such as the large and widely used Mississippi River) and the transportation of materials through pipelines (natural gases, liquids, oil, or coal in a water "slurry" carried from Black Mesa Coal Mine in Arizona to Mojave, Nevada).
• Crude Oil - More than 50% of crude oil comes from land-based, nonpoint sources (40% of it from car owners changing their oil and disposing of it improperly, and the rest from leaking oil pipes from oil production and transportation sites). About 10% of crude oil pollution comes from oil spills. The rest results from marine operations (such as when ships clean out their fuel tanks).
• Household Hazardous Waste Products - It is estimated that 300,000 tons of household hazardous waste (household chemicals, detergent, bleach, etc.) products enter the water system by way of household drains or go unchecked into landfills each year (1992 Environmental Almanac, World Resource Institute).

Figure 5. The effects of a coastal oil spill. click for copyright

Water pollution can cause diseases and poisoning in animals because they may drink the contaminated water or eat the plants that grow from the contaminated water. In essence, the pollution may very well prevent their survival and reproduction.

Phosphates and nitrates, in lakes, coastal waters, rivers, wetlands, etc. throw off the natural balance so that there is too much food for plants and too little oxygen for animals. Such pollutants can cause algae to grow too quickly, which uses up all the nutrients in the water. The algae then die and decompose which uses up all the oxygen in the water. Subsequently, without oxygen the fish die. In large doses, nitrates may cause cancer in humans, which may result in death.

Oil spills may kill aquatic animals, and ultimately, the oil covers ocean floors and beaches. Such large amounts of oil do not allow organisms to reproduce effectively or at all, and prevents normal animal activities (such as, oil-slicked feathers preventing birds from flying and staying warm).

Another effect of water pollution is in our bodies of water that are used for recreation or commercial fishing. Severe pollution restricts commercial fishing because there is little aquatic life left to fish for or because what aquatic life remains is contaminated. And, recreational activities that involve water may not be enjoyed if pollution is present.

There is an excellent history and time-line about water by The National Academy of Engineers at: http://www.greatachievements.org/