Water pollution is any change in water quality that can harm living organisms or make the water unfit for human uses Water pollution can come from a single source, or from a larger, more dispersed source Point sources discharge pollutants into bodies of surface water at specific locations through drain pipes, dtches, or sewer lines. Nonpoint sources are broad and diffuse areas rather than points, from which pollutants enter bodies of surface water or air

One of the major pollution problems that we face is exposure to infectious disease organisms through drinking water contaminated with human and animal waste In 2010, the United Nations reported that each year unsafe water kills more people than war and all other forms of violence combined More than 1.6 million people die every year from largely preventable waterborne infectious diseases

Flowing rivers and streams can recover rapidly from moderate levels of degradable, oxygen-demanding wastes through a combination of dilution and bacterial breakdown of such wastes. The process does not work when streams become overloaded with such pollutants or when drought, damming, or water diversion reduce their flows

Laws enacted in the 1970s to control water pollution have greatly increased the number and quality of wastewater treatment plants in the U.S. A successful story is the cleanup of the U.S. state of Ohio’s Cuyahoga River Fish kills and drinking water contamination still occur occasionally in some of the river and lakes of more-developed countries. Stream restoration, or recovery aided by cleanup efforts, can be done on a large scale

In most less developed countries, stream pollution from discharges of untreated sewage and industrial wastes is a serious and growing problem Half of the world’s 500 major rivers are heavily polluted Most polluted water ways run through less developed countries industrial wastes and sewage pollute more than two thirds of India’s water resources

the flushing and changing of water in lakes and large artificial reservoirs can take from 1 to 100 years. Contaminants can kill bottom dwelling organisms and fish which also can lead to birds. The concentrations of some harmful chemicals are biologically magnified as they pass through food webs in polluted waters.

Eutrophication is the name given to the natural nutrient enrichment of a shallow lake, estuary, or slow moving stream An oligotrophic lake is low in nutrients and its water is clear. Human activity can greatly accelerate the input of plant nutrients to a lake which is a process called cultural eutrophication We can use advanced waste treatment systems to remove nitrates and phosphates before wastewater enters lakes.

We can reserve severe water pollution in a fairly short time if we sharply reduce pollutant inputs. The relentless growth of population, resource use, and urbanization overwhelm Lake Washington Even good solutions to environmental problems cannot work indefinitely if we keep overwhelming the natural systems involved. In 2007, the legislature in Washington State created the Puget Sound Partnership

The five interconnected Great Lakes of North America contain about 95% of the fresh surface water in the U.S. About 38 million people in the U.S. and Canada obtain their drinking water from the Great Lakes In 1972, the U.S. and Canada signed the Great Lakes Quality Agreement. Despite ongoing pollution problems, EPA funding for cleaning of the Great Lakes dropped 80% between 1992 and 2009

Drinking water for about half of the U.S. population and 95% of Americans who live in rural areas comes from groundwater aquifers. Common pollutants such as fertilizers, pesticides, gasoline, and organic solvents can seep into groundwater from numerous sources. When groundwater becomes contaminated, it can not cleanse itself of degradable wastes as quickly as flowing surface water can. The usually cold temperatures of groundwater also slow down chemical reactions that decompose wastes

Groundwater provides about 70% of China’s drinking water. Groundwater used as a source of drinking water can also be contaminated with nitrate ions. A problem is sometime toxic arsenic which contaminates drinking water when a well is drilled into aquifers where soil and rock are naturally rich in arsenic

It can take decades to thousands of years for contaminated groundwater to cleanse itself Nondegradable waste remains in the water permanently Many methods are very expensive

Most of the more developed countries have laws establishing drinking w water standards There are simple ways and complex ways to purify drinking water. The more developed countries usually store water in a reservoir for several days. We have the technology to convert sewer water into pure drinking water.

Several major U.S cities have avoided building expensive water treatment facilities by investing in protection of the forest and wetlands in the watersheds that provide their water supplies. The money that N.Y spent on watershed protection saved the city the $6 million cost of building water purification facilities. New York's drinking water is known for it purity.

About 54 countries, most of them in North America and Europe, have standards for safe drinking water. Water pollution industries are pressuring elected officials to weaken the Safe Drinking Water Act

Some of the world’s cleanest drinking water comes from the U.S. About half of all Americans worry about getting sick from tap water contamination. Every week, ship, trains, and trucks move about 1 billion bottles of water into and around the U.S. Use of bottled water also causes environmental problems.

Many cruise ships dunk waste at sea Water dumping is illegal in the United states. Each year, harmful algal blooms lead to the poisoning of about 60,00 Americans. Water pollutants seriously contaminate about half of China’s shallow coastal waters.

Oil slicks that wash onto beaches can have a serious economic impact on coastal residents. Oil spills can be partially cleaned up by mechanical means

The Exxon Valdez oil tanker went off course and hit a spot that released 41 million liters of crude oil The oil spill caused about 250,000 seabirds and large numbers of marine life to die. Many oil spills cause enormous amount of expenses just for the clean up.

Organic farming can also prevent water pollution There are a number of ways to reduce nonpoint sources of water pollution Farmers can reduce soil erosion by keeping cropland covered with vegetation and using other soil conservation methods

The Federal Water Pollution control Act of 1972control the country’s surface area. The EPA has been experimenting with a discharge trading policy to help water pollution

The Clean Water Act of 1972 led to numerous improvements in the U.S. water quality The percentage of Americans served by a community water system that met federal health standards increase from 79% to 94% The percentage of U.S. stream lengths found by the fishable and swimmable increased from 36% to 60% of those tested. Annual wetland losses decreased by 80%

In urban areas in the U.S. waterborne wastes flow through a network of sewer pipes. There are many process for the water to be divided into parts. A process called primary sewage treatments separates large objects and human waste to be separated. Some cities have two separate networks of pipes.

Using sewer treatment systems can help reduce the cost of tax payers These treatments cause less to build and to maintain The sewer systems reduce the need for energy Many systems creates soil which can be reused.

Little has been done to reduce water pollution in less developed countries. Laws majorly help out the pollution by restricting dumping and spills. Public pressure to the elected officials can cause a change of plan and new ideas for the areas.

Scientist use a variety of methods to measure water quality. To be able to be considered safe drinking a 100 milliliter sample of water should contain no calories of coli form bacteria. Genetic engineers are working to develop bacteria and yeast that glow in the presence of specific pollutants such as toxic heavy metals in the ocean. The technology for testing water have greatly increased and evolved over time.

The world’s third largest oxygen depleted zone forms every spring and summer in a narrow stretch of the Northen Gulf of Mexico off the mouth of the Mississippi River. The Mississippi river and its tributes drain all or parts of the 31 U.S. states and two Canadian provinces. Fisheries have decreased in a large amount

More than 800 cities and towns around the world use natural or artificial created wetlands to treat sewage as a lower alternative to expensive water treatment plants. The purification of sewage water takes a very long time. Operating costs are about the same as those of a conventional sewage treatment plant

The Duwamish River in 1980 was very polluted by many companies and waste being thrown in. Many people helped by making agreements with companies or simply talking to them. A man began planting trees by this polluted area for 15 years After starting his project to restore the river, many volunteers began to help as well