- Slides: 30
WATER POLLUTION Fernando Sequera Steven Correa
Water pollution comes from Point and Nonpoint Sources • 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
Major Water Pollutants Have Harmful Effects • 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
Streams can cleanse themselves, if we do not overload them • 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
Stream pollution in more developed countries • Laws enacted in the 1970 s 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
Global outlook: stream pollution in less-developed countries • 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
Too little mixing and low water flow makes lakes and reservoirs vulnerable to water pollution • 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.
Cultural Eutrophication is too much of a good thing • 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.
Revisiting lake washington and puget sound • 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
Pollution in the great lakes • 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
Groundwater cannot cleanse itself very well • 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 pollution is a serious hidden threat in some areas • 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
Pollution prevention is the only effective way to protect groundwater • 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
There are many ways to purify drinking water • 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.
Protecting watersheds instead of building water purification plants • 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.
Using laws to protect drinking water quality • 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
Is bottled water a good option? • 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.
Ocean pollution is a growing and poorly understood problem • 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.
Ocean pollution from oil • 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 spill • 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.
Reducing surface water pollution from nonpoint sources • Organic farming can also prevent water pollution • There 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
Laws can help reduce water Pollution from point sources • The Federal Water Pollution control Act of 1972 control the country’s surface area. • The EPA has been experimenting with a discharge trading policy to help water pollution
The U. S. experience with reducing point-source 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%
Sewage treatment reduces water pollution • 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.
We can improve conventional sewage treatment • 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.
There are sustainable ways to reduce and prevent water pollution • 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.
Science focus: testing water for pollutants • 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.
Science focus: oxygen depletion in the Northern Gulf of Mexico • 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
Science focus: treating sewage by working with nature • 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
Individuals matter: John Beal planted trees to restore a stream • 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