Water Pollution

1. Water Pollution

2. Learning Natures ways to purify sewage Case Study • Some places are seeking better ways to purify sewage by working with nature. • Instead of using mechanical machines to purify water ecological innovators are treating sewage water with systems called “living machines” • Ultimately, natural filtering processes are being used to clean sewage water

3. 20-1: Types, Effects and Sources of Water Pollution

4. What Are the Major Types and Effects of Water Pollutants? • Water pollution is a chemical, biological or physical change in water quality that has a negative effect on living organisms • Pollution of water causes diseases. • The World Health Organization (WHO) estimates that 3.4 million people die each year from waterborne diseases

5. How Do We Measure Water Quality? • Using Bacterial Counts and Indicator organisms, such as, Fecal coliform • To be considered safe for drinking, water should contain no colonies of bacteria in a sample of 100mL. • For it to be considered safe for swimming, water should contain no more then 200 colonies per 100mL

6. What are Point and Nonpoint Sources? • Point Sources discharge pollutants at specific locations through drain pipes, ditches or sewer lines into bodies of surface water. • Nonpoint sources are scattered and diffused and cannot be traced to any single site of discharge, like acid disposition, runoff from croplands, livestock feedlots and urban streets.

7. Point and Nonpoint Sources

8. What are the Major Sources of Water Pollution? • Agricultural activities, Industrial facilities and mining are the largest causes of water pollution. • Within agriculture activities, sediment eroded from agricultural lands is the largest source of water pollution. • Surface mining disturbs the earths surface creating a source of eroded sediments which eventually turn into runoff and pollute water systems.

9. Is the Water Safe to Drink? • 1 out of 5 people in the world lack access to safe drinking water. • According to the WHO, 1.4 billion people do not have access to clean drinking water. • As a result, about 9,300 people die everyday from infectious diseases found in contaminated water.

10. How Might Projected Climate Change Affect Water Quality? • Global warming projections include changes in precipitation: some areas will experience much more rain while others experience less. • Prolonged droughts reduce river flows, spread infectious diseases more rapidly, threaten aquatic life and increase the growth rates of harmful bacteria.

11. 20-2: Pollution of Fresh Water Streams

12. What are the Water Pollution Problems of Streams? • Rivers and other flowing streams can recover rapidly from moderate levels of degradable oxygen demanding waste through a combination of dilution and biodegradation. • In a flowing stream the breakdown of degradable waste by bacteria depletes dissolved oxygen and creates an oxygen sag curve.

13. Dilution and decay of degradable, oxygen-demanding wastes and heat in a stream, showing the oxygen sag curve (blue) and the curve of oxygen demand (red).

14. What Have Developed Countries Done to Reduce Stream Pollution? • Most developed countries have sharply reduced point source pollution. • Pollution from nonpoint sources are still major problems. • Water pollution control laws from the 1970’s have increased the number of waste water treatment plants in developed countries. • Drinking water is still being contaminated by releases of toxic, inorganic chemicals by industries.

15. What Have Developing Countries Done to Reduce Stream Pollution? • Stream pollution in developing is still a serious and growing problem. • According to a report written in 2003, half of the worlds 500 major rivers, are heavily polluted. Most of which, run through developing countries. • Most of these countries cannot afford to build waste treatment plants.

16. India's Ganges River; Religion, Poverty and Health Case Study • The Ganges is a holy river to India’s Hindu people in which each day more than one million people bathe, drink and/or wash their clothes in this river. • The Hindu belief in cremating the dead to free the soul and throwing the ashes into the holy Ganges to increase the chances of the soul getting into heaven increases the amount of pollution. The ashes cause air pollution, and because some people cannot afford to cremate the bodies, they are often dumped into the river. • The Indian government has launched various plans to help clean up the river, such as building waste treatment plants and 32 electric crematoriums. • Unfortunately, most sewage treatment plants are not completed or do not work very well.

17. Pollution of Fresh Water Lakes

18. Why Are Lakes and Reservoirs More Vulnerable to Pollution than • Lakes and reservoirs have stratified layers of pollution that undergo very little vertical mixing because they have very little flow. • Lakes and reservoirs are more vulnerable then streams to contamination because of the very little mixing. • Concentrations of some chemicals can be biologically magnified as they pass through food webs in lakes.

19. Biological magnification of PCB’s in an aquatic food chain in the Great Lakes

20. What Is Cultural Eutrophication and How Can It Be Reduced? • Eutrophication is the natural nutrient enrichment of lakes. • This increase in nutrients can be beneficial to floating phytoplankton, which can increase the population of some fish. • An excessive increase in nutrients causes very large algal blooms which reduces lake productivity. An example of this is the “red tide”.

21. Lake Washington– A Success Story Case Study • Lake Washington recovered from severe cultural eutrification. • Sewage was diverted into the nearby “Puget sound”, which was a large body of water with a rapid rate of exchange involving Pacific ocean waters that received and diluted sewage wastes. • Today, the lakes water quality is good because it was recovered through an output approach. • The “Puget Sound”, however, has a growing concern of increased urban runoff.

22. Pollution In the Great Lakes- Hopeful Progress Case Study • Pollution in the Great Lakes has dropped significantly, yet they are still vulnerable to pollution from point, and nonpoint sources. • In the 1960s, the Great Lakes suffered from cultural eutrification. • In 1972, Canada in the U.S. created a Great Lakes pollution control program that decreases algal and increases dissolved oxygen levels.

23. Pollution in the Great Lakes

24. 20-3 Pollution of Groundwater

25. Why is Groundwater Pollution Such a Serious Problem? • Groundwater can become contaminated with a variety of chemicals because it cannot effectively cleanse itself and dilute and disperse pollutants. • Although groundwater pollution is considered a low-risk ecological problem, pollutants in drinking water are a high risk health problem. • When groundwater become contaminated, it cannot cleanse itself of degradable waste, as surface water does. It’s take 100’s to thousands of years for groundwater to cleanse itself of contaminated waste.

26. Principle Sources of groundwater contamination in the United States:

27. What is the Extent of Groundwater Pollution? • On a global scale, we don’t know much about groundwater pollution, because few countries go through the great expense of locating, tracking and testing aquifers. • According to the EPA and the U.S. geological survey one or more organic chemicals contaminate about 45% of municipal groundwater supplies in the U.S. • Groundwater can be contaminated by fluoride nitrite ions, and arsenic.

28. How Can We Protect Groundwater? • Prevention is the most effective and affordable way. • Cleaning contaminated aquifers are difficult and expensive because

29. Saltwater Intrusion

30. 20-4: Ocean Pollution

31. How Much Pollution Can the Ocean Tolerate? • The oceans can dilute, disperse and degrade large amounts of raw sewage, oil, and some kinds of degradable industrial waste, especially in deep water areas. • This had lead scientist to believe it is safer to dump sewage sludge into the deep ocean, rather then on land • Other scientists, however, disagree, because we know less about the deep ocean than we do about the moon

32. How Do Pollutants Affect Coastal Areas? • About 40% of the worlds population lives on or within 62 miles of the coast. • Runoffs of sewage and agricultural wastes introduced into coastal waters can cause explosive growth of harmful algae. • This growth of Algae can cause oxygen depleted zones.

33. The Chesapeake Bay: An Estuary in Trouble Case Study • Since 1960, the Chesapeake bay, America's largest estuary, has been in serious trouble because pollutants from 6 states contaminate the shallow water. • Phosphate and nitrate levels have risen sharply causing algal blooms and oxygen depletion. • Point sources account for 60% of the phosphates. • Nonpoint sources account for 60% of the nitrates. • In 1983 the United States implemented the Chesapeake program, since then phosphorous levels have declined 27% and nitrogen levels have declined 16%.

34. 20-5 OCEAN POLLUTION GRAPHS AND CHARTS

35. Can Oysters Help Clean Up the Chesapeake Bay? Should We Bring Them Back? • Rebuilding the Chesapeake bay’s depleted oyster population with disease resistant oysters can reduce water pollution because oysters filter algae from water. • At the peak of the bays oyster population the bays oyster population, the oysters purified the entire water volume every three or four days. • Currently, the population is only about 1% of its all time high point and takes about a year to filter the bays water.

36. What is Being Done to Control the Dumping of Pollutants into the Ocean? • Many countries dump large quantities of “sewage sludge” into the ocean. It is a mixture of toxic chemicals, infectious agents and settles solids removed from sewage treatment plants. • Since 1992, the U.S. has banned this practice. 50 countries with 80% of the world merchants fleet have agreed not to dump sewage. • Unfortunately, this agreement is difficult to enforce and violations are very common.

37. What Are Major Sources of Oil Pollution? • Crude petroleum (oil as it comes out of the ground) and refined petroleum (fuel, gasoline and other processed petroleum products) reach the ocean in different ways. • The Exxon Valdez oil tanker and the Prestige were two of the largest oil spills. These accidents receive a lot of publicity because of their high visibility • More day to day less visible activities, such as the normal operation of oil rigs, leak more oil then that of large spills. • Studies show that most ocean oil pollution comes from land.

38. What are the Effects of Oil Pollution on Ocean Ecosystems and Coastal Communities? • Most have harmful ecological and economic effects, but sometimes disappear within 3 to 15 years. • The effects on ocean ecosystems caused by oil depend on different factors: type of oil, type of aquatic system, amount released, distance of release from the shore, weather conditions and ocean currents. • These factor immediately kill aquatic organisms, especially in their larval forms. Some globs of oil coat the surface of the ocean, feathers of birds and the fur of marine mammals. The oil that sinks to the bottom kills crustaceans and coral reefs.

39. How Well Can We Clean Up Oil Spills? • Current methods can recover no more then 15% of the oil from a major spill, explaining why prevention is the BEST strategy. • If the spills are not too large, they can be partially cleaned up be mechanical, chemical, fire and natural methods.

40. How Can We Protect Coastal Water? • Preventing the flow of pollution from the land and from streams is the key to protecting the oceans.

41. 20-5:Preventing and Reducing Surface Water Pollution

42. How Can We Reduce Surface Water Pollution From Nonpoint Sources? • Nonpoint sources mostly come from agriculture and the best way to reduce pollution is to prevent it from reaching the ocean. • Farmers can reduce soil erosion by covering cropland with vegetation and reforesting water sheds. They can also reduce the amount of fertilizer being used. • In 2003, a large port producer announced plans to build a facility to convert wastes from hogs to make renewable biodiesel fuel for vehicles.

43. How Can We Reduce Pollution From Point Sources? (Legal Approach) • Most Developed countries use laws to set water pollution standards, but developing countries poorly enforce their loose laws. • The Clean Water Act (1972) and the Water Quality Act (1987) forms the basis of US efforts to control pollution. • The Clean Water Act set standards for many levels of pollutants entering the ocean. • The EPA wants to pass a discharge trading policy that markets forces to reduce water pollution. • Developing countries discharge 80-90% of their untreated sewage directly into rivers, streams and lakes, which they use for drinking, washing and bathing.

44. How Can We Reduce Pollution From Point Sources? (Technological Approach) • Septic tanks and various levels of sewage treatment can reduce pollution. • Rural areas with suitable soils discharge wastes into septic tanks. About ¼ of all U.S. home have septic tanks. • Primary sewage treatment is a physical process that removes large floating objects. • Secondary sewage treatment is a biological process which removes 90% of oxygen demanding organic wastes.

45. Primary and Secondary Sewage Treatment

46. What Should We Do With Sludge Sewage? • Sewage sludge can be used as a soil conditioner but this can cause health problems if it contains bacteria or toxins. • 36% of the sludge also known as biosoilds are used to fertilize farmlands, forests, cemeteries, and other masses of land. • 9% of this sludge is placed in large digesters and kept warm for several weeks to allow bacteria to decompose organic material and produce composts for use as a conditioner. • The remaining 55% is dumped in conventional land fills where it can contaminate groundwater, or it is incinerated.

47. Natural capital degradation: some potential problems with using sludge from sewage treatment plants as a fertilizer on croplands.

48. How Can We Improve Sewage Treatment? • Environmentalists call for redesigning sewage treatment systems to prevent toxins and hazardous chemicals from reaching treatment plants, in order to prevent them getting into the water discharged from plants. • Another suggestion is to have buildings install “Composting Toilet Systems”.

49. Wastewater Garden - Hotels, restaurants, and homes in developing countries can use this small gravity-fed artificial wetland system to treat sewage.

50. How Successful Has the U.S. Been in Reducing Water Pollution? • Water pollution laws have improved water quality in the United States but there’s still a long way to go. • The Clean Water Act of 1972 led to a number of improvements in the United Status's water quality • The number of Americans that have met federal health standards has increased from 79% to 94% • Unfortunately, the EPA has found that 45% of the country’s lakes and 40% of the U.S.’s streams too polluted for swimming or fishing.