1. Core Case Study: Using Nature to Purify Sewage  Ecological wastewater purification by a living machine. Uses the sun and a series of tanks containing plants, snails, zooplankton, crayfish, and fish (that can be eaten or sold for bait). Uses the sun and a series of tanks containing plants, snails, zooplankton, crayfish, and fish (that can be eaten or sold for bait). Figure 21-1

2. WATER POLLUTION: SOURCES, TYPES, AND EFFECTS  Water pollution any chemical, biological, or physical change in water quality that has a harmful effect on living organisms or makes water unsuitable for desired uses. any chemical, biological, or physical change in water quality that has a harmful effect on living organisms or makes water unsuitable for desired uses. Point source: Point source: specific locationspecific location drain pipes, ditches, sewer lines drain pipes, ditches, sewer lines Nonpoint source: Nonpoint source: cannot be traced to a single site of dischargecannot be traced to a single site of discharge atmospheric deposition, agricultural / industrial / residential runoff atmospheric deposition, agricultural / industrial / residential runoff

3. Major Water Pollutants and Their Effects

4.  A fecal coliform bacteria test is used to indicate the likely presence of disease-causing bacteria in water. Figure 21-2

5. Major Water Pollutants and Their Effects  Water quality and dissolved oxygen (DO) content in parts per million (ppm) at 20°C. Only a few fish species can survive in water less than 4ppm at 20°C. Only a few fish species can survive in water less than 4ppm at 20°C. Figure 21-3

6. Water Pollution Problems in Streams  Dilution and decay of degradable, oxygen- demanding wastes and heat in a stream. Figure 21-4

7. POLLUTION OF FRESHWATER STREAMS  developed countries reduced point-source pollution reduced point-source pollution toxic chemicals and pollution from nonpoint sources are still a problem toxic chemicals and pollution from nonpoint sources are still a problem  developing countries Stream pollution from discharges of untreated sewage and industrial wastes is a major problem Stream pollution from discharges of untreated sewage and industrial wastes is a major problem

8. Global Outlook: Stream Pollution in Developing Countries  Water in many of central China's rivers are greenish black from uncontrolled pollution by thousands of factories. Figure 21-5

9. Case Study: India’s Ganges River: Religion, Poverty, and Health  Religious beliefs, cultural traditions, poverty, and a large population interact to cause severe pollution of the Ganges River in India. Very little of the sewage is treated. Very little of the sewage is treated. Hindu believe in cremating the dead to free the soul and throwing the ashes in the holy Ganges. Hindu believe in cremating the dead to free the soul and throwing the ashes in the holy Ganges. Some are too poor to afford the wood to fully cremate.Some are too poor to afford the wood to fully cremate. Decomposing bodies promote disease and depletes DO.Decomposing bodies promote disease and depletes DO.

10. Case Study: India’s Ganges River: Religion, Poverty, and Health  Daily, more than 1 million Hindus in India bathe, drink from, or carry out religious ceremonies in the highly polluted Ganges River. Figure 21-6

11. POLLUTION OF FRESHWATER LAKES  Dilution of pollutants in lakes is less effective than in most streams because most lake water is not mixed well and has little flow. Lakes and reservoirs are often stratified and undergo little mixing. Lakes and reservoirs are often stratified and undergo little mixing. Low flow makes them susceptible to runoff. Low flow makes them susceptible to runoff.  Various human activities can overload lakes with plant nutrients, which decrease DO and kill some aquatic species.

12. Cultural Eutrophication  Eutrophication: the natural nutrient enrichment of a shallow lake, estuary or slow moving stream the natural nutrient enrichment of a shallow lake, estuary or slow moving stream mostly from runoff of plant nutrients from the surrounding land mostly from runoff of plant nutrients from the surrounding land  Cultural eutrophication: human activities accelerate the input of plant nutrients (mostly nitrate- and phosphate- containing effluents) to a lake. human activities accelerate the input of plant nutrients (mostly nitrate- and phosphate- containing effluents) to a lake. 85% of large lakes near major population centers in the U.S. have some degree of cultural eutrophication.85% of large lakes near major population centers in the U.S. have some degree of cultural eutrophication.

13. Fig. 21-7, p. 501 Coal strip mine runoff Polluted air Deicing road salt Pesticides and fertilizers Hazardous waste injection well Pumping well Gasoline station Water pumping well Landfill Sewer Buried gasoline and solvent tanks Cesspool, septic tank Groundwater flow Confined aquifer Confined freshwater aquifer Unconfined freshwater aquifer Accidental spills Waste lagoon Leakage from faulty casing Discharge

14. POLLUTION OF GROUNDWATER  It can take hundreds to thousand of years for contaminated groundwater to cleanse itself of degradable wastes. Nondegradable wastes Nondegradable wastes toxic lead, arsenic, flouridetoxic lead, arsenic, flouride there permanentlythere permanently Slowly degradable wastes Slowly degradable wastes DDTDDT there for decadesthere for decades

15. Fig. 21-8, p. 502 Aquifer Water well Migrating vapor phase Contaminant plume moves with the groundwater Free gasoline dissolves in groundwater (dissolved phase) Groundwater flow Water table Gasoline leakage plume (liquid phase) Leaking tank Bedrock

16. OCEAN POLLUTION  Oceans, if they are not overloaded, can disperse and break down large quantities of degradable pollutants.  Pollution of coastal waters near heavily populated areas is a serious problem. About 40% of the world’s population lives near on or near the coast. About 40% of the world’s population lives near on or near the coast. The EPA has classified 4 of 5 estuaries as threatened or impaired. The EPA has classified 4 of 5 estuaries as threatened or impaired.

17. Fig. 21-10, p. 505 Healthy zone Clear, oxygen-rich waters promote growth of plankton and sea grasses, and support fish. Oxygen-depleted zone Sedimentation and algae overgrowth reduce sunlight, kill beneficial sea grasses, use up oxygen, and degrade habitat. Red tides Excess nitrogen causes explosive growth of toxicmicroscopic algae, poisoning fish and marine mammals. Farms Runoff of pesticides, manure, and fertilizers adds toxins and excess nitrogen and phosphorus. Toxic sediments Chemicals and toxic metals contaminate shellfish beds, kill spawning fish, and accumulate in the tissues of bottom feeders. Construction sites Sediments are washed into waterways, choking fish and plants, clouding waters, and blocking sunlight. Urban sprawl Bacteria and viruses from sewers and septic tanks contaminate shellfish beds Oxygen-depleted zone Closed beach Cities Toxic metals and oil from streets and parking lots pollute waters; Industry Nitrogen oxides from autos and smokestacks, toxic chemicals, and heavy metals in effluents flow into bays and estuaries. Closed shellfish beds

18. OCEAN POLLUTION  Harmful algal blooms (HAB) are caused by explosive growth of harmful algae from sewage and agricultural runoff. Figure 21-11

19. OCEAN OIL POLLUTION  Most ocean oil pollution comes from human activities on land. Studies have shown it takes about 3 years for many forms of marine life to recover from large amounts of crude oil (oil directly from ground). Studies have shown it takes about 3 years for many forms of marine life to recover from large amounts of crude oil (oil directly from ground). Recovery from exposure to refined oil (fuel oil, gasoline, etc…) can take 10-20 years for marine life to recover. Recovery from exposure to refined oil (fuel oil, gasoline, etc…) can take 10-20 years for marine life to recover.

20. OCEAN OIL POLLUTION  Tanker accidents and blowouts at offshore drilling rigs can be extremely devastating to marine life (especially diving birds, left). Figure 21-13

21. Reducing Water Pollution through Sewage Treatment  Septic tanks and various levels of sewage treatment can reduce point-source water pollution. Figure 21-15

22. Reducing Water Pollution through Sewage Treatment  Raw sewage reaching a municipal sewage treatment plant typically undergoes: Primary sewage treatment: a physical process that uses screens and a grit tank to remove large floating objects and allows settling. Primary sewage treatment: a physical process that uses screens and a grit tank to remove large floating objects and allows settling. Secondary sewage treatment: a biological process in which aerobic bacteria remove as much as 90% of dissolved and biodegradable, oxygen demanding organic wastes. Secondary sewage treatment: a biological process in which aerobic bacteria remove as much as 90% of dissolved and biodegradable, oxygen demanding organic wastes.

23. Reducing Water Pollution through Sewage Treatment  Primary and Secondary sewage treatment. Figure 21-16

24. Reducing Water Pollution through Sewage Treatment  Advanced or tertiary sewage treatment: Uses series of chemical and physical processes to remove specific pollutants left (especially nitrates and phosphates). Uses series of chemical and physical processes to remove specific pollutants left (especially nitrates and phosphates).  Water is chlorinated to remove coloration and to kill disease-carrying bacteria and some viruses (disinfect).

25. Reducing Water Pollution through Sewage Treatment  Sewage sludge can be used as a soil conditioner but this can cause health problems if it contains infectious bacteria and toxic chemicals.  Preventing toxic chemicals from reaching sewage treatment plants would eliminate such chemicals from the sludge and water discharged from such plants.

26. Fig. 21-17, p. 513 Sludge Groundwater Contamination Harmful chemicals and pathogens may leach into groundwater and shallow wells. Odors Odors may cause illness or indicate presence of harmful gases. Livestock Poisoning Cows may die after grazing on sludge-treated fields. Dust Particles Particles of dried sludge carry viruses and harmful bacteria that can be inhaled, infect cuts or enter homes. Surface Runoff Harmful chemicals and pathogens may pollute nearby streams,lakes, ponds, and wetlands. Exposure Children may walk or play in fertilized fields. BUFFER ZONE

27. Using Laws to Protect Drinking Water  While most developed countries have drinking water quality standards and laws, most developing countries do not.  The U.S Safe Drinking Water Act requires the EPA to establish national drinking water standards (maximum contaminant levels) for any pollutant that may have adverse effects on human health.

28. Using Laws to Protect Drinking Water  The U.N. estimates that 5.6 million Americans drink water that does not meet EPA standards.  1 in 5 Americans drinks water from a treatment plant that violated one or more safety standard.  Industry pressures to weaken the Safe Drinking Act: Eliminate national tests and public notification of violations. Eliminate national tests and public notification of violations. Allow rights to pollute if provider cannot afford to comply. Allow rights to pollute if provider cannot afford to comply.

29. Is Bottled Water the Answer?  Some bottled water is not as pure as tap water and costs much more. 1.4 million metric tons of plastic bottles are thrown away. 1.4 million metric tons of plastic bottles are thrown away. Fossil fuels are used to make plastic bottles. Fossil fuels are used to make plastic bottles. The oil used to produce plastic bottles in the U.S. each year would fuel 100,000 cars.The oil used to produce plastic bottles in the U.S. each year would fuel 100,000 cars.