1. Chapter 21 Water Pollution

2.  Water pollution is 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: specific location (drain pipes, ditches, sewer lines).  Nonpoint source: cannot be traced to a single site of discharge (atmospheric deposition, agricultural / industrial / residential runoff) WATER POLLUTION: SOURCES, TYPES, AND EFFECTS

4. Major Water Pollutants and Their Effects

5.  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. Major Water Pollutants and Their Effects Figure 21-3

6.  Agriculture  Sediment  Fertilizers, pesticides  Animal wastes  Salinization of soil from over irrigation  Industry  NOx and SOx  Mining  Suspended Particulate Matter (dust, ash)  SOx Major Sources of Water Pollution

7. Mining pollution: arsenic, mercury, sulfuric acid

8. Coliform bacteria  Fecal coliform is found in the intestines and colon of animals and humans.  Enters streams through run-off  Drinking can cause dehydration and diarrhea

9.  Flowing streams can recover from a moderate level of degradable (animal wastes and other Organic-based pollutants) water pollutants if they are not overloaded and their flows are not reduced.  In a flowing stream, the breakdown of degradable wastes by bacteria depletes DO (because oxygen is used in decomposition process) and creates an oxygen sag curve.  DO is directly related to water quality POLLUTION OF FRESHWATER STREAMS

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

11. Indicator species  Used to determine health of water  Include many species  Mussels (filter feeders)  Trout  Macro invertebrates

12.  Most developed countries have sharply reduced point-source pollution but toxic chemicals and pollution from nonpoint sources are still a problem.  Why?  How have damming and diversions affected pollution of streams and rivers? POLLUTION OF FRESHWATER STREAMS

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

14. Ganges River in India Religious beliefs Cultural rituals Large population size

15.  Why did this river catch on fire? Cuyahoga River Cuyahoga River in Ohio

16.  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.  Low flow makes them susceptible to runoff.  Various human activities can overload lakes with plant nutrients, which decrease DO and kill some aquatic species.  Fertilizers, pesticides, oil and gas leaks/spills, heavy metal leaching (Hg, Pb, Se) POLLUTION OF FRESHWATER LAKES

17.  Eutrophication: the natural nutrient enrichment of a shallow lake, estuary or slow moving stream, 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.  Primarily from animal wastes, fertilizers, run-off from lawns and golf courses, atmospheric deposition, mining, pesticides, and sediment Cultural Eutrophication

19. Blooms from eutrophication  Algae (red, yellow, brown), cyanobateria, water hyacinth, duckweed  Lower DO (during decomposition), reduce light needed for photosynthesis by phytoplankton  kill fish  Waterborne and airborne toxins kill fish, poison seafood, kills birds, reduces tourism

21. Reduce and Prevent eutrophication Clean-Up  Remove excess weeds  Pump air in  Herbicides and algicides to control plant growth Prevention  Waste water treatment,  Reduce runoff with soil conservation  Ban phosphates in detergents

22.  http://www.youtube.com/watch?v=QtNH0E4XSdQ http://www.youtube.com/watch?v=QtNH0E4XSdQ Great Lakes and pollution

23.  Reasons why ground water cannot cleanse itself and dilute and disperse pollutants.  Flows slowly  Low DO concentration  Less bacteria (lower decomposition)  Lower temperature so reactions to cleanse slowed down.  The drinking water for about half of the U.S. population and 95% of those in rural areas comes from groundwater. POLLUTION OF GROUNDWATER

24. 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

25.  It can take hundreds to thousand of years for contaminated groundwater to cleanse itself of degradable wastes.  Nondegradable wastes (toxic lead, arsenic, flouride) are there permanently.  Slowly degradable wastes (such as DDT) are there for decades. POLLUTION OF GROUNDWATER

27. Fig. 21-9, p. 504 Solutions Groundwater Pollution CleanupPrevention Find substitutes for toxic chemicals Install monitoring wells near landfills and underground tanks Require leak detectors on underground tanks Ban hazardous waste disposal in landfills and injection wells Store harmful liquids in aboveground tanks with leak detection and collection systems Pump to surface, clean, and return to aquifer (very expensive) Pump nanoparticles of inorganic compounds to remove pollutants (may be the cheapest, easiest, and most effective method but is still being developed) Keep toxic chemicals out of the environment Inject microorganisms to clean up contamination (less expensive but still costly)

28.  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.  The EPA has classified 4 of 5 estuaries as threatened or impaired.  What are the most affected coastal areas? OCEAN POLLUTION

29. Estuaries Coral Reefs Mangrove forests

30. 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

31.  A large zone of oxygen-depleted water forms for half of the year in the Gulf of Mexico as a result of HAB.  Prevention:  Use less fertilizer  Reduce N-inputs  Plant forests and grasses  Restore wetlands  Lower NOx emissions Oxygen Depletion in the Northern Gulf of Mexico Figure 21-A

32.  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).  Recovery from exposure to refined oil (fuel oil, gasoline, etc…) can take 10-20 years for marine life to recover.  BP oil spill BP oil spill  Exxon Valdez oil spill in Alaska  http://www.youtube.com/watch?v=DPgIfT5mGVc&feature=fvst http://www.youtube.com/watch?v=DPgIfT5mGVc&feature=fvst OCEAN OIL POLLUTION

33.  Kill fish and other aquatic life in larval stage  Coats bird wings with oil  drown  Smother bottom dwellers (oysters, mussels, crabs)  Kills coral by covering it How do oil spills affect aquatic life?

34. Fig. 21-14, p. 509 Reduce input of toxic pollutants Solutions Coastal Water Pollution PreventionCleanup Use wetlands, solar-aquatic, or other methods to treat sewage Require at least secondary treatment of coastal sewage Sprinkle nanoparticles over an oil or sewage spill to dissolve the oil or sewage without creating harmful by-products (still under development) Improve oil-spill cleanup capabilities Recycle used oil Regulate coastal development Protect sensitive areas from development, oil drilling, and oil shipping Ban ocean dumping of sludge and hazardous dredged material Ban dumping of wastes and sewage by maritime and cruise ships in coastal waters Separate sewage and storm lines Require double hulls for oil tankers

35.  The key to reducing nonpoint pollution – most of it from agriculture – is to prevent it from reaching bodies of water.  Farmers can reduce runoff by planting buffers and locating feedlots away from steeply sloped land, flood zones, and surface water, keeping land covered so it lowers erosions, reduce fertilizer use and pesticide use. PREVENTING AND REDUCING SURFACE WATER POLLUTION

36.  Clean Water Act (1972) regulates discharges of pollutants into water, sets water quality standards for contaminates in surface water  Water Quality Act (1987) set standards for water quality  Ocean Dumping Act (1972) dumping of sewage sludge and industrial waste is prohibited. Radiological, chemical and biological warfare agents and high-level radioactive wastes are prohibited.  Safe Drinking Water Act (1974) sets minimum standards and regulates public drinking water.  Convention of the Prevention of Marine Pollution by Dumping of Waste and other Matter- control ocean pollution  EPA is experimenting with a discharge trading policy like Air Pollution Laws to KNOW!

37.  Septic tanks and various levels of sewage treatment can reduce point-source water pollution if installed and maintained properly. Reducing Water Pollution through Sewage Treatment Figure 21-15

38.  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.  Secondary sewage treatment: a biological process in which aerobic bacteria remove as much as 90% of dissolved and biodegradable, oxygen demanding organic wastes. Reducing Water Pollution through Sewage Treatment

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

40.  Advanced or tertiary sewage treatment:  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). Reducing Water Pollution through Sewage Treatment

41.  Sewage sludge can be used as a soil conditioner but this can cause health problems if it contains infectious bacteria and toxic chemicals.  Sewage sludge is often dumped into landfills or in the deep ocean.  Preventing toxic chemicals from reaching sewage treatment plants would eliminate such chemicals from the sludge and water discharged from such plants. Reducing Water Pollution through Sewage Treatment

42.  http://www.youtube.com/watch?v=chDcTwR5DtM http://www.youtube.com/watch?v=chDcTwR5DtM What is a composting toilet?

43.  Natural and artificial wetlands and other ecological systems can be used to treat sewage.  California created a 65 hectare wetland near Humboldt Bay that acts as a natural wastewater treatment plant for the town of 16,000 people.  The project cost less than half of the estimated price of a conventional treatment plant.  http://www.youtube.com/watch?v=MR7Wj-b2kL8 http://www.youtube.com/watch?v=MR7Wj-b2kL8 Reducing Water Pollution through Natural Processes

44.  Centralized water treatment plants and watershed protection can provide safe drinking water for city dwellers in developed countries.  Exposing water to heat and the sun’s UV rays for 3 hours can kill infectious microbes.  Bolivia and watershed protection:  http://www.youtube.com/watch?v=BLWV9H8jAfQ http://www.youtube.com/watch?v=BLWV9H8jAfQ DRINKING WATER QUALITY

45.  Some bottled water is not as pure as tap water and costs much more.  Filters can collect microbes and harm more than it helps if not changed properly.  1.4 million metric tons of plastic bottles are thrown away.  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. Is Bottled Water the Answer?

46. Fig. 21-18, p. 517 Prevent groundwater contamination Solutions Water Pollution Reduce birth rates Reduce poverty Reduce air pollution Practice four R's of resource use (refuse, reduce, recycle, reuse) Work with nature to treat sewage Find substitutes for toxic pollutants Reuse treated wastewater for irrigation Reduce nonpoint runoff

47. Fig. 21-19, p. 517 What Can You Do? Water Pollution Fertilize garden and yard plants with manure or compost instead of commercial inorganic fertilizer. Minimize your use of pesticides. Do not apply fertilizer or pesticides near a body of water. Grow or buy organic foods. Do not drink bottled water unless tests show that your tap water is contaminated. Merely refill and reuse plastic bottles with tap water. Compost your food wastes. Do not use water fresheners in toilets. Do not flush unwanted medicines down the toilet. Do not pour pesticides, paints, solvents, oil, antifreeze, or other products containing harmful chemicals down the drain or onto the ground.