Chapter 5

1. Chapter 5 Water Quality

2. Chapter Headings • Water Pollution • Basic Parameters of Water • Inorganic Chemicals • Organic Chemicals • Waterborne Diseases • Water Quality Management

3. Water Pollution • Water pollution can affect • Surface waters • Ground waters • Can occur naturally but is usually due to man’s activities • US waters have improved significantly since the Clean Water Act Amendments were passed in 1972 • But many waters still don’t meet standards

5. Contamination discharged through a pipe or other discrete, identifiable location Relatively easy to quantify and evaluate impact Historically, the focus of regulation Point Source Pollution Water. 1993. National Geographic Special Edition

6. Point Sources • Factories and sewage treatment plants • Landfills • Abandoned mines • Underground and above-ground storage tanks • Required to have permits under Clean Water Act

7. Point Sources • 2009 article on number of permit violations by state in NY Times • http://www.nytimes.com/interactive/2009/09/13/us/0913-water.html

8. Contamination from a diffuse source Difficult to measure Not required to have permits under Clean Water Act Focus of recent regulatory efforts Nonpoint Source Pollution Soil erosion from a farm field Gary Hawkins, UGA

9. Nonpoint Sources • Lawns, gardens, and golf courses • Agricultural and forestry practices • Street refuse • Construction activities • Stormwater runoff • Dredging activities

10. Chapter Headings • Water Pollution • Basic Parameters of Water • Inorganic Chemicals • Organic Chemicals • Waterborne Diseases • Water Quality Management

11. Basic Parameters of Water • Temperature • Dissolved oxygen (DO) • pH • Turbidity

12. Temperature • Temperature affects physical, chemical, and biological processes in water • Chemical example: DO decreases as temperature increases • Biological example: fish seek thermal refuges • Temperature affected by depth • Causes lake turnover • Loss of streamside shade trees causes temperature to increase

13. Dissolved Oxygen • Atmosphere consists of 21% O2 • Water consists of <1% O2 • When water and atmosphere come into intimate contact, O2 tends to diffuse into water • Occurs as water passes over riffles, rapids, and falls and to a lesser extent in still water • Aquatic plants also pump O2 into water • During daytime when they are undergoing photosynthesis

14. Fish depend on DO in water O2 diffuses from water to blood in gills When DO concentrations in water drop below 5 parts per million (ppm) most fish have trouble Dissolved Oxygen www.fishdoc.co.uk

15. pH = -log10(H+) If H+ = 10-3 moles then pH = 3 If H+ = 10-11 moles then pH = 11

16. Clarity of water Measured as light penetration in nephelometric turbidity units (NTU) Also measured with a Secchi disk Record the depth at which you can no longer see the banded colors on the disk Turbidity

17. Secchi disk depth comparison from clear (left) to murky (right) http://earthobservatory.nasa.gov/Study/WaterQuality/water_quality2.html Secchi disk depth for Lake Tahoe: http://terc.ucdavis.edu/research/clarity.html

18. Chapter Headings • Water Pollution • Basic Parameters of Water • Inorganic Chemicals • Organic Chemicals • Waterborne Diseases • Water Quality Management

19. Inorganic Chemicals • Compounds that do not contain carbon (C) • Originally defined as compounds that do not originate in plants or animals • Metals, minerals, and nutrients1 1book lists nutrients under organic compounds but most nutrients are in the inorganic form

20. Minerals • All surface and groundwaters contain minerals • At high concentrations they can cause adverse effects • Salt: any compound that dissolves in water • Most common salt is sodium chloride (NaCl) • Salinity: the presence of excess salts in water or in soil • Saline water is undrinkable • Saline soils make water uptake difficult for plants and microbes • Aquatic plants and animals sensitive to salinity (oysters in Apalachicola Bay)

22. Colorado River and Salt • U.S. irrigation and water withdrawals cause Colorado River salinity to be very high by the time it reaches Mexico • 1974 law requires average annual salt concentration <115 ppm at border • Battery of wells at border • 13-mile long 5-mile wide area • Pump low salinity groundwater into river to dilute salt concentrations

23. Nutrients • Major minerals important in animal and plant nutrition: • Nitrogen, phosphorus, potassium, calcium • Trace elements also required • Iron, zinc, manganese, etc. • At high concentrations in streams, lakes, estuaries, and oceans they can cause problems

24. Nutrients: Nitrogen • Nitrogen (N) an important plant nutrient • Takes several forms in nature • Nitrogen gas (N2) • Nitrate (NO3-) • Ammonia gas (NH3) • Ammonium (NH4+) • Organic forms

26. Nutrients: Nitrogen • Nitrate in drinking water is a pollutant • When ingested by babies in milk formula • Causes methemoglobinemia or blue baby syndrome • Converts to nitrite (NO2-) which interferes with oxygen transport in the blood • Baby suffocates • Drinking water standard is <10 ppm nitrate • Very mobile in soil and leaches easily to groundwater • Sources: manures, fertilizers, sewage

27. Nutrients: Phosphorus • Not very mobile in soils • Usually doesn’t leach to groundwater • Instead it runs off into streams • Dissolved in runoff or • Attached to eroded sediment particles • Not harmful to humans directly • Sources: manures, fertilizers, sewage, detergents • P was banned from detergents in 1990’s

28. Eutrophication • High levels of N and P can cause excessive algal growth in fresh and salt water bodies • Called eutrophication or algal blooms • Microbes that decompose dead algae use oxygen and lower DO • Low DO stresses fish and other aquatic life, eventually causing fish kills • P causes eutrophication in freshwater • Concentrations above 0.1 ppm (streams) and 0.01 ppm (lakes) can trigger algal blooms

29. Lake in Canada Divided by plastic curtain For 8 years Nitrogen added each year to one side Nitrogen and phosphorus added to other side Every year there was an algal bloom in response to adding phosphorus Eutrophication

30. Phosphorus concentrations in the Chattahoochee below Atlanta

31. Nutrients and Marine Waters • Algal growth in marine waters is controlled primarily by N • P can be important at certain times of the year • Estuaries (which are intermediate between fresh and marine waters in terms of salinity) are affected by both N and P

32. Gulf of Mexico Hypoxia • Nitrogen (and to a lesser extent P) from the Mississippi River watershed are causing algal blooms and low DO (hypoxia) in the Gulf of Mexico each summer • Dead zone at lower depths kills aquatic species including shrimp • http://www.nytimes.com/interactive/2010/04/28/us/20100428-spill-map.html?ref=us

33. Baltic Sea Algal Bloom July 2005 satellite image http://www.physorg.com/printnews.php?newsid=69420332

34. Chapter Headings • Water Pollution • Basic Parameters of Water • Inorganic Chemicals • Organic Chemicals • Waterborne Diseases • Water Quality Management

35. Organic Chemicals • Compounds that do contain carbon (C) • Often large complex molecules • May be natural or man-made (synthetic) • Synthetic compounds may last for a long time in the environment • Natural decomposing processes are unable to break down these complex molecules

36. Organic Chemicals • Many synthetic organic chemicals are carcinogens: • Benzene (C6H6), commercial solvent • Carbon tetrachloride (CCl4), in fire extinguishers, solvents, and cleaning agents • Polychorinated Biphenyls (PCBs), used as a coolant in electrical transformers • Pesticides are synthetic organic chemicals used to kill unwanted pests • Can be harmful to humans and wildlife

37. Organic Chemicals: Pesticides • Silent Spring by Rachel Carson published in 1962 • Showed that pesticides such as DDT spread in the environment and had unintended victims • DDT caused thinning of egg shells of eagles • Resulted in the banning of DDT in U.S. • http://www.youtube.com/watch?v=aycQKk4qn_Y Start at 2:03

38. Organic Chemical: MCMH • Charleston WV spill • http://www.nytimes.com/2014/01/12/us/the-wait-continues-for-safe-tap-water-in-west-virginia.html?ref=us&_r=0 • What is MCHM • http://en.wikipedia.org/wiki/4-Methylcyclohexanemethanol

39. Chapter Headings • Water Pollution • Basic Parameters of Water • Inorganic Chemicals • Organic Chemicals • Waterborne Diseases • Water Quality Management

40. Waterborne Diseases • Early concerns regarding water quality caused by waterborne diseases • Plagues in the Middle Ages • Cholera epidemic in 1848-1849 caused 53,000 deaths in London • Connection between disease and water was unknown until shown by Dr. John Snow • 1854 Broad Street Pump study

41. Found that cholera causes were clustered around a community water pump at Broad Street in London Water company that supplied pump took it from Thames River downstream of London Advised that the pump handle be removed Dr. John Snow

42. Replica of Broad Street pump with handle removed outside the John Snow pub www.ph.ucla.edu/epi/snow

43. Also a cholera epidemic in Chicago in 1885

44. Waterborne Diseases • Microorganisms include • Viruses – bits of DNA or RNA • Bacteria – single cell organisms • Other – protozoa, worms, blue-green algae • Examples of microorganisms that are pathogens (disease-causing organisms) • Escherichia coli (E. coli) – bacterium • Giardia – protozoa • Cryptosporidium – protozoa

45. E. Coli • E.coli are a common bacteria in the human intestines • Aid digestion, harmless • Used as an indicator organism • One strain of E. coli (0157:H7) is lethal, however • In a town in Ontario in 2000, 2,300 people became ill and 7 died when the water supply became contaminated with 0157:H7 • Attributed to contamination from cattle manure

47. Indicator Organisms • Too costly and dangerous to test water for individual pathogens • Instead we test for indicator organisms • Harmless but indicate fecal origin • Common indicator organism • Fecal coliform bacteria – most common today • E.coli – (not the 0157:H7 toxic strain) will probably replace fecal coliform

48. Indicator Organisms • Standard for drinking water in Georgia is <1 fecal coliform per 100 mL • Standard for streams and lakes is <200 fecal coliforms per 100 mL

49. Fecal coliforms in the Chattahoochee below Atlanta

50. Chapter Headings • Water Pollution • Basic Parameters of Water • Inorganic Chemicals • Organic Chemicals • Waterborne Diseases • Water Quality Management