Understanding Water Pollution and its Impact on Organisms

1. Chapter 14 Water Pollution

2. Water Pollution • Water pollution- the contamination of streams, rivers, lakes, oceans, or groundwater with substances produced through human activities and that negatively affect organisms. • Point sources- distinct locations that pump waste into a waterway. • Nonpoint sources- diffuse areas such as an entire farming region that pollutes a waterway.

4. Human Wastewater • Water produced by human activities such as human sewage from toilets and gray water from bathing and washing clothes or dishes.

5. Three reasons scientists are concerned about human wastewater: • Oxygen-demanding wastes like bacteria that put a large demand for oxygen in the water • Nutrients that are released from wastewater decomposition can make the water more fertile causing eutrophication • Wastewater can carry a wide variety of disease-causing organisms.

6. Cultural Eutrophication • Cause-->bloom--> die off--> aerobic bacteria-->DO down--> anaerobic bacteria -->hydrogen sulfide gas (toxic) • Prevention • Limit phosphate (detergent) • Advanced waste water treatment • Soil conservation • Cleanup • Dredging, remove excess weeds, pump air into lakes

7. Biochemical Oxygen Demand (BOD) • BOD- the amount of oxygen a quantity of water uses over a period of time at a specific temperature. • Lower BOD values indicate the water is less polluted and higher BOD values indicate it is more polluted by wastewater.

8. Oxygen Demanding Wastes • organic waste decomposed by aerobic bacteria • can be determined by BOD • BOD: amount of O2 consumed by decomposers in 5 days at 20oC

9. Mississippi River Basin Ohio River Missouri River Mississippi River LOUISIANA Mississippi River Depleted Oxygen Gulf of Mexico

10. Water Quality DO (ppm) at 20˚C Good 8-9 Slightly polluted 6.7-8 Moderately polluted 4.5-6.7 Heavily polluted Below 4.5 Gravely polluted Below 4 Fig. 19.2, p. 478

11. Eutrophication • Eutrophication is an abundance of fertility to a body of water. • Eutrophication is caused by an increase in nutrients, such as fertilizers. • Eutrophication can cause a rapid growth of algae which eventually dies, causing the microbes to increase the BOD.

12. Oxygen Sag Curve

13. Clean Zone Decomposition Zone Septic Zone Recovery Zone Clean Zone Normal clean water organisms (Trout, perch, bass, mayfly, stonefly) Trash fish (carp, gar, Leeches) Fish absent, fungi, Sludge worms, bacteria (anaerobic) Trash fish (carp, gar, Leeches) Normal clean water organisms (Trout, perch, bass, mayfly, stonefly) Types of organisms 8 ppm 8 ppm Dissolved oxygen Oxygen sag Concentration Biological oxygen demand 2 ppm Direction of flow Point of waste or heat discharge Time of distance downstream Fig. 19.3, p. 479

14. Common Diseases from Human Wastewater • Cholera • Typhoid fever • Stomach flu • Diarrhea • Hepatitis

15. Pathogens • Disease causing agents • bacteria, viruses, protozoa, parasitic worms • lack of clean drinking water causes 80% of diseases in developing countries • coliform bacteria WHO recommends 0 colonies/100 ml drinking water EPA recommends 200 colonies/100ml swimming water

16. Treatments for Human and Animal Wastewater • Septic systems- a large container that receives wastewater from the house.

17. Septic tank Nonperforated pipe Manhole (for cleanout) Household wastewater Drain field Perforated pipe Gravel or crushed stone Distribution box (optional) Vent pipe Fig. 19.14, p. 494

18. Treatments for Human and Animal Wastewater • Sewage Treatment Plants- centralized plants in areas with large populations that receive wastewater via a network of underground pipes.

19. Sewage Treatment • Primary: mechanical-let solids settle out, screens filter out • Secondary: aerobic bacteria remove 90% of organic waste • Trickling filters:sewage seeps through crushed stone (bacteria and protozoa ) 202 in WC • Or Activated sludge: bacteria rich sludge and air bubbles • Doesn’t do much for removal of chemicals

20. Secondary Primary Grit chamber Chlorine disinfection tank Bar screen Settling tank Aeration tank Settling tank To river, lake, or ocean Raw sewage from sewers (kills bacteria) Sludge Activated sludge Air pump Sludge digester Sludge drying bed Disposed of in landfill or ocean or applied to cropland, pasture, or rangeland Fig. 19.15, p. 494

21. Sewage Treatment • Advanced • Removes nitrates and phosphates, expensive • May use reverse osmosis or flocculation (ppt) • Chlorinated water • may cause 7-10% of cancer in US • Ozone or UV can be used as a substitute • Sludge as fertilizer • May lead to health problem (metals) • Natural methods, using bacteria and plants is better than secondary treatment

23. SolutionsTechnology • Septic tanks are used by 25% of all US homes, should be cleaned out every 3-5 years • 1200 US cities (including Wilmington) have combined wastewater, stormwater pipelines

24. Treatments for Human and Animal Wastewater • Manure lagoons- large, human-made ponds line with rubber to prevent the manure from leaking into the groundwater. After the manure is broken down by bacteria, it is spread onto fields as fertilizers.

25. Chesapeake Bay • Point sources e.g. sew treatment plants--> 60% of phosphates • Nonpoint sources --> 60% of nitrates • Air pollution --> 35% nitrates • Commercial fishing, decline since 1960’s due to overfishing, pollution and disease

26. Chesapeake Bay • 1980’s, Chesapeake Bay program (ICM) • Composed of state, fed, indust, sport, envir, etc • Results: P levels down 27%, N down 16%, • So submerged veg up 75%

27. Cooperstown NEW YORK PENNSYLVANIA ATLANTIC OCEAN Harrisburg NEW JERSEY MARYLAND Baltimore Washington WEST VIRGINIA DELAWARE Richmond Chesapeake Bay VIRGINIA Norfolk Drainage basin No oxygen Low concentrations of oxygen Fig. 19.13, p. 490

28. Heavy Metals and Other Substances that can threaten human Health and the Environment • Lead • Arsenic • Mercury • Acids • Synthetic compounds (pesticides, pharmaceuticals, and hormones)

30. Minamata disease • Identified in 1959 • Affects nervous system, first evident in cats then humans. • Insoluble metallic mercury was dumped in Bay, bacteria converted it to soluble methylmercury • It worked its way up the food chain • Worldwide reaction helped to spark the environmental movement

31. Mad Hatters Disease • Mercury was used in production of felt from fur for hats • Workers worked with fumes in confined spaces for the long work day • Characterized by erratic behavior, memory loss and shyness (Alice in Wonderland)

32. World Mercury Production Mostly from coal combustion

34. Acid Mine Drainage • Groundwater in mines becomes acidic (low pH) • Metal atoms dissolve in acid (Fe, Cu, Al, etc) • Low pH water mixes with neutral water and yellow or red iron cmpds precipitate

36. Study of 139 streams in US by USGS • Next page: percentage of streams with indicated contaminant

38. Sources of oil in the ocean • Consumption of petroleum = water bottles, etc

39. Oil Pollution

40. Oil Spill Victim

42. Exxon Valdez • March 24, 1989, Prince William Sound • Double hull could have prevented spill • Best technology can only recover 11-15% • Oil Protection Act, 1990 is ineffective

43. Oil in Oceans 1. In normal operations, 1000x more oil is spilled per year than the Exxon Valdez (1989) (11 million gallons) 2. Oil from oil changes=20x Valdez 3. Gulf oil leak, 2010 (206 million gallons)

44. Oil in Oceans • Cleanup? • Mechanical methods • Booms, skimmer boats, absorbent pads (on beaches) • Chemical methods: coagulating agents, dispersing agents, fire, natural action

45. Ways to Remediate Oil Pollution • Containment using booms to keep the floating oil from spreading. • Chemicals that help break up the oil, making it disperse before it hits the shoreline. • Bacteria that are genetically engineered to consume oil

46. Other Water Pollutants • Solid waste pollution (garbage) • Sediment pollution (sand, silt and clay) • Thermal pollution • Noise pollution

50. Water Laws • Clean Water Act- (1972) supports the “protection and propagation of fish, shellfish, and wildlife and recreation in and on the water”. • Issued water quality standards that defined acceptable limits of various pollutants in U.S. waterways.