1. Chapter 22 Water Pollution

2. Overview of Chapter 22 Types of Water Pollution Water Quality Today
Sewage
Disease-causing agents
Sediment pollution
Inorganic plant and algal nutrients
Organic compounds
Inorganic chemicals
Thermal pollution
Water Quality Today
Improving Water Quality
Laws Controlling Water Pollution

3. Types of Water Pollution
Any physical or chemical change in water that adversely affects the health of humans and other organisms
Varies in magnitude by location
Major water pollution issue globally
Lack of disease-free water
Eight categories
Sewage, disease-causing agents, sediment pollution, inorganic plant and algal nutrients, organic compounds, inorganic chemicals, radioactive substances, and thermal pollution

4. 1. Sewage The release of wastewater from drains or sewers
Includes human wastes, soaps, and detergents
Causes 2 serious environmental problems:
Enrichment
Fertilization of a body of water by high levels of plant and algal nutrients (nitrogen and phosphorus)
Increase in Biological Oxygen Demand (BOD)
Amount of oxygen needed by microorganisms to decompose biological wastes
As BOD increases Dissolve Oxygen (DO) decreases

5. Sewage

6. Sewage- Eutrophication
Oligotrophic
Unenriched, clear water that supports small populations of aquatic organisms

7. Sewage- Eutrophication
Slow-flowing stream, lake or estuary enriched by inorganic plant and algal nutrients such as phosphorus
Often due to fertilizer or sewage runoff

8. 2. Disease-causing Agents
Infectious organisms that cause diseases
Originate in the wastes of infected individuals
Common bacterial or viral diseases:
Typhoid, cholera, bacterial dysentery, polio, and infectious hepatitis

9. Disease-causing Agents
Monitored by testing for presence of E. coli in the water via a fecal coliform test
Indicates the presence of pathogenic organisms

10. Types of Water Pollution
Monitoring for Sewage (Fecal Coliform Test) – small sample of water passed through filter to trap bacteria, transferred to a petri dish with nutrients; incubated until greenish colonies form, which can be counted to indicate the number of E. coli in the original sample

11. Fecal Coliform Test - Results
Safe drinking water = no more than 1 coliform bacterium per 100 mL of drinking water (1/2 cup)
Safe swimming water = no more than 200 bacteria per 100 mL of water
Safe recreational boating = no more than 2,000 per 100 mL of water
Raw Sewage = usually several million coliform bacteria per 100 mL of water!

12. 3. Sediment Pollution Excessive amounts of suspended soil particles
Originates from erosion of agricultural lands, forest soils exposed by logging, degraded stream banks, overgrazed rangelands, strip mines, and construction
Problems
Limits light penetration thereby decreasing photosynthetic activity
Covers aquatic animals and plants, providing less shelter for aquatic organisms
Brings insoluble toxins into waterways

14. 4. Inorganic Plant and Algal Nutrients
Chemicals such as nitrogen and phosphorus that stimulate the growth of plants and algae
Harmful in large concentrations
Sources:
Human and animal wastes, plant residues, atmospheric deposition, and fertilizer runoff
Causes:
Enrichment, bad odors, and a high BOD

15. Inorganic Plant and Algal Nutrient- The Dead Zone

16. 5. Organic Compounds Chemicals that contain carbon atoms
Natural examples: sugars, amino acids, and oils
Human-made examples: pesticides, solvents, industrial chemicals, and plastics

17. Organic Compounds
2002 U.S. Geological Survey of 139 streams in the United States found trace amounts of:
antibiotics, ibuprofen, acetaminophen, insect repellents, fragrances, caffeine, steroids (like hormones from birth control pills)
What is the effect of trace amounts of these in our water supply?????

18. 6. Inorganic Chemicals
Contaminants that contain elements other than carbon
Examples: acids, salts, and heavy metals
Do not degrade easily
Lead
Found in old paint, industrial pollutants, leaded gasoline
Mercury
Mercury bioaccumulates in the muscles & fat of top predators of the open ocean

19. Inorganic Chemicals Mercury:
Vaporizes even at room temperature (so can be inhaled!)
Coal-fired power plants mostly to blame for mercury exposure
Under the current Clean Air Act, mercury emissions are NOT mandated for power plants (unlike sulfur emissions)
Municipal waste incinerators, smelting of metals, industrial chemicals also expose us to mercury

20. 7. Radioactive Substances
Contain atoms of unstable isotopes that spontaneously emit radiation
Sources
Mining
Processing radioactive materials
Nuclear power plants
Natural sources

21. 8. Thermal Pollution
Occurs when heated water produced during industrial processes is released into waterways
Organisms affected
Temperature affects reproductive cycles, digestion rates, and respiration rates
Warm water holds less DO than cold water

22. Water Quality Today Two Types of Water Pollution
-Point Source Pollution
water pollution that can be traced to a specific origin
Discharge via pipes, sewage, and ditches
-Non-point Source Pollution
Pollutants that enter bodies of water over large areas rather than being concentrated at a single point of entry
Diffuse, but its cumulative effect is very large
Ex: runoff from agricultural fields or parking lots

23. Water Pollution from Agriculture
Agriculture is leading source of water pollution in US (72% of the pollution)
Animal wastes and plants residues have high BOD
Chemical pesticides can leach into groundwater
Almost all streams and rivers are polluted with agricultural pesticides

24. Municipal Water Pollution

25. Industrial Wastes in Water
Different industries generate different pollutants
Food processing plants- high BOD
Paper mills- High BOD and toxic compounds
Many industries recover toxins before they go into the waste stream

26. Case-In-Point Green Chemistry

27. Examples of Green Chemistry
Researchers at Carnegie-Mellon U. are using TAML’s (tetra-amido-macro-cyclic ligands) for helping break down synthetic substances before dumping into rivers
Changing chemical processes to use fewer synthetic chemicals in industry
Plastic bottles can now be made from sugars, with no use of harmful chemicals, and also break down in the environment after use
Dry cleaners in California can no longer use perchloroethylene (perc), and have found less harmful alternatives

28. Groundwater Pollution (1/2 the people in the U. S
Groundwater Pollution (1/2 the people in the U.S. get their drinking water from groundwater!)

30. Water Pollution in Other Countries
Lake Maracaibo, Venezuela
10,000 oil wells tap lake bottom
drilling platforms throughout the lake…pipelines running to refineries on land…10,000 oil wells have been drilled…much oil spilled!
Agricultural wastes from local fields
Unit recently raw human waste polluted the lake

31. Water Pollution in Other Countries
Po River, Italy
Similar to Mississippi River
Pollutants: Sewage, industrial wastes, sediment
>16 million Italians depend on the river for drinking water
Pollution is high
Swimming and fishing prohibited
Cleanup will require a national management plan and may take decades

32. Water Pollution in Other Countries
Ganges River, India
Used for bathing and washing clothing
Sewage and industrial waste discharged into river
Ganga Action Plan initiated by government
Construction of 29 sewage treatment plants

33. Improving Water Quality- Purification of Drinking Water
In US most municipal water supplies are treated, typically with chlorine!
First step…water is collected from water or reservoir (dam may be involved, or groundwater wells and water towers used)

34. Improving Water Quality- Purification of Drinking Water
Treated water distributed to customers
Sewer lines bring sewage to treatment plant
Sewage treated at sewage treatment plant

35. Purification of Drinking Water
Chlorine Dilemma
Chlorine kills disease causing organisms!
BUT - Chlorine byproducts are linked to numerous cancers, miscarriages and birth defects
Peru stopped using chlorine
1991- huge cholera epidemic that infected 300,000 people
Fluoridation
Prevents tooth decay
Linked to cancer, kidney disease
With both of these…the risk must be compared to the benefits!

36. Municipal Sewage Treatment
Primary treatment
Removing suspended and floating particles by mechanical processes (usually screens)
Secondary treatment
Treating wastewater biologically to decompose suspended organic material; reduces BOD

39. Municipal Sewage Treatment
Sewage Sludge
Solids remaining after primary and secondary sewage treatment has been completed
This material is either landfilled or used as composting for farms (may contain mercury and other harmful toxins)
Tertiary treatment
Advanced wastewater treatment methods that are sometimes employed after primary and secondary treatments (usually an additional bacterial treatment)
Reduce phosphorus and nitrogen

40. Municipal Sewage Treatment

41. Individual Septic System- Septic Tank

42. Individual Septic System- Drain Field

43. Laws Controlling Water Pollution
Citizen Watchdogs to Monitor Pollution
Safe Drinking Water Act (1974)
Set uniform federal standards for drinking water
Maximum contaminant levels and MCL goals were established for many common water pollutants!
Clean Water Act (1972)
EPA sets up and monitors National Emissions Limitations
Effectively improved water quality from point sources
Still largely ineffective at controlling NONPOINT sources!

44. Laws that Protect Groundwater
Safe Drinking Water Act (1974)
Resource, Conservation and Recovery Act (1976)
Comprehensive Environmental Response, Compensation, and Liability Act (Superfund – 1980)