1. Chapter 14
Water Pollution

2. Water Pollution
Is contamination of surface or groundwater through human activity that negatively affects living things
Can be animal waste, garbage, excess nutrients, chemicals, excess sediment

3. Sources of Pollution Point Source Nonpoint Source
Distinct locations that add pollutants to a body of water
Nonpoint Source
Large areas and many contributors add pollutants to a body of water

5. Human Wastewater
Is produced from human activities such as cooking and bathing
Most common global water pollutant
Separating wastewater from drinking water has been a huge challenge
Infrastructure
Public health

6. Impacts of Wastewater Releases organic nutrients
Causes eutrophication
Increases oxygen demand
Reduces oxygen available to other aquatic organisms
Releases disease-causing organisms
Public health problem

7. Oxygen-Demanding Waste
Is waste that carries organic material that can provide food for bacteria
Sewage
Plant matter
This causes bacterial growth, which uses oxygen
Extreme bacterial growth can cause dead zones

8. Biochemical Oxygen Demand (BOD)
Measures the oxygen use over a period of time at a given temperature
Temperature has an effect because warmer water holds less oxygen
Can show how much organic matter has polluted a body of water

9. Nutrient Release from Waste
Includes limiting nutrients like nitrogen and phosphorus
Comes from bacteria during decomposition of organic matter

10. Eutrophication
Occurs when algae grow rapidly from increased nutrient levels
When this occurs from human activity, it is called cultural eutrophication
Can cause hypoxic zones when the bloom dies and decomposes

11. Disease-Causing Organisms in Waste
Are also called pathogens
Include bacteria, viruses, and parasites
Cause outbreaks when human wastewater mixes with drinking water
Cholera and hepatitis are the major wastewater-borne disease-causing agents worldwide

12. Indicator Species
Show that a given area has been contaminated by pathogens from human waste
Fecal Coliform Bacteria
Escherichia coli
Are tested for in public water by law
Pools, beaches, lakes, rivers, reservoirs

13. Wastewater Treatment
Removes organic matter and pathogens from wastewater
Has several methods
Septic tanks
Sewage treatment plants
Manure lagoon
Relies on beneficial bacteria breaking down organic matter and outcompeting pathogens

14. Septic Systems Use a septic tank Accepts waste
Allows waste to settle into three layers
First layer is floating scum
Second layer is liquid septage
Third layer is semisolid sludge

15. Septic Systems Use a leach field
Uses pipes and gravity to move septage out of the tank
Septage contains water and nutrients that seep out into the ground
Soil filters and purifies water

16. Pros and Cons of Septic Systems
Do not use energy to treat water
Can produce methane
Can produce methane
Need a large area for leach field
Beneficial bacterial levels must be maintained or the system can fail
Sludge must be pumped out every 5-10 years and taken for sewage treatment

17. Sewage Treatment Plants
Remove human waste from water
Can receive wastewater from households, businesses and storm drains
Can recycle water for other uses
Use two to three levels of treatment
Primary
Secondary
Tertiary

18. Primary Sewage Treatment
Involves settling and removal of solids from liquids in wastewater
Leftover sludge can be dried
Sent to a landfill
Used for fertilizer
Some areas have special permits to release liquid extracted from primary treatment directly into the ocean (effluent)

19. Secondary Sewage Treatment
Cleans the liquid remaining from primary treatment
Bacteria are added to the liquid to digest the organic material
Resulting liquid has 80-90% of the organic material removed
Liquid is held in tanks to let bacteria and any remaining solids settle out
Effluent can be released into the environment

20. Tertiary Sewage Treatment
Is required by some areas before effluent can be released into the environment
Is done to ensure the death of all pathogens
Can involve adding chemicals like chlorine to water
Can involve exposing water to high levels of ultraviolet radiation

21. Sewage Overflows
Occur during periods of high water flow that overwhelm treatment plants
Can be legal
Pollute surrounding waterways
Can also occur from blockage
And if that  isn’t gross enough:
Fatbergs in London’s Sewer System

22. Other Treatment Methods
Involve using natural systems to absorb nutrients from water
Constructed wetlands
Marshes
Swamps

23. Pros and Cons of Traditional Sewage Treatment
Reduces illness from waterborne pathogens
Reduces pollution from increased organic matter
Can provide energy (methane)
Can provide nutrients for fertilizer
Can provide reusable water
Expensive
Energy-intensive
People don’t want to reuse sewer water

24. Manure Lagoons
Are where animal wastes from CAFOs and farming are stored
Are lined in rubber or plastic to prevent leaking
Have bacteria added to digest organic waste
Undigested waste is dried and distributed as fertilizer
Also: CAFOs from SPACE!

25. Toxic Chemicals Mostly come from industrial processes
Metals
Lead, arsenic, mercury, cadmium
Acids
Synthetic compounds
Are used in agriculture and consumer products
Pesticides, cleaning chemicals, health and beauty products

26. Lead (Pb) Can leach from pipes and contaminate water
Causes nervous system and kidney damage
Can be eliminated by removing lead pipes and filtering water

27. Arsenic (As)
Exists naturally in the Earth’s crust and can leach into groundwater
Mining tailings and industrial processes also produce arsenic
Can cause cancer from chronic small doses over time or a large acute dose
Has a safe limit of exposure at 10 μg/L (EPA), which may still be too much

29. Mercury (Hg)
Is added to the atmosphere by mining and burning fossil fuels
Can also come from industrial processes and medical waste
Gets into water through leaching or precipitation
Converts to methylmercury
Can bioaccumulate in fish
Can cause nervous system damage in humans (Minamata disease)

31. Cadmium (Cd)* Is released from smelting and mine tailings
Causes Itai-itai disease (“ouch-ouch” disease)
Replaces calcium in bones, making them extremely brittle
Can be absorbed by plant tissues, then bioaccumulate and biomagnify up a food chain

32. Acids Come from mining and industrial process
Form from exposed rock that releases sulfur and hydrogen ions
Make sulfuric acid in nearby water
Form from burning fossil fuels that release sulfur and nitrogen compounds
Make sulfuric and nitric acid in the atmosphere
Accumulate in water and can dissolve even more toxic metals

33. Synthetic Chemicals
Come from industrial point sources or from agricultural or residential nonpoint sources
Include pesticides, pharmaceuticals and cleaning agents
Can cause many different health effects

34. Pesticides
Can kill other organisms besides the intended target species
Are made of a mixture of chemicals that may have yet-undiscovered effects on organisms
Get into water by direct spraying or from agricultural runoff
Can bioaccumulate and biomagnify in a food chain

35. Pharmaceuticals and Hormones
Include prescription and OTC drugs, steroids, and reproductive hormones
Hormones and steroids operate in cells at small concentrations, so they have a larger impact
Can lead to developmental defects
Antibiotics may lead to increased bacterial resistance in nature

36. Industrial Waste
Includes any chemical used in manufacturing and other industrial processes
Was dumped into bodies of water as an easy disposal method
No longer legal to dispose this way
Include many types of chemicals
Perchlorates
Polychlorinated biphenyls
Polybrominated diphenyl ethers

37. Perchlorates (ClO4) Come from rocket fuel
Leach into the ground from poorly disposed military and space waste
Disrupt thyroid function
Reduce hormone production
Can cause birth defects

38. Polychlorinated Biphenyls (PCBs)
Were used to manufacture plastics and electronics until 1979
Are persistent, so they still exist in the environment today
May not be in the water column, but have settled into bottom sediment
Are carcinogenic
Can bioaccumulate in fatty tissues and biomagnify in a food chain

39. Fossil Fuels
Contaminate water by leaked oil from drilling and transportation
Hard to clean up
Persistent
Contains many toxic and carcinogenic compounds
Can leak naturally
Called oil seeps

41. Cleaning Up Oil Spills
Involves cleaning animals, plants, and their habitat
Must be done by hand for wildlife
Chemicals can destroy natural waterproofing
Animals that survive may not be able to live in the wild

42. Cleaning Up Oil Spills Also involves preventing oil from spreading
For underwater plumes:
Containment “curtains” stop spreading
Vacuums or absorbent materials suck up oil
For surface oil:
Apply dispersants to break up oil in water
Use high pressure water jets on shorelines

43. Other Types of Water Pollution
Are not chemicals themselves, but can contribute or elevate chemical pollutants
Solid waste
Sediment
Thermal
Noise

44. Solid Waste Includes garbage Is ugly Is dangerous to aquatic organisms
Is a global problem as it travels far from its disposal site
Pacific Garbage Patch

45. Sediment Is the addition of excess sand, silt, and/or clay to water
Comes from poor farming techniques and deforestation
Increases turbidity (cloudiness) of water
Reduces photosynthesis
Clogs fish gills and buries invertebrates
Can carry excess nutrients

46. Thermal Pollution Is excess heat added to water
Comes from water used to cool power plants and factories
Decreases the amount of oxygen in the water
Causes thermal shock
Death of aquatic species due to extreme temperature change

47. Noise Pollution
Is excess noise from shipping, military exercises, scientific exploration, and fossil fuel mining and prospecting
Harms marine mammals
Disrupts their communication
May cause some biological damage

48. Keeping Drinking Water Safe
Involves federal legislation that mandates standards for water quality
Clean Water Act
Safe Drinking Water Act
Enforced by the EPA and state agencies
States may pass standards that exceed federal limits

49. Clean Water Act Began as the Federal Water Pollution Act of 1948
Expanded in 1972
Sets out standards for maintaining and restoring the chemical, physical, and biological properties of surface water
Does not protect groundwater
Continues to be amended as needed
Addresses levels of specific pollutants

50. Safe Drinking Water Act
Was passed in 1974 and has been amended as necessary
Sets maximum contaminant levels (MCLs) for drinking water

51. Water Pollution in the Rest of the World
Is more of a problem in developing nations
Lack of infrastructure
Lack of legal structure
Poor enforcement
Is often due to rapid industrialization