1. Chapter 14
Water Pollution

2. The Chesapeake Bay Chesapeake Bay – largest estuary in the US
Pollutants:
Excess nitrogen and phosphorus
From 3 major sources:
Consequence
Sediment increase
Causes:
Anthropogenic chemicals
Trying to clean the CB – massive size = monumental effort
2000
2010

3. 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 source pollution
Nonpoint source pollution

4. Types of Pollutants Human wastewater
Inorganic substances (ie. heavy metals)
Organic compounds
Synthetic organic compounds
Oil
Nonchemical pollutants

5. Human Wastewater Water produced by human activities such as:
Can be difficult to prevent wastewater from contaminating drinking water

6. Human Wastewater
Three reasons scientists are concerned about human wastewater:
Oxygen-demanding wastes are broken down by 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

7. Human Wastewater Oxygen Demand
Oxygen demanding waste – organic matter that enters a body of water and feeds the growth of bacteria (decomposers)
BOD (biological oxygen demand)- the amount of oxygen a quantity of water uses over a period of time at a specific temperature
Dead zones – areas where this is so little oxygen, there is so little life

8. Human Wastewater Nutrient Release
Nutrients (ie phosphorus, nitrogen) present from human wastewater
Eutrophication – increase in fertility of a body of water
Cultural eutrophication
Ex: Dead Zone in the Gulf of Mexico

9. Human Wastewater Why is eutrophication a bad thing?
Explosion in algal, bacteria & decomposer populations
Sewage
↑ Enrichment
↑ Biological oxygen demand (BOD)
Fish kills
↓ Oxygen levels in water

10. Human Wastewater Disease-causing Organisms
Pathogens – illness-causing viruses, bacteria and parasites
Illnesses include:
Indicator species
Fecal coliform bacteria test

11. Human Wastewater Treatments
Septic systems- a large container that receives wastewater from the house
Consists of a septic tank and leach field
Septic tank
Leach field
Environmental advantages to septic system:
Downside:

12. Human Wastewater Treatments
Sewage Treatment Plants- centralized plants in areas with large populations that receive wastewater via a network of underground pipes
Primary treatment
Secondary treatment
Problems?

14. Human Wastewater What is removed…

15. Human Wastewater Animal Wastewater
Manure lagoons- large, human-made ponds line with rubber to prevent the manure from leaking into the groundwater Risks:

16. Heavy Metals and Other Substances
Lead
Arsenic
Mercury
Acids
Synthetic compounds
Pesticides
Pharmaceuticals
Hormones

17. Lead Heavy metal Rarely found in natural sources of drinking water
Most at risk
Risks:
In mid-1990’s- 10% + municipal water supplies contained lead levels that exceeded max permitted by Safe Drinking Water Act

18. Arsenic
Occurs naturally in Earth’s crust, can dissolve into groundwater
Human activities (ie mining) can increase
Can be removed via:
Problems associated with:
Many people suffer from arsenic poisoning with no other options

19. Mercury Image – mercury releases from different regions of world
Comes from:
Inorganic mercury (Hg) not dangerous
Bacteria (in wetlands and lakes) convert Hg into methylmercury
Methylmercury is highly dangerous to humans
Most at risk
Can cause:

20. Acid Deposition and Acid Mine Drainage
Wet deposition vs. Dry deposition
What’s being done to prevent?
Acid mine drainage
Lower pH = harmful metal ions become water soluble
What can be done?
Problem

21. Synthetic Organic Compounds
Synthetic – human made
Includes:
Pesticides
Concerns :
Pharmaceuticals/hormones
Military compounds – from manufacturing, testing, dismantling rockets
Industrial cleaners
PCBs – used in manufacturing plastics and insulating electrical transformers until 1979
PBDEs – flame retardants

22. Oil Pollution
Petroleum products – highly toxic to many marine organisms, birds, mammals
Very difficult to remove
Sources:
Drilling for undersea oil using offshore platforms
Spills from oil tankers
Natural seeps

23. Oil Pollution Ways to Remediate
Where does oil accumulate?
So how do we clean up surface oil?
Containment?
Dispersants - chemicals that help break up the oil
Bacteria that are genetically engineered to consume oil
Underwater plumes
Treatment of rocky coastlines:

24. Non-Chemical Pollutants
Solid waste pollution (garbage)
Sediment pollution (sand, silt and clay)
Thermal pollution
Noise pollution

25. Solid Waste Pollution
Garbage - discarded materials from homes and industries that do not pose a toxic hazard to humans/other organisms
1997 – scientists discovered the Great Pacific Garbage Patch
More of a problem in developing countries
Coal ash and coal lag Contains harmful chemicals (lead, mercury, arsenic)

26. Sediment Pollution Sediment – particles of sand, silt, clay
Carried by moving water
Sediment pollution –increased movement of sediment due to human activities
Activities that loosen soil
Effects?

27. Thermal Pollution Substantial change in water temperature
Can be increase or decrease, most commonly is increase
Methods to reduce thermal pollution:
Thermal shock

28. Noise Pollution
Sound emitted by ships/submarines – interfere with animal communication
Esp sonar

29. Water Laws
Clean Water Act- (1972) supports the “protection and propagation of fish, shellfish, and wildlife and recreation in and on the water”
Originated as the Federal Water Pollution Control Act of 1948
Issued water quality standards that defined acceptable limits of various pollutants in U.S. waterways

30. Water Laws
Safe Drinking Water Act- (1974, 1986, 1996) sets the national standards for safe drinking water
Responsible for establishing maximum contaminant levels (MCL) for 77 different elements or substances in both surface water and groundwater

32. We still have work to do…