1. Chapter 21 Water Pollution

2. Types of Water Pollution
Any physical or chemical change in water that adversely affects the health of humans and other organisms
Sewage
disease-causing agents
sediment pollution
inorganic plant and algal nutrients
organic compounds
inorganic chemicals
radioactive substances
thermal pollution

3. 1. Sewage Causes 2 serious environmental problems: 1. Enrichment
Fertilization of water by high levels N and P
2. Increase in Biological Oxygen Demand (BOD)
BOD-amount of oxygen needed by microorganisms to decompose biological wastes
BOD Dissolved Oxygen (DO)

4. Sewage

5. Sewage: Eutrophication
Oligotrophic
Unenriched, clear water that supports small populations of aquatic organisms

6. Sewage: Eutrophication
Slow-flowing stream, lake or estuary enriched by inorganic plant and algal nutrients such as phosphorus

7. 2. Disease-causing Agents
Infectious organisms that cause diseases
from wastes of infected individuals
Examples:
Typhoid, cholera, bacterial dysentery, polio, and infectious hepatitis
India

8. 3. Sediment Pollution
Excessive amounts of suspended soil particles. From:
erosion of agricultural
lands
logging
degraded stream banks
overgrazing
mining
construction

9. 4. Inorganic Plant and Algal Nutrients
N and P stimulate the growth of plants and algae
Sources:
Human and animal wastes, plant residues, atmospheric deposition, and fertilizer runoff
It Causes:
Enrichment, bad odors, and a high BOD

10. Inorganic Plant and Algal Nutrients: The Dead Zone

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

12. Volatile Organic Compounds in Groundwater

13. 6. Inorganic Chemicals
Contaminants that contain elements other than carbon
Do not degrade easily
Examples:
Lead-
Mercury-
Found in old paint, industrial pollutants, leaded gasoline
bioaccumulates in the muscles of top predators of the open ocean

14. 7. Radioactive Substances
Unstable isotopes that emit radiation
Sources:
Mining
Processing radioactive materials
Nuclear power plants
Natural sources

15. 8. Thermal Pollution Factories release heated water into waterways
Why is this bad?
Temperature affects reproductive cycles, digestion rates, and respiration rates
Warm water holds less DO than cold water

16. Two Types of Water Pollution
1. Point Source Pollution
Water pollution that can be traced to a specific origin
2. Non-point Source Pollution
Pollutants that enter bodies of water over large areas rather than being concentrated at a single point of entry

17. Water Pollution from Agriculture
Agriculture is leading source of water pollution in US
Animal wastes and plants residues have high BOD
Chemical pesticides
Almost all streams and rivers are polluted with agricultural pesticides
Important****
There is little regulation!!!!

18. Municipal Water Pollution

19. Industrial Wastes in Water
Different industries generate different pollutants
Food processing plants- high BOD
Paper mills- High BOD and toxic compounds
Green Chemistry

20. Groundwater Pollution

21. Water Pollution in Other Countries
Lake Maracaibo, Venezuela
Po River, Italy
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

22. Purification of Drinking Water
In US most municipal water supplies are treated

23. Purification of Drinking Water
Treated water distributed to customers

24. Purification of Drinking Water
Chlorine Dilemma
Chlorine byproducts are linked to numerous cancers, miscarriages and birth defects
Peru
Fluoridation
Prevents tooth decay
Linked to cancer, kidney disease

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

26. Municipal Sewage Treatment

27. Laws Controlling Water Pollution
Citizen Watchdogs to Monitor Pollution
Safe Drinking Water Act (1974)
Set uniform federal standards for drinking water including maximum contaminant level
Clean Water Act (1972)
EPA sets up and monitors National Emissions Limitations
Effectively improved water quality from point sources