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Chapter 21 Water Pollution

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Presentation on theme: "Chapter 21 Water Pollution"— Presentation transcript:

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

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