1. Water Pollution

2. Water Pollution Water pollution Major water pollution issue globally
Any physical or chemical change in water that adversely affects the health of humans and other organisms.
Major water pollution issue globally
Lack of disease-free water
Increasing demand for fresh water as the human population increases

3. 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
The cumulative effect is very large
Ex: runoff from agricultural fields or parking lots

4. Nonpoint Source Water Pollution

5. Point source and nonpoint source water pollution

6. Types of Water Pollution
Sewage (human)
Disease-causing agents
Sediment pollution from soil erosion
Chemical fertilizers and agricultural runoff
Organic compounds: pesticides and herbicides
Inorganic chemicals: copper, lead and other compounds
Thermal pollution

7. Sewage Increases the Biological Oxygen Demand (BOD)
BOD a measure of dissolved oxygen required to break down the organic material in a given volume of water through aerobic biological activity.
Bacteria consume oxygen when decomposing organic matter in water.

8. Sewage The release of wastewater from drains or sewers
Includes human wastes, soaps, and detergents
Causes environmental problems:
Nutrient Enrichment leading to algal blooms..
Fertilization of a body of water by high levels of plant and algal nutrients (nitrogen and phosphorus)

9. BOD and DO can be used to monitor pollution
Measure BOD
A high biochemical oxygen demand means there is a lot of organic matter in the water.
Measure DO
Low dissolved oxygen levels mean that the lake is polluted

10. Sewage recovery curve: BOD decreases and DO rises downstream from a sewage spill.

11. 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

12. 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

13. 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
Covers aquatic animals and plants
Brings insoluble toxins into waterways

15. Agricultural runoff and sewage
Chemicals such as nitrogen and phosphorus that stimulate the growth of plants and algae
Sources:
Human and animal wastes, plant residues, atmospheric deposition, and fertilizer runoff
Causes:
Enrichment, bad odours, and a high biological oxygen demand (BOD)

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

17. Eutrophication
The natural or artificial enrichment of a body of water, particularly with respect to nitrates and phosphates, that results in depletion of the oxygen content of the water.
Eutrophication is accelerated by human activities that add detergents, sewage or agricultural fertilizers to bodies of water.

18. Eutrophication: The natural or artificial enrichment process in lakes
Oligotrophic (young lake)
Unenriched, clear water that supports small populations of aquatic organisms

19. Eutrophication Eutrophic-
Over time, sediments and nutrients will enter the lake and it will become nutrient rich. Eventually, the lake will fill in completely, but this takes a long time.

20. Cultural eutrophication: runoff from agriculture adds nutrients to the water

22. Compare

24. Cultural Eutrophication
Fertilizers, sewage, and/or sediment enter the lake from runoff.
Algae and other plants grow. (Algal Blooms)
Some algae die, this increases the BOD.
Bacteria and other microorganisms decompose the dead plants, consuming oxygen.
Dissolved oxygen decreases.
Sometimes fish die.

25. Agricultural runoff creates the Dead Zone in the Gulf of Mexico

26. 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 dissolved oxygen than cold water

27. Direct and indirect measures of pollution
Direct measurements are measurements of the pollutants.
Indirect measurements are measurements of consequences of the pollution.

28. Direct measurements of pollution
Copper
Heavy metals
Turbidity (the ability to see through the water.)
BOD (biological oxygen demand) Indicates the amount of organic matter in the water

29. Indirect measurements of pollution
Biotic index-
An index which shows the level of pollution by looking at the types of organisms living in the water.
Indicator Species –
Species that are found if the water is iether polluted or unpolluted.
DO - Dissolved Oxygen

30. In the US, there are Laws Controlling Water Pollution
Citizen Watchdogs to Monitor Pollution
Safe Drinking Water Act (1974)
Set uniform federal standards for drinking water
Maximum contaminant level
Clean Water Act (1972)
EPA sets up and monitors National Emissions Limitations
Effectively improved water quality from point sources

31. Laws that Protect Groundwater
Safe Drinking Water Act
Resource, Conservation and Recovery Act