1. Water Resources & Pollution
Environmental Science

2. Water Cycle

3. How much water on Earth is available for human use?

4. Surface Water—fresh water found in lakes, rivers, streams, and wetlands

5. Surface water provides most of the water supply for large cities
Resources
Drinking water
Water for crops
Food- fish & shellfish
Hydrologic power
Transportation

6. Watershed– the area of land drained by a river
Human impacts on watersheds
Dams
Re-routing rivers & tributaries
Pollution runoff

7. Water table– level of groundwater
Groundwater– stored beneath the Earth’s surface in sediment & rock formations
Water table– level of groundwater
In a desert, the water table could be hundreds of meters below the surface. In low-lying areas (New Orleans), the water table is at or right below the surface.
Aquifer– underground formation of rocks, sand, & gravel where water accumulates
Materials that are porous & permeable

8. Recharge Zone—the area of land above the aquifer that restores & replenishes its water supply
Percolation
Any pollution in the recharge zone can be introduced into the aquifer
Man-made structures can act as a barrier for water replenishing the aquifer

9. Global Water Use 67% 14% 19% Residential Drinking Washing Cooking
Toilets
Agricultural
Crops– irrigation
Livestock
Industrial
Manufacturing
Waste-disposal
Power
As cooling systems
67%
14%
19%

10. Water use varies by country

11. For residential use, water has to be treated to be potable

12. Water Management dams, canals, diversion projects
Bring water to naturally drier areas
Create reservoirs for drinking, recreation, power
Interrupts natural water flow
Disrupts ecosystems

13. Water Conservation In Agriculture In Industry In Residences
Drip irrigation systems
Developing crops that are drought-tolerant (need less water)
In Industry
Recycling cooling water & waste water
Re-using “grey” water
In Residences
Xeriscaping
Water-saving faucets, toilets, & shower heads

14. Water Pollution– the introduction of chemical, physical, or biological agents in to water that degrade water quality and adversely affect the organisms
Most significant contributions to water pollution are industrialization & human population growth

15. Point-source pollution– comes from a single source (pipe)– factory, wastewater treatment plant, leaking tanker
Nonpoint-source pollution non-specific source from runoff– roads, farms, construction, residential areas. Very difficult to identify.

16. Pollution Types Pollutant Agent Major Sources Pathogens
Bacteria, viruses, parasites
Mostly nonpoint; sewage, livestock feces, wastewater
Organic Matter
Decomposing material, debris from food waste
Mostly nonpoint sources
Organic Chemicals
Pesticides fertilizers, plastics, detergents, oil
Mostly nonpoint sources; golf courses, roads, wastewater
Inorganic chemicals
Acids, bases, industrial chemicals
Point & nonpoint sources; industrial waste, roads, wastewater
Heavy metals
Lead, mercury, cadmium, arsenic
Point & nonpoint sources; industrial discharge, landfills, household chemicals
Physical agents
Thermal pollution & solids
Point & nonpoint sources; thermal pollution from industrial processes, suspended soil from erosion

17. Principle Sources of Water Pollution
Wastewater
Eutrophication
Thermal pollution
Groundwater
Ocean Pollution

18. Wastewater– sewage or industrial waste
Wastewater treatment involves filtration, aeration, settling, removal of semi-solid sludge, bacteria, and chlorination.

19. What to do about sludge?
Treated sludge is mostly “safe” decomposing plant & animal material; however, sludge often contains high concentrations of toxic chemicals
Some communities are developing ways to reduce toxins in the sludge, so it can be safely disposed or put to use (fertilizers or fuels)

20. Tertiary wastewater treatment
Constructed wetlands offer another level of cleaning and filtration, naturally. They require no special chemicals, little extra energy.

21. Artificial Eutrophication– unnatural addition of nutrients to slow-moving waters
Most artificial eutrophication comes from runoff of fertilizers and detergents, adding phosphates & nitrates to the water
Causes excessive algae to grow
When algae dies, decomposers/bacteria thrive in the water and deplete the oxygen
Fish & other organisms suffocate

22. What can be done about eutrophication?
Limit or eliminate phosphates in detergents
Prevent runoff of nitrogen-containing fertilizers
Use organic fertilizers
Plant crops that need less fertilizers

23. Thermal Pollution– heated water is released from manufacturing or power plants
Can cause large-scale fish kills
Can cause the dissolved oxygen of the water to decrease
What can be done about thermal pollution?

24. Groundwater Pollution– when pollution percolates down into aquifers
pesticides, herbicides, chemical fertilizers
Leaking underground storage tanks– commonly contain gas & heating oil
Septic tanks, landfills, industrial wastewater
Groundwater pollution is perhaps the most difficult type to control and clean up.

25. Ocean Pollution Runoff from activities on land causes 85% Oil spills
Garbage & wastewater dumped directly from ships
Even though major oil spills seem catastrophic… ten times more oil enters the ocean through nonpoint-source runoff each year.

26. Water pollution affects organisms all along the food chain
Biomagnification– the accumulation of pollutants in the bodies of organisms going up the food chain. Tertiary consumers have much higher concentration of toxins in their bodies than primary producers or consumers.

27. Federal Water Pollution Legislation
Year
Legislation
Requirements
1972
Clean Water Act
Banned pollutant discharge into surface water; required metals be removed from wastewater
1972, 1988
Marine Protection, Research, and Sanctuaries Act
Empowerd the EPA to control dumping of sewage and toxic chemicals in U.S. waters
1975, 1996
Safe Drinking Water Act
Introduced programs to protect groundwater & surface water
1980
Superfund Act
Required owners, operators, and customers of hazardous waste sites to be responsible for clean up
1987
Water Quality Act
Supported state & local efforts to clean polluted runoff
1990
Oil Pollution Act
Required oil tankers to be double-hulled in U.S. waters

28. What can individuals do to prevent water pollution?
Refuse to support companies that fail to take responsibility
Use phosphate-free detergents
Prevent nonpoint-source pollution in your own yard– do not dispose toxic chemicals, clean up spills, keep car maintained
Recycle– especially plastics
Do not litter at the beach