Fig. 15-2 p. 307

Freshwater Readily accessible freshwater

Biota0.0001%

Rivers0.0001%

Atmosphericwater vapor

0.0001%

Lakes0.0007%

Soilmoisture0.0005%

Groundwater0.592%

Ice capsand glaciers

0.592%

0.014%

Humans use about 54% of reliable runoff

Agriculture

Industry

Domestic

Power plants

Fig. 15-4 p. 309

United States

Industry 11%Public 10%

Powercooling

38%

Agriculture38%

Two types of water subject to pollution•Surface water – rivers, lakes, oceans

• Uses: drinking, recreational [fishing, boating, swimming], irrigation.

•Groundwater- occurs beneath a water table in soils or rocks; subject to pollution from toxic chemicals.

• Uses: drinking, irrigation, etc

• Water pollution

• Point sources• Located at specific places• Easy to identify, monitor, and regulate• Examples

Nonpoint sources◦ Broad, diffuse areas◦ Difficult to identify and control◦ Expensive to clean up◦ Examples

Other sources of water pollution◦ Parking lots◦ Human-made materials

E.g., plastics◦ Climate change due to global warming

Fig. 20-A, p. 535

Good 8–9

Water Quality DO (ppm) at 20°C

Slightly polluted 6.7–8

Moderately polluted 4.5–6.7

Heavily polluted

Gravely polluted Below 4

4–4.5

Fig. 20-5, p. 536

Point source

Pollution-tolerant fishes

(carp, gar)Types of organisms

Normal clean water organisms

(Trout, perch, bass,

mayfly, stonefly)

Fish absent,

fungi, sludge worms, bacteria

(anaerobic)

Pollution-

tolerant fishes

(carp, gar)8 ppm

Normal clean water organisms

(Trout, perch, bass,

mayfly, stonefly)

Dissolved oxygen (ppm)

8 ppm

Biochemical oxygen demand

Clean Zone

Recovery ZoneSeptic Zone

Decomposition

ZoneClean Zone

Low flow rates Few bacteria Cold temperatures Low oxygen

Sources of contamination◦For Surface water

Rivers and lakes Point source: -sewage [municipal or private]

- industrial wastes Non-point source:

Agricultural activity [e.g. pesticides, fertilizers]. urban and highway water runoff.

Ocean [oil spills, dumping, land-based sources] Oil spills – during transportation, either

accidentally or intentionally Dumping –sewage, chemical disposal, radioactive

materials Land-based sources –migration of chemical

substances.

I) Fund pollutants ◦ -Environment has some assimilative

capacity. If capacity for absorption higher than rate of injection, they may not accumulate.

a) Degradable◦ degrades/break into component parts within water.

Are normally organic residuals attacked and broken down by bacteria and become less harmful.

b) Thermal pollution◦caused by injection of heat into watercourses

by an industrial plant or electric utility using surface water as a coolant, and returning the heated water to the watercourse.

Fig. 20-12, p. 543

Leaking tank

AquiferBedrock

Water table

Groundwater flow

Gasoline leakage plume (liquid phase)

Free gasoline dissolves in groundwater (dissolved phase)

Migrating vapor phase

Contaminant plume moves with the groundwater

Water well

c) Plant nutrients [nitrogen and phosphorus][eutrophic/ eutrophication =excess supply of nutrients in a lake]◦ stimulate growth of aquatic plant life, e.g. algae and

water weeds.◦ can produce odor if in excess.

d) Infectious organisms [e.g. bacteria and viruses]◦ carried into both ground and surface water by

domestic and animal wastes; industrial wastes e.g. tanning and meat packaging

◦ Are live organisms that may thrive and multiply in water or decline.

Fig. 20-15, p. 548

Industry Nitrogen oxides from autos and smokestacks, toxic chemicals, and heavy metals in effluents flow into bays and estuaries.

Cities Toxic metals and oil from streets and parking lots pollute waters; sewage adds nitrogen and phosphorus.

Urban sprawl Bacteria and viruses from sewers and septic tanks contaminate shellfish beds and close beaches; runoff of fertilizer from lawns adds nitrogen and phosphorus.

Construction sites Sediments are washed into waterways, choking fish and plants, clouding waters, and blocking sunlight.

Farms Runoff of pesticides, manure, and fertilizers adds toxins and excess nitrogen and phosphorus.

Red tides Excess nitrogen causes explosive growth of toxic microscopic algae, poisoning fish and marine mammals.

Toxic sediments Chemicals and toxic metals contaminate shellfish beds, kill spawning fish, and accumulate in the tissues of bottom feeders.

Oxygen-depleted zone Sedimentation and algae overgrowth reduce sunlight, kill beneficial sea grasses, use up oxygen, and degrade habitat.

Healthy zone Clear, oxygen-rich waters promote growth of plankton and sea grasses, and support fish.

Closed shellfish bedsClosed

beach Oxygen-depleted zone

I) Oil spills – covered under the Clean Water Act: ◦ prohibits discharges of harmful quantities of oil into

navigable waters◦ industry assume responsibility for any damage

[clean up; compensation for environmental restoration.

II) Dumping◦ Marine Protection Research and Sanctuaries Act,

1972. address discharges of waste

within U.S. territorial limits by U.S. vessels or persons in any ocean waters.

Unlike point source, is largely state responsibility◦ Federal grants for state-initiated plans for waste

treatment management. ◦ Federal programs for aiding control of non-point

sources e.g. Conservation Reserve Program

aimed at removing 40-45 million acres of erodible land from cultivation.

Fig. 20-13, p. 545

SOLUTIONSGroundwater Pollution

Prevention CleanupFind substitutes for toxic chemicals

Pump to surface, clean, and return to aquifer (very expensive)

Keep toxic chemicals out of the environment

Install monitoring wells near landfills and underground tanks

Inject microorganisms to clean up contamination (less expensive but still costly)

Require leak detectors on underground tanks

Ban hazardous waste disposal in landfills and injection wellsStore harmful liquids in aboveground tanks with leak detection and collection systems

Pump nanoparticles of inorganic compounds to remove pollutants (still being developed)

Fig. 20-17, p. 551

SOLUTIONSCoastal Water Pollution

Prevention CleanupReduce input of toxic pollutants

Improve oil-spill cleanup capabilities

Separate sewage and storm lines

Use nanoparticles on sewage and oil spills to dissolve the oil or sewage (still under development)

Ban dumping of wastes and sewage by ships in coastal watersBan ocean dumping of sludge and hazardous dredged material Require secondary

treatment of coastal sewageRegulate coastal

development, oil drilling, and oil shipping Use wetlands, solar-

aquatic, or other methods to treat sewage

Require double hulls for oil tankers

Reservoirs and purification plants

Process sewer water to drinking water

Expose clear plastic containers to sunlight (UV)

Nanofilters

The LifeStraw

Non-point source control is the least developed of water pollution control programs/policies.