Presentation on

WATER POLLUTION

Dr. Vivek Kumar

Water makes us unique and gives life to Earth.

What is water pollution?What is water pollution?

Any chemical, biological, or physical change in water quality that has a harmful effect on living organisms or makes water unsuitable for desired usage.

What is water pollution?

WHO:• 3.4 million premature

deaths each year from waterborne diseases

• 1.9 million from diarrhea

• U.S. 1.5 million illnesses• 1993 Milwaukee

370,000 sick

What is water pollution?Need to study Table 22-1 Page 492

Infectious Agents: bacteria and viruses often from animal wastes

Oxygen Demanding Wastes: organic waste that needs oxygen often from animal waste, paper mills and food processing.

Inorganic Chemicals: Acids and toxic chemicals often from runoff, industries and household cleaners

What is water pollution?Organic Chemicals: oil, gasoline, plastics,

detergents often from surface runoff, industries and cleaners

Plant Nutrients: water soluble nitrates, ammonia and phosphates often from sewage, agriculture and urban fertilizers

Sediment: soils and silts from land erosion can disrupt photosynthesis, destroy spawning grounds, clog rivers and streams

Heat Pollution and Radioactivity: mostly from powerplants

How do we measure water qualityBacterial Counts: Fecal

coliform counts from intestines of animals

• None per 100 ml for drinking

• >200 per 100 ml for swimming

Sources: human sewage, animals, birds, raccoons, etc.

See table 22-2 on page 493 for diseases transmitted by contaminated drinking water.

How do we measure water qualityDissolved Oxygen: BOD

Biological Oxygen Demand…the amount of oxygen consumed by aquatic decomposers

Chemical Analysis: looking for presence of inorganic or organic chemicals

Suspended Sediment water clarity

How do we measure water quality

Indicator Species: organisms that give an idea of the health of the water body.

• Mussels, oysters and clams filter water

Types, Effects and Sources of Water Pollution

Point sources Point sources

Nonpoint sources Nonpoint sources

Water quality Water quality

Fig. 22-3 p. 494Fig. 22-3 p. 494

Point and Nonpoint SourcesNONPOINT SOURCES

Urban streets

Suburban development

Wastewater treatment plant

Rural homes

Cropland

Factory

Animal feedlot

POINT SOURCES

Fig. 22-4 p. 494

Major Sources of Water Pollution

Agriculture: by far the leader

• Sediment, fertilizers, bacteria from livestock, food processing, salt from soil irrigation

Industrial: factories and powerplants

Mining: surface mining toxics, acids, sediment

Freshwater Stream PollutionFlowing streams can recover from

moderate level of degradable water pollution if their flows are not reduced.

• Natural biodegradation process

• Does not work if overloaded or stream flow reduced

• Does not work against non biodegradable pollutants

Pollution of Streams Oxygen sag curve Oxygen sag curve Factors influencing recovery Factors influencing recovery

Fig. 22-5 p. 496

What factors will influence this oxygen sag curve?

Two WorldsDeveloping Countries:Serious and growing

problem• Half of world’s 500 major

rivers heavily polluted• Sewage treatment

minimal $$$• Law enforcement difficult• 10% of sewage in China

treated• Economic growth with

little $$$ to clean up

India’s Ganges River• Holy River (1 million take daily

holy dip)• 350 million (1/3rd of pop) live

in watershed• Little sewage treatment• Used for bathing, drinking etc.• Bodies (cremated or not)

thrown in river• Good news is the Indian

government is beginning to work on problem

Freshwater Lake PollutionDilution as a solution in

lakes less effective• Little vertical mixing• Little water flow

(flushing)Makes them more

vulnerable• Toxins settle• Kill bottom life• Atmospheric deposition• Food chain disruptions

Biomagnifications of PCBs in an aquatic food chain from the Great Lakes.

See figure 22-6 on page 498

Eutrophication of LakesEutrophication: nutrient

enrichment of lakes mostly from runoff of plant nutrients (nitrates and phosphates)

• During hot dry weather can lead to algae blooms

• Decrease of photosynthesis• Dying algae then drops DO

levels • Fish kills, bad odor

Pollution of LakesEutrophication Eutrophication

Fig. 22-7 p. 499

Groundwater Pollution: Causes Low flow rates Low flow rates Few bacteria Few bacteria

Cold temperatures Cold temperatures

Coal strip mine runoff

Pumping well

Waste lagoon

Accidental spills

Groundwater flow

Confined aquifer

Discharge

Leakage from faulty casing

Hazardous waste injection well

Pesticides

Gasoline station

Buried gasoline and solvent tank

Sewer

Cesspool septic tank

De-icing road salt

Unconfined freshwater aquifer

Confined freshwater aquifer

Water pumping well Landfill

Low oxygen Low oxygen

Fig. 22-9 p. 502

Groundwater Pollution Prevention

Monitor aquifers Monitor aquifers

Leak detection systems Leak detection systems

Strictly regulating hazardous waste disposal Strictly regulating hazardous waste disposal

Store hazardous materials above ground Store hazardous materials above ground

Find less hazardous substitutes Find less hazardous substitutes

Ocean Pollution

Oceans can disperse and break down large quantities of degradable pollution if they are not overloaded.

• Pollution worst near heavily populated coastal zones

• Wetlands, estuaries, coral reefs, mangrove swamps

• 40% of world’s pop. Live within 62 miles of coast

Ocean Pollution

Fig. 22-11 p. 504