ENVSCI 101 The Global Environment

WATER RESOURCES

Lecture 14

WHY SHOULD YOU CARE
ABOUT WATER RESOURCES?

Humans and environment
depend on water

– Life made primarily of water
– Survival without water a few days
– Industry and agriculture use large

amounts

Water unevenly distributed on
earth

– Too much floods
– Too little becomes main focus of life

-Low cost encourages waste

WE ARE MANAGING FRESHWATER POORLY

• Access to freshwater a global health issue
− An average of 9,300 people die each day from lack of access

to safe drinking water

• Economic issue
− Water vital for producing food and energy

• National and global security issue

• Environmental issue
− Excessive withdrawal

THE EARTH’S WATER SUPPLY

• LIQUID WATER COVERS 3/4 SURFACE

– MOST SALTWATER

– AVAILABLE LIQUID FRESHWATER 0.024% OF TOTAL

– SURFACE WATER (LAKES, RIVERS AND STREAMS)

– GROUNDWATER

• HYDROLOGIC CYCLE

-MOVEMENT OF WATER IN THE SEAS, LAND, AND AIR

-DISTRIBUTED UNEVENLY

• HUMANS ALTER THE HYDROLOGIC CYCLE

-WITHDRAWING AND POLLUTING WATER AND CAUSING CLIMATE CHANGE

GROUNDWATER

• ZONE OF SATURATION
• SPACES IN SOIL BELOW A CERTAIN DEPTH ARE

FILLED WITH WATER

• WATER TABLE
• TOP OF ZONE OF SATURATION

• AQUIFERS
• RECHARGED NATURALLY BY PRECIPITATION OR BY

NEARBY LAKES, RIVERS, AND STREAMS

SURFACE WATER

• SURFACE WATER
• SURFACE RUNOFF

• WATERSHED OR DRAINAGE BASIN

WATER USE IS INCREASING

• TWO-THIRDS OF SURFACE RUNOFF LOST TO SEASONAL
FLOODS

• RELIABLE RUNOFF
• REMAINING ONE-THIRD IS RELIABLE SOURCE OF

FRESHWATER

• WORLDWIDE AVERAGES
• IRRIGATION FOR CROPS AND LIVESTOCK: 70%
• INDUSTRIAL USE: 20%
• CITIES AND RESIDENCES: 10%

• WATER FOOTPRINT
• VOLUME OF WATER USED DIRECTLY OR INDIRECTLY

WATER USE IS INCREASING
• VIRTUAL WATER

– WATER USED TO PRODUCE FOOD AND OTHER PRODUCTS

CASE STUDY:
FRESHWATER RESOURCES

IN THE UNITED STATES

• MORE THAN ENOUGH RENEWABLE
FRESHWATER

-UNEVENLY DISTRIBUTED AND
POLLUTED

THE COLORADO RIVER BASIN
• RUNS THROUGH DRY SOUTHWESTERN

U.S.

– 14 MAJOR DAMS

– MOST WATER REMOVED

– ELECTRICITY

– IRRIGATION

– PUBLIC WATER

– 15% OF U.S. FOOD PRODUCTION
AND 13% LIVESTOCK

– FLOW GREATLY DECREASED

– SILTATION

FRESHWATER SHORTAGES WILL GROW

• MANY OF THE WORLD’S MAJOR RIVER SYSTEMS ARE HIGHLY STRESSED
• NILE, JORDAN, YANGTZE, AND GANGES

• MORE THAN 30 COUNTRIES FACE FRESHWATER SCARCITY
• ESTIMATE: 60 COUNTRIES BY 2050

• 30% OF THE EARTH’S LAND AREA EXPERIENCES SEVERE DROUGHT
• RESEARCH PREDICTS THIS WILL WORSEN

GROUNDWATER DEPLETION

• GROUNDWATER WITHDRAWALS UNSUSTAINABLE IN SOME AREAS
• BEING PUMPED FROM AQUIFERS IN SOME AREAS FASTER THAN IT IS RENEWED BY

PRECIPITATION

• WIDESPREAD DRILLING OF WELLS BY FARMERS
• ACCELERATED AQUIFER OVERPUMPING
• WATER TABLES FALLING

• IN 2008, SAUDI ARABIA ANNOUNCED THAT

IT HAD DEPLETED ITS MAJOR DEEP AQUIFER

OVERPUMPING OF THE OGALLALA AQUIFER

• OGALLALA AQUIFER—LARGEST KNOWN
AQUIFER

• IRRIGATES THE GREAT PLAINS

• VERY SLOW RECHARGE

• WATER TABLE DROPPING
• WATER PUMPED 10–40 TIMES FASTER

THAN RECHARGE RATE

• GOVERNMENT FARM SUBSIDIES RESULT
IN FURTHER DEPLETION

• BIODIVERSITY THREATENED IN SOME
AREAS

OVERPUMPING AQUIFERS CAN HAVE HARMFUL
EFFECTS

• LIMITS FOOD PRODUCTION AND RAISES PRICES

• WIDENS GAP BETWEEN RICH AND POOR

• LAND SUBSIDENCE
• SAN JOAQUIN VALLEY IN CALIFORNIA
• MEXICO CITY

• GROUNDWATER OVERDRAFTS NEAR COASTAL REGIONS
• CONTAMINATION OF GROUNDWATER WITH

SALTWATER

DEEP AQUIFERS MIGHT BE TAPPED

• MAY CONTAIN ENOUGH WATER TO
PROVIDE FOR BILLIONS OF PEOPLE FOR
CENTURIES

• MAJOR CONCERNS
• NONRENEWABLE
• LITTLE IS KNOWN ABOUT THE GEOLOGICAL

AND ECOLOGICAL IMPACTS OF PUMPING
DEEP AQUIFERS

• NO INTERNATIONAL TREATIES GOVERN
ACCESS

• COSTS OF TAPPING ARE UNKNOWN
• WATER IS CONTAMINATED

HOW CAN WE INCREASE FRESHWATER SUPPLIES?

• LARGE DAM-AND-RESERVOIR SYSTEMS
• GREATLY EXPANDED WATER SUPPLIES IN SOME

AREAS

• DISRUPTED ECOSYSTEMS AND DISPLACED PEOPLE

• MAIN GOAL OF A DAM AND RESERVOIR SYSTEM
• CAPTURE AND STORE RUNOFF
• RELEASE RUNOFF AS NEEDED FOR:

• FLOOD CONTROL
• GENERATING ELECTRICITY
• SUPPLYING IRRIGATION WATER
• RECREATION (RESERVOIRS)

LARGE DAMS PROVIDE BENEFITS AND CREATE
PROBLEMS

• RESERVOIRS

• INCREASE THE RELIABLE RUNOFF AVAILABLE FOR USE (33%)

• DISPLACE PEOPLE (40-80MILLION)

• IMPAIR ECOLOGICAL SERVICES OF RIVERS (NUTRIENT CYCLING, CLIMATE
MODERATION, WASTE TREATMENT, GROUNDWATER RECHARGE, HABITAT)

• ENDANGER PLANT AND ANIMAL SPECIES (1 OUT OF 5 SPECIES)
• FILL UP WITH SEDIMENT WITHIN 50 YEARS
• GLACIERS FEEDING THE RIVERS ARE MELTING FAST

WATER TRANSFERS

• TRANSFERRING WATER FROM ONE PLACE TO ANOTHER HAS
GREATLY INCREASED WATER SUPPLIES IN SOME AREAS

-HAS ALSO DISRUPTED ECOSYSTEMS

• WATER TRANSFERRED FROM WATER-RICH TO POOR REGIONS
– CANALS AND PIPELINES

– BENEFITS WHERE WATER TRANSFERRED

-WATER LOSS THROUGH EVAPORATION AND LEAKS

– ECOSYSTEMS CHANGE BOTH PLACES

– CALIFORNIA WATER PROJECT

– SACRAMENTO RIVER DEGRADED

– POLLUTION PROBLEMS

CASE STUDY: THE ARAL SEA DISASTER

• LARGE-SCALE WATER TRANSFERS IN DRY CENTRAL ASIA HAVE LED TO:
• WETLAND DESTRUCTION

• DESERTIFICATION
• GREATLY INCREASED SALINITY
• FISH EXTINCTIONS AND DECLINE OF FISHING
• BLOWING SALT AND DUST DESTROYING WILDLIFE AND CROPS
• INCREASED GLACIAL MELTING IN THE HIMALAYAS

CASE STUDY: THE ARAL SEA DISASTER

• SHRINKAGE OF THE ARAL SEA HAS ALTERED LOCAL
CLIMATE

• HOT, DRY SUMMERS, COLDER WINTERS, AND A
SHORTENED GROWING SEASON

• RESTORATION EFFORTS
• COOPERATION OF NEIGHBORING COUNTRIES
• MORE EFFICIENT IRRIGATION
• DIKE CONSTRUCTION RAISED LEVEL OF

NORTHERN SEA BY 2 METERS

• SOUTHERN SEA MAY DRY UP WITHIN FEW
YEARS

DESALINATING SEAWATER

OCEAN WATER ABUNDANT

– REMOVAL OF SALT = FRESHWATER

– DISTILLATION OR REVERSE OSMOSIS

– CURRENTLY <1% OF FRESHWATER FOR THE WORLD AND U.S.

– PROBLEMS

– VERY EXPENSIVE

– HIGH ENERGY USE

– DISPOSAL OF SALTY WATER

– MOSTLY IN MIDDLE EAST, NORTH AFRICA,

CARIBBEAN, AND MEDITERRANEAN

(18, 400 ACROSS THE WORLD)

CONSERVING WATER

• WAYS TO USE FRESHWATER MORE SUSTAINABLY
– 66% OF WATER WASTED

– RAISE WATER PRICES

– SHIFT WATER SUBSIDIES

– INCREASE IRRIGATION EFFICIENCY.

– NIGHT IRRIGATION

– SEVERAL CROPS TOGETHER

– MORE WATER-EFFICIENT CROPS

– IMPORT WATER-DEMANDING CROPS

– USE TREATED WASTEWATER

– CONSERVE WATER IN INDUSTRY

– CONSERVE WATER IN HOMES

WHAT WOULD YOU DO?

• WAYS TO REDUCE WATER USE

– SHORT SHOWERS

– WASH FULL LAUNDRY LOADS

– DRIP IRRIGATION

– FIX LEAKS

– WATER SAVING DEVICES

– DON’T RUN WATER WHEN NOT USING

– REDUCE MEAT AND WATER RICH FOOD CONSUMPTION

– REPLACE LAWNS WITH LOW-WATER PLANTS

– WASH CAR BY HAND

ATMOSPHERE AND
AIR POLLUTION

Lecture 15

WHY IS THE
ATMOSPHERE SO
IMPORTANT?

WHAT IS THE NATURE OF THE
ATMOSPHERE?

Atmosphere: Thin layers of gases surrounding the
earth

Layers defined largely by differences in
temperature

Innermost layers of the atmosphere:
­ Troposphere
­ Supports life

­ Stratosphere
­ Contains the protective ozone layer

THE ATMOSPHERE CONSISTS OF SEVERAL LAYERS

Density and pressure play major roles in weather

Density
• Number of gas molecules per unit of air volume
• Decreases with higher altitude

Atmospheric pressure
• Measure of the weight of molecules above you (Force per unit area of a column of air)
• Decreases with higher altitude

AIR MOVEMENT AND CHEMICALS IN THE TROPOSPHERE
AFFECT THE EARTH’S WEATHER AND CLIMATE

Troposphere
­ 75–80% of the earth’s air mass
­ Closest to the earth’s surface

Two primary gas types
­ Permanent

­ Oxygen and Nitrogen

­ Variable
­ Water Vapor
­ Carbon Dioxide

Permanent gases make up over 95% of
total atmosphere

THE STRATOSPHERE IS OUR GLOBAL SUNSCREEN
Stratosphere: 17–48 kilometers above the earth’s
surface
­ Similar composition to troposphere except:
­ Higher concentration of ozone (O3)

Ozone layer
­ Filters 95% of harmful UV radiation
­ Allows life to exist on land

WATER H2O,
THE MOST IMPORTANT VARIABLE GAS

0-4% in atmosphere

Varies with temperature and location

Greenhouse Gas (GHG)

Only GHG which absorbs both incoming
and outgoing radiation

CARBON DIOXIDE CO2
0.04% concentration

Seasonably Variable

GHG

Natural and Human produced

Absorbs outgoing radiation

WHAT IS THE GREENHOUSE EFFECT AND HOW
DOES IT WORK?

GREENHOUSE EFFECT

Natural process which enables life
on Earth

Earth thermal radiation held in by
greenhouse gases

Atmospheric blanket

AIR POLLUTION COMES FROM
NATURAL AND HUMAN SOURCES

Natural sources
­ Wind-blown dust
­ Pollutants from wildfires or volcanic

eruptions
­ Volatile organics released by plants

Human sources
­ Mostly in industrialized and urban areas
­ Stationary sources
­ Power plants and industrial facilities

­ Mobile sources
­ Motor vehicles

AIR POLLUTANTS

Air pollution–presence of chemicals
in the atmosphere
­ Concentrations high enough to harm

organisms, ecosystems, human-made
materials, or alter climate

Primary pollutants
­ Emitted directly into the air

Secondary pollutants
­ Formed from reactions of primary

pollutants

ATMOSPHERIC
BROWN CLOUDS

Atmospheric brown clouds
­ Particles of dust, smoke, ash, soot
­ Caused by wind erosion, fire
­ Found throughout Asia and the western Pacific

Pollutions travels to remote areas
­ Absorbed into glaciers

MAJOR OUTDOOR AIR
POLLUTANTS

Carbon oxides
­ Carbon monoxide (CO) and carbon

dioxide (CO2)
­ Some sources of CO are cars, burning

forests and grasslands, and fossil fuel
burning power plants
­ Some sources of CO2 include natural

carbon cycle and burning of fossil fuels

MAJOR OUTDOOR AIR
POLLUTANTS

Nitrogen oxides and nitric acid
­ Nitrogen dioxide (NO2 ) reacts with

water vapor in atmosphere to form nitric
acid and nitrate salts, part of acid
deposition
­ Some sources are fertilizer and burning

of fossil fuels
­ NO and NO2 play a role in the

formation of photochemical smog, a
mixture of chemicals formed under the
influence of sunlight in cities with heavy
traffic.
­ Nitric acid HNO3 , secondary pollutant

and a major component of acid rain.

MAJOR OUTDOOR AIR
POLLUTANTS

Sulfur dioxide and sulfuric acid
­ One-third of sulfur dioxide and sulfuric acid are from

natural sources, such as volcanoes
­ Other sources include combustion of coal and oil

refining
­ Reduce visibility and aggravate breathing problems,

damage crops, corrode metals, and damage stone

MAJOR OUTDOOR AIR
POLLUTANTS

Particulates
­ Suspended particulate matter (SPM)–

variety of solid particles and liquid
droplets that are small and light
enough to remain suspended in the air
for long periods
­ About 62% of the SPM in outdoor air

comes from natural sources such as
dust, wildfires, and sea salt
­ The other 38% comes from human

sources, such as coal-burning power
and industrial plants

MAJOR OUTDOOR AIR
POLLUTANTS

Ozone

•One of the major ingredients of
photochemical smog

•Can cause coughing and breathing problems

•Ozone in the troposphere can be harmful at
high enough levels and ozone in the
stratosphere is beneficial because it protects
us from harmful UV radiation

•Human activities have decreased the amount
of beneficial ozone in the stratosphere
and increased the amount of harmful
ground-level ozone

MAJOR OUTDOOR AIR
POLLUTANTS

Volatile organic compounds
(VOCs)
­ Organic compounds that exist as gases

in the atmosphere or that evaporate
from sources on the Earth’s surface into
the atmosphere
­ Example: Methane from rice paddies,

landfills, natural gas wells and
pipelines, and from cows

LEAD: A HIGHLY TOXIC
POLLUTANT

In air, water, soil, plants,
and animals

Does not break down in the
environment

Impacts human health and
environment
­ Children most vulnerable
­ Can cause death, brain damage,

and paralysis

Lead exposure for adults
and children working in e-
waste recycling

BURNING COAL PRODUCE
INDUSTRIAL SMOG

Chemical composition of
industrial smog
­ Sulfur dioxide, sulfuric acid, and

suspended solid particles

Combustion of coal and oil
forms carbon monoxide,
carbon dioxide, and soot

Common in industrialized
urban areas
­ Examples: China, India, Ukraine
­ Beijing air quality among world’s

worst

SUNLIGHT PLUS CARS EQUALS
PHOTOCHEMICAL SMOG

Photochemical smog formed
under the influence of sun’s
UV radiation

VOCs + NOx + heat +
sunlight yields:
­ Ground level O3 and other

photochemical oxidants
­ Aldehydes
­ Other secondary pollutants

SEVERAL FACTORS AFFECT LEVELS
OF OUTDOOR AIR POLLUTION

Natural factors that help
reduce outdoor air pollution
­ Gravity allows particulates to

settle
­ Rain and snow
­ Salty sea spray from the ocean
­ Winds
­ Natural chemical reactions

remove some pollutants

SEVERAL FACTORS AFFECT LEVELS
OF OUTDOOR AIR POLLUTION

Factors that increase outdoor
air pollution
­ Urban buildings
­ Hills and mountains
­ High temperatures
­ VOC emissions from certain trees

and plants
­ The grasshopper effect
­ Temperature inversion
­ Warm air above cool air prevents mixing

ACID DEPOSITION

Human-generated NOx and
SOx in the atmosphere

Wet deposition
­ Acidic rain, snow, fog, or cloud vapor

Dry deposition
­ Acidic particles

Substances remain in the
atmosphere for 2–14 days

HARMFUL EFFECTS OF ACID DEPOSITION

Contributes to respiratory disorders

Releases toxic metals from soils and rocks
­ Bioaccumulation in fish

Lowers pH in aquatic ecosystems

Leaches soil nutrients

Damages forests

Damages statues and buildings

INDOOR AIR POLLUTION IS A SERIOUS PROBLEM
Less-developed countries
­ Indoor burning of wood, charcoal, dung, crop

residues, and coal
­ Greatest risk to low-income populations

More-developed countries
­ Tobacco smoke
­ Formaldehyde
­ Radioactive radon-222 gas

HEALTH EFFECTS OF AIR
POLLUTION

Air pollution can contribute
to
­ Asthma
­ Chronic bronchitis
­ Emphysema
­ Lung cancer
­ Heart attack
­ Stroke

YOUR BODY’S NATURAL AIR POLLUTION
DEFENSES CAN BE OVERWHELMED

125,000 people develop
cancer in the United States
each year from breathing
diesel fumes

14% of the U.S. population
exposed to excessive
particulate pollution levels
daily

LAWS AND REGULATIONS CAN REDUCE OUTDOOR
AIR POLLUTION
United States
­ Clean Air Acts: 1970, 1977, and 1990 created regulations enforced by states and cities

EPA
­ Established air quality standards for six outdoor pollutants
­ Carbon monoxide, nitrogen dioxide, sulfur dioxide, suspended particulate matter, ozone, and lead

LAWS AND REGULATIONS CAN REDUCE OUTDOOR AIR
POLLUTION

EPA’s national emission standards for 188 hazardous air pollutants (HAPs) mostly
includes VOC’s, organic hydrocarbons and toxic metals
­ Toxic Release Inventory (TRI) (1990) requires factories, power plants, mines and chemical manufacturers

to report their release and waste management methods.

New U.S. regulations
­ Limit CO2 emissions from coal-fired power plants

New air quality standards in China
­ Ban on high-sulfur, high-ash-content coal in major cities

2018: Policy changes considered by EPA likely to lead to less healthy air

USING THE MARKETPLACE TO
REDUCE OUTDOOR AIR POLLUTION

Buy and sell air pollution
allotments in the
marketplace
­ 1990 Clean Air Act authorized

emissions trading or cap-and-
trade program
­ Success depends on:
­ How low initial cap is set

­ How often it is lowered

WAYS TO REDUCE OUTDOOR AIR POLLUTION

Technologies used on coal-burning power
plants
­ Electrostatic precipitator
­ Wet scrubber

Motor vehicle pollution
­ Prevention and reduction

REDUCING INDOOR AIR
POLLUTION

Greater threat to human
health than outdoor pollution

What can be done?
­ Prevention
­ Cleanup

THE USE OF CERTAIN CHEMICALS
THREATENS THE OZONE LAYER

Ozone is thinning over
Antarctica and the Arctic

Chlorofluorocarbons (CFCs)
­ Persistent chemicals that attack ozone

in the stratosphere

WHY SHOULD WE WORRY ABOUT OZONE
DEPLETION?

Ozone protects the earth’s surface from
damaging UV radiation
­ Human health concerns
­ UV radiation affects plankton

REVERSING STRATOSPHERIC OZONE DEPLETION

Stop producing ozone-depleting chemicals immediately
­ Will take at least 60 years to recover to 1980 levels

Agreements with a prevention approach
­ Montreal Protocol
­ Cut emissions of CFCs

­ Copenhagen Amendment
­ Accelerated phase-out of CFCs

WATER
POLLUTION

Lecture 16

HUMANS AND MUCH OF LIFE DEPENDS ON WATER

– ABUNDANT BUT FINITE SUPPLY

– CONTINUALLY RECYCLED AND PURIFIED

WATER POLLUTION

– CHANGE IN WATER WITH HARM TO HUMANS OR OTHER
ORGANISMS

MAJOR THREAT TO HUMAN HEALTH

SPREAD OF DISEASE

TOXIC MATERIALS

WHY SHOULD YOU CARE
ABOUT WATER POLLUTION?

THE EARTH’S WATER SUPPLY

WATER COVERS ABOUT 73% EARTH SURFACE

– 0.024% OF TOTAL WATER AVAILABLE

– REMAINDER SALTY, TOO DEEP OR FROZEN

– 30% AVAILABLE FRESHWATER IN AQUIFERS

– HALF WORLD DRINKING WATER

– 25% WATER USED IN U.S.

 WATER NOT EVENLY DISTRIBUTED

MANY DON’T HAVE ACCESS TO ENOUGH

WATER HABITAT FOR MANY ORGANISMS

– AQUATIC LIFE ZONES

– MARINE AQUATIC SYSTEMS

– – FRESHWATER AQUATIC SYSTEMS

 LAYERS OF WATER DIFFERENT PROPERTIES

– UPPER WARMER WITH LIGHT

– MIDDLE SOME LIGHT, COLDER

– DEEPER DARK, COLD

– DISSOLVED OXYGEN

WATER AS HABITAT

MARINE AQUATIC SYSTEMS

LARGEST AQUATIC SYSTEM

 FOUR OCEANS

– PACIFIC (LARGEST)

– ATLANTIC

– ARCTIC

– INDIAN

MARINE ZONES

– COASTAL ZONE

– OPEN SEA

– OCEAN BOTTOM

FRESHWATER AQUATIC
SYSTEMS

TWO TYPES

STANDING BODIES

– LAKES, PONDS

– INLAND WETLANDS

– HIGH BIODIVERSITY

– ABSORB WATER

– MANY FORMED BY GLACIERS

– CLASSIFIED BY AMOUNTS OF
NUTRIENTS

• EUTROPHIC OR OLIGOTROPHIC

FRESHWATER AQUATIC SYSTEMS

FLOWING SYSTEMS

– RIVERS AND STREAMS

– WATERSHED OR DRAINAGE BASIN

– SOURCE ZONE

– TRANSITION ZONE

– FLOODPLAIN ZONE

WHAT ARE THE PROBLEMS?
HUMAN IMPACTS ON NATURAL CYCLES

THREE MAJOR IMPACTS

1. FRESHWATER TAKEN FROM STREAMS, LAKES, AND
AQUIFERS

– OFTEN FASTER THAN REPLACEMENT

2. CLEAR LAND AND MAKE IMPERMEABLE TO WATER

– FASTER RUNOFF

– SLOWER RECHARGE OF AQUIFERS

3. DRAINING AND FILLING WETLANDS

– NATURAL “SPONGES”

– RUNOFF INCREASES

 SUBSTANCES DUMPED INTO WATER
CAN REDUCE USEFULNESS

– DRINKING, FISHING, SWIMMING,
IRRIGATING & OTHER USES OF WATER

POLLUTANT SOURCE

– POINT

– NONPOINT

SOURCES OF
WATER POLLUTION

POLLUTION OF RIVERS LAKES

 HALF OF WORLD’S 500 RIVERS HEAVILY POLLUTED

– UNTREATED SEWAGE

– INDUSTRIAL WASTE

 DEVELOPING COUNTRIES

• CHINA’S RIVERS

-1/2 CAN’T BE USED FOR ANY PURPOSE

• INDIA’S RIVERS

-275 OUT OF 445 SEVERELY POLLUTED

 WATER POLLUTION OFTEN REVERSIBLE

– REMOVE SOURCE OF POLLUTION

– BIODEGRADABLE POLLUTANTS

– NONBIODEGRADABLE

POLLUTION OF LAKES

LAKES AND RESERVOIRS LESS EFFECTIVE AT DILUTING
POLLUTANTS THAN STREAMS

-STRATIFIED LAYERS WITH LITTLE VERTICAL MIXING

-LITTLE OR NO WATER FLOW

-CAN TAKE UP TO 100 YEARS TO FLUSH AND CHANGE
THE WATER IN A LAKE

-BIOLOGICAL MAGNIFICATION OF POLLUTANTS

OCEAN POLLUTION

37% WORLD 40% U.S. LIVE NEAR SEA

– HUMAN IMPACTS ON OCEAN WATERS

– 80-90% LESS DEVELOPED COUNTRIES SEWAGE
DIRECTLY DUMPED

 EXCESS NUTRIENTS

– MICROBES

– OXYGEN-DEMANDING WASTES

– OXYGEN DEPLETED ZONES

OCEAN POLLUTION

 EXCESS NUTRIENTS
– OXYGEN DEPLETED “DEAD” ZONES
– MISSISSIPPI RIVER DISCHARGE

 CORAL REEFS VERY SUSCEPTIBLE
– SLOW GROWTH
– FAIRLY SHALLOW WATER

 OIL POLLUTION
– LARGE AND SMALL SPILLS
– RUNOFF FROM CITIES

 PLASTIC
– GREAT PACIFIC GARBAGE PATCH

GROUNDWATER POLLUTION

MUCH OF WORLD DEPENDS ON
GROUNDWATER

– DRINKING AND IRRIGATION WATER

POLLUTANTS

– FERTILIZERS, PESTICIDES

– GASOLINE, OIL, PAINT THINNERS

– SEPTIC SYSTEMS

– WASTE PONDS

– UNDERGROUND STORAGE TANKS

WHAT CAN BE DONE?
CLEAN-UP VERSUS PREVENTION

TWO WAYS CLEANUP OR PREVENTION

– PREVENTION BETTER

– ONLY 15% OF OIL SPILLS RECOVERED

– DAMAGE BEFORE CLEANUP

– BETTER REGULATIONS

– GROUNDWATER IS PARTICULARLY HARD TO CLEAN UP

LEGAL MEASURES

WATER POLLUTION MAJOR POLITICAL PROBLEM

– U.S. CLEAN WATER ACT

• PERMISSIBLE POLLUTANT LEVELS

– PERCENT WASTEWATER TREATMENT

• INCREASED FROM 33% TO 75%

– SAFE STREAMS INCREASED 33-60%

– NATIONAL AND INTERNATIONAL LAWS

– OIL TANKERS

TECHNOLOGICAL SOLUTIONS

NONPOINT-SOURCE POLLUTION DIFFICULT

– DIFFICULT TO ENFORCE A LAW

• IDENTIFICATION OF RESPONSIBLE PARTY HARD

• LARGE AREA

– LANDSCAPE APPROACH

• KEEP CROPLAND VEGETATED

• FENCE OUT LIVESTOCK

• WISE USE OF FERTILIZERS

TECHNOLOGICAL SOLUTIONS

WASTEWATER OR SEWAGE TREATMENT PLANTS

• PRIMARY SEWAGE TREATMENT
• PHYSICAL PROCESS

• SECONDARY SEWAGE TREATMENT
• BIOLOGICAL PROCESS USING BACTERIA

• TERTIARY OR ADVANCE SEWAGE TREATMENT
• SPECIAL FILTERING PROCESSES

• BLEACHING AND DISINFECTION

ECONOMIC AND POLITICAL SOLUTIONS

LEGAL REQUIREMENTS OFTEN SPUR TECHNOLOGY

– DISCHARGE TRADING POLICY

– PERMITS FOR DISCHARGE INTO WATERWAYS

– ABILITY TO POLLUTE CAN BE SOLD AND TRADED

– CREATES A MARKET

– CAPS LOWERED EVERY FEW YEARS

WHAT WOULD YOU DO?

Mindful of water use

• use only needed
water

• no dumping of
harmful substances

• no yard waste in
stream

Personal choices

• buy from companies
with good policies

• only activities that
minimize pollution

• use manure or
compost, not
fertilizers

Social activity

• talk about water
pollution

• support politicians
with good policies

• emphasize
preventing pollution