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Chapter 18
Environmental Issues
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Environmental Issues
• Environmental health: the area of health
concerns that focuses on the interactions of
humans with all aspects of their environment
– Diseases associated with contaminated water,
food, waste, and other pollutants
– Pollutants that result from human and industrial
activities and that cause chronic diseases and
global environmental damage
– Climate change, the depletion of resources, and
world overpopulation
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Water and Water Quality
• Water cycle: natural process by which the
earth’s supply of water is continuously
collected, purified, and distributed
• Surface water: precipitation stored in lakes,
reservoirs, and wetlands on the surface of
the earth
• Groundwater: precipitation that sinks into
the ground and makes up 95% of the
world’s supply of freshwater
• Deep aquifers: giant underground reservoirs
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Water Supplies and
Shortages
• In U.S. and Canada water supplies
abundant but much of it is contaminated
• Withdrawal rates of surface water projected
to double in the next 20 years
• Conflicts between regions and states over
water supplies
• Main cause of water waste is artificially low
cost of water
– Government subsidies to agriculture and industry
lead to limited financial incentive to invest in
water-saving technologies
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Water Supplies and
Shortages
• Consumers and businesses need to use
water-saving technologies
• Farmers and the agricultural industry need
to develop ways to irrigate crops more
efficiently
• Government and policy makers must
manage water basins and groundwater fairly
and effectively
• Failure to address our water-related
problems will lead to economic and health
problems, increased environmental
degradation, and loss of biodiversity
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Virtual Water
• Virtual water: water used to produce foods,
consumer products, and other services
– One hamburger = 640 gallons of water
• The amount of water needed to produce a
give amount of a product is its water
footprint
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Water Footprint for Food
Production
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Water Pollution
• Any chemical, biological, or physical change
in water quality that harms living organisms
or makes water unsuitable for desired use
• Most surface-water reservoirs are
contaminated by pollutants at specific
locations through sewers, pipes, or ditches
• Main sources of groundwater contamination:
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Storage lagoons
Septic tanks
Landfills and hazardous waste dumps
Underground storage tanks filled with gasoline,
oil, solvents, and hazardous waste
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Safe Drinking Water
• The Safe Drinking Water Act (1974)
established many health standards for
drinking water
• 98% of Americans have plumbing where
lead can leach into tap water as pipes and
fixtures deteriorate over time
– Cold water from the tap is less likely to contain
lead from supply pipes
– Run water after being away to flush out potential
contamination
• Many benefits to water fluoridation, but
excessive fluoride consumption can lead to
fluorosis
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Conserving Water
• Americans use three times the water per
capita of the average worldwide
– 70% used for washing and carrying away waste
• There are many ways to use less water:
– Bathroom: shorter showers, turn off faucet when
brushing teeth; low-flow toilet; water-saving
showerheads
– Laundry: wash only when full load; buy only
Energy Star appliances
– Kitchen: run dishwasher only with full load; do not
run water continuously when doing dishes by
hand
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Earth’s Atmosphere
• Troposphere: lower atmosphere, containing
about 80% of the earth’s air
• Stratosphere: upper atmosphere, 11 to 30
miles above the earth’s surface
• Greenhouse effect: warming of the earth’s
surface by heat trapped by gases in the
lower atmosphere
– Greenhouse gases: carbon dioxide, water vapor
• Ozone in the upper atmosphere shields us
from about 95% of the sun’s UV rays
– Protective in upper atmosphere, but at ground
level it is a main source of air pollution
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Air Pollution
• Air pollution: the presence of one or more
chemicals in the atmosphere in sufficient
quality and quantity to cause harm to life
• Air Quality Index (AQI): measure of air
pollution issued daily by the EPA
• 100 or higher, air is considered unhealthy for
sensitive groups, such as people with asthma
• 300 or higher, air is considered hazardous
• The EPA charts four pollutants: ozone,
particle pollution, carbon monoxide, and
sulfur dioxide
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Air Quality Index
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Ozone and
Particulate Matter
• Ozone is poisonous to most living organisms
– Ground-level ozone causes respiratory irritation,
aggravates respiratory and heart disease, and
damages the lungs, especially in those with
respiratory problems
• Particulate matter consists of particles or
droplets of dust, soot, oil, metals, or other
compounds suspended in the air
– Small particles may remain in the lungs and irritate
and damage alveoli; and may also trigger an
immune system response that contributes to heart
disease and lung disease
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Smog
• Smog: mixture of pollutants in the lower
atmosphere that makes the air hazy
– Industrial smog: air pollution that forms mostly in
cold weather
• Coal and oil burning
– Photochemical smog: sits as a thick haze over
cities in the summer
• Vehicle exhaust, industry, and other sources
combine, producing large amounts of ozone and
more than 100 other chemicals
• Fossil fuels: oil, coal, natural gas
• Problems amplified by temperature inversion
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Acid Deposition and
Precipitation
• Acid deposition: the depositing of acidic
pollutants from the atmosphere on the
earth’s surface, in either dry or wet form
• Acid precipitation: mixing of acidic pollutants
in the atmosphere with moisture and their
precipitation in the form of rain, snow, sleet,
hail, or fog
• Environmental damage depends on the
ability of the soil to neutralize acid
• Less damage where soils are alkaline—Midwest
• Extensive damage where soils are neutral or acidic
—northwestern U.S., northeastern North America
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Reducing Outdoor Air
Pollution
• Clean Air Act (1990) empowered the EPA to
set emission standards
– Improved air quality
• Clear Skies Initiative (2002) set mandatory
caps to reduce emissions of sulfur dioxide,
nitrogen oxide, and mercury
• A new car today emits 75% less pollution
than cars built in 1970
• 57% of Americans still live in areas where
the air is considered unhealthy at some time
of the year
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Global Warming and
Climate Change
• Climate change is the long-term changes in
average daily weather that occurs over
many years
– Substantial evidence of earth’s warming; debate
over whether it’s natural or human-caused
• Human activities have increased the amount
of greenhouse gases in our atmosphere
• As a result, global temperatures have risen
– Melting glaciers and polar ice caps; rising sea
levels
• Intensification of greenhouse effect has led
to global warming
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The Greenhouse Effect
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Greenhouse Gases from Food
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What Needs to Be Done?
• Kyoto Protocol (1997), not ratified by Congress
• 2009 Copenhagen Accord: produced a
nonbinding pledge to reduce greenhouse gas
emissions
• 2013 world’s top scientist endorsed a cap on
greenhouse gases
– Scientists now worried about feedback loops and
that delaying prevention efforts could be devastating
• Substantial reductions will require massive
changes in industrial processes, transportation,
energy sources, and personal lifestyles
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21
Predicted Effects of Climate
Change
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Your Carbon Footprint
• Every time you use fossil fuels you
contribute to carbon dioxide emissions
– Driving a car, turning on a light, running a
dishwasher
• The more CO2 you generate, the larger
your carbon footprint
www.nature.org/greenliving/carboncalculator/index.htm
www.epa.gov/climatechange/ghemissions/ind_calculator.html
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Walk more; drive less
Consume less electricity
Recycle
Eat less or no meat
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Indoor Air Pollution
• Indoor air pollution can be higher and more
hazardous than outdoor air pollution; yet we
spend 80–90% of our time indoors
• Eleven of the most common air pollutants are
usually 2 to 5 times higher inside the home
• Environmental tobacco smoke, formaldehyde,
radon, carbon monoxide, mold, polybrominated
diphenyl ethers (PBDEs)
• Also dust mites, animal dander, mildew
• Reduce many pollutants by keeping the
house, pets, and bedding clean; maintaining
30–50% humidity; and removing shoes
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Solid Waste
• Any unwanted or discarded material that is
not a liquid or gas; garbage
– 1,600 pounds per person per year in U.S.
– E-waste is the fastest growing problem; the U.S.
sends most to Afghanistan and Haiti for disposal
and recycling
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Hazardous Waste
• Any discarded solid or liquid material that
meets one or more of four criteria:
– Contains a toxic, carcinogenic, or mutagenic
compound at levels that exceed EPA standards
– Catches fire easily
– Can explode or release toxic fumes
– Corrodes metal containers
• Direct exposure poses health hazards
• Federal laws restrict the storage of
hazardous waste in sanitary landfills
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Hazardous Waste
• Common forms:
– Household hazardous waste: batteries, paints,
household cleaners, oils, pesticides
– Emergent contaminants: pharmaceuticals,
cosmetics, antibacterial soap, shampoo, shaving
cream, dishwashing liquids, plastic, flame
retardants, and other chemical compounds
– Medical waste: any solid or liquid waste that is
generated in the medical diagnosis, treatment, or
immunization of human beings or animals
– Radiation and radioactive waste: low-level
radiation used in medical and dental procedures;
high-level radioactive waste from nuclear weapons
and power plants
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Approaches to Waste
Management
• Sanitary landfills are carefully selected sites
where waste is buried in plastic-lined pits
• Incinerators burn waste and sometimes sell the
energy generated by the burning
• “Not in my backyard”
• Living near a hazardous waste dump increases
risk for respiratory disorders and cancer
• Recycling: circle, or loop, program; materials
collected, sorted, cleaned, and processed into
raw materials to make new products
• Many communities provide curbside pickup; and
many states have deposit/refund programs
• Individuals can also buy recyclable, reusable, or
compostable materials
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Recycling Plastic
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Ecosystems and
Biodiversity
• Ecosystem: an interconnected community
of organisms living together as a balanced,
mutually supportive system
• Biodiversity: variety of different animal and
plant species on earth and the genetic
variation in their gene pools
• Human activities significantly disrupt these
ecosystems and have caused a decline in
biodiversity through:
– Deforestation
– Desertification
– Loss of freshwater resources
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Protecting Ecosystems
• Stringent federal and state protection of
animal and plant habitats in forest, deserts,
and wetlands is a component of sustainable
land management programs
– Protecting endangered species; controlling
climate change
• Individuals can help:
– Reusing and recycling paper products
– Refusing the buy products or materials made from
endangered or threatened species
– Purchasing wood with the Good Wood Seal
– Stopping junk mail
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Energy Resources
• World energy consumption continues to rise
• World’s largest consumers:
1. China
2. United States
3. India
• Nonrenewable energy provides 93% of the
commercial energy used in the U.S.
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Energy Resources
• Crude oil: U.S. reserves will be depleted
by 2100
• Coal: largest domestic source for heat and
electricity; dirtiest of all fossil fuels
• Natural gas: a mixture of gases, mostly
methane; costly to extract
– Could meet U.S. energy demands for about 82 to
118 years
– Fracking: environmental and health costs
unknown
• Nuclear power: problems with storing
nuclear waste, and concerns about safety
– Three Mile Island (1979); Chernobyl (1986);
Fukushima (2011)
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Solar Energy, Liquid Biofuels,
and Energy Conservation
• Solar energy: could meet 25% of consumer
demand by 2050
• Wind, geothermal, and hydro power also
being explored
• Biofuels—biodiesel and bioethanol—made
from plants and other biological material
– Problems include increased forest clearing and soil
erosion, use of water, loss of biodiversity
• Environmentalists believe the solution is to
conserve
– Reduce ecological effects, diminish energy waste;
shift to renewable, nonpolluting energy sources
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Your Electronic Footprint
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Population Growth
• How many people can the planet support?
• Global carrying capacity is estimated at 50
billion people
• Cultural carrying capacity—the number the
earth can support at an optimum standard of
living—is much less
• As it stands today, there are probably not
enough resources to extend an optimum
standard of living to everyone on planet right
now
– Currently about 1.4 billion people are living in
extreme poverty
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Approaches to Population
Control and Management
• Family planning: informed decisions about
the number and spacing of children
– Programs provide information on birth control,
birth spacing, breastfeeding, and prenatal care
– Could have a significant effect if implemented in
developing countries
• Smart growth: concentrates growth in
compact urban centers and environmentally
sustainable communities
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A Sustainable Planet
• An ecological footprint compares human
consumption of resources with the planet’s
capacity to regenerate them
– Can reveal how sustainable a particular lifestyle is
– Can point out inequities of resource use and
consumption
• The ecological footprint of the United States
is the largest in the world
– Consume more resources, generate more
pollution, and discard more waste
• Each of us can take actions today to reduce
that footprint
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