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:– 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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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 footprintwww.nature.org/greenliving/carboncalculator/index.htm

www.epa.gov/climatechange/ghemissions/ind_calculator.html

– 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);

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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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