AP Environmental Science
Unit Ten
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Pollution: I. Solid Waste &
Hazardous Materials/Chemicals
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Solid and Hazardous Wastes
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Overview
Solid Waste Waste Prevention
Reducing the Amount of Waste Reusing Products Recycling Materials
Hazardous Waste Types of Hazardous Waste Management of Hazardous Waste
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Solid Waste
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Solid Waste
US generates more solid waste per capita than any other country 2.1 kg per person per day
Waste stream- describes the steady production of all waste products that human produce
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Types of Solid Waste
Municipal solid waste Solid material discarded by homes, office
buildings, retail stores, schools, etc. Relatively small portion of solid waste
produced Non-municipal solid waste
Solid waste generated by industry, agriculture, and mining
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Composition of Municipal Solid
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Disposal of Solid Waste
Three methods Sanitary Landfills Incineration Recycling
“open dumps” cheap not compacted not covered dirty, smelly more common in developing countries
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Disposal of Solid Waste
United States Landfilling most common method of disposal
Japan Recycling most common method of disposal
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Sanitary Landfill
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Sanitary Landfill
Considerations for choosing a Landfill local topography and drainage patterns proximity to aquifer recharge zones permeability of underlying rock formations community attitudes
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Sanitary Landfill
Compacting and burying waste under a shallow layer of soil
Most common method of disposal Problems
Methane gas production by microorganisms Contamination of surface water & ground
water by leachate Not a long-term remedy Few new facilities being opened Closing a full landfill is very expensive
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Special Problem: Tires Made from materials
that cannot be recycled Can be incinerated or
shredded
Sanitary Landfill
Special Problem: Plastic Much of plastic is from packaging Chemically stable and do not readily break
down and decompose
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Incineration
Volume of solid waste reduced by 90% Produces heat that can make steam to
generate electricity Produce less carbon emissions than fossil fuel
power plants Byproduct
Bottom ash Fly ash
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Incineration Types of Incinerators
Mass burn (below) Modular Refuse-derived
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Composting
Municipal Solid Waste Composting Includes: Food scraps, Sewage sludge,
Agricultural manure, Yard waste Reduces yard waste in landfills and total
waste volumes Can be sold or distributed to community
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Waste Prevention
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Waste Prevention
Three Goals (the three “R’s”) (1) Reduce the amount of waste (2) Reuse products (3) Recycle materials
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Reducing Waste
Purchase products with less packaging
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Reducing Waste
Source reduction Products designed and manufactured to
decrease the volume of solid waste Pollution Prevention Act (1990) Dematerialization
Progressive decrease in the size and weight of a product as a result of technological improvements
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Reusing Products
Refilling glass beverage bottles Heavier glass that costs more
Japan recycles almost all bottles Reused 20 times
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Recycling Materials
Recycling involves melting or shredding old products to make new products
Every ton of recycled paper saves: 17 trees 7000 gallons of water 4100 kwatt-hrs of energy 3 cubic yards of landfill space
Recycle Glass bottles, newspapers, steel cans, plastic
bottles, cardboard, office paper
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Recycling
Recycling Paper US recycles 50% Many developed
countries are higher
Recycling Glass US recycles 25% Costs less than
new glass (right)
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Recycling Recycling Aluminum
Making new can from recycled one costs far less than making a brand new one
49% of aluminum was recycled in 2007 saves: energy, materials (bauxite ores), land
and it reduces pollutants Recycling Metals other than Aluminum
Lead, gold, iron, steel, silver and zinc Metallic composition is often unknown
Makes recycling difficult
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Recycling
Recycling Plastic 12% of all plastic was
recycled in 2007 Less expensive to make
from raw materials 37% of PET was
recycled in 2007 Mostly water and soda
bottles
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Recycling
Recycling Tires Few products are made from old tires
Playground equipment Trashcans Garden hose Carpet Roofing materials
36% of tires are currently recycled to make other products
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Integrated Waste Management
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Hazardous Waste
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Love Canal Toxic Waste Site
Hazardous Waste Any discarded chemical that threatens
human health or the environment Reactive, Corrosive, Explosive, Mutagenic
(carcinogenic) or Toxic chemicals Types of Hazardous Waste
Dioxins PCBs Radioactive waste
Often measured in ppm parts per million
1 ounce in 1 million ounces
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Hazardous Waste
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Case-In-Point Hanford Nuclear
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Management of Hazardous Waste
Chemical accidents National Response Center notified Typically involves oil, gasoline or other
petroleum spill Current Management Policies
Resource Conservation and Recovery Act (1976, 1984)
Comprehensive Environmental Response, Compensation, and Liability Act (1980) Commonly known as Superfund
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Superfund Program
Cleaning up existing hazardous waste: 400,000 waste sites Leaking chemical
storage tanks and drums (right)
Pesticides dumps Piles of mining
wastes Must be cleaned up
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Management of Hazardous Waste Superfund National Priorities List
2009: 1,264 sites on the list States with the greatest number of sites
New Jersey (114) California (94) Pennsylvania (94) New York (85) Michigan (65)
Race is the strongest determinant of who is exposed to environmental hazards
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Management of Hazardous Waste
Biological Treatment of Hazardous Chemicals Bioremediation - use of bacteria and other
microorganisms to break down hazardous waste into relatively harmless products Time consuming
Phytoremediation - use of plants to absorb and accumulate hazardous materials in the soil Ex: Indian mustard removed heavy metals
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Examples of Phytoremediation
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Management of Hazardous Waste
(1) Source reduction (2) Conversion to less hazardous materials (3) Long-term storage
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Hazardous Waste Landfill
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Pollution: II. Human Health &
Environmental Toxicology
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Human Health and Environmental Toxicology
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Overview
Human Health In developed countries In developing countries
Environmental Pollution and Disease Environmental Contaminants Endocrine Disrupters Pesticides
Determining Health Effects of Pollutants Ecotoxicology Risk Assessment
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Human Health
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Human Health Two indicators of human health
Life expectancy - how long people are expected to live
Infant mortality - how many children die before age of 1 year
Vary greatly between countries
Developed countries Developing countries
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Health in Highly Developed Countries Health is generally good in these countries Average life expectancy
Men = 75 years Women = 80 years
Leading causes of death in US Cardiovascular disease, Cancer, Lung Disease
Premature deaths caused by lifestyle Poor diet, Lack of exercise, Smoking, Obesity
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Health in Developing Countries Biggest problems
Malnutrition, unsafe water, poor sanitation Life Expectancy
Overall is 65 years Very poorest developing countries = 45 years
Due to AIDS epidemics
Childhood mortality is high Diarrheal diseases Malnutrition Malaria AIDS/HIV
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Emerging and Reemerging Diseases Emerging Disease - not previously observed in humans
Usually jumps from animal host Ex: AIDS, lime disease, West Nile Virus
Reemerging Disease - existed in the past and are recently increasing in incidence Ex: tuberculosis, yellow fever, malaria
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Reasons for Emergence/Reemergence Evolution of disease so it transitions to human
host Evolution of antibiotic resistance in disease Urbanization and overcrowding Increased pop. of elderly - susceptible to disease Pollution and environmental degradation Growth in international travel and commerce Poverty and social inequality
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Environmental Pollution and
Disease
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Environmental Pollution and Disease Pathways of
Pollution Often difficult to
link pollutants to their effects on people Persistence Bioaccumulation
& magnification
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Persistence
A characteristic of certain chemicals that are extremely stable and may take many years to be broken down into simpler forms by natural processes Synthetic chemicals (those not found in
nature) Ex: DDT
Natural decomposers (bacteria) have not evolved a way to break it down
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Bioaccumulation
The buildup of a persistent toxic substance in an organism’s body, often in fatty tissues Synthetic chemical do not metabolize well They remain in the body for extended periods
of time
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Biomagnification The increased
concentration of toxic chemicals in the tissues of organisms that are at higher levels in food webs
Diagram (right) is example of biomagnification of DDT
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Endocrine Disrupters A chemical that mimics, interferes with or
disrupts the normal hormone functions in humans and wildlife Hormones-chemical messengers
Examples include: PCBs, Dioxins Heavy metals - lead and mercury DDT
Animals exposed to these chemicals have altered reproductive development and are often sterile
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Endocrine Disrupters Case Study: 1980 chemical spill into Lake
Apopka, FL Male alligators began to exhibit low
testosterone levels and high estrogen levels
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Endocrine Disrupters and Humans Infertility and hormonally related cancers
are increasing Breast cancer and testicular cancer
Phthalates have been implicated as potential endocrine disrupters Common ingredient in: cosmetics, fragrances,
nail polish, medication, toys, food packaging
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Cancer Cancer- uncontrolled cell growth
benign tumor-mass of cells not life threatening
malignant tumor-mass of cells that impede the functions of other cells (life threatening)
Mutagens compounds that cause mutations in DNA
Carcinogens compounds that cause mutations that lead to
cancer Not all mutagens are carcinogens but all
carcinogens are mutagensFriday, March 18, 2011
Pesticides
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What is a Pesticide Broad spectrum pesticide
A pesticide that kills a variety of organisms, not just the targeted organisms
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First generation pesticide Inorganic compounds (minerals)
lead, mercury, arsenic not used much today because they are
highly toxic and remain in soil for a long time
Botanicals (organic): plant derived pesticides nicotine, rototene, pyrethrin (from
chrysanthemum flowers seen on previous slide)
highly toxic BUT biodegradable and they will not persist in soil for long
What is a Pesticide
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What is a Pesticide
Second generation pesticide Synthetic organic poisons 20,000+ are registered currently Ex: DDT
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Major Groups of Insecticides Largest group of pesticides are insecticides
Chlorinated Hydrocarbons (example: DDT) Organic compound containing Chlorine Slow to degrade and persist in the environment Banned or largely restricted low toxicity towards humans
Organophosphates Cabamates
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Major Groups of Insecticides Organophosphates
Organic compounds that contain phosphorus Most poisonous insecticide Do not persist as long as chlorinated hydrocarbons
(low persistence explained shortly) low bioaccumulation also explained shortly
Cabamates Broad spectrum; derived from cabamic acid Do not persist as long as chlorinated hydrocarbons
(low persistence explained shortly) low bioaccumulation also explained shortly
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Problems with Pesticides
Evolution of Genetic Resistance Pest populations
are evolving resistance to pesticides (right)
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Pesticide Resistance
Pesticide Treadmill Cost of applying pesticide increases While their effectiveness decreases
Resistance Management Strategies for managing genetic resistance in
order to maximize the period in which a pesticide is useful
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Problems with Pesticides Imbalances the
Ecosystem Spraying to kill
insects can affect birds, rabbits, etc.
Despite 33-fold increase in pesticides since the 1940s, crop loss has not decreased much
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Problems with Pesticides Creation of New Pests
Infestation of red scale insects on lemons after DDT sprayed to control another pest
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Problems with Pesticides
Persistence, Bioaccumulation Biological Magnification
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Problems with Pesticides
Persistence - trait of certain chemicals that are stable and take a long time to be biodegraded can cycle through environment for years
Bioaccumulation - The buildup of a persistent pesticide or other toxic substance in an organism’s body cells selectively absorb and store molecules
Biological magnification - Increased concentration of toxic chemicals in tissues of organisms at higher trophic levels in food webs
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Problems with Pesticides
Mobility in the Environment Do not stay where they are applied
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Mild: nausea, vomiting, headaches
Severe: damage to nervous system,
Risk of Pesticides to Human Health Short-term Effects of Pesticides
Handling food with pesticide residue
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Risk of Pesticides to Human Health Long-term Effects of Pesticides
Cancer - lymphoma Breast cancer Sterility Miscarriage Birth defects Decreases body’s ability to fight infection Potential connection to Parkinson’s disease
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Reducing Pesticides in Your Life Reducing pesticides residues in your diet
peel fruits & veggies when possible cook foods that you believe have residue buy organic wash fruits & veggies before eating
Reducing pesticide exposure use other insects like lady bugs to protect
your garden plants wash aphid infested veggies with water accept slightly blemished fruits & veggies keep wood piles away from the house
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Laws Controlling Pesticide Use
Food, Drug, and Cosmetics Act (1938) Pesticide Chemicals Amendment (1954) Delaney Cause (1958) Federal Insecticide, Fungicide, and
Rodenticide Act (1947, updated most recently in 2008)
Food Quality Protection Act (1996)
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Toxicology
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Determining Health Effects of Pollutants Toxicology is the study of the effect of
toxicants on the human body Toxicant - chemical with adverse human
health effects Nearly anything can be toxic at some level! example caffeine
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Determining Health Effects of Pollutants Toxicity measured by dose and response
Dose: amount that enters that body of an exposed organism
Response: the amount of damage caused by a specific dose
Detection of Toxic Chemicals depends on sensitivity of measuring
techniques how much/many chemicals are present
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Toxicology
Acute toxicity Adverse effects occur within a short period
after exposure to toxin Chronic toxicity
Adverse effects occur some time after exposure, or after prolonged exposure to toxin
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Toxicity
LD50 Lethal dose to
50% of the test organisms
Smaller the LD50, the more lethal the chemical
Determined for all new synthetic chemicals
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Toxicity
ED50 Effective dose to 50% of the test organisms ED50 causes 50% of the population to exhibit
whatever effect is under study Dose-Response Curve
Illustrates the effect of different doses on a population
Threshold Level Maximum dose with no measurable effects
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Toxicity: ED50
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Toxicity: Dose Response Curve
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Children and Chemical Exposure Children more susceptible to chemicals
Weigh less than adults Bodies are still developing Play on floors and lawns Put things into their mouths
Diagram (right) Children in foothills not exposed to pesticides Children in valley were exposed
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Identifying Cancer Causing Substances Toxicologist
Dose rats with varying levels of chemicals to see if they develop cancer
Difficult to extrapolate results to humans Epidemiologists
Look at historical exposure of groups of humans
See if exposed group have increased cancer rate
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Review Cancer Cancer- uncontrolled cell growth Mutagens
compounds that cause mutations in DNA Carcinogens
compounds that cause mutations that lead to cancer Not all mutagens are carcinogens but all
carcinogens are mutagens
Cancer is a chronic effect of pesticides on humans
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Chemical Mixtures Most studies look at one chemical, but
humans tend to be exposed to chemical mixtures Ex: automobile exhaust
Chemical Mixtures interact by Additivity-expected interaction 1=1=2 Synergy-greater than expected 1+1=3 Antagonism-less than expected 1+1=1.5
These studies are expensive and take a while to complete
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Ecotoxicology Dilution Paradigm is not valid
“Dilution is the solution to pollution” Boomerang Paradigm is accepted
“What you throw away can come back and hurt you”
Ecotoxicology The study of contaminants in the biosphere
and their harmful effects on ecosystems Helps policy makers determine costs and
benefits of industrial and technological “advances”
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Case Study: The Ocean
Land based nutrient and pollution runoff into ocean is affecting microorganisms
Ex: Red Tide Red pigmented
poisonous algal blooms Toxins kill off fish and
make humans sick
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Risk Assessment Risk- probability that a particular adverse
effect will result from some exposure or condition
We assess risk daily with four steps Hazard identification Dose response assessment Exposure assessment Risk characterization
As a society we tend to focus money and attention on health risks that most well publicized and scary
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Risk Assessment
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Risk Assessment
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Ecological Risk Assessment
Difficult to assess because effect occur at wide range of scales Individual plants and animals Ecological communities over wide regions
Human-induced environmental stressors also range greatly
There is a need to quantify risks to the environment
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