AP Environmental Science Study Guide Units 1-4
The Living World - Ecosystem Structure
Abiotic Components: Nonliving components of Earth (e.g., atmosphere, hydrosphere, lithosphere).
Biotic Components: Living components of Earth (e.g., animals, plants, fungi, protists, bacteria).
Biosphere: Formed by the biotic components.
Population: A group of organisms of the same species.
Community: Populations of different species in the same geographic area.
Habitat: The area or environment where an organism lives.
Ecological Niche: The role and position of a species, including how it uses resources, where it lives, and what it eats.
Interactions of Organisms
Competition: When individuals compete for resources.
Resource Partitioning: Species coexist by sharing resources without conflict.
Predation: One species feeds on another, driving population size changes (e.g., cat & mouse, polar bear & seals).
Symbiotic Relationships
Symbiotic Relationships: Close, prolonged associations between different species.
Mutualism: Both organisms benefit (e.g., pollinators and plants).
Commensalism: One organism benefits, the other is neither harmed nor benefits (e.g., barnacles on scallop shells).
Parasitism: One organism benefits by harming the other (e.g., mistletoe on a tree).
Types of Ecosystems
Blending: Biomes blend into each other with no distinct boundaries.
Ecotones: Transitional areas where two biomes meet.
Ecozones/Ecoregions: Small regions within ecosystems with similar physical features.
Edge Effects: Ecotones have high species diversity and biological density; some species only live on the edge of certain habitats.
Energy Flow
Cell Respiration: Autotrophs make ATP (adenosine triphosphate) from carbohydrates.
Bioenergetics: The study of energy flow through living organisms.
All energy on Earth comes from the Sun.
Photosynthetic organisms convert and into carbohydrates, releasing .
Biological macromolecules store energy in chemical bonds.
Cells use respiration to transfer energy from macromolecules to ATP, GTP, NADH, NADPH and FADH2, releasing and .
High-energy molecules power cellular reactions.
Photosynthesis: Plants and algae convert solar energy into chemical energy, primarily in leaves.
Light-Dependent Reactions:
Purpose: Convert light energy to chemical energy.
Reactants: Sunlight +
Products: + ATP + NADPH
Light-Independent Reactions:
Purpose: Use ATP and NADPH to build organic molecules from .
Reactants: + ATP + NADPH
Product:
Cellular Respiration: All living organisms require a source of energy and use the same metabolic pathways. Glucose is oxidized to , powering ATP synthesis.
Classifying Organisms in Ecosystems
Autotrophs: Produce complex organic compounds from simple substances.
Photoautotrophs use energy from light.
Some use inorganic chemical reactions.
Serve as primary producers (e.g., producers, saprotrophs).
Heterotrophs: Consume other organisms.
Depend on autotrophs for nutrients and food energy.
Examples: primary consumers, secondary consumers, tertiary consumers, decomposers, detritivores.
Food Chains & Food Webs
Food Chain: Shows step-by-step energy flow from producers to consumers (e.g., rice → humans → microorganisms).
Energy Pyramid: Shows energy available at each trophic level.
Food Webs: Show complex interactions between many species.
Ecosystem Diversity
Ecosystem Diversity: Variability within a geographical location.
Biodiversity: Number and variety of organisms.
Result of evolution.
More biodiversity means a larger gene pool, leading to greater adaptation and survival.
Evolution
Evolution: Change in a population’s genetic composition over time.
Natural Selection: Advantageous traits change population makeup.
Charles Darwin's Theory: Beneficial traits are passed down, unfavorable traits become less common.
Acts on a whole population over time.
Genetic Drift: Chance events change population makeup, regardless of traits.
Phylogenetic Tree: Diagram showing evolutionary relationships.
Species: Group of organisms capable of breeding with each other.
Speciation: Formation of new species from preexisting species.
Extinction: Species cannot adapt quickly enough to environmental change.
Biological Extinction: Extermination of a species (e.g., Dodo birds).
Ecological Extinction: Species cannot perform its ecological function (e.g., Alligators in Everglades in 1960).
Commercial or Economic Extinction: Effort to harvest species is not worth the expense (e.g., Groundfish population of the Grand Banks).
Ecosystem Services
Ecosystem Services: Benefits humans gain from the natural environment.
Provisioning Services: Physical items (e.g., food, raw materials, water, energy, medicinal resources).
Cultural Services: Non-material benefits (e.g., recreation, science & education, tourism, inspiration, spiritual experience).
Regulating Services: Benefits from regulating ecosystems (e.g., pest & disease control, water & air purification, climate regulation, waste decomposition, pollination).
Support Services: Allow other ecosystem services to be present (e.g., nutrient recycling, soil formation).
Natural Ecosystem Change
Keystone Species: Maintain biotic balance; extinction leads to large ecosystem changes (e.g., Fig trees, Wolves).
Indicator Species: Evaluate ecosystem health; early warning system (e.g., Trout).
Ecological Succession:
Primary Succession: Begins in lifeless area (e.g., area below retreating glacier).
Secondary Succession: Occurs where a community has been cleared, but soil remains intact.
Pioneer Species: First organisms in succession with wide environmental tolerance.
Climax Community: Dynamic balance between abiotic and biotic components.
Habitat Fragmentation: Natural habitat is reduced or fragmented.
Unit 3: Populations
Population Ecology:
Population Density: Number of individuals per unit area.
Population Dispersion: How individuals are spaced.
Clumped Dispersion: Most common, “birds of a feather” (e.g., plants, fish).
Uniform Dispersion: Uniform spacing due to competition (e.g., trees).
Random Dispersion: Uncommon, position not influenced by others.
Population Growth & Carrying Capacity:
Biotic Potential: Population growth with unlimited resources (impractical).
Carrying Capacity: Maximum population size supported by resources.
Graphing Population Growth:
J-Curve Model: Exponential growth.
Logistic Population Growth (S-Curve): Initial burst, then growth rate drops.
Rule of 70: Time to double population ≈ 70 / growth rate.
years.
Reproductive Strategies:
R-Selected Organisms: Reproduce early, high capacity for growth, little care for offspring (e.g., bacteria, algae).
K-Selected Organisms: Reproduce later, fewer offspring, significant nurturing (e.g., humans, lions).
Survivorship and Population Cycles:
Boom-and-Bust Cycle: Rapid increase → rapid drop-off (common in r-strategists).
Predator-Prey Cycle.
Factors Influencing Population Growth:
Density-Dependent Factors: Increased predation, competition, disease, toxic buildup.
Density-Independent Factors: Fires, storms, earthquakes.
Survivorship Curve:
Type I: Most offspring live long, then die off.
Type II: 50-50 chance of survival to old age.
Type III: Most offspring die young, but those that survive live longer.
Human Population
World Population:
Birth Rate: Live births per 1,000 members per year.
Death Rate: Deaths per 1,000 members.
Growth Rate:
Population Changes:
Emigration: Movement out of a population.
Immigration: Movement into a population.
Total Fertility Rate (TFR): Number of children a woman will bear based on past data.
Replacement Birth Rate: Number of children to replace parents (≈ 2.1 worldwide;
3.4 in developing countries).
Factors Affecting TFR: Birth control, labor force demand, education for women, retirement systems, religious beliefs.
Factors Affecting Growth Rate: Education for women, religion, retirement systems.
Human Impact on Earth
Ecological Footprint: Environmental impact of a population.
IPAT Model:
I = Total Impact
P = Population Size
A = Affluence
T = Level of Technology
Environmental Problems:
Overgrazing & Desertification:
Green Revolution: Increased crop production via technology, pesticides, and fertilizers.
Extensive Pastoralism: Shifting animal herds between pastures.
Population Pressure: Too many people/animals on too little land.
Overgrazing: Leads to denuded, eroded, desertified grasslands.
Desertification: Human process turning vegetated land into desert.
Soil Salinization: Increased salt content in soil.
Irrigation Agriculture:
Irrigation: Controlled water application to plants.
Aquifers: Underground water tables being depleted rapidly.
Deforestation: Clearing forests without replanting.
Threatened & Endangered Species
Vulnerable Species: Likely to become endangered if no action is taken.
Endangered Species: Likely to become extinct.
Critically Endangered: Very high risk of extinction.
Background Extinction Rate.
Species Most Endangered Have: Large habitat range, low reproductive rates, specialized feeding habits, value to humans, low population numbers.
Threats:
Fragmentation: Habitats broken into smaller pieces.
Degradation: Pollutants added to the environment.
Overexploitation: Contribution to extinction.
Biodiversity Hotspot: Area with high biodiversity under threat.
HIPPCO: Causes of extinction (Habitat Destruction, Invasives, Population, Pollution, Climate Change, Overharvesting).
Unit 4: Earth Systems and Resources
The Lithosphere
Tectonic Plates: Float on the asthenosphere.
Plate Boundaries: Edges of tectonic plates.
Convergent Boundary: Plates pushed together.
Divergent Boundary: Plates move apart.
Transform Fault Boundary: Plates slide against each other.
Subduction: Denser plate sinks beneath lighter plate.
Ocean-Continent Convergence: Oceanic plate subducts under continental plate, forming a trench (e.g., Cascade Range).
Earthquakes: Vibrations releasing energy.
Epicenter: Surface location.
Seismograph: Measures magnitude.
Richter Scale: Measures amplitude of S-wave.
Volcanoes: Geological events from plate movement.
Active: Erupted within 10,000 years.
Dormant: Not erupted in 10,000 years but expected to.
Extinct: Not expected to erupt again.
Recharging: Pressure builds between eruptions.
Subduction Zone: Convergent boundaries between oceanic and continental plates (e.g., Ring of Fire).
Rift Valley: Divergent boundaries between oceanic plates forming new ocean floor (e.g., East African Rift).
Hotspots: Middle of tectonic plates with rising magma (e.g., Hawaiian Islands).
Types of Volcanoes:
Shield Volcanoes: Tall, broad base, gentle slope (e.g., Kohala).
Composite Volcanoes: Tall, broad base, steep slope (e.g., Mount Fuji).
Cinder Cones: Small, short, steep slope, symmetrical cone
Lava Domes: Small, short, steep slope, dome.
The Atmosphere
Layers of the Atmosphere:
Exosphere: Gases are thinnest.
Thermosphere: Gases are very thin, auroras occur.
Ionosphere: Absorbs X-rays and UV radiation.
Mesosphere: Low air pressure, temperature decreases with altitude, meteors burn up.
Stratosphere: Includes ozone layer, gases not well mixed, temperature gradually warmer with altitude.
Tropopause: Between troposphere and stratosphere.
Troposphere: Weather takes place, well-mixed, temperature gradually colder with altitude, contains 99% of water vapor and clouds.
Greenhouse Gases:
Water Vapor (): 0-4% of troposphere.
Carbon Dioxide (): 0.033% of troposphere.
Methane (): 0.0002% of troposphere.
Weather & Climate
Weather: Day-to-day properties (wind, temperature, sunlight, pressure, humidity).
Climate: Patterns constant over many years (average temperature, precipitation).
Seasons: Earth's motion around the Sun causes variation in insolation.
Northern Hemisphere Tilted Towards the Sun: North = Summer, South = Winter.
Southern Hemisphere Tilted Towards the Sun: North = Winter, South = Summer.
The Hydrosphere
Includes Earth’s oceans and freshwater bodies, covering ~75% of the planet
Freshwater: Minimal dissolved salts, from precipitation.
Watershed: Land area collecting rainwater draining into a stream or river.
Freshwater Biomes:
Deltas: Landforms at river-ocean juncture, made of sediment.
Estuaries: “Arm” of sea meeting river mouth, rich in species, high nutrients and sediments.
Wetlands: Diverse ecosystems along fresh water (marshes, swamps, bogs, floodplains).
Saltwater:
Saltwater Biomes:
Barrier Islands: Landforms off coastal shores, built from sediments, shifting boundaries, buffer shoreline.
Coral Reef: Type of barrier island formed by living community, high diversity, delicate, vulnerable to stresses.
Water Problems & Issues
Water Risk: Possibility of water-related challenge (scarcity, stress, flooding, drought).
Water Stress: Demand exceeds available amount (1,000-2,000 m³ per person per year).
Water Scarcity: Lack of sufficient water to meet demand (< 1,000 m³ per person per year).
Water Conservation: Policies and strategies for sustainable water management.
Soil & Soil Dynamics
The Pedosphere:
Soil: Complex material with organisms, weathered rock (45%), organic matter (~5%), air (~25%), water (~25%).
Soil Chemistry: pH ranges from 0-14, most soils 4-8, acidic (<7), alkaline/basic (>7).
Importance: Links abiotic and biotic components, nutrient cycling, supports plant life, foundation for growth, water, and nutrients. Nonrenewable resource.
Rocks
Rock Cycle.
Types of Rocks:
Igneous: Melted by heat and pressure (e.g., basalt, granite).
Sedimentary: Sediment builds up and is compressed (e.g., limestone, shale, coal).
Metamorphic: Transformed by pressure and heat (e.g., slate, marble).
Rock Weathering
Types of Weathering:
Physical: Weakened by forces, no chemical change, dominates in cold/dry environments.
Chemical: Chemical alteration with water, oxygen, etc., breakdown and reorganization, dominates in warm/moist environments.
Biological: Weathering by living organisms.
Types of Soil:
Sand: Large particles, don’t adhere, large pores, drains quickly.
Clay: Small particles, adhere easily, small pores, holds water and doesn’t drain.
Soil Problems
Arable soil needed for agriculture.
Soil fertility is essential.
Erosion: Removal of soil, rock, or material to another location.
Problems With Modern Agriculture:
Monoculture vs. Polyculture:
Monoculture: Single crop, depletes specific nutrients, decreases genetic diversity.
Polyculture: Many crops, increases sustainability, limits depletion, increases diversity.
Crop rotation another good solution.
Other Problems: Damaged soil from machinery, repeated plowing breaks down soil aggregates, large energy consumption, pollution from pesticides/fertilizers.
Green Revolution:
Increase in agricultural productivity.
Cons: Detrimental effects, pesticide resistance, salinization.
Solutions: Genetically modified plants, drip irrigation.
Soil Conservation
Practices: Manure/compost, organic agriculture, changing tillage, using wind barriers.
Unit 5: Land and Water Use
Resource Utilization
“The Tragedy of the Commons”: Foundation for modern conservation.
Conservation: Management or regulation of a resource.
Preservation: Maintenance of a species or ecosystem.
Renewable & Non-renewable Resources:
Renewable: Regenerated quickly (e.g., trees).
Nonrenewable: Formed by slow geologic processes (e.g., minerals, fossil fuels).
Main Sources of Energy:
Fossil Fuels: Provide 65% of world’s electricity (oil, coal, natural gas).
Nuclear Energy: Primary non-fossil fuel, nonrenewable (13% of world’s electricity).
Renewable Energy: Biomass, solar, wind, geothermal, hydropower (15% of energy).
Agriculture
Agricultural Innovations:
Neolithic Agricultural Revolution:
Vegetative Planting.
Seed Agriculture.
Horticulture.
Animal Domestication.
Husbandry.
Second Agricultural Revolution: Technological innovations, reduced labor.
Green Revolution: Mechanized farming, booming crop yields.
Positive Effects: Improved crop production, reduced hunger, decreased food costs, genetic engineering.
Negative Effects: Suffering small farms, environmental impact, chemical use, pesticide resistance, genetic engineering distrust.
Agricultural Activity & the Environment
Irrigation:
Problem: Repeated irrigation → salt buildup.
Addressed: Flooding fields to move salt deeper.
Drawbacks: Waterlogging, depletion of aquifers.
Prevention of Soil Degradation:
Intercropping (Strip Cropping).
Contour Plowing.
Terracing.
No-Till Method.
Crop Rotation.
Types of Pesticides:
Biological.
Carbamates.
Chlorinated Hydrocarbons & Persistent Organic Compounds (POPs).
Fumigants.
Inorganic.
Organic/Natural.
Organophosphates.
Livestock & Overgrazing
Livestock Grazing: Shifting herds, sustainable if area is sufficient.
Overgrazing: Too many people/animals on too little land, leads to denuded grasslands and erosion.
Solutions: Rotating animals, controlling herd numbers.
Animal Waste:
Manure not used as fertilizer due to transport.
Widespread water pollution.
Forestry
Deforestation: Clearing trees for agriculture or exportation.
Slash & Burn: Reduces forests and contributes to deforestation.
Tree Plantations and Old Growth Forests:
Old Growth Forests: Never cut, high biodiversity.
Second Growth Forests: Cutting occurred, new forest arose naturally.
Plantations & Tree Farms: Planted trees, harvested for commercial use.
Forest Management:
Silviculture: Management of plantations for timber.
Clear-Cutting: Removal of all trees.
Selective Cutting: Removal of select trees.
Natural Events & Forest Fires.
Rangelands.
Types of Mining
Strip Mining.
Mountaintop Removal.
Shaft Mining.
Fishing
Fishing Techniques:
Drift Nets.
Long-Lining.
Bottom Trawling.
Overfishing & Aquaculture.
Unit 6: Energy Resources and Consumption
Energy Concepts
Forms of Energy:
Potential: Energy at rest, stored energy.
Kinetic: Energy in motion.
Radiant: Sunlight, electromagnetic energy.
Thermal: Heat, internal energy.
Chemical: Stored in chemical bonds.
Electrical: Motion of electrons.
Nuclear: Stored in nuclei of atoms.
Laws of Thermodynamics:
First Law: Energy neither created nor destroyed, only transferred/transformed (e.g., Photosynthesis).
Second Law: Entropy increases, most energy transformed is lost as heat (e.g., Food chains).
Sources of Energy:
Nonrenewable: Electricity, Nuclear, Fossil Fuels (Oil , Coal, Natural Gas), Synfuels.
Renewable: Hydroelectric, Solar, Wind, Biomass, Geothermal, Ocean Waves and Tides, Hydrogen fuel cells.
Fossil Fuels
What Are Fossil Fuels?
Oil: Long chains of hydrocarbons.
Coal: Mixture of carbon, hydrogen, oxygen, and other atoms
*Types of coals:
*Anthracite = Purest Form.
*Bituminous.
*Subbituminous.
*Lignite = Least Pure.
*Natural Gas:
*Mostly methane gas () with a mixture of other gases such as Pentane () and Butane ().
Where Are Fossil Fuels Found?
*Oil & Natural Gas
*Source = Ancient marine organisms such as zooplankton; Organisms in ancient swamps, especially plants
*Locations:
*Deep in the Earth
*Under both land and ocean floor
*Stored in spaces between rocks
*Long continuous deposits called seams
*At various depths underground
*Coal
*Source = Living organisms found in landfills, swamps, wetlands, and the intestines of various animals
*Location = Many locations around the world
Extraction & Use of Fossil Fuels
Crude Oil:
*Raw or fresh oil when it is pumped up from a reserve
*Methods of Extracting Oil:
*Primary Extraction
*Oil well is tapped and pumped to the surface
*Easiest way to extract oil
*Pressure Extraction
*This method is used when oil is harder to extract
*Mud, saltwater, or CO2 is used to push oil out from the reserve
*Heat Extraction
*Steam, hot water, or hot gases are used to partially melt very thick crude oil
*This makes the oil easier to extract
*Coal
*Coal mining occurs through two processes
*Strip Mining
*Removal of the Earth’s surface, all the way down to the level of coal seam
*Removed earth is called the overburden
*Coal is removed; overburden is replaced with and topped with soil
*Area contoured and re-vegetated
*Underground Mining
*Sink shafts to reach underground deposits
*Networks of tunnels are dug or blasted
*Humans enter these tunnels to manually retrieve coal*Natural Gas:
*Uses
*Heating homes
*Cooking
*Burned to generate electricity
*Can be used in some cars and trucks
*Pros
*Produces only CO2 and H2O when it burns
*Cleaner than burning oil or coal
*Cons
*A leak can cause a violent explosion
*More difficult to transport than oil or coal
*Liquified before transportation, which requires energy
*Can be transported via pipes, but these can leak and explode, as well as damage habitats when they’re installed*Synfuels:
*Characteristics
*Synthetic fuel
*Obtained from non-petroleum sources such as coal, natural gas, or biomass
*Can also be derived from waste such as plastic or rubber
*Can be liquid or gas
*A mixture of carbon monoxide and hydrogen
*Pros
*Large potential supply
*Lower air pollution than coal
*Can replace oil or natural gas in some cases
*Used in transportation and industry
*Holds promise to be a more sustainable or renewable energy source in the future
*Cons
*Low to moderate net energy yield
*More costly than fossil fuels
*Currently still requires coal
*High water use
*Higher CO2 emissions than coal
Environmental Considerations of Fossil Fuels
*Oil Drilling
*Pros
*Drilling for oil is only moderately damaging to the environment
*Little land is needed to drill
*Cons
*Oil is transported thousands of miles by tankers, pipelines, and trucks
*A lot of environmental damage can occur during transportation
*Burning Coal
*Burning coal produces:
*Air pollutants such as CO2, NOx, Hg, and SO2
*Fly ash - small dark flecks that are carried into the air
*Boiler residue - solid waste left at the bottom of the boiler
Nuclear Energy
*Fusion & Fission
*Fusion
*Combining two small atoms to produce heavier atoms and energy
*Can release more energy than fission without producing as many radioactive by-products
*Reactions occur in the Sun
*Practice is still being developed
*Fission
*Discovered first
*Energetic splitting of large atoms into two smaller atoms
*To split an atom, you have to hit in with a neutron
*Several neutrons are released, which continue the chain reaction
*Used by all commercial nuclear power plants
*Nuclear Reactors
*Steam is piped directly to the turbines
*Steam spins turbines to generate electricity Steam is piped directly to the turbines
*Water is cooled back into a liquid then pumped back to the core to be turned into steam again
Renewable Energy
See Table in the provided text for each type of renewable energy (Hydroelectric, Solar, Biomass, Wind, Geothermal, Ocean Waves & Tides, and Hydrogen Fuel Cells)
Unit 7-8: Atmospheric, Terrestrial and Aquatic Pollution
Types of Pollution: Noise, Light, Thermal, Air, Water, Solid Waste, Hazardous.
*Biggest source of pollution: Burning fossil fuels, Mining, Industrial processes, Deforestation, and Hazardous waste.Anthropogenic Uses of Water: Agriculture, Industry, Household Use. *Water footprint - the total daily per capita use of freshwater.
Agriculture (70%).
Industry (20%).
Household Use (10%).
*The United States is the country that uses the most water globally.
*Different scenarios regarding geological differences (Eg. West v. East. China uses the least amount of water globally.
*Irrigation - technological advances have made water use for crops more efficient:
*Furrow - a trench that is flooded with water
*Flood - the entire field is flooded with water
*Spray - an apparatus sprays water across the field
*Drip - a slow dripping hose is laid on or buried beneath the soil
*Hydroponic Agriculture
*The cultivation of plants in greenhouse conditions by immersing roots in a nutrient-rich solution
*An alternative to irrigation, hydroponic agriculture is more expensive but has several advantages
*Requires little to no pesticide use
*Uses up to 95% less water than traditional irrigation
*Crops can be grown year-round
Water is also used for industrial processes and household use.After agriculture, the most common use of water is in industry.
Industry.
Water is used mainly for: Generating electricity and Cooling down systems.
*Household Use (Anthropogenic Uses)
*About 10% of water use in the U.S
*Eg. Normal activities, recreational activities
*U.S is the leading user of water for households.
*Advocacy for reduction in household use of water
*Gray Water - wastewater from bath, showers, bathrooms and washing machine.
*Contaminated Water - wastewater from toilets, kitchen sinks and dishwashers.
Wastewater From Humans + Livestock Could Pose Multiple Problems
*Water Pollution - the contamination of streams, rivers, lakes, oceans or groundwater with substances produced through anthropogenic activities
*Wastewater produced by livestock operations and human activities, including human sewage from toilets and gray water from bathing and washing laundry.
Problems w. Wastewater
*Oxygen depletion
*Lack of nutrients
*Disease-causing organisms + contaminants
Oxygen Problems
*Biochemical oxygen demand (BOD) - the amount of oxygen a quantity of water uses over a period of time at specific temperatures
*Dead zone - an area w. Extremely low oxygen concentration + very little life
*Anoxic - no oxygen present in an area.
Excessive Nutrient Release
*Eutrophication - a phenomenon which a body of water becomes rich in nutrients
*Cultural eutrophication - an increase in fertility in a body of water; the result of anthropogenic inputs of nutrients
*Eutrophication caused by an increase in nutrients (Eg. fertilizers)
*Eutrophication can cause rapid growth of algae which eventually dies causing the microbes to increase the BOD
Disease-Causing Organisms
*Wastewater can carry a variety of pathogens
*Eg. Cholera, Typhoid, Stomach Flu, Diarrhea, and Hepatitis
*Indicator species - a species that indicates whether or not disease-causing pathogens are likely to be tested
*Fecal coliform bacteria - a group of generally harmless microorganisms in human intestines that can serve as an indicator species for potentially harmful microorganisms associated w. contaminated sewage.
Wastewater Treatment
*Septic Systems
*Septic systems.
*Septic tank.
*Sludge.
*Septage.
*Leach field
*Sewage Treatment Plants
*In developed countries, municipalities use centralized sewage treatment plant that receive wastewater from hundreds or even thousands of households
*In traditional waste treatment plants, there are two phases of treatment; primary and secondary
Animal Feedlots and Manure Lagoons
*Manure from concentrated animal feeding operations is a problem because of volume. It can also contain hormones and antibiotics that are given to the animals.
*Manure lagoons - human-made ponds lined with rubber built to handle large quantities of manure produced by livestock
*After the manure is broken down by bacteria, it is spread onto fields as fertilizers
Heavy Metals and Other Chemicals
*Three Heavy Metals are of particular concern
*Lead: Found in pipes and other materials in older construction.
*Arsenic: Occurs naturally and through human activity such as mining and industry
*Mercury: Occurs naturally and through human activity; primarily burning coal
*Deposition
*Acids deposition on Earth as rain or snow or as gases and particles that attach to the surface of plants, soil and water.
*Acid deposition occurs when burning coal releases sulfur dioxide and nitrogen dioxide into the air
*In the atmosphere, these chemicals are converted to sulfuric acid and nitric acid, which falls back to Earth as acid deposition.
*Acid deposition reduces the pH of water bodies to levels that are lethal to many organisms
*Many coal-burning facilities have installed coal scrubbers to combat this problem
Synthetic Organic Compounds and Human-Produced Chemicals
*Synthetic compounds can enter the water supply from industrial point sources or from nonpoint sources when they are applied over large areas.
*Compounds include pesticides, pharmaceuticals, military compounds and industrial compounds. Synthetic organic compounds can be toxic, cause genetic effects and interfere with growth and sexual development
*Military Compounds
*Perchlorates - a group of harmful chemicals used for rocket fuel
*Sometimes contaminates the soil in regions of the world where military rockets are manufactured, tested or dismantled
*Industrial Compounds
*Industrial compounds - chemicals used in manufacturing
*It use to be common for manufacturers in the United States to dump industrial compounds directly into bodies of water
*Polychlorinated biphenyls (PCBs) - a group of industrial compounds used to manufacture plastics and insulate electrical transformers and responsible for many environmental problems
Oil Pollution
*Petroleum products are