apes semester 2

Semester 2

Unit 5: Land and Water Use

Module 29: Impacts of Mining

Lesson 29.1: How are natural resources extracted from Earth through mining?

Abundance of Ores and Materials

crustal abundance: The average concentration of an element in Earth’s crust

• 4 most common: oxygen, silicon, aluminum, iron make up most of crust

• chemical composition highly variable in various locations

scientists study distribution + types of minerals to locate and manage extraction and conservation

• ore: A concentrated accumulation of minerals from which economically valuable materials can be extracted

  • typically characterized by presence, but sometimes abundance

• metals: An element with properties that allow it to conduct electricity and heat energy and to perform other important functions

  • copper, nickel, aluminum, varying concentrations and mixed w/ other metals

  • as demand for HEV increases, their manufacturing increases, and the demand for metals like lithium increase

ores formed by various geologic processes

• some form in magma, some form in little/great abundance

• nonmetallic resources like clay occur in concentrated deposits bc of physical/chemical separation from other materials by water

• mine most accessible and high concentration first

  • less concentration and availability → more energy, disturbance, air pollution, etc.

difficult to quantify global mineral sources

• reserve: In resource management, the known quantity of a resource that can be economically recovered (publicly known estimate)

• economically recoverable resource → concentration high enough to be profitably mined

• increased recycling and substitution will replace metals as they decrease

Mining Techniques

extract resources thru mining ore and separating other stuff from the sought metal

• high concentration = less energy and waste

→ Surface Mining

strip mining: The removal of overlying vegetation and “strips” of soil and rock to expose underlying ore

• overburden = overlying soil, rock, vegetation

• increases erosion

• mine parallel to surface → remove large volume of material, extract resources, return unwanted stuff

  • mine tailings: Unwanted waste material created during mining; chemical compounds and rock residues that are left behind after the desired metal or ore is removed

open-pit mining: A mining technique that creates a large visible pit or hole in the ground

• close to surface, but extends horizontally and vertically, i.e. copper

mountaintop removal: A mining technique in which the entire top of a mountain is removed with explosives

• deposit tailings in low elevation rivers

placer-mining: The process of looking for minerals, metals, and precious stones in river sediments

• river water separates heavier materials from lighter sand/mud

→ Subsurface Mining
subsurface mining: Mining techniques used when the desired resource is more than 100 m (328 feet) below the surface of Earth

• economically more expensive

• horizontal dig into side of mountain, then vertical shifts with elevators

• coal, diamond, gold

Lesson 29.2: What are the ecological and economic impacts of mining?

Mining Impacts our Ecosystems

several impacts on water, soil, biodiversity + economic and human health

construction of roads → erosion, bad waterways, fragmentation

• mine tailings → health and eco consequences

• coal mining → methane, greenhouse gas

  • can contaminate land with acids and metals

mountaintop removal for coal mining is much safer

• companies make efforts to restore land, debate over efficacy of reclamation

  • damage to streams and groundwater

placer mining contaminates a lot of water and adjacent areas with sediment and chemicals

• mercury is volatile and harmful

subsurface impacts less visible

• acid mine drainage → water passes through tailings, becomes acidic, contains metals leached

pumps must always drain mines

• lowers pH of nearby soil → another acid mine drainage

Mining affects Human Safety and the Economy

subsurface mining is a dangerous occupation

• burial, explosion, fire, black lung disease, asbestosis

deposits of methane bw coal beds

• dangerous to miners → explosive, suffocating

population growth → greater demand for mineral resources

• demand for certain increases, but coal is decreasing

• as easily mined stuff r depleted, efforts become more expensive economically and environmentally

  • more tailings

• design systems that reuse and use mineral sources → protect environment and humans and lower costs for humans bc less healthcare needs

Unit 6: Energy Resources and Consumption

Module 35: Renewable and Nonrenewable Resources and Global Energy Consumption

Lesson 35.1: What are the characteristics of nonrenewable energy resources?

fossil fuels: Fuels derived from biological material that became fossilized millions of years ago

• coal, oil, natural gas

• anaerobic conditions → decomposers can’t break detritus, sediment, exposed to heat and pressure, transformed into things combustible easily, also adding co2 to atmosphere

nonrenewable energy source: An energy source with a finite supply, primarily the fossil fuels and nuclear fuels

• unit of energy - Joule

• calorie - Amount of energy it takes to heat 1 gram of water 1 °C; 1 calorie = 4.184 J → energy in food systems and food consumption

• Calorie - Calories in food; 1 Calorie = 1000 calories = 1kcal = 4184 J; food labels, human food consumption

• Btu - Amount of energy it takes to heat 1 pound of water 1 °F; 1055 J; Energy transfer in air conditioners and home water heaters

• Kilowatt-hour (kWh) - Amount of energy expended by using 1 kilowatt of electricity for 1 hour; 3.6 mil J; Energy use by electrical appliances; often given in kWh per year

2 aspects

• relatively large amount of energy in relatively small volume and mass

• converted to useful heat energy quickly

• best replacements → renewable, wind and solar

Lesson 35.2: What are the characteristics of renewable energy resources?

petroleum, natural gas, coal are finite and nonrenewable → depleted faster than replaced, uranium also finite

renewable energy sources: Sources of energy that are infinite

• potentially renewable: An energy source that can be regenerated indefinitely as long as it is not overharvested

  • biomass, trees

• nondepletable: An energy source that cannot be used up

  • solar, wind, geothermal, tidal, hydroelectric

humans have been using renewable energy sources for a while like wood, plants, manure, fish/animal oils before fossil fuels became available

• still, in developing parts, rely on local biomass

• Sub-Saharan Africa

Lesson 35.3: What are the trends of energy use worldwide and in the United States?

Worldwide Patterns of Energy use

oil, coal, natural gas (80%), renewable, nuclear makes up all energy use

• 600 EJ per year, 77 gj per person

• hydroelectricity is largest renewable source, then wind and solar

US → 320 GJ per person per year

• china great energy consumption, US greatest per capita

developed countries + urban areas more likely to use individual fossil fuels directly and indirectly

• commercial energy sources: Energy sources that are bought and sold, such as coal, oil, and natural gas

• subsistence energy sources: Energy sources gathered by individuals for their own immediate needs including straw, sticks, and animal dung

energy demand changes reflect industrialization level

• more automobiles → more gasoline and diesel fuels, more electric vehicles → more electricity

• more factories + more house fridges = more electricity

Patterns of Energy in the United States

wood predominant until 1875, then coal and natural gas 1900s

• 1960 → nuclear and hydroelectricity joined

• 1970 less oil resurge coal

• recent increase in natural gas consumption, decrease in coal bc fracking reduces cost + more availability

• renewable energy passes coal

energy based on inputs and outputs of big system, bounded by tech and politics

• oil domestic and foreign, hydroelectric from within

• output is work - transportation, residential, commercial, industrial

u.s. energy consumption and energy mix

• total energy use about 100 ej per year with fossil fuels dominating

• renewables now exceed coal in the energy mix reflecting recent change

• most energy is domestically produced with industry and transportation as top users

energy usage varies regionally and seasonally

• midwest/southeast → coal for electricity

• west/northeast → electricity from nuclear, natural gas, hydroelectric

expanding domestic production → changing energy portfolio

• type of energy applied based on ease of transport and amount of energy it contains

Quantities of Fossil Fuels in the United States and Worldwide

finite and important → assessed worldwide reserves of fossil fuels via geologic formations

• DOE EIA and IEA estimate reserved and project how much underground, potentially recoverable, and usage rate changes

• estimated reserves + projected consumption rate → number of years remaining for fuel

does it even matter that we know it’s finite?

• indomitable human spirit → develop new energy sources and reduce demand for current

• leveled off rn, slightly decreasing per capita

• energy intensity: The energy use per unit of gross domestic product (GDP).

  • steadily decreasing → using energy more efficiently per dollar of GDP

→ The Hubbert Curve

fossil fuel usage isn’t sustainable bc can’t limit consumption to rate of formation → debates on economy being limited

• shift from availability to consequences of fossil fuel combustion: The chemical reaction between any fossil fuel and oxygen resulting in the production of carbon dioxide, water, and the release of energy

hubbert curve: A graph that represents oil use and projects both when world oil production will reach a maximum and when world oil will be depleted.

• upper and lower estimate of total world petroleum reserves

• total reserves didn’t hugely influence time to use all

• peak oil: The point at which oil extraction and use would increase steadily until roughly half the supply had been used up

future of petroleum use and energy transition

• petroleum use is limited to a relatively short historical window regardless of total reserves (200 years)

• societies switch fuels when better options appear, not when resources run out

• focus is shifting from peak oil to identifying and developing next energy sources

The Future of Fossil Fuel Use

fossil fuel availability and shift toward energy transition

• conventional oil and gas may be depleted within decades while coal could last centuries

• projections are changing due to technology advances renewables and altered use patterns

• climate change concerns are pushing focus from reserves to transitioning energy sources

Lesson 35.4: What is the importance of energy efficiency and conservation?

true sustainability = energy conservation + energy efficiency

• energy conservation: Methods for finding and implementing ways to use less energy

• energy efficiency: The ratio of the amount of energy expended in the form you want to the total amount of energy that is introduced into the system

least expensive and most environmentally sound, sometimes easiest to implement

Different Forms of Energy

best energy form depends on what its used for

• transportation → liquid compact, high energy to mass ratio, oil diesel; harder w coal, carry much more

• energy in batteries increase and price decrease, electricity is becoming more ideal

wood and coal vehicle starts slowly, no quick acceleration

• large amount of air pollution per joule of energy and much more refining

Quantifying Energy Efficiency
both the process to get the energy and the process of converting it to fuel for work

second law of thermodynamics → energy transforms, ability to work diminishes bc some lost as heat

• 66% of coal energy ends up as heat

• lost during extraction, transporting, process, combustion, electricity generation, disposal, transmission

energy return on energy investment: The amount of energy we get out of an energy source for every unit of energy expended on its production.

• energy obtained from fuel/energy invested to obtain fuel

Module 37: Distribution of Natural Energy Resources: Fossil Fuels

Leeson 37.1: Why are fossil fuels and ores found only in certain locations?

Fossil fuel and ore distribution around the globe depends on the geology of the region

coal forms from remains of trees and ferns

• organic matter to make coal must undergo the circumstances to stop it from decomposing → buried quickly without air exposure

  • tropical locations, wetlands deltas

• coal locations today depend where coal formation circumstances were found 300k years ago

crude oil formed from remains of ocean phytoplankton died millions years ago

• did not decompose normally

• deposits of phytoplankton found where porous sedimentary rocks r capped by nonporous rocks, so after millions of years, crude oil fills the porous spaces

• fossilized organic matter that becomes oil becomes less dense → up to highest point of porous, blocked by nonporous

• sometimes flows similarly to how water comes from artesian wall, but mostly, need drill well and refined via pipeline

natural gas in crude oil separates naturally and floats to top

• oil workers burn off natural gas to capture it for fuel

• transportation, petrochemicals, plastics, lubricants

Lesson 37.2: What are the advantages and disadvantages of fossil fuels including oil extraction and fracking?

Advantages of Coal

energy dense and abundant

• provides heat for industrial processes and electricity generation

• low economic costs and tech demand (surface)

• easy transportation, easy use

Disadvantages of Coal

subsurface mining has several negative impacts

burning of several impurities on coal releases emissions like sulfur

• combustion can release air pollutants, or stay in ash

wash coal w organic compounds

• leaks can contaminate water and cause residual ash

large deposits of ash near coal power plants can leak and release a muddy flow of ash

lots of air pollution

Advantages of Oil

easy transportation and use

• slightly more energy dense and cleaner, good for mobile combustion engines

• produces less co2

Disadvantages of Oil

contains trace metals that when burned, release greenhouse emissions

risk of leaks when extracting and transporting, contaminating water and wells

most oil spills occur from land runoff, airplanes, boats,

lots of debates of habitat consequences and domestic oil extraction

• habitat interference, railing accidents

explorers say arctic wildlife council will yield so much liters, opponents mark

local air pollution problems, health, human rights

Advantages of Natural Gas

powers half of homes in the US

• fewer impurities, emits less particles during combustion

• emits less co2 than coal

Disadvantages of Natural Gas

releases less co2 when burned compared to other fossil fuels but

• methane leaks are highly effective greenhouse gases and contribute to climate change

• extraction methods like fracking cause environmental concerns

→ Fracking

fracking: Short for hydraulic fracturing, a method of oil and gas extraction that uses high-pressure fluids to force open existing cracks in rocks deep underground

• can extract more at a lower gas cost

• reliance on domestic energy sources and jobs

• initially appeared more beneficial

large amounts of water used, potential contamination

many chemicals are added to fracking

• nearby drinking water wells show higher natural gas contamination

• wastewater injection linked to increased earthquake activity

steps of fracking

1. water acquisition

2. chemical mixing

3. well injection

4. flowback and wastewater

5. wastewater treatment

volatile organic compounds: An organic compound that evaporates at typical atmospheric temperatures

methane leakage and climate change

• natural gas escapes during fracking and extraction as fugitive emissions

• leakage estimates are uncertain and range from 2 to 9 percent

• methane’s high heat trapping ability makes leakage a serious climate concern

Lesson 37.3: How are fossil fuels used for electricity generation?

Fuel is converted to electricity and releases carbon dioxide and heat energy

coal is burned in a boiler

• energy of combustion fuel is transferred to water to become steam

• energy of steam transfers to turbine: A device that can be turned by water, steam, or wind to produce power such as electricity

• shaft turns generator, generates electricity

• distributed to other places, used for heat, light

• after passing through turbine, condenses back to water → cooling tower or discharged in water body

as coal is burned, some of its energy is lost as heat

energy losses from plant to light bulb

• transmission lines lose about 10 percent of electrical energy

• incandescent bulbs convert only 5 percent of electricity into light

• overall efficiency is found by multiplying each stage’s efficiency

calculating energy efficiency

• coal to electricity x transport of electricity x light bulb efficiency = overall efficiency

Energy Quality

energy quality: The ease with which an energy source can be used to do work

• high-quality = concentrated, convenient

energy quality of gasoline versus wood

• gasoline has high energy concentration and easy transport

• infrastructure allows efficient conversion to work and heat

• wood has lower energy density and greater usage challenges

Module 38: Nuclear Power

nuclear power: Electricity generated from the nuclear energy contained in nuclear fuel

Lesson 38.1: How is nuclear energy used to generate electricity?

Nuclear reactors use fission to generate electricity

same basic process as electricity from fossil fuels

• fuel releases heat, converts water to steam, turns turbine, turns generator for electricity

• uranium-235 isotope is used as fuel

nuclei of atom stability based on mass of isotope and number of neutrons

• radioactivity: The emission of ionizing radiation or particles caused by the spontaneous disintegration of atomic nuclei

• transferred to surrounding environment, hotter, to create steam

fission: A nuclear reaction in which a neutron strikes a relatively large atomic nucleus, which then splits into two or more parts, releasing additional neutrons and energy in the form of heat

• chain reaction fissions

• 2-3 million times more energy than coal

harness kinetic energy from additional neutrons to produce self-sustaining nuclear fission chain reaction

• byproduct = radioactive waste for millions of years

fuel rods: A cylindrical tube that encloses nuclear fuel within a nuclear reactor.

• uranium processed into pellets then put here

heat transferred to circulating loop of water, then follows same process for other electricity generators

harness heat from fission for steam, but slow fission to allow collisions to happen appropriately

• moderator like water slows down neutrons

• control rods: A cylindrical device inserted between the fuel rods in a nuclear reactor to absorb excess neutrons and slow or stop the fission reaction.

• rods uncontrolled → meltdown

Concentrating the Uranium Ore
uranium mining and nuclear fuel preparation

• 900 kg of uranium ore must be mined and processed to produce 3 kg of nuclear fuel

• uranium mining requires fossil fuel energy and generates mine tailings though less material is needed than coal for electricity

  • remove lots of host rock, extract and concentrate, leave remaining in tailing pilings

• most uranium contains U238 (not ez fission) and not U235 → chemically enriched to increase concentration of U235 (>3% = suitable nuclear fuel_

Lesson 38.2: What are the advantages and disadvantages of nuclear power?

no air pollution during operation

• achieve independence from imported oil

• france, china, russia, south korea, canada, ukraine

1/5 electricity USA from nuclear

• early proponents → too cheap to meter

• new construction is now expensive bc public protests of nuclear accidents and waste, legal battles, delays

nuclear reactors and environmental considerations

• number of us nuclear reactors has declined since 1990 but interest is increasing

• overall emissions from nuclear power is 10% of coal even accounting for fuel and construction

• main environmental concerns are radioactive waste disposal and accident risks

Lesson 38.3: What are radioactivity and radioactive waste?

Nuclear power depends on radioactivity but as a result, it generates radioactive waste

less fuel required to operate nuclear plant than coal plant

• fuel stays radioactive even after not useful for electricity

• radioactivity - emission of radiation or particles from spontaneous decay of atomic nuclei

Radioactive Isotopes Undergo Radioactive Decay

radioactive decay: When a parent radioactive isotope emits alpha or beta particles or gamma rays

• half-life: The time it takes for one-half of an original radioactive parent atom to decay

• determine length of how dangerous a radioactive element will be

Radioactive Waste: The By-Product of Electricity Generated from Nuclear Power

radioactive waste: Nuclear fuel that can no longer produce enough heat to be useful in a power plant but continues to emit radioactivity

• high level - used rods → ionizing radiation to cause immediate human damage

• low level - contaminated items during plant maintenance → damage human DNA, cancer, tumor, eyes, reproduction

• mine tailings - residue after uranium mined and enriched

Measuring Half-Lives

radioactive half life and nuclear waste disposal

• spent fuel rods lose efficiency as radioactive isotopes decay

• u-235 has an extremely long half life (700 mil) causing slow reduction in radioactivity

• long half lives make safe long term disposal of nuclear waste a major concern

becquerel (Bq): A measurement of the rate at which a sample of radioactive material decays; 1 Bq is equal to the decay of one atom per second

curie: A unit of measure for radiation, a curie is 37 billion decays per second

Radioactive Waste Disposal

store spend rods at plant itself, first in pools of water to act as a shield

• run out of space → lead-lined dry containers, eventually moved to permanent waste disposal facility

radioactive waste disposal challenges

• waste cannot be destroyed or dumped or in space without risking environmental contamination

• long term storage on earth must prevent leakage protect groundwater and limit human exposure

• sites must be secure remote and safe during storage and transport and prevent terrorists bombing it

→ Long-term Storage

yucca mountain seems like a nice place

• protests and controversy, released report conforming soundness of its safety, later abandoned efforts to license waste repository

nuclear energy and sustainability debate

• nuclear power releases low co2 emissions and none electricity generation

• it creates large amounts of long lived high level radioactive waste → is it sustainable?

• will there ever be a safe enough place?

Lesson 38.4: What are the three major nuclear accidents?

Three Mile Island, Chernobyl, and Fukushima are the three nuclear accidents

march 28 1979 Three Mile Island Pennsylvania

• cooling water valve closed one day → lack of cooling → partial meltdown, reactor core severely damaged, contaminant structure became radioactive plus unknown radiation released

• children and pregnant women evacuated

lots of anxiety, potential explosive gas bubble

• nothing really happened, but still concerns and claims of mortality and cancer

april 26 1986 chernobyl

• tried testing (not allowed) disconnecting emergency systems and removed control rods → reactions uncontrolled and overheated, explosion and fire, deaths from immediate impacts and burns

• wind blew radiation across Europe, contaminated food, evacuations, thyroid cancer and deaths in children and adults from radioactive iodine

March 11, 2011, Fukushima

• earthquake → tsunami → flooding damaged plant, hydrogen gas explosions, released radioactive gases, fires

• thousands killed, evacuated

• no deaths from radiation itself

Nuclear Power Compared with Other Fuels

future of nuclear energy in the united states

• nuclear energy offers low emissions but raises concerns about accidents and waste containment

• us nuclear construction has resumed slowly with a few plants approved, halted, or planned since 2006

• future expansion is uncertain, with limited growth in the us and more rapid development in countries like china

Module 40: Geothermal Energy and Hydrogen Fuel Cells

Lesson 40.1: How do humans harness geothermal energy?

geothermal energy: Heat energy that comes from the natural radioactive decay of elements deep within Earth

• convection brings hot magma to Earth’s surface → groundwater becomes heated → drives to surface as geysers or hot springs, or drill it

clean renewable from US, Indonesia, Philippines, Turkey

• little GW (15)

Harvesting Geothermal Energy

can be piped directly into household radiators to heat homes

• heat exchangers collect heat by circulating cool liquid, heat flows in, goes to surface → Iceland

generate electricity, but steam comes from water evaporated by internal heat

heat from this is basically nondepletable during human time

• groundwater can be depleted

• long harvesting periods → unsustainable, so return it to the ground

25% of electricity in Iceland from geothermal energy

• US → only 1%, but largest producer of geothermal electricity cs uses so much electricity, mostly west/southwest

• less growth potential cs not easily accessible + expense of drilling

• hazardous gases and steam can release → hydrogen sulfide, methane

Ground Source Heat Pumps

ground source heat pumps: A technology that transfers heat from the ground to a building

• underground temp constant bc retains heat better than air → heat and cool residential and commercial buildings

• technically solar instead of geothermal → nondeplatable

ground source heat pumps do not remove steam or hot water from ground

• cycles fluid through pipes underground

• winter → fluid absorbs heat

• slightly warm fluid compressed to increase temperature → distributed through house → expands and cools, repeat again

• summer → fluid is cooled underground and pulls heat from house

→ Hot Water Heat Pumps
hot water heat pumps and home energy efficiency

• extract heat from air in a basement or garage and transfer it to domestic hot water (showers, dishwashing)

• efficiency exceeds 100 percent because it adds heat from surrounding air to the electrical energy used

• increasingly popular in the us with financial incentives, reducing fuel use, co2 emissions, and costs

Lesson 40.2: What is a hydrogen fuel cell and what is its potential for providing electricity?

Hydrogen fuel cells use hydrogen as an energy source and are almost pollution free
fuel cell: An electrical-chemical device that converts fuel, such as hydrogen, into an electrical current

• similar to a battery - electricity generated by 2 chemical reactants in a closed container w no additions, used up, dies

• cell → reactants continuously added, alternate to nonrenewable

2H₂ + O₂ → energy + 2H₂O (NO POLLUTANTS!)

1. hydrogen molecules split into protons and electrons in upper reaction layer

2. protons across membrane

3. electrons go another way to form an electric current

4. oxygen split and combine with protons and electrons to form water lower reaction layer

constant supply of hydrogen required, but free hydrogen is rare and unsafe

• separate it from water or gases → energy-intensive process that releases co2

• electrolysis: The application of an electric current to water molecules to split them into hydrogen and oxygen.

  • no fossil fuels or emissions

hydrogen acts as an energy carrier

• wind and sun energy sources can’t produce electricity constantly, but the electricity produced can be used to generate hydrogen → stored

• generate electricity for electrolysis using clean nondepletable energy source → hydrogen could be sustainable energy carrier

• when warm, use sun, when cold, use stored hydrogen via powerplant

The Viability of Hydrogen

hydrogen fuel cells and energy potential

• convert hydrogen and oxygen into electricity with about 80 percent efficiency and water as the only by-product

• currently limited use in the us with 160 fuel cells at 100+ power plants, less than 0.2 percent of electricity generation

• potential applications in vehicles, offering zero co2 and pollutant emissions, but widespread adoption faces skepticism

diadvantages

1. obtain hydrogen without expending more fossil fuels than we save → renewable source

2. distribution network to safely deliver to consumers, stored as liquid or gas   

   1. full cell vehicle → large gas tank with high pressure → tank rupture risk

sustainable bc uses electric motor just like electric vehicles

• more efficient than internal combustion engines

• hydrogen from natural gas → total amount used to move electric vehicle will be less than gasoline, even lower if hydrogen from renewable sources

hydrogen fuel cell vehicles and geothermal energy

• toyota offers a hydrogen fuel cell vehicle, but fueling stations in the us are limited to about 40, mostly in california

• both hydrogen fuel cells and geothermal energy are currently small contributors to total energy use

• both have potential to expand in the us energy mix with minimal co2 and air pollutant emissions

Unit 7: Atmospheric Pollution

Module 43: Photochemical Smog, Thermal Inversions, Atmospheric CO₂ ^, and Particulates

Lesson 43.1: What is photochemical smog and how can we reduce it?
Photochemical smog is a complex combination of compounds and it can be reduced by decreasing emissions of its precursors
4 in 10 americans today live in counties w bad air quality

• sulfur, nitrogen, co have been reduced since the Clean Air Act, but controlling secondary pollutants like smog and ozone is hard

• daytime increase in ozone bc of smog formation and atmospheric behavior when weather changes

• In most cities, mid- to late-afternoon ozone concentrations are higher than the daily average as a result of an increase in nitrogen oxides in the early morning hours

Chemistry of Ozone and Photochemical Smog Formation

smog is combo of oxidants and particulate matter, reducing sunlight and increasing haziness; 2 categories

• photochemical smog: Smog that is dominated by oxidants such as ozone. Also known as Los Angeles–type smog; brown smog

• sulfurous smog: Smog dominated by sulfur sulfur dioxide, sulfate compounds, and particulate matter. Also known as London-type smog; gray smog; industrial smog

economic harm since poor visibility = less tourism revenue and income for hotels and restaurants

complex problem still unsolved bc number of pollutants → based on intensity/duration of sunlight, water, and VOCs

chemical process of photochemical smog

1. during the day, UV warms the atmosphere

2. lots of NOx (little VOCs) → splits into NO₂ and free oxygen O

3. energy from sun makes O combine with O₂ into ozone O₃

• so as nitrogen dioxide increases, ozone accumulates → highest early/mid afternoon during summer

even when sunlight intensity decreases, nitrogen oxide is still present, and the ozone combines with NO to make O₂ and NO₂

• ozone destruction natural at night, but some compounds can interfere with this

VOC chemicals easily released into air, either evaporate or sublimate

• evaporate:The process of converting from liquid to a gas or vapor

• sublimate: The process of converting from a solid to a gas or vapor

• can come from tree fires or gasoline or formaldehyde: A naturally occurring compound that is used as a preservative and as an adhesive in plywood and carpeting

if large amounts of VOCs are present, they combine with nitrogen oxide to a stronger bond and can’t combine with ozone

• ozone isn’t broken down → larger accumulations in urban areas and rush hour

→ The Importance of Temperature

emissions of VOCs and evaporation of liquid VOCs increase as temperature increases

• NO emission too bc more cooling

→ Smog and Human Health

harms human health a lot

• itchy eyes, irritates respiratory system, risk of infection bc inflamed

• aggravates asthma emphysema bronchitis

• decreased lung capacity, more admissions for asthma

• apps tell u air quality, but poor people dont have a choice

Lesson 43.2: What are thermal inversions and how do they relate to air pollution?
Thermal inversions trap air pollutants close to Earth’s surface

normally, as altitude decreases, temperature increases

• thermal inversion: An atmospheric condition in which a relatively warm layer of air at mid-altitude covers a layer of cold, dense air below

• inversion layer: The layer of warm air that traps emissions in a thermal inversion

  • esp in cities bc vehicle exhaust and industrial emissions

lead to problems resulting from other pollutions

• a temperature inversion trapped carbon monoxide and particulate matter from coal-burning stoves after a cold spell, where the city shut down municipal heating and made houses burn their own coal

• thousand people suffered carbon monoxide poisoning or respiratory illness and few people died

• thermal inversions are natural, investigating whether climate change is increasing their frequency and worsening both anthropogenic and natural pollution effects

Lesson 43.3: What are the natural sources of particulates and CO₂?

Volcanoes, forest fires, respiration, and decomposition are natural processes responsible for particulate emissions and carbon dioxide

volcanoes, lightning, fire, and plants also release pollutant compounds, not just human activity

• lightning → nitrogen oxide, forest fires → PM, NOx, CO_x, fragrant terpene VOCs from fires

• natural VOCs created smog in mountain ranges

Natural Sources of Particulates

large agricultural fields can release PM when plowed, like Dust Bowl

• SO_x 30% natural, NOX 40% natural, VOCS 89% natural

• places like NA make anthropogenic contribution bigger

effects depends on wind direction

• westerlies distributes PM and SOx from st helen explosion, lowering rain pH

PM comes from volcanoes forest fires dust storms, ranging from 0.01 to 100 micrometers

• >10 micrometers is nose filtered

• PM₁₀: Particles smaller than 10 μm are called Particulate Matter-10 and are not filtered out by the nose and throat and can be deposited deep within the respiratory tract

• PM_2.5: Particles of size 2.5 μm and smaller can travel further within respiratory tract and are of even greater health concern

PM scatters and absorbs sunlight

particulate matter and sunlight reduction

• high concentrations after forest fires or volcanic eruptions can reduce solar radiation enough to limit photosynthesis

• haze results from light scattering by particulate matter, with ozone and photochemical oxidants also contributing indirectly to haze formation

Natural Sources of Carbon Dioxide
natural sources of carbon dioxide in biological and chemical processes

• aerobic and anaerobic respiration, decomposition, and combustion, all of which convert biomass or sugars into energy, water, and carbon dioxide

• decomposition with or without oxygen and the combustion of biomass in fires are major natural global sources of carbon dioxide

• anaerobic decomposition: sugar → carbon dioxide + methane + less energy

Module 44: Indoor Air Pollutants

Lesson 44.1: What are the major indoor air pollutants and where do they come from?

indoor air pollutants: Compounds that adversely affect the quality of air in buildings and structures

• indoor air pollutants are compounds that reduce air quality in buildings and affect occupant health and comfort

• some pollutants, like carbon monoxide and particulates, are shared with outdoor air, while others, such as radon and asbestos, are primarily indoor concerns

• sources include combustion inside buildings, off-gassing from building materials, and the transfer of outdoor pollutants into indoor spaces

Carbon Monoxide

carbon monoxide as an indoor air pollutant

• extremely dangerous indoors, binding to hemoglobin more effectively than oxygen and causing oxygen deprivation, headaches, dizziness, nausea, loss of consciousness, or death

sources and risks in developed countries

• malfunctioning natural gas heaters or furnace exhaust systems release colorless, odorless carbon monoxide into living spaces

• lack of detection can allow dangerous accumulation, especially while occupants are asleep, making carbon monoxide detectors essential

sources and risks in developing countries

• indoor carbon monoxide exposure arises from burning biomass in open-pit fires with little or no ventilation

• poor combustion and absence of exhaust systems make CO and particulate matter major hazards, with children at higher risk due to faster respiration rates

Particulates

→ Smoke

indoor particulate matter and smoke

• smoke and soot from fires inside or outside buildings, as well as tobacco smoke, are major sources of indoor particulate matter

• prolonged exposure can cause respiratory infections, bronchitis, pneumonia, and cancer

• second-hand smoke exposes non-smokers to high concentrations of particulate matter, increasing health risks

→ Dust and Mold

dust and mold as natural indoor pollutants

• household dust contains particulate matter, pollen, bacteria, and dust mite waste, fueled by millions of shed human skin cells each day

• dust mites live in bedding, pillows, flooring, and carpets, and their body fragments and droppings contribute to asthma and allergic reactions

• mold grows on damp organic matter indoors, often hidden behind walls, and exposure can trigger allergies, lung inflammation, and asthma

Asbestos

ASBESTOS: A long, thin, fibrous silicate mineral with insulating properties, which can cause cancer when inhaled

• used historically for insulation and building materials, all harmful when inhaled

• respiratory diseases such as asbestosis and mesothelioma, especially among miners and workers

• safe when undisturbed, but old or damaged materials release fine fibers into the air, requiring careful removal by qualified abatement personnel

Radon

radon-222: radioactive gas that occurs naturally from the decay of uranium and is an indoor air pollutant

• can enter buildings through foundation cracks or contaminated groundwater

• decays into polonium-210, which can attach to dust and be inhaled, increasing the risk of lung cancer

• second leading cause of lung cancer, and recommends testing, ventilation, mitigation systems, and sealing cracks to reduce indoor exposure

Volatile Organic Compounds

• building materials, furniture, glues, paints release (VOCs), with formaldehyde being one of the most toxic → homes and wood

• irritation, asthma, cancer

• detergents, dry-cleaning fluids, deodorizers, plastics, fabrics, paints, synthetic carpets, and outdoor emissions from nearby chemical or waste facilities

Lead

• primarily comes from old lead-based paint, last used in the u.s. in the 1960s by demolishing these buildings

• can come from outside soil or air, but ingestion of paint chips remains the greatest exposure risk for young children

Other Pollutants

• NOX and SOX, common outdoor pollutants, can also accumulate indoor via poorly insulated or loosely sealed buildings

• NOX from indoor combustion sources like cooking, while proximity to outdoor pollution sources strongly influences indoor air quality

Lesson 44.2: How does indoor air pollution differ in the developing and developed world?

worldwide health hazard, ~4 million deaths yearly → pneumonia, heart disease, pulmonary disease mostly from low/middle income countries

Developing Countries

indoor air pollution from indoor combustion in developing countries

• burning wood, animal manure, or coal indoors for heat and cooking produces high concentrations of particulate matter near occupants, super high PM

• poor building insulation and ventilation may allow some pollutants to escape, but if outdoor air quality is also poor, ventilation provides only limited improvement

Developed Countries
indoor air quality and sick building syndrome in developed countries

• modern lifestyles and building practices have increased the importance of indoor air quality, as people spend more time indoors and buildings are more tightly sealed for energy efficiency, trapping pollutants inside

• widespread use of materials containing VOCs, formaldehyde, plastics, and petroleum-based products leads to off-gassing of chemicals, contributing to high indoor pollutant levels

• sick building syndrome: A buildup of toxic pollutants in weatherized spaces, such as newer buildings in the developed world

  • when ventilation is inadequate and contaminants accumulate, causing headaches, nausea, eye/throat irritation, and fatigue, with causes including indoor sources (glues, furniture, cleaning agents), outdoor pollution, and molds or pollen

Unit 8: Aquatic and Terrestrial Pollution

Module 47: Sources of Pollution, Human Impacts on Ecosystems, and Endocrine Disruptors

Endocrine Disruptors

endocrine disruptors: A chemical that interferes with the normal functioning of hormones in an animal’s body

• low concentrations move through blood stream and “bind” to specific cells → causes them to produce a response relating to body function: growth, metabolism, reproductive organ development

• endocrine disruptors bind/mimic receptive cells and cause responses

wastewater: The water produced by livestock operations and human activities, including human sewage from toilets and gray water from bathing and washing of clothes and dishes

• exposure to hormones → male organisms become feminizied - low sperm, male and female organs, less production of estrogen to testosterone

Chesapeake Bay → estrogen causes 23% largemouth and 80% smallmouth fish to have both male female organs

• grow eggs in male organs

pesticides can mimic animal hormones → disrupt endocrine system

• worries about humans → developmental disorders, low sperm, increased breast cancer risk

Module 48: Human Impacts on Wetlands and Mangroves, Eutrophication, and Thermal Pollution

Lesson 48.1: What are the human impacts on water availability?

humans have creatively moved water by channeling flow of flood water, block river flow to store water, transport it far away, extract fresh water from salt water

Levees and Dikes

before human intervention, periodically overflowed banks → nutrient rich water made fertile floodplains

• now, we want to prevent flooding for commercial/residential use

• levee: An enlarged bank built up on each side of a river

  • largest system in Mississippi

levees have many problems

• 1) reduce fertility of floodpains bc no sediment deposition

• 2) sediments further downstream and settle where river meets ocean → delta

• 3) force floodwater downstrean to cause worse flooding

• 4) levees means development in floodplains, but these areas still flood → human and economic risk

high floodwaters → levees collapse from pressure or erode hole in levee → flooding

• levees couldn’t handle Hurricane Katrina, super expensive and human death

dikes: Structure built to prevent ocean waters from flooding adjacent land

• Northern Europe → lots of farmland below sea level esp Netherlands

• pumps move intruding water back to ocean → ppl can farm and live in areas previously uninhabitable

• originally with windmills, now electricity and diesal

Dams

dam: barrier that runs across a river or stream to control the flow of water

• reservoir: The water body created by damming a river or stream

  • human consumption, generate electricity, flood control, recreation

  • largest in Missouri River

turn waterwheels at grain mills or modern turbines for hydroelectric plants (little percent)

• built for recreation, flood control, hydroelectricity, or aesthetics

example: Three Gorges Dam, Yangtze River

good: generates large amount of hydroelectric power

• reduces fossil fuel usage

• prevent deadly seasonal floodings

bad: human and environmental costs

• large amount of energy and materials

• displacement, flooding, forced relocation

• disrupted free flowing rivers, only free flow in remote areas

interruption of natural water flow organisms have adapted to

• migrating fish like salmon can’t breed → bears can’t eat them

• fish ladders: A stair-like structure that allows migrating fish to get around a dam

  • alleviates and allows them to migrate

• kills many fish when water passes through turbines

seasonal flooding scours pools and shorelines

• favors colonization of certain plants/animals

• people try to experiment and simulate seasonal flooding, promising

dams can be removed when no longer necessary

• Klamath river used to be very successful for salmon migration

• now, damned for electricity, irrigated for farming → less salmon, fishermen and natives suffered

hydroelectric company removed the four dams

• farmers conserved water

• better river flow → salmon population recovers

• largest dam removal in history

with dam removal, water flow and ecology restores

• dramatic increase in plant species along riverbanks

Aqueducts

canals, ditches, or pipes used to carry water from one place to another

• ancient r made of limestone, now made with concrete canals and pressurized steel pipes → efficient water carriers

• older aqueducts lose 55% from evapotranspiration, not good in Levant

NYC and LA rely on aqueducts for their daily needs

• Colorado River aqueduct and Catskill Aqueduct

costs and benefits

• clean supply of water

• expensive construction, disturbs natural habitats

• drying rivers

water diversion projects can have international impacts

• india made large scale project to divert a lot of water from north, but worries about reducing water flow in bangladesh

• reduce fresh water in estuaries → salty water further north

Chinese super dam

• primarily for hydroelectricity, worried about using it for agriculture n taking from bangladesh and india

most infamous water diversion was soviet union aral sea

• less freshwater, more saltwater, split into north and south

• without moderating effect of water, more extreme conditions

world bank funded kazakhstan to stop north from flowing into south aral

• depth increased, fishing increased, economic boom

• south aral sea drying too expensive, dried completely

Humans are converting saltwater into freshwater by desalination

desalination/desalinization: The process for obtaining fresh water by removing the salt from salt water

• used in waterpoor countries like Middle East (50% of world’s desalinated water)

• slowly reduced costs bc of tech

• ocean or salty lakes

two common techniques

1) distillation: A process of desalination in which water is boiled and the resulting steam is captured and condensed to yield pure water

• lots of energy to boil and condense water → financially and environmentally expensive

2) reverse osmosis: A process of desalination in which water is forced through a thin semipermeable membrane at high pressure

• new tech → efficient, less expensive

• remaining liquid is brine → high salt concentration, cant be deposited in ground or coastal area bc impacts wildlife → dump in middle of ocean

all water management systems require large investment to build maintain repair

• 1.2 billion people live in water scarcity areas

Lesson 48.2: What are the human impacts on wetlands and mangroves?

human activities impact waterbodies, visible in wetlands

• wetlands → standing water, water-saturated soil during some part of the year

• hydric soils

many ecosystem services

• purify water by removing pollutants and nutrients

• absorb floodwaters and buffer shorelines

• habitat for migrating birds and other organisms

• protection for young fish

• major carbon sinks

historically, drained for irrigation and to reduce diseased mosquito populations

• wetlands converted to development of homes and businesses → pollution

• others into lakes for flood control or recreation

• commercial fishing declines fish population → alters food webs by affecting dispersal of seeds

huge loss of wetlands

• hurricanes, rising sea levels, human development

• disappearing faster than forests

• less water purification and flood buffering

Lesson 48.3: What are the causes and consequences of eutrophication and sediments?

eutrophication: Excess nutrients from human activities that make their way into waterbodies; it causes nutrient pollution that alters food webs and harms water quality

Algal Blooms

phosphorus and nitrogen enter water and can cause algal blooms/red tides → water becomes red

• bad treated sewage, fertilizer runoff, storm runoff

rapid increase in abundance of algae in water bc of super high water fertility

• bad for swimming, recreation, some species produce toxins that harm organisms

populations decompose and die

• bc of low concentrations of oxygen → hypoxic water makes species migrate or die

• 5 → 87 deadzones

increased concern of freshwater algal blooms

• oligotrophic → low nutrient, clear water, high oxygen, less harmful algal blooms

• eutrophic experience natural blooms → inputs can make them more hypoxic and harmful

Oxygen Sag Curves

similar oxygen concentration dip in sewage or other organic pollutants that quickly decay

• measure O2 concentration in water in diff places to see if there’s a point source input

  • measure water near sewage pipe because bacteria consume the oxygen

• downstream → less sewage → oxygen normal

• oxygen sag curve: The relationship of oxygen concentrations to the distance from a point source of decomposing sewage or other pollutants

Sediments

some inputs of nutrients = sediments eroding from landscapes and traveling in water

• ex: Mississippi River and other fast-moving streams dump water into lakes

• sediment accumulation → harder for boats to navigate bc shallow water

• dredging → dig up sediments to let boats move

impacts on organisms

• reduce sunlight penetration in water → stunt growth or die

• harder for visual predators to find prey + clog gills = less oxygen

• bury organisms that r stationary at the bottom

Lesson 48.4: What are the sources of thermal and noise pollution?

thermal pollution: Occurs when humans cause a substantial change in the temperature of a water body

noise pollution → elevated sounds that harm organisms

Thermal Pollution

water bodies near logged forests → more sunlight

• outside range of tolerance + less dissolved oxygen for organisms

• industry removes cold water to absorb heat for cooling processes and returns warm water

thermal shock: A dramatic change in temperature that can kill many species

• warm water = less dissolved O2 = suffocation

• steps to reduce include pump heated water into outdoor holding pools where it can cool before being returned

EPA regulates how much heated water returned to natural bodies

• hard to comply esp during summer → high demand for electricity = high demand for cooling water despite low river depth and high temp

• solution: cooling towers use evaporation to reduce temperatures (like for nuclear energy); built closed systems that cool hot water in a tower and recycle it → neither extract nor release

Noise Pollution

noise is a type of water pollution

• sounds from ships and submarines hinder animal communication

• loud sonar negatively affects low-frequency long distance communication animals like whales

concerns raised by naval operations

• navy conducts training like ship sonar, torpedoes, detonating bombs underwater

• negligible effect on fish and whales according to NOAA

• over years, though, estimate 30% of marine wildlife will be negatively affected → ships with quiet propellers

Module 49: Persistent Organic Pollutants (POPs), Bioaccumulation, and Biomagnification

Lesson 49.1: How do persistent organic pollutants affect ecosystems?

Chemical Persistence

persistence: The length of time a chemical remains in the environment

• based on pH, temp, etc., often measured by half life

• persistent organic chemical pollutants (POPs): Synthetic, carbon-based molecules that break down very slowly in the environment

  • can travel long distance via water and wind, or stored in fat tissues

harmful chemicals even worse if they r persistent → modern chemicals are short-lived

Persistent Organic Chemicals of High Concern

PCBs are lethal, carcinogenic, and highly persistent; though banned, still persist

we can reverse it though (Hudson River and General Electric)

PFAs ruin immune and reproductive systems → “forever chemicals” 1k years

• some towns only bad groundwater → install water filter systems in every home or installing public water lines for every home

Lesson 49.2: How do routes of exposure and solubility determine the concentration of chemicals that organisms experience?

to understand effects of chemical concentrations that organisms experience, we must understand the following

Routes of Exposure

routes of exposure: The way in which an individual might come into contact with an environmental hazard, such as a chemical

• complex - consumption, water, air, etc.'

• some can be tracked, like for a baby - bisphenol A from toys, food containers, bottles

also important for animals

• pesticides from ingestion or droplets or gills

  • some animals r permeable and exposed to pesticides

Solubility of Chemicals

solubility: How well a chemical dissolves in a liquid

• herbicides in water, insesticides in fats/oils

• highly soluble in water → washed off as run off

• soluble in fats → no runoff, bound to soils under water

Lesson 49.3: How can bioaccumulation and biomagnification increase the concentrations of chemicals in organisms?

Bioaccumulation

bioaccumulation: The selective absorption and concentration of a chemical within an organism over time

• chemicals soluble in fats accumulate in fatty tissues

• accumulation of mercury is why govt recommends to not eat meals of tuna more than once a month

pesticides after WW2 bioaccumulate

• modern ones are designed to not be in tissue

• rate of accumulation = concentration, rate of intake, rate of chemical breakdown, rate of excretion

Biomagnification

biomagnification: The increase in chemical concentration in animal tissues as the chemical moves up the food chain

• best example: insectide DDT seemingly only killed pests without any impact on humans

• however, not water soluble → binds to particulates like algae, then zooplankton, becomes even more concentrated

biomagnification causes birds to make thin shelled eggs

• DDT still used in africa for high malaria concerns

similar effects in humans

• advise mercury PCB POPs consumption

• cancer, reproduction, nervous issues

• development abnormalities, long-term learning and motor skill issues

Module 51: Waste Reduction Methods

Lesson 51.1: What are the three Rs that divert materials from the waste stream?

reduce, reuse, recycle: A popular phrase promoting the idea of diverting materials from the waste stream. Also known as the three Rs

• most environmentally beneficial to least, most energy to least energy use

Reduce

most energy efficient → optimal way to start decline in solid waste generation

• less material → less to discard

• source reduction: An approach to waste management that seeks to cut waste by reducing the use of potential waste materials in the early stages of design and manufacture

• increases energy efficiency bc less waste, less disposal processes, less resources = economic benefit

applied by individuals, companies, institutions

• electronic copies > printing

manufacturing companies can do source reduction in many ways

• new packaging, same protection, less material

• decreased CD wrapping bc using online music is an example of source reduction for companies, downloading online music is for individuals

source reduction by substituting materials

• ex: switching from paper cups to personal reusable mugs reduces MSW, despite requiring energy to clean and use water

• break-even point for plastic is lower than ceramic cs less energy used

• switched from oil-based paint with toxic lead to nontoxic paint

reduce material use, solid waste, without spending extra materials or energy

Reuse

reuse: Using a product or material that would otherwise be discarded

• used longer before wasted; ideally, no additional energy/resources for reusing

• others may involve repair - costs time, labor, energy, materials, but less waste than discarding

energy required sometimes to transport for reuse

• ex: milk/soda bottles shipped to factory - washed, sterilized, refilled

super common esp in USA

• reuse in other ways, like newspapers for bedding/art

• universities w surplus equipments donate items

• thrifting, flee markets

• expenditure of energy and generates other waste - like washing milk bottles creates wastewater

Recycle

recycling: The process by which materials destined to become municipal solid waste (MSW) are collected and converted into raw materials that are then used to produce new objects (two categories)

• closed-loop recycling: Recycling a product into the same product

  • ex: aluminum cans collected, melted, made into new cans

  • prevents waste indefinitely

• open-loop recycling: Recycling one product into a different product

  • soda bottle → jacket; prevents from going into landfill, but doesn’t reduce demand for raw material (petroleum) for new bottles

not new, but since 2000 it’s been really encouraged and embraced by individuals and cities bc belief in environmental quality

• both waste and recycling rates increased, sharp increase since 1985

• 1/3 MSW today recycled

• 56% rate in germany

helpful cs extracting resources takes more time energy labor and money and generates pollution

• zero-sort recycling programs → mix all recyclables in one container that they deposit on the curb or transfer

  • saves time for residents + more likely to recycle

• at the sorting facility, workers organize materials by highest demand → best economic return

volatile glass/paper markets → recycle when financially worthwhile

• always demand for copper and aluminum bc less expensive than extracting

• easier to make new bottles from petroleum than using existing plastic bottles

• degraded plastic from recycling, not degraded metal from recycling

time, processing, cleaning, transport, modification → most energy used

• high recycling costs can influence cities to suspend glass recycling, which was a major shift from recycling as much as possible

• sorting glass and plastics from recyclables was not cost effective

much recycled material shipped to China for production into new products

• 2018 - china stopped accepting recycled paper and plastic products, so smaller market for purchasing recycled items → companies charge more for picking up recycled items

• rising costs → cities reduce or end recycling programs → more MSW in landfills

Lesson 51.2: How does composting reduce materials entering the waste stream?

fourth approach to 3 Rs focused on organic material like food and yard waste

• these can break down anaerobically → methane gas more potent than carbon dioxide

avoid landfills by composting: The breakdown of organic materials into organic matter (humus)

• vegetables, cornstalks, grass, manure, leaf litter, paper fiber are great

• no meat and dairy - don’t decompose well, smell, and attract other animals

simple pile of food/waste in a yard or sophisticated boxes and drums rotated for mixing and aeration

• 30:1 carbon to nitrogen ratio best for microbial activity

  • layer “brown material” like leaves or dried cut grass with wet kitchen vegetables/green material

• frequent turning ensures aerobic process and maintains proper moisture; nice odor of fresh compost within 2-3 months

• humus enhances soil structure, cation exchange capacity, and land fertility

large-composting facilities may exist in cities to divert organic material from waste streams

• waste is dumped and separated into compostable and non compostable material (delivered to landfill)

• compostable material is aerated and turned at least once for a period of 30-365 days using rotating blades or tractors - high respiration kills any pathogenic bacteria; turn more to reduce heat

• composed material cures and when finished, transported for use

outdoors is convenient, but can be done inside in a room, kitchen, or basement

• compost kitchen waste w red wriggler worms → small recycling bin and if properly maintained, no odors

takes time and space

• separating materials is difficult and storing materials before adding to pile attracts organisms

• pile itself attracts unwanted animals

• high organic matter → high cation exchange capacity and nutrients → soil quality

Lesson 51.3: How do life-cycle analysis and integrated waste management reduce municipal solid waste?

how do we decide what waste management techniques r the best? use life cycle analysis and a holistic approach

Life-Cycle Analysis

life-cycle analysis: A systems tool that looks at the materials used and released throughout the lifetime of a product—from the procurement of raw materials through their manufacture, use, and disposal. Also known as cradle-to-grave analysis

• in theory, helps community determine if incinerator or landfill is better, but has limitations; difficult to determine overall environmental impact

  • is the production of particulates and NOx worse than production of methane?

  • is SO2 from paper cup or VOC from plastic cp worse?

• city begins analysis from point of receiving solid waste to final point of disposal

economically, compare costs of disposal methods

• better to receive 5 dollars for a ton of glass from a bottle manufacturing plant than paying $50 fee for landfill deposit

• also consider low cost of nearby landfill versus further glass plant

always some cost to waste disposal

• some covered by taxes, others individuals pay

• disposing recyclables (lower tipping fee or revenue) usually cheaper than landfills bc always tipping fee, but can depend on fluctuating prices of recyclables

energy use wise, considers energy content of gasoline/diesel and pollution in trucking material

• monetary, energy, pollution savings if new glass made from old glass vs new materials

• super debatable, so now people take holistic approach

Integrated Waste Management

integrated waste management: An approach to waste disposal that employs several waste reduction, management, and disposal strategies in order to reduce the environmental impact of MSW

• source reduction + any combo of three Rs, composting, landfills, etc

• start with source reduction during manufacturing and identify behaviors for less waste and desired outcome (no forcing)

• pay for incinerator - u need lots of people to use it to make up for the cost, detracting incentive for recycling/landfill

• free to consider all options - efficient, cost-effective, least harmful

McDonough’s Cradle to Cradle favors minimizing waste generation before, during, and after manufacturing

some industries design future recycling into their products

• ex: automobile manufacturers build cars they can be easily taken apart w different materials of composition ez to separate for recycling

• design carpets so when they wear out, it’s easy to recycle for new carpeting

• turtles create shells without making toxic waste - observe turtles to make production with less toxic materials

• upcycle something of lesser value to something w more value

Module 52: Sewage Treatment

Lesson 52.1: What three major problems are caused by wastewater pollution?

three major reasons for wastewater pollutant concerns

• decomposition by bacteria created large oxygen demand in water

• nutrients released from decomposition can make land fertile

• carries lots of pathogens

Oxygen Demand

as waste increases, microbes increase, increased oxygen demand

• biochemical oxygen demand: The amount of oxygen a quantity of water uses over a period of time at specific temperatures

  • measure initial dissolved O2, incubate 5 days 20 C and measure second dissolved O2 → 2nd - 1st = amount of consumption done

  • low BOD → less pollution from wastewater

large microbial demand → less oxygen for other organisms

• positive feedback as more fish die and get decomposed

Nutrient Release

cultural eutrophication: An increase in fertility in a body of water, the result of anthropogenic inputs of nutrients

• wastewater contains phosphorus and nitrogen nutrients

algal blooms → rapid growth of algae

• dies, microbes digest dead algae, consuming bunch of dissolved oxygen → dead zones

• most caused by human activities

Disease-Causing Organisms

worldwide, drinking water source same as bathing, washing, sewage → pathogens via contact or ingestion

major waterborne diseases - cholera, typhoid fever, hepatitis, dysentery

• hepatitis in USA from lack of restaurant sanitation

¼ population has insufficient supplies for access to drinking water

• 2.3 billion don’t have proper sanitation, half in India and China

Monitoring for Wastewater Contamination

fecal coliform bacteria: A group of microorganisms that live in the intestines of humans, other mammals, and birds that serve as an indicator species for potentially harmful microorganisms associated with contaminated sewage

public water supplies routinely tested for e coli

• acceptable e coli amount for swimming higher than drinking (0)

• beaches thus can close from animal feces

Lesson 52.2: How do we treat wastewater to prevent pollution?

all solutions follow same basic approach

• bacteria used to break organic matter into CO2 and inorganic compounds → N, P

• harmful pathogens outcompeted by nonharmful

Septic Systems

septic system: A relatively small and simple sewage treatment system, made up of a septic tank and a leach field, often used for homes in rural areas

• septic tank: A large container that receives wastewater from a house as part of a septic system and buried underground adjacent to the house

• wastewater enters one end, leaves another

• three layers form

  • top: scum

  • middle: septage: A layer of fairly clear water found in the middle of a septic tank; can contain lots of bacteria and N/P

  • bottom: sludge: Solid waste material from wastewater

leach field: A component of a septic system, made up of underground pipes laid out below the surface of the ground

• small holes → septage seeps out of pipe, slowly absorbed and filtered by surrounding soil

• harmful bacteria outcompeted by nonharmful bacteria or get degraded, organic matter break into CO2 and inorganic nutrients

• soil filtered water taken by plants or aquifer

no electricity needed to run system bc they rely on natural gravity to make water flow downhill to the tank

• sludge must be pumped every 5 yrs and taken to a plant

Sewage Treatment Plants

septic systems not feasible for urban areas w little open land

• developed → use centralized sewage plans from multiple houses via underground pipes

• wastewater gets primary and secondary treatment

primary treatment involves physical removal of large objects by filtering through grates → settles sludge layer

• secondary treatment → bacteria breaks down 90% of organic matter in remaining wastewater, converts it to CO2 and inorganic nutrients

• aerates the water and adds oxygen → more aerobic bacteria, less bad smell than anaerobic

• treated water settles, settled particles added to sludge

before sludge taken away from plant, exposed to bacteria so it’s lighter n less disease

• landfill, burned, or fertilizer pellets

very effective at breaking down into CO2 and nutrients

• bad effects on waterways they r released into

  • algal blooms from nutrients

  • tertiary treatments - physical, chemical treatments to remove inorganic compounds (nutrients, metals) and pathogens often via precipitating or mesh filters or disinfection

Legal Sewage Dumping

even in developed countries, raw sewage can directly be dumped into water bodies

• treatment plants handle local house and industry wastewater

• older plants get water from stormwater drainage systems; when it rains, it overwhelms the capacity → pump water into adjacent body

concentrated in older cities in northeast and midwest

• contaminates water, beaches, fishes/shellfish → human illness

straightforward and expensive answer: modernize systems to prevent influx of stormwater

• expensive long tunnels are dug for such things

Animal Feed Lots and Manure Lagoons

small scale → animal manure contaminates local water sources w hormones n antibiotics

farms w lots of animals use manure lagoons

• after bacteria break down manure w the same processes, manure spread onto farm as fertilizer

• leak in lining risk → groundwater/soil contamination

• overflow into nearby water risk → disease in organisms

• if used as a fertilizer, runoff

Module 53: Lethal Dose 50% (LD₅₀) and Dose-Response Curves

Lesson 53.1: How are dose-response curves used to estimate lethal doses of chemicals?

three techniques to determine harmful concentrations
Dose-Response Studies

dose-response studies: A study that exposes animals or plants to different amounts of a chemical and then looks for a variety of possible responses, including mortality or changes in behavior or reproduction; 1-4 days for efficiency

• acute studies: An experiment that exposes organisms to an environmental hazard for a short duration

• chronic studies: An experiment that exposes organisms to an environmental hazard for a long duration

most commonly measure mortality responses; graphs follow an S-curve typically

• threshold - dose at which an effect can be detected

LD₅₀: The lethal dose of a chemical that kills 50 percent of the individuals in a dose-response study

• estimate by draw horizontal line from 50% y-axis until it intersects the curve

assesses relative toxicity of a chemical for a certain species, like comparing LD₅₀ of new chemical to older chemicals

chronic studies done from birth to maturity

sometimes, scientists measuring in other stuff like teratogens, carcinogens, neurotoxins

• sublethal effects: The effect of an environmental hazard that does not kill an organism but which may impair an organism’s behavior, physiology, or reproduction

• ED₅₀: The effective dose of a chemical that causes 50 percent of the individuals in a dose-response study to display a harmful, but nonlethal, effect

• no-observed effect level (NOEL): The highest concentration of a chemical that causes no lethal or sublethal effects

LD₅₀ Studies

Toxic Substances Control Act of 1976 allowed EPA to regulate chemicals, but not food cosmetics, and pesticides (separate law for pesticides 1996)

• won’t cause unreasonable bad effects

scientists developed a method of testing the most sensitive bird, mammals, fish, and invertebrates

• regulations to protect the most sensitive apply to the rest → extrapolate results from mice and rats, representing all mammals

• pigeons/quails for birds, trout for all fish, water fleas for all invertebrates

no separate standards for reptiles/amphibian bc nobody cared

• aquatic → fish, terrestrial → bird

LD50 and ED50 levels determine concentrations in the environment that do no harm

• usually, LD50/10 is a safe concentration

regulatory agencies r conservative in setting concentrations for humans

• LD50/ED50 values for mice, divide by 10 for safe mice/rats, divide by 10 again bc humans r more sensitive, and divide by 10 again for extra caution

Lesson 53.2: How do we estimate potential harm of chemicals in the environment?

three steps to risk analysis

1. Risk Assessment

   1. Identify hazard

   2. Characterize toxicity (dose/response)

   3. Determine exposure extent

2. Risk Acceptance

   1. Determine acceptable level of risk

3. Risk Management

   1. Determine policy with input from private citizens, industry, and interest groups.

Risk Assessment

risk analysis seeks to find a potential hazard and determine how bad it can harm

• two types of assessment: qualitative and quantitative

• environmental hazard: Anything in the environment that can potentially cause harm

  • substances like pollutants/chemicals, human activities like driving, natural catastrophes like volcanoes

qualitative judgments → low, medium, high risk

• personal risk assessments, e.g. slowing down on a highway, are not quantitative and often don’t match actual risk

• make sure perception of risk matches actual risk

data on probability of death from various hazards

• can determine probabilities quantitatively

• however, our perception messes w this; when we see news and media talking a bunch abt nuclear meltdown damage, we think it’s more dangerous than an airplane

• we downplay risks that give us cultural, political, economic advantages

→ Quantitative Risk Assessment

Risk = probability of being exposed to hazard * probability of being harmed if exposed

→ A Case Study in Risk Assessment

noticed PCB might have harmful effects - live damage, impaired learning

now, start risk assessment

• exposed rats to diff concentrations of PCBs; examined cancer cases of workers w PCBs

• determine concentrations people experience → examine current concentrations in air, soil, water and half-life

• persistent → high probability of PCB contact; contamination routes include eating fish, drinking water, breathing air

eating fish > water > breath → policies in Massachusetts: warned about not eating fish caught

• risk of developing cancer is low, but high enough to dredge Hudson River and remove lots of settled PCBs

Risk Acceptance

second step - level of risk that can be tolerated

• conflict bw those willing to have some risk and those who want no risk

• EPA - 1 in 1 million is acceptable for most environmental hazards

  • some think too high, some think the minimal risk from nuclear deaths is worth less compared to electricity generation

Risk Management

integrates 1st and 2nd steps w economic, social, ethical, political issues

• always trade offs when deciding amount of chemical allowed in environment; regulatory activity carried out by government

example: arsenic in drinking water for assessment v. management

• even if 50ppb killed arsenic, FDA kept max at 50 ppb; then lowered it to 10ppb, which economically hurt mining companies and western states w high arsenic water

• returned to 50 ppb, but new analysis determined 5ppb, so then they settled at 10ppb

Lesson 53.3: What are the major philosophies of regulating chemicals in the environment?

key factor to determining type of chemical regulation is guided by innocent-until-proven guilty principle or precautionary principle

innocent-until-proven guilty principle: A principle based on the belief that a potential hazard should not be considered an actual hazard until the scientific data definitively demonstrate that it actually causes harm

• beneficial chemicals added sooner, but chemicals can affect wildlife for a while before scientists determine enough evidence for harm

precautionary principle: A principle based on the belief that when a hazard is plausible but not yet certain, we should take actions to reduce or remove the hazard.

• scientific basis and intervention in proportion to hazard → fewer harmful chemicals enter environment

• if chemicals indicates plausible risk and it proves harmless but beneficial, introduction for use can be delayed → less financial motivation for manufacturers to invest in research for new chemicals

• great safety and slow addition vs greater potential risk and fast addition

• most of world and Europe uses precautionary, USA uses innocent until proven guilty

benefit of precautionary principle example: asbestos

• first mined → no evidence of harm 1879; deaths in 1906 → test mice 1911 shows harmful effects → 1930s lots factory workers suffered → 1955 high lung cancer isk → 1965 rare cancer

despite growing evidence, little was done

• EU didn’t ban until 1998 → extra PPE → 250k-400k people today will die from past exposure to asbestos, could’ve been prevented with precautionary principle

• netherlands banned in 1965 → less deaths and wayyyyy less expensive

International Agreements on Hazardous Chemicals

stockholm convention: A 2001 agreement among 127 nations concerning 12 chemicals to be banned, phased out, or reduced.

• DDT pesticides, industrial PCBs, certain by-product chemicals of manufacturing

• all known endocrine disruptors and banned or declining in use

• all countries tg in forum to discuss controlling most harmful chemicals - huge achievement

REACH: A 2007 agreement among the nations of the European Union about regulation of chemicals; the acronym stands for registration, evaluation, authorization, and restriction of chemicals

• embraces precautionary principle → more responsibility on chemical manufacturer

• enacted bc many chemicals didn’t have rigorous risk analyses

• phased in thru 2018 to allow sufficient time for required testing

Module 54: Pollution, Human Health, Pathogens, and Infectious Diseases

Lesson 54.1: How can we establish cause and effect between pollutants and human health?

other than testing on mice and extrapolating, another way to test effects of chemicals is studying populations already exposed everyday

• two ways of conductive this research

1) Retrospective Studies

retrospective studies: A study that monitors people who have been exposed to an environmental hazard such as a harmful chemical at some time in the past

• two groups usually - exposed to in past, never exposed, monitored for several years

• helps determine immediate and chronic effects on development, births, body systems, etc.

help identify harmful effects of many common pollutants

• exposed to vs not raw sewage → lots of bad chemicals and pathogens → emphasis on good sewage treatment worldwide

• asbestosis!

• tropospheric ozone → lung damage

2) Prospective Studies

prospective studies: A study that monitors people who might become exposed to an environmental hazard, such as a harmful chemical in the future

• ask lots of participants to keep track of their habits for many years → determine if associated with future health problems

• difficult cs lots of other risk factors, like socioeconomic status, included

• synergistic interactions: A situation in which two risks together cause more harm than expected based on the separate effects of each risk alone

  • asbestos and smoking

lead poisoning in children is usually prospective

• studied lead on children’s intelligence

• accounted for other factors like mother’s IQ, tobacco exposure, intellectual development in home

• high lead exposure = lower IQ

Lesson 54.2: What are the different types of human diseases?

¾ of death caused by disease: Any impaired function of the body with a characteristic set of symptoms

• infectious disease: A disease caused by a pathogen

  • ¼ of all deaths

pathogens include everything yk + parasitic worms helminths

• 4 types of infectious disease make up ¾ of all infectious disease deaths

• respiratory infections, HIV/AIDs, tuberculosis, diarrheal diseases

acute diseases: A disease that rapidly impairs the functioning of a person’s body

• chronic diseases: A disease that slowly impairs the functioning of a person’s body

Risk Factors for Chronic Diseases in Humans

risk factors very diff between low and high income countries

• low income → malnutrition, poor sanitation, underweight, bad drinking water

• high income → less young age deaths and more lifestyle diseases - tobacco, less activity, poor nutrition, overeating → obesity and blood pressure

Lesson 54.3: What historic human pathogens have cycled through the environment?

historically, pathogens have big toll on human health and mortality

• epidemic: A situation in which a pathogen causes a rapid increase in disease

• pandemic: An epidemic that occurs over a large geographic region, such as an entire continent

• diseases associated w bad sanitation and water → cholera, hepatitis

• dysentery: An infection of the intestines that causes diarrhea, which results in dehydration and can cause death; often caused by cholera

• hepatitis can be caused by direct transmission bw 2 people, contaminated food

3 historically important diseases cycled bw environment and host

Plague

plague: An infectious disease caused by a bacterium (Yersinia pestis) that is carried by fleas

• transmitted by flea bites or handling rodents

• swollen glands, black spots, bad pain

• still small outbreaks bc of few rodents; modern antibiotics work very well

Malaria

malaria: An infectious disease caused by one of several species of protists in the genus Plasmodium.

• one stage of life in mosquitoes, next stage in humans

• recurring flulike symptoms

• hardest in subsaharan africa, asia, middle east, central/south america

• USA malaria usually from travel

• traditionally, insecticides with DDT were used to eradicate mosquitoes; ineffective

Tuberculosis

tuberculosis: highly contagious disease caused by the bacterium Mycobacterium tuberculosis that primarily infects the lungs

• spreads thru coughing and droplets, persists in air, infects via inhalation

• weakness, cold sweats, coughing blood

• 1/3 of world has infection, but few million get disease and die

year long antibiotics usually fixes infection in USA → huge drop in cases and deaths

• leading cause of death by disease elsewhere in the world → medicine not accessible, not properly taken for full duration

  • pathogens quickly rebuild, last few bacteria most drug resistant

  • drug resistant strains r becoming new concern for new medicine

Lesson 54.4: What are the major emergent infectious diseases in humans?

emergent infectious diseases: An infectious disease that has not been previously described or has not been common for at least 20 years

• at least 1 emergent disease per year; usually from diseases in animal hosts that happen to accidentally go to humans → rapidly mutate, new genotype for infecting humans

• usually local, then spread across world

• animal to human diseases include: hiv/aids, ebola, mad cow, bird flu, SARS, west nile virus

• concern bc of increased movement of ppl and cargo

HIV/AIDs

Acquired Immune Deficiency Syndrome: An infectious disease caused by the human immunodeficiency virus (HIV)

• Human Immunodeficiency Virus: A type of virus that causes Acquired Immune Deficiency Syndrome (AIDS

  • spreads through sex and blood transfusions - mother to kid, shared needles

hypothesized to have come from contact and consumption of chimps in africa

new antiviral drugs help maintain low viral levels + expand life expectancy

• combinations of drugs to avoid evolving resistance → expensive and hard for low-income, but still increasing in availability and distribution

Ebola Hemorrhagic Diseases

ebola hemorrhagic fever: An infectious disease with high death rates, caused by several species of Ebola virus

• first DRC → central africa; big issue bc has high mortality once infected

• fever, vomiting, in and ex bleeding

• kill other primate at high rates; they can’t have it, where is it from? → fruit bats

• 2019 first ebola vaccine approved

Mad Cow DIsease

mad cow disease: A disease in which prions mutate into deadly pathogens and slowly damage a cow’s nervous system.

• prions: A small, beneficial protein that occasionally mutates into a pathogen

• lose control of nervous system :(

transmits to humans by eating beef

• prions hard to destroy even with cooking

• CJD disease

transmits only through consumption of another cow w disease

• 1980s → cows ate other ground up cow, spread disease rapidly, spread to humans

• can exist for many yrs before causing symptoms

• hugely decreased cs no more cattle to cattle!

Swine Flu and Bird Flu

swine flu: A type of flu caused by the H1N1 virus

• sometimes jumps from pigs to humans → may be lethal

• vaccines help

bird flu: A type of flu caused by the H5N1 virus

• people w close contact to birds; not deadly in wild birds but yes in domesticated birds

• no evolutionary history w H5N1 → little defenses, high mortality

• declined, but worried abt future mutation

SARs, MERS-CoV, and SARS-CoV-2

severe acute respiratory syndrome: A type of flu caused by a coronavirus

• first in southeast asia → similar respiratory symptoms

• wild animal infects person, then spreads

MERS-CoV: A coronavirus that causes the disease known as Middle Eastern Respiratory Syndrome

• camels

SARS-CoV-2: A coronavirus that causes the disease known as Covid-19

• traveled and rapidly spread globally → rapidly developed vaccines had good defense + social distancing + protective masks

West Nile Virus

west nile virus: A virus that lives in hundreds of species of birds and is transmitted among birds by mosquitoes

• most birds survive, mosquitoes bite horses n humans n then it gets bad

• 1999 in NYC → spread to USA

• now, ez to combat mosquito populations and protect against bites, declined

Lyme Disease

Lyme Disease: A disease caused by a bacterium (Borrelia burgdorferi) that is transmitted by ticks

• hatches on forest floor → first attached to birds and small rodents → if infected, tick can also get infected cs feeding on → attach to larger mammals in winter → kiss humans n infect them

infections in northeast USA

• red bullseye mark, flu, arthritis symptoms, neurological disorders

• modern antibiotics work, some problems may persist

• first discovered in schoolchildren in lyme

Zika Virus Disease

zika virus disease: disease caused by a pathogen that causes fetuses to be born with unusually small heads and damaged brains

• bitten thru mosquito or sex w infected person

• mostly mild effects of fevers and rashes weeks after infection, but huge risk of transferring to fetus while pregnant

• rapid spread over time → no cure, just limit mosquitoes

Future Challenges to Human Health

combat diseases in low income

• nutrition, more availability of clean drinking water, better sanitation

high income

• more physical activity, balanced diet, limit tobacco and alcohol

educate everywhere

pathogen resistance is a big concern, esp when developing country people pause their medication

changing climates bring mosquitoes and diseases to new areas and infect new people

no experience to new diseases and no prediction → must develop rapid response plans

• better notification and quarantine strategies → slow spread, give time for researchers

Lesson 54.5: What laws protect human health from pollutants and pathogens?

two important laws for aquatic pollution and pathogen protection in USA

The Clean Water Act

Clean Water Act: Legislation that supports the “protection and propagation of fish, shellfish, and wildlife and recreation in and on the water” by maintaining and, when necessary, restoring the chemical, physical, and biological properties of surface waters

• not groundwater, passed in 1972

• Federal Water Pollution Control Act 1948 → first major water quality bill

• 1960s → water quality poor, growing awareness encouraged series of laws

traditionally focused on chemical aspects of water, new attention to biological aspects like species

• acceptable limits of pollutants in waterways → EPA and state controls how much pollution cities and industries dump

The Safe Drinking Water Act

safe drinking water act: Legislation that sets the national standards for safe drinking water.

• maximum contaminant levels: The standard for safe drinking water established by the EPA under the Safe Drinking Water Act for 77 things in surface/ground water

• account for harm and ease of reducing concentration

• arsenic has 10ppb, e coli has 0

subjective to economic and political pressures

overall very successful

• bodies of water based on purpose, determine if a waterway fully supports designated uses

• municipal water systems are generally safe bc water regulations eliminated big point sources, nonpoint sources not covered and fracking too

Water Pollution Legislation in the Developing World

developed countries underwent industrialization and had horrible air and water quality, but then enacted legislation to clean up areas and prevent future problems

developing countries are still industrializing → hard to afford water-quality investments + political instability and corruption

• polluting industries outsourced to developing nations; benefit from new jobs associated with their creation, but still pollution sucks

water pollution prevalent problems in africa, asia, latin america, eastern europe

• china and india industrialized n sm people - uh oh

• more affluence → more interest in addressing environmental issues, i.e. Tiete river

Unit 9: Global Change

Module 55: Stratospheric Ozone Depletion and its Reduction

Lesson 55.1: How does stratospheric ozone form and what benefits does it provide?

Formation of Stratospheric Ozone

O₂ + UV-C → O + O

• very short duration bc O mostly stays as O₂

then, a free oxygen atom from that reaction meets with O₂

• O + O₂ → O₃

UV-B and UV-C can break this ozone into atomic and compound oxygen

• O₃ + UV-B or UV-C → O₂ + O

indefinitely occurs as long as there is UV

• normal conditions → ozone amount stays constant

Benefits of Stratospheric Ozone

ozone filters out harmful UV radiation

• all types of UV can damage tissue of organisms

• UV-B specifically increases skin cancer, cataracts, bad immune response, less photosynthesis in plankton → food chain impacted

stratospheric ozone is good, tropospheric ozone is bad

Lesson 55.2: What has caused the depletion of stratospheric ozone?
The Chemical Reactions between CFCs and Ozone

chlorofluorocarbons: Chemical that can be used for cooling refrigerators and air conditioners

• also in aerosol spray cans and Styrofoam, essential to modern life + multibillion industries

• seemed safe bc nontoxic and nonflammable

CFCs released into the air in use and in landfills, and they release chlorine that can react with ozone

• O₃ + Cl → ClO + O₂

chlorine monoxide reacts with a free oxygen

• ClO + O → Cl + O₂

ozone and free oxygen make 2 oxygen molecules, but chlorine starts and ends as free chlorine

CFC Destruction of the Ozone Layer

stratospheric ozone has been overall decreasing, depleting most at the poles

• occurs august through november → '“ozone hole”

key cause is CFCs bc when they r exposed to UV, they break into Cl

• Cl reacts with ozone to make O₂

• manufacturing more CFCs → more chlorine in stratosphere → destruction of ozone each spring (southern hemisphere))

as ozone decrease, UV-B radiation reaching earth increased, esp in Antarctica

Lesson 55.3: What efforts have been made to reduce ozone depletion?

montreal protocol: A commitment by 24 nations to reduce CFC production by 50 percent by the year 2000

• new coolers and propellants developed → HFCs, which are still a greenhouse gas

CFC concentration in atmosphere has been declining and chlorine too

• depletion of ozone should decrease in following decades, and decrease skin cancer maybe

Module 57: Increases in the Greenhouse Gases and Global Climate Change

Lesson 57.1: How have CO₂ concentrations changed over the past 7 decades?

IPCC - Intergovernmental Panel on Climate Change

• understand effects of and mitigate effects of climate change

• new understanding of greenhouse gas and temp link, esp CO₂

Measuring CO₂ Concentrations

earlier, most assumed excess CO₂ absorbed by oceans and vegetation, and it’s so little it’s hard to measure

Charles Keeling was the first to overcome hard measuring of CO₂

• u dont need 2 separate measurements years apart, so Keeling measured CO₂ in hawaii for a year → varied seasonally, increased each year

seasonal variation bc each spring, plants turn green and increase absorption of CO₂

• also, warmer bodies of water → algae more active

CO₂ Emissions Among Nations

most carbon dioxide produced in the developed world

• however, as developing nations industrialize, this number is changing

• 2009 → developing passed developed in carbon dioxide production, esp in China and India

  • however, lower per capita emissions  in developing, more in developed

Lesson 57.2: How have temperatures and greenhouse gases varied historically?

since 1880, there’s been enough direct land and ocean temp measurements to generate a global temperature change over time graph

• increased 1.1 C F, seven warmest years 2014-2020

not even distributed globally

• antarctica and other areas cooler, some areas unaffected, but extreme northern latitudes have 1 to 4 C increase - northern ice cap melting

gradual warming over last century, but it’s also part of a natural warming

• scientists estimate temp changes based on preserved protists (foraminifera) → major periods of cooling and warming

• ancient air bubble isotopes with increasing and decreasing co2 concentrations

1958-present, CO₂ concentrated went from 300ppm to 415ppm!!

methane and nitrous oxide dramatically increased bc of industrial revolution

Climate Models Predicting Future Global Temperatures

determine how well a model approximates by applying it to a time in the past where we have accurate data on temperature, vegetation, co2, ice coverage, etc.

• modern models r fairly accurately produce temperature fluctuations over large spatial scales

not 100% accurate but huge confidence

• if multiple models predict similar changes, increased confidence

• generally agree temp rise 1.8 to 4 C by 2100, depending on CO2 emissions

expect climate change

• more extreme weather

• change in precipitation and ocean currents

  • some regions benefit from more yields and recharged aquifers

  • but also flooding, soil leaching, erosion

  • less precipitation elsewhere - famine, drought, water

Lesson 57.3: How has global climate change affected the environment?

Melting Polar Ice Caps

ice cap significantly reduced, collected each september

• thinner remaining ice - vulnerable to future melting

• arctic expected to warm 4 to 7 more C → large openings in sea ice

ice melting in greenland and antarctica

• ice cap loses thickness, so overall mass reduced

• sea levels rise

Melting Glaciers

glaciers dramatically disappearing

loss of ecosystem services

• recreation

• clean water source - if melts too fast during summer, none in winter

• more exposed soil, less albedo, more warmth, positive feedback loop

Ocean Currents

more fresh water released from ice, changing currents and heat distribution

• more melting from greenland and north ice cap dilutes thermohaline salty cold water to stop it from sinking in greenland, cutting off thermohaline circulation

• europe gets way colder temp

Warming Soils and Permafrost

high temps → more activity in carbon packed soil → increased decomposition → more CO2

melting permafrost makes overlying lakes smaller as water drains deeper

• problems w buildings built on permafrost like houses and oil pipelines

lots of organic matter in tundra permafrost will decompose

• wet, low oxygen conditions → decomposition releases a lot of methane

• melts more, more methane positive feedback loop

Rising Sea Levels

rising temp affects sea levels 2 ways

1. water from glaciers and ice sheets adds to volume of water

2. as water expands, the ocean becomes warmer

endangers coastal, low lying cities

• saltwater intrusion in aquifers, more soil erosion

• some countries use dikes on shoreline to mitigate flood

• poor countries can’t respond as well

• new habitats for aquatic organisms along flooded shorelines

• deep water species no longer in photic zone

Lesson 57.4: How is global climate change affecting populations?

temperature-induced changes in plant flowering and animal behavior + ability of plants and animals to find more hospitable habitats

• northern hemisphere plants’ growing season increased in highest latitudes w most temp change

• everything breeds and plants and comes earlier

• grape growers in France having hard time bc too warm and diff rain, but in England, the warmth is helping them

effects on human health and agriculture

• disease vectors shift north → affect human health and crop pests make food decline

• people move

rapid changes harm organisms if they don’t adapt or move in time

• historically, organisms migrate - so temp changes r not usually catastrophic

• now, habitat fragmentation allows global warming to promote species extinction

flycatcher example

• bc of global warming, trees produces leaves earlier and peak caterpillar abundance is two weeks earlier than normal

• however, bird hatching still the same, so when they hatched, there wasn’t enough caterpillars and they suffered :(

arctic experiencing extreme effects

• polar bears hunt seal blubber (good energy) by searching for holes in ice and pouncing on seals that come up

• rest of carcass important for arctic fox

• fewer weeks polar bears can stand on ice to hunt cs ice melts earlier → polar bears lost sm weight

• less seal predation, less carcasses for other organisms

• polar bear in hudson bay declining, increasing in or stable in arctic

new skipping lines - reduce distance ships have to travel

• lots of oil and natural gas under polar cap, but fossil fuels bad

Module 58: Ocean Warming and Ocean Acidification

Lesson 58.1: How is ocean warming altering ocean ecosystems?

2 C warming in bodies of water

Impacts on Marine Species

alters species distribution bc each species has diff optimized factors

• others migrate to better temp, those in higher latitudes can’t really

southern fish moved to northern sea bc of warmer temps there

• incoming species worth less, departing fish species worth more

corals at risk bc low temperature range

• coral bleaching → stressed colors eject mutualistic algae that provide coral w energy → coral turns white

• long lasting → death

Lesson 58.2: How does climate change affect ocean pH?

more co₂ absorbed by oceans

• CO₂ + H₂O → H₂CO₃ → releases positively charged hydrogen atoms (protons)

• CO₂ quickly reacts with H₂O to form H₂CO₃ (acid) that releases H⁺

• equilibrium reaction

• ocean acidification: A process in which an increase in ocean causes more to be converted to carbonic acid, which lowers the pH of the water.

problem for species that build shells and skeletons made of calcium carbonate

• pH decreases, calcium carbonate dissolves and saturation point for calcium carbonate declines → less material for shells and skeletons + break down

• decline of corals = high temp + low pH + more coral disease

affects behavior of organisms

• less ability to detect predators

• sea urchins grow smaller, while lobsters grow larger and thicker shells as a response

• some species perform better

affects human health and food supply

• declining pH → huge monetary loss in shellfish industry

• threatens jobs

• algae produce more toxins harming humans

Lesson 58.3: What are the international agreements on global climate change?

nations must work tg → developing nations have it worse cs worse effects and less benefits

Kyoto Protocol: An international agreement that sets a goal for global emissions of greenhouse gases from all industrialized countries to be reduced by 5.2 percent below their 1990 levels by 2012.

• varying emission reduction per country; developing nations didn’t bc they argued that the poorest didn’t contribute but have been exposed

• countries w historically most emitting co2 must pay costs to reduce co₂

based off precautionary principle

• enough evidence to see humans altering earth → stabilize gg concentrations by reducing or removing them

• first option) increase fuel efficiency or switch to better options

second option) carbon sequestration

• taking co2 out of atmosphere, like storing in soils, former farms, forests, and pastures

  • atmospheric carbon returns as plant biomass and soil carbon

• cost effective ways to capture atmospheric and power plant co2 being researched → compressed and pumped into old wells or ocean

developed countries → reducing co2 means we gotta change a lot of things, huge expenses and economic impact

• kyoto protocol not legally binded to the US because Senate voted that US won’t agree to any international agreement that lacked restrictions on developing nations

• 192 countries ratified this (most developed and developing), though 100 developing like india and china are exempt

• US is the only unratified developed one

US gov takes more steps to regulate co2 emissions

• 2007 → SCOTUS said EPA can regulate greenhouse gases thx to Clean Air Act + REQUIRED to do so, so 2009 EPA started regulating

• automakers increased fuel efficiency → invest in new tech, less fossil fuels, save money

mixed co₂ emissions

• germany, russia, and USA have significantly decreased bc of fuel efficiency or natural gas use

• canada increased

Paris Climate Agreement: A pledge by 196 countries to keep global warming less than 2°C above pre-industrial levels. Also known as the Paris Climate Accord

• each nation decides itself how they wanna contribute, went into effect 2020

• no enforcements by UN

Module 59: Invasive Species, Endangered Species, and Humans Impacts on Biodiversity

Lesson 59.1: What are the threats posed by invasive species?

native species - historical range, exotic species out

• exotic species that quickly spread across large areas, decline native species, harm ecosystems, or negatively impact humans - invasive species

r selected, generalist species - mosquitoes, Norway rats

Great Lakes lots of invasive species introduced from other ships

• zebra mussel from black sea quickly grow - outcompete native mussels, clams, etc.

• clog pipes, impede flow of industrial water

• most r too numerous to be controlled, arriving on every continent

most arrive accidentally, some intentionally introduced like honeybees from Europe

• good for honey and pollination, but decline native populations

kudzu vine from japan and southeast china

• planted in southeast to reduce erosion, great climate rapid growth

• grows so fast, overshadows sm flowers and trees

silver carp from Asia spread quickly thru rivers

• may outcompete native species for algae

• randomly jumps out and attacks boater

act as predators, pathogens, competitor

Controlling Invasive Species

remove aquatic plants when they r first observed and low in abundance

introduce enemy from their native range

• cactus introduced from south america to australia and outcompeted plants with sheeps grazed on

• cactu moth eats prickly pear and reduces abundance

best way to reduce is to prevent - prohibit untreated wood crates to prevent pests

Lesson 59.2: Why are species becoming endangered?

The Percentage of Endangered Plants and Animals

extinct species existed in 1500 but no longer exist today

• endangered species: Species that are likely to go extinct in the near future

• threatened species: likely to go to endangered soon

• near-threatened to be threatened later

• least-concern r widespread and abundant

International Union for Conservation of Nature had 50k

• 1/3 are threatened / endangered

• higher for reptile and mammals, highest conifers and amphibians

Cause of Endangered Species

human activities make it harder to survive and adapt fast enough

• overharvest, clear habitat, competitors

Lesson 59.3: How are human activities affecting genetic biodiversity?

low genetic diversity - cant survive cs theres not enough phenotypes and not enough mutations

cheetahs have little genetic diversity, florida panther

Declining Genetic Diversity of Domesticated Species

38 species of livestock come from 7 mammals and 4 birds

• bred for diff characteristics to survive their location

farmers breed based on economic productivity

green revolution - fewer crop varieties w only high yield ones

• lost 75% of crop diversity

• very vulnerable if environmental conditions change

store seed diversities in special warehouses for the future - Svalbard Global Seed Vault Norway

• designed to resist global warming and natural disaster, but at risk of destruction from warfare

Lesson 59.4: What are the causes of declining biodiversity?

underlying cause for less biodiversity is human increase - less habitats, more invasive species, population growth, pollution, climate change, and overexploitation

Habitat Destruction

human development removes natural landscapes, replaces with homes, industries, fields, malls, roads

• specialists r prone to population declines

forests have been destroyed for lumber and agriculture historically, humans replanted them but not as diverse

• developing areas - accelerated clearing

woodland/shrubland in mediterranean also lost a lot of land, and wetlands

carribean losing a lot of coral - warming oceans, pollution, removal

species can decline without full destruction

• no cooler areas to go during winter - animals cant go

• some larger species need more undisturbed land

increased interactions with harmful species

Invasive Species and Human Population Growth

increased demand for resources from nature

Pollution

toxic contaminants, endocrine disruptors, nutrient pollution, thermal pollution

huge oil spill, used chemical dispersant to cleanup but thats also harmful/

Climate Change

species have varying responses to diff climate change

Overexploitation

most direct - used faster than can be replenished, recent past

• more legal protections

billions of passenger pigeons shot/caught at once

• tried replenishing, but lay one egg at a time

increased federal regulations

• poaching: harvesting outside of seasonal time

• international treaties r very successful

• however, not enforced or illegal everywhere, esp for rare sought after species

Lesson 59.5: How do we conserve biodiversity?

Conservation of Single Species

one species at a time

• increase ideal conditions, or if very few, capture and breed them

• major functions of zoos and aquariums

• many laws

→ The Lacey Act 1900

Lacey Act: A U.S. act that prohibits interstate shipping of all illegally harvested plants and animals

→ The Maine Mammal Protection Act

marine mammal protection act: A 1972 U.S. law that prohibits the killing of all marine mammals in the United States and prohibits the import or export of any marine mammal body parts

→ The Endangered Species Act 1973

Endangered Species Act: A 1973 U.S. law designed to protect plant and animal species that are threatened with extinction, and the habitats that support those species

authorized US fish and wildlife service to categorize species and prohibit their harming

• purchase habitat to conserve these species

as of 2022, 1600 species r endangered or threatened

controversial bc restricts human usage of their land - less construction, limits people’s jobs

lack of personnel and funds to enforce law

→ Convention on International Trade in Endangered Species of Wild Fauna and Flora

CITES: A 1973 treaty formed to control the international trade of threatened plants and animals.

• each country has agency to monitor and regulate spread of species on Red list

still occurs

Conserving Entire Ecosystems

worried about mass sixth extinction - preserve biodiversity hotspots, increased protection rates

→ Configuring Protected Areas

apply theory of island biogeography

• protected areas are far apart - less species travel, so if lost from one ecosystem, hard to recolonize

• small areas should be close enough for species to move between

single large area supports lot, but a species is more likely to survive if scattered in multiple small areas

• SLOSS - single large or several small

• due to human development, several small may be the only viable option

• also determine how much edge habitat we should care about

→ Biosphere Reserves

we want to preserve pretty areas but not have tm human degradation - UNESCO made biosphere reserves: protected areas of zones that vary in permissible human impact

• buffer zone surounds core areas - modest tourism, environmental education, scientific research

• farther transition area - sustainable logging agriculture residence for locals

→ The Restoration of Habitats

restoration ecology - florida everglades and chesapeake bays

• restore water flow, nutrient inputs