Unit 8 Ap Environmental

8.1 Sources of Pollutants

Suggested Skill 1.A: Concept Explanation

  • Objective/EKs/Skill
      Describe environmental concepts and processes.

  • Learning Objective STB-3.A
      Identify differences between point and nonpoint sources of pollution.

  • Essential Knowledge
      - STB-3.A.1 A point source refers to a single, identifiable source of a pollutant, such as a smokestack or waste discharge pipe.
      - STB-3.A.2 Nonpoint sources of pollution are diffused and can therefore be difficult to identify, such as pesticide spraying or urban runoff.

Point vs. Nonpoint Sources of Pollution

  • Point Source:
      - Pollutant that enters the environment from an easily identified and confined place.
      - Example: A smokestack, waste discharge pipe (You can "point" to it).

  • Nonpoint Source:
      - Pollutants entering the environment from many places at once.
      - Difficult to "point" to one individual source.

Must-Know Pollution Examples

  • Point Source Examples:
      - Emissions from smokestack of a coal power plant (CO2, NOx, SO2, PM).
      - BP Oil Spill (hydrocarbons, benzene).

  • Nonpoint Source Examples:
      - Animal waste runoff from a Concentrated Animal Feeding Operation (CAFO) (ammonia (N), fecal coliform bacteria).
      - Urban runoff (motor oil, nitrate fertilizer, road salt, sediment).
      - Pesticides sprayed on agricultural fields carried by wind to bodies of water.

  • Note: Estuaries and bays are polluted by many nonpoint pollution sources from the large watersheds that empty into them.

Pollution Definitions

  • Pollutants:
      Specific chemicals or groups of chemicals from specific sources with specific environmental and human health effects.
      - Much more likely to earn credit on Free Response Questions (FRQ).

  • Pollution:
      Vague, nondescript term for any substance that is harmful to the environment.
      - Never acceptable on an APES FRQ.
      - On any pollution-related FRQ:
        1. Specific pollutant names:
           - Their sources.
           - Their environmental & human effects.
           - Their mitigation strategies.
      - Exceptions: Specific categories of pollution - Thermal pollution, Noise pollution, Sediment pollution.

Practice FRQ 8.1

  • Describe the difference between a point and nonpoint source of pollution.

  • Identify ONE point source of NOx emissions and ONE nonpoint source of NOx emissions.

8.2 Human Impacts on Ecosystems

Learning Objective STB-3.B

  • Objective/EKs/Skill
      Describe the impacts of human activities on aquatic ecosystems.

  • Suggested Skill 6.B: Mathematical Routines
      Apply appropriate mathematical relationships to solve a problem, with work shown (e.g., dimensional analysis).

Essential Knowledge

  • STB-3.B.1 Organisms have a range of tolerance for various pollutants.
      - Organisms have an optimum range for each factor where they can maintain homeostasis.
      - Outside of this range, organisms may experience physiological stress, limited growth, reduced reproduction, and in extreme cases, death.

  • STB-3.B.2 Coral reefs have been suffering damage due to a variety of factors, including:
      - Increasing ocean temperature.
      - Sediment runoff.
      - Destructive fishing practices.

  • STB-3.B.3 Oil spills in marine waters cause organisms to die from the hydrocarbons in oil.
      - Oil that floats on the surface of water can coat feathers of birds and fur of marine mammals.
      - Some components of oil sink to the ocean floor, killing some bottom-dwelling organisms.

  • STB-3.B.4 Oil that washes up on the beach can have economic consequences on:
      - The fishing industry.
      - The tourism industry.

Range of Tolerance

  • Organisms have range of tolerance for abiotic conditions in their habitat:
      - Factors include: pH, temperature, salinity (saltiness), sunlight, nutrient levels (ammonia, phosphate).

  • Organisms also have a range of tolerance for pollutants released into their habitats.

  • Pollutants can cause physiological stress such as:
      - Limited growth.
      - Limited reproductive function.
      - Difficulty breathing (respiring) potentially leading to asphyxiation (suffocation).
      - Hormonal disruption.
      - Death (if concentration of pollutant is high enough).

  • A significant theme in Unit 8 is explaining specific effects of pollutants on organisms.

Environmental Effects of Acid Rain

  • As pH decreases (more acidic) outside optimal range for a species, population declines.
      - When pH leaves the range of tolerance, organisms cannot survive at all, due to:
        - Aluminum toxicity.
        - Disrupted blood osmolarity (Na+/Cl- balance disrupted at low pH).

  • pH Tolerance:
      - Aquatic species have different pH tolerances.
      - Indicator species can be surveyed to determine conditions of an ecosystem (soil, water, etc.).
        - Example: High whitemoss/filamentous algae population indicates pH < 6.0.     - High crustacean population indicates pH > 6.0.

Temperature Tolerance of Reef Algae

  • Coral reef represents a mutualistic relationship between coral and photosynthetic algae called zooxanthellae.
      - Algae supply sugar and coral supply CO2 + detritus (nutrient containing organic matter).

  • Algae have a narrow temperature tolerance and leave the reef when temperature rises.

  • Coral loses color and becomes stressed and vulnerable to disease without algae (main food source).

  • Pollutants from runoff (sediment, pesticides, sunscreen) can also force algae from the reef.

Human Impacts on Coral Reef

  • Humans disrupt coral reef ecosystems via greenhouse gas emissions (warming ocean temperature & bleaching coral).

  • Urban and agricultural runoff also damages coral reef ecosystems:
      - Sediment pollution: Sediment carried into the ocean by runoff makes coral reef waters more turbid, reducing sunlight (photosynthesis).
      - Toxicants: Chemicals in sunscreen, oil from roadways, pesticides from agricultural runoff.
      - Nutrients (P/N): Ammonia from animal waste, nitrates/phosphates from agricultural or lawn fertilizers.

  • Overfishing decreases fish populations in coral reef ecosystem.
      - Bottom trawling can break reef structure and stir up sediment.

Oil Spill Effects

  • Hydrocarbons in crude oil (petroleum) are toxic to many marine organisms and can kill them.
      - Particularly if ingested (eaten) or absorbed through gills/skin.

  • Physiological effects include:
      - Decreased visibility.
      - Decreased photosynthesis due to less sunlight penetrating water surface.
      - Oil sticking to bird feathers.
      - Oil sinking to bottom, killing bottom-dwellers through direct toxicity or suffocation.

  • Oil can wash ashore, decreasing tourism revenue and killing fish, impacting fishing industry revenue.

  • Can harm restaurants that serve fish, and oil can settle deep in root structures of estuary habitats like mangroves or salt marshes.

  • Toxic to salt marsh grasses, killing them and loosening their root structure which can lead to coastline erosion and removal of habitats used by fish & shellfish for breeding grounds.

Oil Spill Cleanup

  • Oil spills can occur from underwater oil well explosions (e.g. BP Gulf Spill) or when tankers run into rocks/icebergs.
      - Cleanup can involve:
        - Booms on the surface to contain spread.
        - Ships with vacuum tubes to siphon oil off the surface.
        - Physical removal of oil from beach sand/rocks with towels, soaps, shovels.
        - Chemical dispersants sprayed on oil slicks to break up oil and sink it to the bottom (may clear up surface but can smother bottom-dwellers, and dispersant chemicals may be harmful).
        - Burning oil off surface.

8.3 Endocrine Disruptors & Industrial Water Pollutants

Learning Objective STB-3.C: Describe Endocrine Disruptors

  • Essential Knowledge
      - STB-3.B.7 Heavy metals used for industry, especially mining and burning of fossil fuels, can reach groundwater and impact the drinking water supply.
      - STB-3.B.10 When elemental sources of mercury enter aquatic environments, bacteria in water convert it to highly toxic methylmercury.
      - STB-3.C.1 Endocrine disruptors are chemicals that can interfere with the endocrine system of animals.
      - STB-3.D Describes the effects of endocrine disruptors on ecosystems.
      - STB-3.D.1 Endocrine disruptors can lead to birth defects, developmental disorders, and gender imbalances in fish and other species.

Endocrine Disruptors

  • Chemicals that interfere with the endocrine (hormonal) systems of animals.
      - Mechanism: Bind to cellular receptors meant for hormones, blocking the hormone from being received, or amplifying its effects.

  • Common Sources:
      - Human medications that pass through urine & into sewage or flushed down toilets (meant to influence human hormones, so they can also disrupt animals).
      - Examples: Atrazine (herbicide) binds to receptors in cells that turn on aromatase, causing male frogs to convert testosterone into estrogen, leading to:
        - High estrogen concentrations in males.
        - Low sperm count.
        - Even feminization (development of eggs in the testes or ovary formation).

Specific Endocrine Disruptors

  • Atrazine:
      - Broad-spectrum herbicide used to control weeds & prevent crop loss.
      - Can run off into local surface or groundwater or be carried by wind, contaminating human well-water.

  • DDT:
      - Broad-spectrum insecticide that was phased out but still persists in the environment.

  • Phthalates:
      - Compounds used in plastic and cosmetic manufacturing that enter surface & groundwater due to improper disposal and landfill leaching.

  • Heavy Metals:
      - Lead, arsenic, mercury are of particular focus in upcoming slides.
      - Many human medications that enter sewage via human urine or flushed medications.

Mercury

  • Naturally occurring in coal, released by anthropogenic activities:
      - Coal combustion, trash incineration, burning medical waste, burning limestone for cement.
      - Attaches to particulate matter (PM) released by burning coal and deposits in soil/water.
      - Endocrine disruptor that inhibits estrogen & insulin (interferes with menstrual cycles & ovulation).
      - Teratogen: Can accumulate in fetus brain & affects development.
        - Pregnant women can reduce risk by eating less seafood.

  • Mercury itself isn’t toxic, but bacteria in water sources convert it to methylmercury, which is highly toxic to animals (neurotoxicant that damages the central nervous system).

Arsenic & Lead

  • Arsenic:
      - Naturally occurring element that can be dissolved into drinking water.
      - Natural release into groundwater can be worsened by mining.
      - Carcinogenic and endocrine disrupting.
      - Can be removed with water filters.

  • Lead:
      - Found in old paint, water pipes, and soils.
      - Neurotoxicant that damages the central nervous system (especially in children).
      - Can be removed with water filters.

Coal Ash

  • Coal ash can be a source of mercury, lead, and arsenic.
      - Can attach to fly ash from smokestack and carried by wind, deposited far from source.
      - Both fly and bottom coal ash are often stored in ponds, dug into soils lined with plastic and can leach into groundwater.

Practice FRQ 8.3

  • Identify a toxic metal other than mercury that has a negative effect on human health and describe how it is introduced into the environment.

8.4 Human Impacts on Wetlands and Mangroves

Learning Objective STB-3.E

  • Describe the impacts of human activity on wetlands and mangroves.

  • Essential Knowledge
      - STB-3.E.1 Wetlands are areas where water covers the soil, either part or all of the time.
      - STB-3.E.2 Wetlands provide various ecological services, including water purification, flood protection, and habitat.
      - STB-3.E.3 Threats to wetlands and mangroves include commercial development, dam construction, overfishing, and pollutants from agriculture and industrial waste.

Watersheds

  • All of the land that drains into a specific body of water (river, lake, bay, etc.).

  • Determined by slope; ridges of land divide watersheds (diverse runoff directions).

  • Factors affecting watershed drainage:
      - Vegetation, soil composition, slope, leading to more infiltration & groundwater recharge if vegetated.
      - Greater slope leads to faster velocity of runoff and more soil erosion.
      - Soil permeability affects runoff vs. infiltration rates.

Human Impacts on Watersheds

  • Activities such as agriculture, clear-cutting, urbanization, dams, and mining can significantly impact water quality.

Wetlands

  • An area with submerged/saturated soil in water for at least part of the year, shallow enough for emergent plants (cattails, lily pads, reeds).

  • Ecosystem Services of Wetlands:
      - Provisioning: Habitat for animal & plant foods.
      - Regulating: Groundwater recharge, absorption of floodwater, and CO2 sequestration.
      - Supporting: Water filtration, pollinator habitats, nutrient cycling, pest control.
      - Cultural: Tourism revenue, fishing licenses, camping fees, education/medical research.

Threats to Wetlands

  • Pollutants: Nutrients (N/P), sediment, motor oil, pesticides, and endocrine disruptors.

  • Water diversion upstream for flood control, agriculture, or drinking water can reduce water flow and dry up wetlands (e.g., in Everglades).

  • Dam construction for flood control/hydroelectricity reduces the flow of water/sediments to wetlands.

  • Overfishing disrupts the food web of wetlands (decrease in fish predators leads to an increase in prey).

  • Development can fill in or drain wetlands to create homes, parking lots, stores, or agricultural land.

Solutions to Watershed Pollutants

  • Strategies:
      - Riparian Buffers
      - Enhanced Nutrient Removal
      - Animal Manure Management
      - Cover Crops: Crops that absorb nutrients.
      - Septic Tank Upgrades
      - Biological Nutrient Removal

Benefits of and Threats to Mangroves

  • Ecosystem Services:
      - Wood: A valued source of timber and fuel.
      - Livelihoods: 120 million people living near mangroves.
      - Climate regulation: Carbon storage potential is 3-5 times higher compared to tropical upland forest.
      - Coastal protection: Restoring mangroves for coastal defense is cost-effective compared to gray infrastructure.
      - Water filtration: 2-5 hectares of mangroves can treat effluents of aquaculture.
      - Fisheries: More than 3000 fish species found in mangrove ecosystems.

  • Threats:
      - Coastal development and pollution can damage mangroves.

Practice FRQ 8.4

  • Describe how one specific human activity can lead to increased phosphorus levels in an estuary ecosystem.

  • Describe one step that could be taken to reduce phosphorus inputs from the activity you described above.

8.5 Eutrophication

Learning Objective STB-3.F

  • Explain the environmental effects of excessive use of fertilizers and detergents on aquatic ecosystems.

  • Essential Knowledge
      - STB-3.F.1 Eutrophication occurs when a body of water is enriched in nutrients.
      - STB-3.F.2 The increase in nutrients in eutrophic aquatic environments causes an algal bloom.
      - When the algal bloom dies, microbes digest it along with the oxygen, leading to a decrease in dissolved oxygen levels, which can result in large die-offs of fish and other aquatic organisms.
      - STB-3.F.3 Hypoxic waterways are low in dissolved oxygen.
      - STB-3.F.4 Oligotrophic waterways have low nutrients, stable algae, and high dissolved oxygen.
      - STB-3.F.5 Anthropogenic causes of eutrophication are agricultural runoff and wastewater release.

Eutrophication Process

  • Limiting Nutrients:
      - Because nitrogen (N) and phosphorus (P) are limiting nutrients in aquatic ecosystems, extra input leads to eutrophication (excess nutrients) fuel algae growth.

  • Algal Bloom:
      - Algae bloom covers the surface of water, blocking sunlight for plants below.

  • Decomposition:
      - Algae eventually die-off; bacteria that break down dead algae use up O2 in the water (aerobic process).

  • Result:
      - Lower O2 levels (dissolved oxygen) kill aquatic animals, especially fish; Bacteria use more O2 to decompose dead aquatic animals leading to further decreases.

  • Positive Feedback Loop:
      - Less O2 → more dead organisms → more bacterial decomposition → less O2.

Major N/P Sources of Eutrophication

  1. Discharge from sewage treatment plants (N/P from human waste & phosphates in detergents).

  2. Animal waste from CAFOs (Concentrated Animal Feeding Operations).

  3. Synthetic fertilizer from agricultural fields and lawns.

Oligotrophic Waterways

  • Waterways with low nutrient (N/P) levels, stable algae, and high dissolved oxygen.

  • Aquatic ecosystems frequently undergo succession.

  • Natural Shift:
      - Sediment buildup on the bottom causes higher nutrient levels over time, leading to shifts from oligotrophic to eutrophic stages due to nutrient pollution or aging of the water body.

Dissolved Oxygen & Dead Zones

  • Decrease in dissolved oxygen (hypoxia) causes dead zones.
      - All aquatic life requires dissolved oxygen for respiration; as DO decreases, fewer species can be supported.

  • Most fish require at least 3.0 ppm to survive, 6.0 ppm to reproduce.

Oxygen Sag Curve

  • Types of organisms are impacted by varying levels of dissolved oxygen.

  • Normal Clean Water Organisms: Fish such as trout, perch; presence indicates a clean aquatic environment.

  • Decomposition and Recovery Zone: As organic waste increases, organisms die due to oxygen depletion.

Practice FRQ 8.5

  • Make a claim about which state's fishing industry likely had lower-than-average profits in the summer of 2011, justifying with evidence from data.

8.6 Thermal Pollution

Learning Objective STB-3.G

  • Objective/EKs/Skill
      Describe effects of thermal pollution on aquatic ecosystems.

  • Essential Knowledge
      - STB-3.G.1 Thermal pollution occurs when heat released into the water produces negative effects on organisms in that ecosystem.
      - STB-3.G.2 Variations in water temperature affect the concentration of dissolved oxygen because warm water does not contain as much oxygen as cold water.

Solubility of Oxygen & Temperature

  • Solubility:
      - The ability of a gas to dissolve in liquid (oxygen dissolving in water).
      - Inverse relationship between water temperature and oxygen solubility; as water temperature increases, dissolved oxygen decreases.

  • Thermal Pollution:
      - Heat increases the respiration rate of aquatic organisms (thermal shock).
      - Hot water has less oxygen, leading to suffocation of organisms unable to support respiration.

Sources of Thermal Pollution

  • Power plants often use cool water to cool steam that turns turbines and return warmed water to local surface waters.

  • Other manufacturing plants, such as steel mills and paper mills, also utilize cooling water.

  • Nuclear power plants:
      - Require exceptionally large amounts of cooling water to operate (cool steam and reactor core).

  • Urban stormwater runoff can also cause thermal pollution due to heat from blacktop/asphalt.

Cooling Towers

  • Cooling Towers:
      - Standard in nuclear power plants, facilitate cooling of water better or hold it longer before returning to surface waters.

Practice FRQ 8.6

  • Explain how increased nuclear power generation may lead to decreased biodiversity in nearby aquatic ecosystems.

8.7 Persistent Organic Pollutants (POPs)

Learning Objective STB-3.H

  • Describe the effect of persistent organic pollutants on ecosystems.

  • Essential Knowledge
      - STB-3.H.1 POPs do not easily break down in the environment as they are synthetic, carbon-based molecules (e.g. DDT, PCBs).
      - STB-3.H.2 POPs can be toxic to organisms as they are soluble in fat, allowing them to accumulate in organisms' fatty tissues.
      - STB-3.H.3 POPs can travel long distances via wind and water before being redeposited.

POPs

  • Definition: Persistent (long-lasting) organic (carbon-based) pollutants.
      - Synthetic compounds that do not easily break down in the environment; accumulate in water & soil.
      - Fat-soluble: Accumulate and persist in animals’ fat tissue instead of being excreted.

  • Can be slowly released from fatty tissue into the bloodstream, impacting brain & organs over time (especially the reproductive system).

PFAS (Per- and Polyfluoroalkyl Substances)

  • Exposure primarily through contaminated water or food, products made with PFAS, or breathing air with PFAS.

  • Due to slow breakdown, people and animals often face repeated exposure, leading to elevated blood levels of PFAS.

  • Widespread presence (97% of Americans), thousands of PFAS chemicals used across various products, challenging to assess health/environmental risks.

Sources of POPs

  • Examples:
      - DDT: Outdated insecticide previously widely used, still persists in soils & sediments.
      - PCBs: Plastic/paint additives that harm aquatic ecosystems.
      - PBDEs: Fireproofing compounds.
      - BPA: Plastic additive.
      - Dioxins: Byproducts of fertilizer production/combustion of waste.
      - Phthalates: Present in plastics and cosmetics.
      - Perchlorates: Used in rockets, fireworks.

Transport of POPs

  • POPs often enter aquatic systems through industrial wastewater or leachate from landfills, impacting organisms far away.

Practice FRQ 8.7

  • Explain the more prolonged negative impacts of PCBs compared to synthetic nitrates on aquatic ecosystems.

8.8 Biomagnification

Learning Objective STB-3.1

  • Describe bioaccumulation and biomagnification.

  • Essential Knowledge
      - STB-3.1.1 Bioaccumulation is the selective absorption and concentration of elements/compounds by cells in living organisms, commonly fat-soluble compounds.
      - STB-3.1.2 Biomagnification is the increase in concentration of substances per unit of body tissue that occurs in successively higher trophic levels of a food chain.
      - STB-3.J Describe the effects of biomagnification.
      - STB-3.J.1 Effects in ecosystems may include eggshell thinning and developmental deformities in top carnivores.
      - STB-3.J.2 Humans can experience harmful effects, including reproductive, nervous, and circulatory system issues.

Bioaccumulation

  • The process of pollutants (especially fat-soluble ones like POPs) accumulating in the fat tissues of organisms.
      - Mechanism: Fat-soluble compounds do not dissolve easily in water, leading to buildup over time.

Biomagnification

  • The increasing concentration of fat-soluble compounds up the trophic pyramid or food web.
      - Begins at the base with sediment/plants (e.g. phytoplankton) containing POPs.
      - Primary consumers (e.g. zooplankton) accumulate POPs by feeding off producers, which leads to further concentration at higher trophic levels.
      - Large predators (e.g. salmon, dolphins, whales) have the highest levels of POPs due to consuming numerous prey over their lifetimes.

Case Study: DDT

  • Despite being banned in many nations, DDT persists in sediments, accumulating in aquatic food webs.
      - Biomagnified at higher trophic levels, particularly affecting predatory birds like eagles, leading to eggshell thinning and population declines (prompted the Endangered Species Act).

  • Mercury:
      - Emitted during coal burning and can be converted into toxic methylmercury by bacteria, biomagnifying up the food chain.

  • Human exposure arises through consuming large predatory fish (tuna, salmon), impacting the nervous system and reproductive health.

Practice FRQ 8.8

  • Propose a hypothesis about compounds from worn-down bike tires biomagnifying in aquatic ecosystems.

8.9 Solid Waste Disposal

Learning Objective STB-3.K

  • Describe solid waste disposal methods.

  • Essential Knowledge
      - STB-3.K.1 Solid waste is any discarded material that is neither a liquid nor a gas, generated across domestic, industrial, business, and agricultural sectors.
      - STB-3.K.2 Most solid waste is disposed of in landfills, which can contaminate groundwater and release harmful gases.
      - STB-3.K.3 Electronic waste (e-waste) consists of discarded electronics like TVs, phones, and computers, often considered hazardous waste.
      - STB-3.K.4 A sanitary landfill consists of:
        - Bottom liner (plastic or clay).
        - Stormwater collection system.
        - Leachate collection system.
        - Cap.
        - Methane collection system.
      - STB-3.L.1 Landfill decomposition influences include composition of trash and conditions for microbial decomposition.
      - STB-3.L.2 Incineration significantly reduces volume but releases air pollutants.
      - STB-3.L.3 Illegal disposal of hazardous waste leads to environmental issues.
      - STB-3.L.4 Ocean dumping creates floating islands of trash, harming wildlife.

Types and Sources of Solid Waste

  • Municipal Solid Waste (MSW): Solid waste from urban areas including households, businesses, schools, etc.

  • E-Waste: Consists of old electronics, often containing hazardous heavy metals (lead, mercury, cadmium).
      - Only ~2% of MSW but poses significant risks through leachate.

Composition of MSW Generated by Material (2018)

  • 292.4 million tons total MSW.

  • Major components by percentage:
      - Paper and Paperboard: 23.05%.
      - Food: 21.59%.
      - Plastics: 12.20%.
      - Metals: 8.76%.
      - Rubber and Leather: 3.13%.
      - Glass: 4.19%.

Landfills

  • APES lingo refers to how developed nations manage trash, differing from “dumps.”

  • Landfills have engineered features:
      - Clay/Plastic Bottom Liner: Prevents pollutants from leaking into groundwater.
      - Methane Recovery System: Collects methane from anaerobic decomposition for energy generation.
      - Clay Cap: Allows vegetation to regrow and contains smell.

Landfill Contents & Decomposition

  • Landfills experience low decomposition rates due to the absence of oxygen, moisture, and organic materials.

  • Hazards that should NOT go to landfills include hazardous waste (e.g., electronics, paints).

  • Acceptable materials include:
      - Food cans and cardboard.
      - Styrofoam, plastic wraps.

Landfill Issues

  • Landfills pose risks such as groundwater contamination with heavy metals and pathogens from leachate.

  • Greenhouse Gases: Methane (CH4) and carbon dioxide (CO2) released from decomposition contribute to global warming.

  • NIMBY (Not In My Backyard): Communities often resist landfill placement due to environmental concerns.

Incineration and Ocean Dumping

  • Incineration reduces waste volume by up to 90% but emits CO2 and air pollutants.

  • Ocean dumping, often done illegally, contributes significantly to marine pollution, resulting in suffocation and entanglement of wildlife.

Practice FRQ 8.9

  • Propose a government solution to reduce landfill waste by at least 15% based on data.

8.10 Waste Reduction

Learning Objective STB-3.M

  • Describe changes to practices that could reduce generated waste.

  • Essential Knowledge
      - STB-3.M.1 Recycling is the process of converting solid waste into new products.
      - STB-3.M.2 Recycling reduces global demand for minerals but can be costly and energy-intensive.
      - STB-3.M.3 Composting decomposes organic matter and produces fertilizer.
      - STB-3.M.4 Reusing and recycling e-waste prevents contamination and conserves valuable resources.
      - STB-3.M.5 Landfill mitigation can involve waste-to-energy strategies or habitat restoration on former landfills.
      - STB-3.M.6 Combustion of landfill gases can generate electricity, reducing volume.

The Three Rs

  • Reduce: The most sustainable method to lower consumption and resource harvesting.
      - Examples: Metal water bottles, walking instead of driving, buying used.

  • Reuse: Next most sustainable; minimizes energy and material consumption.

  • Recycle: Least sustainable; often requires high energy input to process materials like glass and plastic.

Pros and Cons of Recycling

  • Pros:
      - Reduces habitat destruction from mining, shipping costs, conserves landfill space.

  • Cons:
      - Sorting incorrect recyclables increases costs; fluctuating demand leads to waste of "recycled" materials.

Composting

  • Controlled decomposition of organic waste produces rich material for soil improvement.

  • Potential issues: Foul smells and attracting pests.

E-Waste

  • Difficult to manage properly due to hazardous heavy metals it contains.

  • Often improperly discarded in developing countries, leading to environmental contamination.

Waste-to-Energy

  • Incineration can generate energy and reduce waste volume significantly.

Practice FRQ 8.10

  • Calculate percent increase in mobile device sales and the total grams of gold used for the production of all devices sold in 2007.

8.11 Sewage Treatment

Learning Objective STB-3.N

  • Describe best practices in sewage treatment.

  • Essential Knowledge
      - STB-3.N.1 Primary treatment involves physical removal of large objects using screens, followed by sedimentation of solid waste.
      - STB-3.N.2 Secondary treatment is biological, as bacteria decompose organic matter.
      - STB-3.N.3 Tertiary treatment utilizes ecological or chemical processes to eliminate remaining pollutants.
      - STB-3.N.4 Disinfected water is treated with chlorine, ozone, or UV light before discharge.

Treatment Processes

  • Primary Treatment: Physical debris removal; grit chamber allows for sedimentation of sand and gravel.

  • Secondary Treatment: Bacteria decompose organic matter with oxygen in aeration tanks.
      - Removes 70% of phosphorus and 50% of nitrogen but does not eliminate persistent organic pollutants (POPs).

  • Tertiary Treatment: Further chemical filtration removes excess nutrients before effluent discharge.

Sewage Treatment Issues

  • Combined sewage/stormwater systems can overflow during heavy rains, releasing untreated sewage into surface waters.

  • Treated wastewater often contains elevated nutrient levels and endocrine disruptors.

8.12 & 8.13 LD50 & Dose Response Curve

Learning Objectives

  • EIN-3.A: Define lethal dose 50% (LD50).

  • EIN-3.B: Evaluate dose-response curves.

Essential Knowledge

  • EIN-3.A.1 LD50 is the dose lethal to 50% of the population of a species.

  • EIN-3.B.1 A dose-response curve illustrates the effect on an organism based on toxin concentration.

Dose-Response Concepts

  • Independent Variable: Concentration of the chemical.

  • Dependent Variable: Measured response (death, impairment).

  • LD50 Reference: Dose concentration expressed as mass per body weight.

  • Dose-Response Curve Characteristics: Typically “S-shaped”, illustrating increased mortality at higher doses.

ED50 and Other Dose Responses

  • ED50: Refers to a concentration causing a non-lethal effect in 50% of the population.

Extrapolating Human Risk

  • Maximum allowable human levels are often calculated by dividing animal data by a safety factor.

Practice FRQ 8.12 & 8.13

  • Use data from a dose-response study to determine maximum allowable levels for human exposure and identify response thresholds.

8.14 Pollution and Human Health

Learning Objective EIN-3.C

  • Identify sources of human health issues linked to pollution.

  • Essential Knowledge
      - EIN-3.C.1 Establishing cause and effect linkage between pollutants and health issues is complex due to multiple exposures.
      - EIN-3.C.2 Dysentery occurs from untreated sewage in water sources.
      - EIN-3.C.3 Mesothelioma is caused by asbestos exposure.
      - EIN-3.C.4 Respiratory issues can arise from elevated tropospheric ozone levels.

Routes of Exposure

  • Major Pollutant Pathways:
      - Lead from water pipes; Mercury from seafood; PM from dust; Arsenic from rice/water sources.

Synergistic Effects

  • The interaction of substances can compound health risks, e.g., asthma exacerbated by combined exposures.

Dysentery

  • Bacterial infection from fecal contamination causing severe dehydration, especially in developing regions.

Mesothelioma

  • Cancer caused primarily by asbestos exposure affecting respiratory structures.

Tropospheric Ozone

  • Contributes to respiratory complications, present mainly from vehicle and industrial emissions.

Practice FRQ 8.14

  • Propose a hypothesis for studying sewage treatment impacts on human health based on observational data.

8.15 Pathogens and Infectious Diseases

Learning Objective EIN-3.D

  • Explain human pathogens and their cycling through the environment.

  • Essential Knowledge
      - Pathogens adapt to exploit opportunities for spreading through hosts.
      - Contaminated environments can harbor spreadable pathogens.

Pathogens & Vectors

  • Pathogen Definition: Living organisms causing disease.

  • Vector Definition: Organisms transmitting pathogens (e.g., rats, mosquitoes).

Expanding Disease Range

  • Climate change permits pathogen/vector spread into broader latitudes.

Infectious Disease & Development

  • Poverty-stricken regions see higher infectious disease rates due to inadequate waste management and healthcare.

Specific Diseases

  • Plague: Bacterial infection via fleas; treatable but instances persist.

  • Tuberculosis: Respiratory bacillus spread via air; treatable but deadly in developing areas.

  • Malaria: Parasitic disease from infected mosquitoes; can be managed with insecticides.

  • Other viruses: West Nile and Zika pose significant public health challenges.

  • Cholera: Waterborne bacterial illness resulting in severe gastrointestinal distress.