Unit 8

📚 UNIT 8 NOTES (Simplified + Organized)

🌍 Sustainability & Pollution

  • Big idea: Human activity impacts ecosystems (physical, chemical, biological)

Types of Pollution

  • Point source: One clear source (ex: pipe, smokestack)

  • Nonpoint source: Spread out (ex: runoff, pesticides)

🌊 Human Impacts on Water Ecosystems

Major Issues

  • Oil spills

    • Kill marine life

    • Damage bird feathers & mammal fur

    • Hurt fishing/tourism

  • Nutrient pollution (Nitrates)

    • Causes hypoxia (low oxygen)

    • Leads to dead zones (ex: Gulf of Mexico)

  • Oxygen Sag Curve

    • Bacteria break down waste → use oxygen → fish die

  • Heavy metals (mercury, lead)

    • Contaminate groundwater

    • Hard to clean → prevention is key

  • Litter

    • Choking + toxins in food chain

  • Sediment

    • Blocks sunlight → hurts plants

🧬 Endocrine Disruptors

  • Chemicals that mess with hormones

  • Cause:

    • Birth defects

    • Development issues

    • Gender imbalances in animals

  • Examples: BPA, PCBs, PFAS

🌿 Wetlands & Mangroves

  • Benefits:

    • Water filtration

    • Flood protection

    • Habitat

  • Threats:

    • Development

    • Pollution

    • Dams

🌱 Eutrophication

  • Too many nutrients → algae bloom

  • Algae die → bacteria use oxygen → fish die

  • Eutrophic: high nutrients, low oxygen

  • Oligotrophic: low nutrients, high oxygen

🌡 Thermal Pollution

  • Warm water = less oxygen

  • Harms aquatic organisms

☣ Persistent Organic Pollutants (POPs)

  • Don’t break down easily (ex: DDT)

  • Stored in fat → toxic

  • Travel long distances

🐟 Bioaccumulation vs Biomagnification

  • Bioaccumulation: builds up in ONE organism

  • Biomagnification: increases up the food chain

Effects:

  • Eggshell thinning

  • Deformities

  • Human health issues

🧪 Human Health

LD50

  • Amount of chemical that kills 50% of test organisms

Dose-Response Curve

  • Shows effect of toxin as dose increases

Diseases from Pollution

  • Dysentery → dirty water

  • Mesothelioma → asbestos

  • Lung problems → ozone

🦠 Pathogens

Spread more due to climate + poor sanitation

Examples:

  • Malaria → mosquitoes

  • Tuberculosis → air

  • Cholera → water

  • Zika → mosquitoes

🗑 Solid Waste

Landfills

  • Problems:

    • Leachate → pollutes water

    • Methane gas → greenhouse gas

Other Methods

  • Incineration: burns waste (air pollution)

  • Ocean dumping: harms wildlife

♻ Waste Reduction

  • Recycling (energy intensive)

  • Composting (organic waste → fertilizer)

  • E-waste recycling

⚠ Hazardous Waste

  • Dangerous materials (batteries, chemicals)

  • Love Canal disaster

    • Toxic waste site → major health crisis

🐾 Biodiversity

Invasive Species

  • Non-native species that harm ecosystems

  • Often outcompete natives

🐼 Endangered Species

Causes:

  • Hunting

  • Habitat loss

  • Invasive species

  • Limited diet

🌎 Major Biodiversity Threats (HIPPCO)

  • Habitat destruction

  • Invasive species

  • Population growth

  • Pollution

  • Climate change

  • Overexploitation

🌳 Habitat Fragmentation

  • Land broken into smaller pieces

  • Hurts species survival

🛡 Protection Strategies

  • Protected areas

  • Wildlife corridors

  • Sustainable practices

💧 Wastewater Treatment (NEW)

There are 4 main steps:

  1. Physical – removes large objects (screens, settling tanks)

  2. Biological – bacteria break down organic waste

  3. Chemical – chemicals remove nutrients (like phosphorus)

  4. Disinfection – kills pathogens (chlorine/UV)

🧪 BOD (Biological Oxygen Demand) (NEW)

  • Measures how much oxygen bacteria need to break down waste

  • High BOD = low oxygen = bad for fish

➡ Connects to:

  • Oxygen sag curve

  • Eutrophication

🚽 Fecal Coliform Bacteria (NEW)

  • Comes from human/animal waste

  • Indicates water contamination

  • Can cause disease

🗑 Landfills (Expanded)

Problems:

  • Leachate → toxic liquid into groundwater

  • Methane gas → greenhouse gas

Solutions (Sanitary Landfill):

  • Liners prevent leaks

  • Collection systems remove leachate

  • Methane captured for energy

♻ 3 Rs (NEW emphasis)

  • Reduce → best (use less)

  • Reuse → use again

  • Recycle → process materials

⚖ Environmental Laws (NEW)

  • RCRA (Resource Conservation and Recovery Act)

    • Regulates hazardous waste from creation → disposal

  • CERCLA (Superfund)

    • Cleans up toxic waste sites

➡ Example:

  • Love Canal disaster led to CERCLA

🧪 Case Studies (NEW Context)

Flint Water Crisis

  • Lead contamination in drinking water

  • Caused by poor water treatment decisions

Woburn, Massachusetts

  • Groundwater contamination → cancer cluster

🎬 Environmental Awareness

  • Dark Waters

    • About PFAS chemical pollution

🧫 Experimental Design Reminder (NEW)

Know how to:

  • Identify variables (independent, dependent, control)

  • Design a valid experiment

  • Interpret resultsto draw meaningful conclusions and support or refute the initial hypothesis.