Pollution and Human Health

8.1 Sources of Pollutants

• Point vs. Nonpoint Pollution Sources

  • Point Source

  • Pollutants enter the environment from a single, identifiable source.

  • Example Sources:

    • Animal waste runoff from concentrated animal feeding operations (CAFO) (e.g., ammonia)

    • Emissions from smokestacks of coal power plants (e.g., CO2, NOx, SO2, PM)

    • BP Oil Spill (hydrocarbons, benzene)

  • Nonpoint Source

  • Pollutants arise from multiple, diffuse sources, making them hard to pinpoint.

  • Example Sources:

    • Urban runoff (e.g., motor oil, nitrate fertilizer, road salt, sediment)

    • Pesticides sprayed on agricultural fields washed into water bodies

    • Polluted estuaries from large watersheds

• Learning Objective: Identify differences between point and nonpoint sources of pollution.

• Essential Knowledge:

  1. A point source is a specific, identifiable source of pollution (e.g., smokestack).

  2. Nonpoint sources are diffuse pollutants (e.g., urban runoff).

• Pollutants vs. Pollution:

  • Pollutants: Specific harmful chemicals with known sources and effects on health and the environment.

    • Important for FRQ: name, sources, effects, and mitigation strategies.

  • Pollution: A broad term for harmful substances in the environment.

  • Exceptions: Thermal, noise, sediment pollution.

8.2 Human Impacts on Ecosystems

• Range of Tolerance

  • Organisms have a range of tolerance for abiotic factors (e.g., pH, temperature, salinity).

  • Organisms also have tolerance for pollutants causing stress leading to:

  • Limited growth and reproduction

  • Breathing difficulties

  • Hormonal disruptions

  • Potential death

• Environmental Effects of Acid Rain:

  • Coral reefs:

  • Mutualistic relationship between coral and algae (zooxanthellae).

  • Algae's narrow temperature tolerance affects the ecosystem when runoff pollutants are involved.

  • Learning Objective: Describe human impacts on aquatic ecosystems.

• Essential Knowledge:

  1. Range of tolerance impacts organism survival when pollution exceeds optimal levels.

  2. Coral reefs are threatened by rising temperatures, sedimentation, and overfishing.

  3. Oil spills introduce hydrocarbons harming wildlife.

  4. Oceanic dead zones result from nutrient pollution causing low oxygen levels.

  5. Heavy metals from industry can contaminate groundwater.

  6. Litter impacts wildlife mechanisms and introduces toxins into the food chain.

8.3 Endocrine Disruptors & Industrial Water Pollutants

• Arsenic & Lead:

  • Arsenic:

  • Found in groundwater; elevated through mining and pesticides.

  • Carcinogenic and disrupts endocrine functions.

  • Lead:

  • Occurs in old pipes and paints; neurotoxic.

• Mercury:

  • Found in coal and released through combustion.

  • Bioaccumulates as methylmercury, affecting nervous systems.

• Endocrine Disruptors:

  • Interfere with hormonal systems causing birth defects and developmental disorders.

• Persistent Organic Pollutants (POPs):

  • Long-lasting, accumulate in food chains, harming ecosystems.

8.4 Human Impacts on Wetlands and Mangroves

• Wetlands:

  • Serve essential ecological services (e.g., filtration, flood protection).

• Threats:

  • Development, pollutants, overfishing decrease ecosystem health.

8.5 Eutrophication

• Eutrophication Process:

  • Caused by nutrient overload leading to algal blooms and decreased oxygen.

• Cultural Eutrophication:

  • Nutrient pollution from sources like sewage and fertilizers.

8.6 Thermal Pollution

• Effects of Thermal Pollution:

  • Increased temperature harms aquatic life by reducing oxygen solubility.

8.7 Solid Waste Disposal

• Types of Solid Waste:

  • Includes MSW, e-waste with hazardous materials.

• Sanitary Landfills:

  • Optimized features to mitigate pollution but still face groundwater contamination risks.

8.10 Waste Reduction Methods

• Waste Reduction Strategies:

  • Emphasizes recycling and reusing materials.

8.11 Sewage Treatment

• Sewage Treatment Processes:

  • Involve physical and biological methods to handle wastewater.

8.12 Lethal Dose 50% & Dose Response Curves

• LD50 Measurement:

  • Indicates toxicity levels to organisms.

8.13 Pollution and Human Health

• Health Effects of Pollution:

  • Includes respiratory issues from ozone and diseases spread by contaminated water.

8.15 Pathogens and Infectious Diseases

• Human Pathogens:

  • Infectious diseases spread varying by environmental conditions.

• Key Points:

  • Adaptation of pathogens increases disease spread.

These notes cover essential concepts related to pollution sources, human influences on ecosystems, and the health impacts of pollutants. Use these summaries to prepare for your exam effectively.