Unit 8 Aquatic and Terrestrial Pollution Study Notes

Unit 8: Aquatic and Terrestrial Pollution

Table of Contents

  • A. Sources of Pollution

  • B. Human Impacts on Ecosystems

  • C. Eutrophication

  • D. Thermal Pollution

  • E. Human Impacts on Wetlands and Mangroves

  • F. Endocrine Disruptors

  • G. Persistent Organic Pollutants (POPs)

  • H. Bioaccumulation and Biomagnification

  • I. Solid Waste Disposal

  • J. Waste Reduction Methods

  • K. Sewage Treatment

  • L. Lethal Dose 50% (LD50)

  • M. Dose Response Curve

  • N. Pollution and Human Health

  • O. Pathogens and Infectious Disease

A. Sources of Pollution

  • Pollution Definition: Contamination of streams, rivers, lakes, oceans, or groundwater with substances produced through human activities, adversely affecting organisms.

  • Point Sources:

    • Defined as single, identifiable sources of pollution (e.g., smokestacks, discharge pipes).

    • Example: A factory discharging waste into a stream.

  • Nonpoint Sources:

    • Diffused sources that can be challenging to identify (e.g., agricultural runoff, urban runoff).

    • Example: Runoff from farmland or suburban lawns.

    • More difficult to control due to their widespread nature.

  • Negative Externalities: Pollution represents a negative externality as environmental costs are not accounted for in product pricing.

B. Human Impacts on Ecosystems

  • General Impact: Human activities lead to various impacts on ecosystems through physical and chemical means, affecting aquatic and terrestrial organisms.

  • Tolerance and Homeostasis: Organisms have optimum ranges for factors that sustain homeostasis; exceeding these ranges leads to stress, reduced growth, reproduction, and potentially death.

  • Oil Spills:

    • Marine organisms die due to hydrocarbons in oil, coating feathers and fur of birds and marine mammals, and impacting bottom-dwellers.

    • Economic impacts on fishing and tourism from oil washing ashore.

  • Dead Zones: Areas in oceans with low oxygen caused by nutrient pollution, leading to significant biodiversity loss.

  • Oxygen Sag Curve: A graph showing the concentration of dissolved oxygen versus distance from a pollution source.

  • Heavy Metals:

    • Metals like lead and mercury enter waterways via industrial processes and can contaminate drinking water supplies.

    • Lead: Found in old water pipes, can damage the brain and nervous system, particularly in infants.

    • Arsenic: Naturally occurring, linked to mining, can cause cancer; problematic in groundwater in specific regions.

C. Eutrophication

  • Definition: Eutrophication is the process of nutrient enrichment in a body of water.

  • Consequences: Leads to algal blooms, which decompose and consume dissolved oxygen, resulting in hypoxic conditions, fish kills, and loss of aquatic biodiversity.

  • Anthropogenic Sources: Agricultural runoff and wastewater discharges contribute significantly to nutrient loading in water bodies, often leading to cultural eutrophication.

D. Thermal Pollution

  • Definition: The discharge of heated water into aquatic systems affects ecosystem dynamics.

  • Effects on Oxygen Levels: Warmer water holds less dissolved oxygen, thereby negatively impacting aquatic life.

  • Thermal Shock: Sudden temperature changes can lead to high mortality rates among organisms adapted to specific thermal ranges.

  • Regulatory Measures: The EPA has guidelines to limit the temperature of water discharged from industrial processes.

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E. Human Impacts on Wetlands and Mangroves

  • Wetlands: Areas that are saturated with water either permanently or seasonally, providing critical ecosystem services (e.g., water purification, flood protection).

  • Threats: Activities like commercial development, dam construction, overfishing, and pollution significantly impact wetland ecosystems, leading to biodiversity loss.

  • Mangrove Swamps: Coastal ecosystems providing protection against erosion and serving as nurseries for marine species.

F. Endocrine Disruptors

  • Definition: Chemicals that interfere with the endocrine system, leading to various health issues including reproductive and developmental problems.

  • Examples: Examples include pesticides like DDT, which thin eggshells in birds of prey, and substances found in wastewater that mimic hormones.

G. Persistent Organic Pollutants (POPs)

  • Definition: Synthetic chemicals that do not easily break down in the environment.

  • Characteristics: They are fat-soluble and accumulate in fatty tissues of organisms, leading to toxicity.

  • Global Concern: POPs can travel long distances through water and air, affecting ecosystems and human health worldwide.

H. Bioaccumulation and Biomagnification

  • Bioaccumulation: Refers to the accumulation of chemicals in an organism over time, primarily fat-soluble compounds.

  • Biomagnification: Occurs when these accumulated chemicals move up the food chain, with higher concentrations found in higher trophic levels.

  • Effects: Can lead to declining populations of top predators, reproductive issues, and health problems in humans from eating contaminated fish.

I. Solid Waste Disposal

  • Solid Waste: Any discarded material that is not a liquid or gas, generated from domestic, industrial, and agricultural activities.

  • Disposal Methods: Landfills (can result in groundwater contamination) and incineration (reduces waste volume but emits pollutants).

  • E-Waste: A growing problem, containing hazardous materials but often not properly recycled, leading to environmental damage and health risks.

J. Waste Reduction Methods

  • Recycling: Processing solid waste materials into new products, essential for reducing resource consumption but often energy-intensive.

  • Composting: Decomposition of organic matter to produce nutrient-rich soil amendments.

  • Three Rs Campaign: Encourage reducing, reusing, and recycling as strategies to minimize waste generation.

K. Sewage Treatment

  • Sewage Treatment Process:

    • Primary Treatment: Physical removal of solids from wastewater.

    • Secondary Treatment: Biological breakdown of organic material by bacteria.

    • Tertiary Treatment: Removal of remaining pollutants through chemical and ecological methods before discharge.

L. Lethal Dose 50% (LD50)

  • Definition: The dose of a chemical that kills 50% of a tested population.

  • Dose-Response Curves: Graphs demonstrating the effect of different doses of a substance on a population, used to assess toxicity.

M. Dose Response Curve

  • Characteristics: Illustrates the relationship between the dose of a substance and the extent of biological effect.

  • Threshold: The minimum dose at which an effect can be observed.

  • Sublethal Effects: Changes that may not cause death but still affect organism behavior and physiology.

N. Pollution and Human Health

  • Health Risks: Pollution can lead to various health impacts, including respiratory diseases, cancers, and infections connected to contaminated water and air.

  • Dysentery: An illness stemming from fecal contamination, affecting millions, especially in underdeveloped regions.

  • Monitoring Human Health: Risk assessments track potential hazards as they relate to human exposure and health impacts.

O. Pathogens and Infectious Disease

  • Pathogens: Infectious agents responsible for diseases, including bacteria, viruses, and parasites.

  • Examples of Diseases:

    • Dysentery: Spread through contaminated water.

    • Plague: transmitted by infected organisms.

    • Malaria: From mosquito bites.

    • Tuberculosis: Primarily affects lungs, transmits through the air.

  • Emerging Infectious Diseases: New pathogens or those re-emerging, often as a result of human and environmental changes.