Aquatic Pollution Notes

Wastewater from Humans and Livestock

  • Water pollution: Contamination of water bodies with human-produced substances.
  • Wastewater: Water from livestock operations and human activities (sewage, gray water).
  • Point source: Direct pollution source.
  • Nonpoint source: Diffuse pollution source.
  • Problems:
    • Oxygen demand.
    • Nutrient release.
    • Disease-causing organisms.

Oxygen Demand

  • Biochemical oxygen demand (BOD): Oxygen used by water over time at specific temperatures.
  • Dead zone: Area with extremely low oxygen concentration.

Nutrient Release

  • Eutrophication: Water body becomes rich in nutrients.
  • Cultural eutrophication: Increase in fertility due to anthropogenic nutrient inputs.
  • Can cause rapid algae growth, increasing BOD when algae die.

Disease-Causing Organisms

  • Wastewater carries pathogens, causing diseases like cholera, typhoid fever, stomach flu, diarrhea, and hepatitis.
  • Indicator species: Indicates presence of pathogens.
  • Fecal coliform bacteria: Indicates potential contamination.

Wastewater Treatment Technologies

  • Septic systems: Small treatment systems for rural areas.
    • Septic tank: Receives wastewater, solids settle, bacteria break down sewage.
    • Sludge: Solid waste material.
    • Septage: Clear water layer in septic tank.
    • Leach field: Underground pipes for water distribution.
  • Sewage treatment plants: Centralized plants for municipalities, with primary and secondary treatment phases.

Animal Feed Lots and Manure Lagoons

  • Manure lagoons: Lined ponds for storing and treating livestock manure.
  • Manure can contain hormones and antibiotics.
  • After bacterial breakdown, manure is spread on fields as fertilizer.

Heavy Metals

  • Toxic to organisms.
    • Lead: From pipes in older buildings.
    • Arsenic: Naturally occurring and from mining/industry.
    • Mercury: Naturally occurring and from burning coal.

Acid Deposition and Acid Mine Drainage

  • Acid deposition: Acids deposited as rain, snow, gases, or particles.
  • Burning coal releases sulfur dioxide and nitrogen dioxide, which convert to sulfuric and nitric acid.
  • Reduces pH of water bodies.
  • Coal scrubbers can mitigate this.

Synthetic Organic Compounds

  • From industrial/nonpoint sources; include pesticides, pharmaceuticals, military/industrial compounds.
  • Can be toxic, cause defects, and interfere with growth/sexual development.
  • DDT example: Affected eagles through contaminated fish; banned in 1972.

Military Compounds

  • Perchlorates: Harmful chemicals used for rocket fuel.
  • Contaminate soil where rockets are manufactured/tested.

Industrial Compounds

  • Chemicals used in manufacturing often dumped into water.
  • Polychlorinated biphenyls (PCBs): Used in plastics/electrical transformers, cause environmental issues.

Oil Pollution

  • Toxic to marine organisms.
  • Sources: Undersea drilling, oil tanker spills, natural seeps.
  • Remediation methods:
    • Containment (booms, oil vacuums).
    • Chemicals to disperse oil.
    • Bacteria to consume oil.

Nonchemical Water Pollution

  • Solid Waste:
    • Garbage and sludge from sewage treatment.
    • Dangerous to marine organisms/people.
  • Sediment Pollution:
    • From natural sources (30%) and human activities (70%).
    • Suspended particles reduce sunlight, clog gills.
  • Thermal Pollution:
    • Change in water temperature from human activities.
    • Thermal shock: Sudden temperature change that can kill organisms.
    • Cooling towers can release excess heat into the atmosphere.
  • Noise Pollution:
    • Interferes with animal communication.
    • Loud sonar affects whales.
    • Quieter ship propellers can help.

Water Pollution Laws

  • Clean Water Act:
    • Protects and restores chemical, physical, and biological properties of surface waters.
    • Sets water quality standards.
  • Safe Drinking Water Act:
    • Sets national standards for safe drinking water.
    • Establishes maximum contaminant levels (MCL) for elements/substances.
  • Developing countries are industrializing and have fewer resources for water-quality improvements, but legislation is becoming more common as affluence increases.