Unit 8 - Aquatic and Terrestrial Pollution

8.1 Sources of Pollution

• water pollution - point source & nonpoint source
  • water quality standards set by EPA
  • point source - pollution from a clearly identified single source
  • ex. wastewater plants, paper/pulp mills, oil refineries, CAFOs, gas tanks, etc.
  • industries required to get permission from state/EPA to release waste into water + have the plan to treat waste before release
  • nonpoint source: pollution that cannot be traced back to a single source; comprised of multiple sources built up over time
  • ex. fertilizers, insecticides, herbicides, runoff from precipitation, sediment from construction sites and croplands
  • managed through business and landowner partnerships

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8.2 Human Impacts on Ecosystem

• coral reefs → support 25 percent of marine species underwater
  • affected by destructive fishing practices
  • bottom trawling: crushes coral as nets scrape ocean floor
  • marine debris: damages reefs and organisms that are dependent on them
  • overfishing: removes fish and inhibits regulated algae growth
  • cyanide fishing: poisons coral; done to catch large amounts of fish for commercial use easily
• sedimentation → traps coral from sunlight → no photosynthesis → death of coral
  • optimal: middle portion of range of tolerance; implies homeostasis and proper maintenance
  • coral bleaching: releases symbiont resulting from heat (rising temperatures) → loss of food and color
• dissolved oxygen: decreases as a result of algal blooms caused by runoff
  • measured in ppm
  • displayed in the oxygen sag curve → dissolved oxygen levels in relation to distance from the source
  • clean zone: balance of oxygen and dissolved oxygen levels; biologically diverse species
  • septic zone: very few species; dangerously low oxygen levels;
  • recovery zone: demand is lower; dissolved oxygen increases
  • increase in the distance from the source = increase in dissolved oxygen levels and decrease in biological oxygen demands
• oil spills affects wildlife and ecosystems negatively
  • impairs birds ability to fly by coating their feathers
  • impairs temperature regulation and waterproofing of ocean mammals as their fur is saturated with oil
  • can poison organisms from hydrocarbons
  • alter food chains by killing organisms living at the bottom of the ocean
  • damages fisheries financially and hinders their development
  • decreases oxygen levels in water
  • smother eggs/larvae of aquatic organisms
• toxic metals found in drinking water → cancer, organ damage, neurological issues
  • ex. mercury poisoning → methylmercury → neurological damage/birth defects
  • includes lead arsenic cadmium mercury copper and chromium
  • metals infiltrate groundwater reserves when released by miners in nearby water reserves
  • plastic waste threatens wildlife in ocean
  • blocks digestive system of organisms
  • leads to entanglement/suffocation
  • acclamation of microplastics → increased toxicity

8.3 Endocrine Disruptors

groups of different chemicals that interfere the process of hormones being used in the body

• cell signaling is disrupted by mimicking its structure or block the signal from reaching the receptor
• leads to reproductive abnormalities, birth defects, and neurological changes
• found in toxic waste from natural and synthetic processes
• can be accumulated and magnified in high-level organisms by eating prey with endocrine disruptors in body tissue

8.4 Human Impact on Wetlands & Mangroves

• wetlands: areas filled with mostly water on the surface during all or most of the year
  • fluctuates in level and sanity from tidal influence or seasonal change
  • can be mitigated through filtration
  • plant roots take up excess nutrients from runoff for growth or decomposition
  • controls flood by holding water
  • recharges groundwater reserves during dry periods
  • home to diverse habitats and filled with resources to thrive
• mangroves provide shelter for animals & absorb great deal of CO2
  • threatened by commercial development ad dam construction
  • dam construction: reduces water flow and inhibits fish migration
  • protected by the wetlands protection and restoration act
  • overfishing → removing some essential fishes from the ecosystem
  • impacts by CAFO pollutants (ie. waste)

8.5 Eutrophication

• algal blooms in water which occurs as a result of nutrient excess
  • nutrient excess caused by agricultural and waste runoff
  • also sourced from phosphorus in detergents
  • ex. sewage, excess fertilizer, phosphate, nitrogen from animal manure
  • washed into bodies of water by precipitation and irrigation
  • causes rapid growth
• eutrophic: waterway with high levels of algae with excess nutrients, low dissolved oxygen
• oligotrophic: waterway with low amounts of nutrients stable algae growth and high dissolved oxygen
• hypoxic aquatic system: algal bloom dies → sinks to ocean floor → dead cells consumed by microbes → oxygen is consumed additionally → decreases dissolved oxygen → low oxygen levels
  • leads to mass dieoff of fish → creates more waste → creation of dead zones
• dead zones: areas of low oxygen in bodies of water caused by nutrient pollution
• oxygen sag: plot of dissolved oxygen far from the pollution source

8.6 Thermal Pollution

• waste resulted from heated water that is discharged after use
  • often from power/industrial plants
  • other sources: soil erosion, deforestation, wastewater discharge, urban runoff
• has many adverse effects on aquatic ecosystems
  • warm water holds less dissolved oxygen → decreased dissolved oxygen levels → dieoffs from low DO levels
  • doesn’t affect marine mammals (ie. manatees) as they come up to the surface for air
  • can impact the survival of organisms with narrow ranges of tolerance
  • alteration of feeding, behavior, and migration behaviors

8.7 Persistent Organic Pollutants (POPs)

• organic: often in rings with chlorine outside of it
  • synthetic & nonpolar (made with carbon) & cyclical (chlorine atoms)
  • fat-soluble: not easily removed once bound on chlorine strands → accumulation over time
  • can travel long distances: based on wind directions or waterways
• DDT (dichloro-diphenyl-trichloroethane): crystal-like insecticide banned in the US
  • used to reduce agricultural pests (ie. mosquitos)
  • can cause harm to nearby organisms
• PCBs (polychlorinated biphenyl): yellow industrial fluid also banned in the US
  • used as a cooler and lubricant

8.8 Bioaccumulation & Biomagnification

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8.9 Solid Waste Disposal

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8.10 Waste Reduction Methods

8.11 Sewage Treatment

8.12 Lethal Dose 50% (LD50)

• amount of a chemical that is lethal to half of a species’ population
  • measured in mg/kg
  • used to predict its effects on humans and compare the strength of different substances
  • ex. water - least toxic, cyanide - most toxic known to humans
  • can be amplified by bioaccumulation

8.13 Dose-Response Curve

• graph that displays the effect of toxins on the human population
  • used to determine LD50
  • uses data from testing drugs/toxins on a given population
  • typically an S-shaped curve
  • x-axis: dose (mg/kg)
  • y-axis: response% (ie. number of individuals dead)

8.14 Pollution & Human Health

• difficult to establish the relationship between pollutants and human health issues due to the various chemicals/toxins humans are exposed to
  • dysentery: inflammation of intestines resulting from bacteria/parasites
  • causes bloody stools and cramping
  • caused by untreated sewage in rivers/streams
  • can be found by fecal coliform testing
  • mesothelioma: type of lung cancer resulted from asbestos exposure
  • damages heart, lungs, and abdomen
  • respiratory issues arises from exposure to ground level ozone (NOx, VOCs, etc.)
  • can be mitigated by interpreting AQI
  • can compromise lung function by inflaming the linings in the lungs

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8.15