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

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

8.9 Solid Waste Disposal

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

8.15