APES CH 14 NOTES
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Water Pollution
 Water pollution- the _____________________ of streams, rivers, lakes, oceans, or groundwater
with substances produced through human activities and that negatively affect organisms.
 Point sources- __________ locations that pump waste into a waterway. (ex: factory, oil spill)
 Nonpoint sources- ____________ areas such as an entire farming region that pollutes a
waterway. (ex: parking lot runoff, farm lot)
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Most common pollutants
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Broad range of pollutants can be found in water:
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Human and animal _______, inorganic substances, organic compounds, synthetic
organic compounds, and nonchemical pollutants.
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For each we need to consider the _________, its negative effects, and what can
be done to reduce these effects.
Human Wastewater
 Water produced by human activities such as human sewage from toilets and _________ water
from bathing and washing clothes or dishes.
 Three reasons scientists are concerned about human wastewater:
 Wastewater dumped into bodies of water naturally undergo __________________ by bacteria,
which creates a large demand for oxygen in the water.
 Nutrients that are released from wastewater decomposition can make the water more fertile
causing ____________________
 Wastewater can carry a wide variety of _________________-causing organisms.
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Biochemical Oxygen Demand (BOD)
 Oxygen-demanding waste is organic matter that enters a body of water and feeds the growth of
microbes that are decomposers. These microbes require _________ to decompose waste, so
the more waste that enters the water, the more microbes grow and the more oxygen they
demand.
 _________- the amount of oxygen a quantity of water uses over a period of time at a specific
temperature.
 _________________ BOD values indicate the water is less polluted and ___________________
BOD values indicate it is more polluted by wastewater. (measured in mg)
 Example: decomposition of leaves and such might have 5 to 20 mg of oxygen vs. human
waste water which might have 200 mg.
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Eutrophication
 Eutrophication is an abundance of ___________________ to a body of water.
 Eutrophication is caused by an increase in nutrients, such as ____________________.
 Eutrophication can cause a rapid growth of _____________ which eventually dies, causing the
microbes to increase the BOD.
 In some areas there is so little oxygen we call them dead zones (___________________).
 Easily form positive feedback loops (dying organisms from lack of oxygen cause even
more break down and less oxygen)
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Cultural Eutrophication
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When a body of water undergoes eutrophication because of
______________________________ inputs.
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UN estimates there are over 200 dead zones
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Common Diseases from Human Wastewater
 Cholera, Typhoid fever, Stomach flu, Diarrhea, Hepatitis
 The World Health Organization (WHO) estimates ____ billion people, nearly 1/6 of the world
population do not have access to sufficient supplies of safe drinking water.
 Half of the 3.1 million annual deaths from diarrheal diseases and malaria could be prevented
with safe drinking water, proper sanitation and hygiene.
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Indicator species
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Since it is not possible to test for all of the different pathogens that could be present in drinking
water, scientists have settles on indicator species which are organisms that indicate whether or
not disease-causing pathogens are likely.
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The best indicators for water are the ________________ bacteria (E. coli is an example)
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Swimming and fishing water safe level=500-10,000 colonies per 100mL of water.
Public Health authorities may find that any bacteria found is unsuitable for
drinking standards.
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Ways to handle wastewater
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Same basic approach to all:
-__________ down organic matter with bacteria, turning it into carbon dioxide and inorganic
compounds.
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Two most widespread systems are the ____________ system and the _____________ treatment
plant.
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Manure from livestock fields usually handled by a manure lagoon.
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Treatments for Human and Animal Wastewater
 Septic systems- a large container that receives wastewater from the _________________.
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Septic System
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Requires space to lay out a septic tank and leach field. Usually found in rural areas. No
electricity needed to make a septic system work: all works using _________________.
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Septic tank: receives waste water from the house (capacity 1900-4700 Liters, needing to be
emptied every 5-10 years). Water flows in one end and leaves the other end.
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Leach field Combination of pipes and lawn.
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The pipes contain small _______________________ that water slowly seeps out of and spreads
across the field.
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________________- seeps out and is slowly absorbed and filtered by the surrounding soil.
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Three layers develop:
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____________ (anything that floats and rises to top)
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Septage Flows to leach field (___________ water layer, contains
bacteria and pathogens)
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_______________-pumped out every 5-10 yrs. (anything heavier than
water and sinks)
Treatments for Human and Animal Wastewater
 Sewage Treatment Plants- ______________________- plants in areas with large populations
that receive wastewater via a network of underground pipes.
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In a traditional sewage treatment plant, wastewater is handled using primary and secondary
treatment.
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Primary treatment involves the _____________ waste settling out of the wastewater. The solid
is then dried and classified as sludge. Usually burned or sent to landfills.
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After the sludge has settled out of the wastewater, the remaining wastewater undergoes a
secondary treatment.
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This treatment uses __________________ to break down 85-90% of the organic matter in the
water and convert it to carbon dioxide and other inorganic nutrients.
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The treated water sits for a few days to let particles settle out of it.
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The water is then disinfected with ozone, chlorine or UV light to kill any remaining pathogens.
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The water is then _________________- into a nearby river, stream or lake where it join the
water cycle again.
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Treatments for Human and Animal Wastewater
 Manure lagoons- large, human-made ponds lined with rubber to prevent the manure from
leaking into the groundwater. After the manure is broken down by bacteria, it is spread onto
fields as ___________________.
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Heavy Metals and Other Substances that can threaten human Health and the Environment
 Some compounds such as nitrogen and phosphorous cause environmental problems by
overfertilizing the water. Other inorganic compounds including heavy metals (Lead, Arsenic,
Mercury), Acids, Synthetic compounds (pesticides, pharmaceuticals, and hormones) can directly
harm humans and other organisms.
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Oil Pollution
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Petroleum is highly ______________ to marine organisms.
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It is a _______________________ substance that can spread below and across the surface of
the water and spreads to the shoreline making it very difficult to remove.
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One source of oil in the water is offshore ________________-.
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____________ offshore oil platforms in North America, 3000 more in other parts of the world.
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Estimate of 322,000 lbs of oil leak into North American water per year.
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Other sources oil spills from tankers, naturally occurring from ________ in the ocean floor,
runoff from roads on land
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Ways to Remediate Oil Pollution
 Containment using ____________ to keep the floating oil from spreading, then oil vaccuums to
suck it up.
 ______________ that help break up the oil, making it disperse before it hits the shoreline.
 Bacteria that are genetically engineered to ________________ oil
 Famous cases:
 Exxon Valdez oil spill of 1989. (____ million gallons, cleanup has been ongoing for 20
years)
 BP oil spill of 2010. (______ million gallons, cleanup still ongoing, large amounts of oil
discovered on the ocean floor)
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Other Water Pollutants
 Solid waste pollution (garbage)
-Great pacific garbage patch. (____________)
 Sediment pollution that flows downstream from rivers (sand, silt and clay)
-Caused mainly by ______________ and lack of plants (roots)
 ________________ pollution (usually heated water returned to the water after cooling
machines)
-Thermal shock, lack of O2
 Noise pollution
-Interferes with animal _________________
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Water Laws
 ___________ Water Act- (1972) supports the “protection and propagation of fish, shellfish, and
wildlife and recreation in and on the water”.
 Issued water quality standards that defined acceptable limits of various pollutants in U.S.
waterways.
 Maintains and restores the natural chemical, physical and biological properties of water.
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Water Laws
 Safe ______________ Water Act- (1974, 1986, 1996) sets the national standards for safe
drinking water.
 It is responsible for establishing maximum ___________________ levels (MCL) for 77 different
elements or substances in both surface water and groundwater.
 Includes well known microorganisms, disinfectants, organic chemicals and inorganic chemicals.
 Ex: Mercury maximum contaminant level is ___ ppm