Water Pollution

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Chapter 14 Water Pollution
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Water Pollution

• Water pollution- the contamination of streams,
  rivers, lakes, oceans, or groundwater with
  substances produced through human activities and
  that negatively affect organisms.
• Point sources- distinct locations that pump waste
  into a waterway.
• Nonpoint sources- diffuse areas such as an entire
  farming region that pollutes a waterway.

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Human Wastewater

• Water produced by human activities such as human
  sewage from toilets and gray water from bathing
  and washing clothes or dishes.

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Three reasons scientists are concerned about
human wastewater

• Oxygen-demanding wastes like bacteria that put a
  large demand for oxygen in the water
• Nutrients that are released from wastewater
  decomposition can make the water more fertile
  causing eutrophication
• Wastewater can carry a wide variety of
  disease-causing organisms.

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Biochemical Oxygen Demand (BOD)

• BOD- the amount of oxygen a quantity of water
  uses over a period of time at a specific
  temperature.
• Lower BOD values indicate the water is less
  polluted and higher BOD values indicate it is
  more polluted by wastewater.

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Eutrophication

• Eutrophication is an abundance of fertility to a
  body of water.
• Eutrophication is caused by an increase in
  nutrients, such as fertilizers.
• Eutrophication can cause a rapid growth of algae
  which eventually dies, causing the microbes to
  increase the BOD and decrease oxygen for use by
  other animals.

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Common Diseases from Human Wastewater

• Cholera
• Typhoid fever
• Stomach flu
• Diarrhea
• Hepatitis

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Treatments for Human and Animal Wastewater

• Septic systems- a large container that receives
  wastewater from the house.

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Treatments for Human and Animal Wastewater

• Sewage Treatment Plants- centralized plants in
  areas with large populations that receive
  wastewater via a network of underground pipes.

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Treatments for Human and Animal Wastewater

• Manure lagoons- large, human-made ponds line 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
  fertilizers.

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Heavy Metals and Other Substances that can
threaten human Health and the Environment

• Lead
• Arsenic
• Mercury
• Acids
• Synthetic compounds (pesticides, pharmaceuticals,
  and hormones)

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Arsenic in US Water
A cancer causing element that is mostly natural
but also a byproduct of mining and wood
preservation
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World Mercury Production
Comes mostly from burning coal harmful to the
nervous system
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Acid Deposition and Acid Mine Drainage
Caused by gasses from burning coal mixing with
water in the atmosphere and coming back to earth,
abandoned coal mines that get flooded and water
returns to the surface, and mountaintop removal
waste is dumped into watersheds.
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Syntheic organic compounds

• Pesticides kill the target organism, but can also
  kill/harm beneficial organisms. (DDT)
• Inert ingredients in pesticides are classified as
  trade secrets and most are not required to be
  tested for safety, so their affects are not known
  before the product comes on the market. (roundup)
• Many pharmaceuticals are considered endocrine
  disrupters and affect organisms at low dosages
  Need more research
• Perchlorates used by the military affect the
  thyroid and hormones in humans.
• Polychlorinated biphenyls (PCBs) used in
  manufacturing plastics is cancer causing and now
  banned in the US
• Polybrominated diphenyl ethers (PBDEs) are used
  as flame retardants in many things and can cause
  brain damage

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Cuyahoga River
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Synthetic Organic Compounds
Streams in the US contain a wide variety of
chemicals. They come from a variety of sources
including wastewater, agriculture, forestry, and
industry
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Sources of Oil Pollution in the Ocean
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Oil Catastrophes
Oil is highly toxic to all life and is very
persistent in the environment. 2010 Deepwater
Horizon explodes killing 11 people and dumping an
estimated 780 million Liters of oil in the Gulf
of Mexico. 1989 Exxon Valdez runs aground off
of the Alaskan coast spilling 41 million L of
crude oil
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Ways to Remediate Oil Pollution

• Containment using booms to keep the floating oil
  from spreading.
• Chemicals that help break up the oil, making it
  disperse before it hits the shoreline. These are
  often highly toxic.
• Bacteria that are genetically engineered to
  consume oil

Other Water Pollutants

• Solid waste pollution (garbage)
• Sediment pollution (sand, silt and clay)
• Thermal pollution
• Noise pollution

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Oil Remediation Methods

• All animals must be cleaned by hand using soap.
• Surface oil is contained by using booms (plasitic
  floating barriers) to prevent oil from spreading
  out. Once contained it can be vacuumed up or
  burned.
• Absorbent materials are used at the coastline to
  suck up the oil
• Dispersants (chemicals) are also used to break up
  the oil, however they are toxic.
• Genetically enginneered bacteria can also be used
  to clean up oil
• Currently no method for dealing with underwater
  plumes.
• High pressure hot water is used on rocky
  coastlines, but this removes nutrients and
  sediments necessary for many organisms

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Solid Waste Pollution
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Sedimentary Pollution

• Affects light penetration and aquatic
  productivity
• Can clog fish gills and hinder their ability to
  get oxygen
• Can carry nutrients that cause algal blooms.

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Thermal Pollution

• When human activities cause a substantial change
  in water temperature. (Mills and power plants)
• Thermal shock a dramatic change in water
  temperature outside of the organisms tolerance
  range. Increases respiration and warmer water
  contains less oxygen.
• EPA regulates this

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Noise Pollution

• Sounds from ships, air blasts for exploration,
  and sonar from submarines
• Can deafen fish and mammals, affect
  communication, and affect their navigation.

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Water Laws

• Clean 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.
• Safe Drinking Water Act- (1974, 1986, 1996) sets
  the national standards for safe drinking water.
• It is responsible for establishing maximum
  contaminant levels (MCL) for 77 different
  elements or substances in both surface water and
  groundwater.

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