Water Pollution

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Chapter 14

• Water Pollution

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The Chesapeake Bay

• Chesapeake Bay largest estuary in the US
• Pollutants
• Excess nitrogen and phosphorus
• From 3 major sources
• Consequence
• Sediment increase
• Causes
• Anthropogenic chemicals
• Trying to clean the CB massive size
  monumental effort
• 2000
• 2010

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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 source pollution
• Nonpoint source pollution

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Types of Pollutants

• Human wastewater
• Inorganic substances (ie. heavy metals)
• Organic compounds
• Synthetic organic compounds
• Oil
• Nonchemical pollutants

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Human Wastewater

• Water produced by human activities such as
• Can be difficult to prevent wastewater from
  contaminating drinking water

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Human Wastewater

• Three reasons scientists are concerned about
  human wastewater
• Oxygen-demanding wastes are broken down by
  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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Human WastewaterOxygen Demand

• Oxygen demanding waste organic matter that
  enters a body of water and feeds the growth of
  bacteria (decomposers)
• BOD (biological oxygen demand)- the amount of
  oxygen a quantity of water uses over a period of
  time at a specific temperature
• Dead zones areas where this is so little
  oxygen, there is so little life

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Human Wastewater Nutrient Release

• Nutrients (ie phosphorus, nitrogen) present from
  human wastewater
• Eutrophication increase in fertility of a body
  of water
• Cultural eutrophication
• Ex Dead Zone in the Gulf of Mexico

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Human Wastewater Why is eutrophication a bad
thing?

• Sewage

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Human Wastewater Disease-causing Organisms

• Pathogens illness-causing viruses, bacteria and
  parasites
• Illnesses include
• Indicator species
• Fecal coliform bacteria test

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Human Wastewater Treatments

• Septic systems- a large container that receives
  wastewater from the house
• Consists of a septic tank and leach field
• Septic tank
• Leach field
• Environmental advantages to septic system
• Downside

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Human Wastewater Treatments

• Sewage Treatment Plants- centralized plants in
  areas with large populations that receive
  wastewater via a network of underground pipes
• Primary treatment
• Secondary treatment
• Problems?

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Human Wastewater What is removed
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Human Wastewater Animal Wastewater

• Manure lagoons- large, human-made ponds line with
  rubber to prevent the manure from leaking into
  the groundwater Risks

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Heavy Metals and Other Substances

• Lead
• Arsenic
• Mercury
• Acids
• Synthetic compounds
• Pesticides
• Pharmaceuticals
• Hormones

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Lead

• Heavy metal
• Rarely found in natural sources of drinking water
• Sources
• Most at risk
• Risks
• In mid-1990s- 10 municipal water supplies
  contained lead levels that exceeded max
  permitted by Safe Drinking Water Act

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Arsenic

• Occurs naturally in Earths crust, can dissolve
  into groundwater
• Human activities (ie mining) can increase
• Can be removed via
• Problems associated with
• Many people suffer from arsenic poisoning with
  no other options

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Mercury

• Image mercury releases from different regions
  of world
• Comes from
• Inorganic mercury (Hg) not dangerous
• Bacteria (in wetlands and lakes) convert Hg into
  methylmercury
• Methylmercury is highly dangerous to humans
• Most at risk
• Can cause

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Acid Deposition and Acid Mine Drainage

• Acid deposition
• Wet deposition vs. Dry deposition
• Whats being done to prevent?
• Acid mine drainage
• Lower pH harmful metal ions become water
  soluble
• What can be done?
• Problem

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Synthetic Organic Compounds

• Synthetic human made
• Includes
• Pesticides
• Concerns
• Pharmaceuticals/hormones
• Military compounds from manufacturing, testing,
  dismantling rockets
• Industrial cleaners
• PCBs used in manufacturing plastics and
  insulating electrical transformers until 1979
• PBDEs flame retardants

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Oil Pollution

• Petroleum products highly toxic to many marine
  organisms, birds, mammals
• Very difficult to remove
• Sources
• Drilling for undersea oil using offshore
  platforms
• Spills from oil tankers
• Natural seeps

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Oil PollutionWays to Remediate

• Where does oil accumulate?
• So how do we clean up surface oil?
• Containment?
• Dispersants - chemicals that help break up the
  oil
• Bacteria that are genetically engineered to
  consume oil
• Underwater plumes
• Treatment of rocky coastlines

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Non-Chemical Pollutants

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

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Solid Waste Pollution

• Garbage - discarded materials from homes and
  industries that do not pose a toxic hazard to
  humans/other organisms
• 1997 scientists discovered the Great Pacific
  Garbage Patch
• More of a problem in developing countries
• Coal ash and coal lag Contains harmful chemicals
  (lead, mercury, arsenic)

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Sediment Pollution

• Sediment particles of sand, silt, clay
• Carried by moving water
• Sediment pollution increased movement of
  sediment due to human activities
• Activities that loosen soil
• Effects?

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Thermal Pollution

• Substantial change in water temperature
• Can be increase or decrease, most commonly is
  increase
• Methods to reduce thermal pollution
• Thermal shock

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Noise Pollution

• Sound emitted by ships/submarines interfere
  with animal communication
• Esp sonar

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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
• Originated as the Federal Water Pollution Control
  Act of 1948
• Issued water quality standards that defined
  acceptable limits of various pollutants in U.S.
  waterways

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Water Laws

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

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We still have work to do