Groundwater Pollution

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Groundwater Pollution

• 0331 Types of Pollution

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• http//techalive.mtu.edu/meec/module04/title.htm

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• Contaminants are separated into four main
  categories
• Physical
• Biological
• Inorganic chemicals
• Organic chemicals

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• These categories may overlap sometimes. eg a
  biological organism might make organic chemicals
  and the organisms have a physical effect on the
  water.

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• Contaminants can have effects at very small
  concentrations.
• Measure amounts of contaminants in terms of
  concentration.
• ppm and ppb and ppt, which are parts per million
  and parts per billion and parts per trillion.
• PPM is the amount of contaminant units in
  1,000,000 (1 million) units of groundwater.
• PPB is lthe amount of contaminant units in
  1,000,000,000 (1 billion) units of groundwater.
• PPT is the amount of contaminant units in
  1,000,000,000,000 (1 trillion) units of
  groundwater.

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• http//techalive.mtu.edu/meec/module04/GWContamina
  tionBasics1.htm

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• Very small concentrations of some groundwater
  contaminants could have serious health effects.
• Different kinds of contaminants have different
  concentration limits.
• It is necessary to find out both the specific
  type of contaminant and the concentration of the
  contaminant.

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• http//techalive.mtu.edu/meec/module04/GWContamina
  tionBasics3.htm

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Contamination Movement

• As contamination moves it disperses.
• The concentration decreases as it moves farther
  away from the source of the pollution.
• So there are different concentrations of
  contaminants at different points in the aquifer.

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• The representation of these different
  concentrations is called a contamination plume.
• http//techalive.mtu.edu/meec/module04/Contaminati
  onMovement.htm

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Area of Contamination

• A contaminant may be released into the
  groundwater for only a short time and in a very
  small area, but as it disperses the contaminant
  can affect a very large area and number of
  people.
• http//techalive.mtu.edu/meec/module04/AreaofConta
  mination.htm

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Plumes can be very irregular
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http//techalive.mtu.edu/meec/module04/PlumeExampl
e.htm

• Watch and say
• Where is the source of the contamination?
• Is the source continuous or a one-time event?
• Based on the direction of the plume, which way is
  the groundwater moving?
• How far does the contamination travel in 16
  years?
• What important areas of the city are affected by
  the contamination?

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Finding Contaminants

• Look at the history of the site.
• See if a nearby river is contaminated or what
  possible above-surface sources exists.
• To find the contaminant plume drill test wells or
  use other technology to find concentrations at
  different points underground.
• http//techalive.mtu.edu/meec/module04/PlumeSource
  Game.htm

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• Some specific contaminants.

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• Sites to search for contaminants
• http//www.clu-in.org/contaminantfocus/default.foc
  us/sec/General_Contaminant_Information/cat/Overvie
  w/
• http//www.clu-in.org/contaminantfocus/default.foc
  us/sec/General_Contaminant_Information/cat/Overvie
  w/
• has a large list of sites, including
• http//www.nature.nps.gov/hazardssafety/toxic/entr
  y.cfm

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Suspended Solids

• Organic and inorganic particles in water are
  termed suspended solids
• May be distinguished from colloids, particles
  that do not settle readily
• Measured by filtering a water sample, drying and
  weighing the filter

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Suspended Solids

• Problems
• sedimentation
• may exert oxygen demand
• primary transport mechanism for many metals,
  organics and pathogens
• aesthetic
• complicates drinking water treatment
• Sources
• storm water
• wastes
• erosion

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Pathogenic Organisms

• Many organims that cause human or animal diseases
  colonize the instinal tract but can live for a
  period of time outside the body
• Carriers (who may or may not exhibit disease
  symptoms) excrete these intestinal tract organims
  in very large numbers
• When water is contaminated by excretia, the
  organisms can be transmitted to those who contact
  the water

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Pathogenic Organisms
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Pathogenic Organisms
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Toxic and Hazardous Substances

• Volatile organic compounds
• Hydrophobic organic compounds
• Endocrine disruptors
• Surfactants
• Petroleum Additives
• Pesticides

• Heavy metals
• Other inorganic elements
• Acids/bases
• Oxidants/reductants
• Chlorination by-products
• Combustion by-products

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Volatile Organic Compounds

• Petroleum constituents
• benzene and substituted benzenes
• prevalent in gasoline, diesel fuel, heating oil
• most easily transported, slow degradation, toxic

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Volatile Organic Compounds

• Oxygentated gasoline additives
• added to gasoline to improve air quality
• very soluble, resistant to degradation, toxic
• attempt to solve one problem caused another
  (spills)

Methyl tertiary butyl ether (MTBE)
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Volatile Organic Compounds

• Chlorinated solvents
• C1 and C2 aliphatics
• widely used in degreasing, dry cleaning,
  extraction
• somewhat soluble, volatile, difficult to degrade

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Hydrophobic Organic Compounds

• Polycyclic aromatic hydrocarbons (PAHs)
• potent carcinogens, tend to associate with
  particles
• also combustion by-products

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Hydrophobic Organics/ Chlorinated Aromatics

• Chlorinated Pesticides
• Polychlorinated dibenzodioxins (PCDDs)
• Polychlorinated biphenyls (PCBs)

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Some Other Categories

• Trihalomethanes
• Explosives and Propellants
• Phenolics
• Aldehydes
• Organometallics
• Asbestos

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Arsenic

• Occurs naturally in rock and soil
• Released to groundwater under some conditions
• Health effects include cardiovascular diseases,
  skin cancer, nervous system effects, and kidney
  disease
• Major problem in Bangladesh
• Drinking water standard being lowered in U.S.