Groundwater%20Pollution

1
Groundwater Pollution

• Lecture 13 Exam Revision

2

• Question 1 Are the following statements True (T)
  or False (F)?
• Eg. Repeating the language is very important in
  learning English. T
• Groundwater is often moving.
• There is lots of freshwater available for all
  people.
• The natural movement of groundwater is from
  downhill recharge areas to uphill discharge
  areas.
• If ground water has been contaminated, it is
  usually very difficult and costly to
  clean.
• Inflows and outflows never result from human
  activity.
• Question 2 Fill in the missing word.
• For many years people thought that groundwater
  was protected from _______________________________
  _ by the layers of soil and rock above it.
• The hydrologic cycle includes inflows,
  ________________________ and storage.

3

• 1. State whether the following statements are
  True (T) or False (F)
• a. The aerated zone of the ground is usually
  above the water table. ___
• b. Groundwater usually occurs in underground
  lakes and rivers. ___
• c. Clay can stop the flow of groundwater. ___
  
• 2. Fill in the missing word
• a. Water can enter into the soil, or can soak
  into holes and cracks in rocks.
• This is called ____________________________.
• b. The _____________________ zone is where all
  spaces in the ground are filled with water.
• c. Rock layers that let water flow through are
  called ______________________.
• d. Rock layers that prevent the flow of
  groundwater are called _____________________.
• 3. Answer the following questions.
• a. What is permeability?
• b. What is discharge?

4

• Match the word with the related meaning
• The first one is done as an example.
• WordMeaningAArtesianAn aquifer that crops out and
  is exposed at the surface.DBDrawdownThe level
  which the water rises in boreholesCTransmissivityG
  roundwater is pumped from a borehole, the water
  level is lowered in the surrounding
  areaDUnconfinedIf a hole is drilled into the
  aquifer water rises up and may overflow at the
  surface EPotentiometric surfaceThe ability of an
  aquifer to transmit water.
• 2. Choose whether the statements are True (T) or
  False (F).
• a. Because of earth movements in the past, many
  aquifers dip below younger layers of impermeable
  clay. ___
• b. Water flows into a borehole from all
  directions in response to pumping. __
• c. In groundwater the water flows very slowly
  through the ground. ___

5

• Are the following True (T) or False (F)?
• a. Groundwater can be polluted with salt
  water. ___
• b. Pollutants are sometimes injected into the
  groundwater. ___
• c. Gasoline cannot dissolve in
  groundwater. ___
• 2. What is groundwater pollution?
• 3. Aquifier exchange is when water from one
  aquifier can get into another aquifier. This can
  be because of drilling activities by people. Draw
  a picture of showing how aquifier exchange can
  happen.

6

• Label the following as True or False.
• a. High bacteria or nitrate levels in well water
  can indicate that the groundwater has been
  contaminated by animals. ____
• b. Leachate is material washed out of a layer of
  soil by rainwater as it moves through the
  soil. ____
• c. Improper handling of materials is probably the
  biggest cause of groundwater pollution.
  ____
• d. Often people notice pollution by the smell and
  taste of the water. ___
• 2. What are the two basic categories of water
  pollution?
• ____________________________________
  ___________________________________

7

• Are the following statements True or False?
• a. The first and most important step of a
  typical soil and/or groundwater remediation
  project is to find out the extent of
  contamination. ____
• b. Site characterization is to determine the
  conditions away from the site. ____
• c. Contaminants could be sitting on top of
  bedrock. ____
• 2. Give three questions that could be asked about
  the contaminant plume?
• 3. What are LUSTs?
• 4. What is a monitoring well?

8

• What is an NPAL? _________________________________
  __________________
• Draw and label a diagram showing the distribution
  of a dense NAPL which has been spilled onto the
  ground over an aquifer.
• If the concentration of an organic contaminant in
  groundwater reaches 5 to 10 percent of the
  maximum what does that indicate?
  ________________________
• What are the main processes that affect plume
  movement?
• Explain, using a diagram, what a sand lens is and
  what it does to the movement of a plume.

9

• What is mobility? ________________________________
  ______________________
• What is toxicity? ________________________________
  ______________________
• Is it easy to say what will happen to chemicals
  in the soil? Why? _______________
• __________________________________________________
  ____________________
• What is a redox reaction? ________________________
  _____________________
• What do we call the chemical which gains
  electrons? _______________________
• What do we call the chemical which loses
  electrons? _________________________
• How can some metal oxides be used to remove
  organic contaminants from the soil or
  groundwater? _____________________________________
  ___________________
• __________________________________________________
  ____________________
• What is solubility product and how can we use it
  to find out if a substance will precipitate out
  of solution? _____________________________________
  _______
• __________________________________________________
  __________________
• What is sorption? ________________________________
  _______________
• How does sorption affect the travelling of
  contaminants though the groundwater?
• __________________________________________________
  _________________
• What is adsorption? ______________________________
  ___________________
• What is absorption? ______________________________
  _____________________
• Why is the polarity of contaminants important?
  _____________________________
• __________________________________________________
  _____________________

10

• What are non-aqueous phase liquids (or NAPLs)?
  __________________________________________________
  _______
• How are they divided? ____________________________
  ____________________________
• What is their allowable concentration in drinking
  water? ___________________________________________
  ______________
• Where have LNAPLs been found to be a continual
  source? (describe fully)
• __________________________________________________
  ___________
• Describe the problem with DNAPLs.
  ____________________________
• __________________________________________________
  ___________
• Draw a diagram showing the migration of DNAPLs.
• Why is a good knowledge of sub-surface structure
  important when dealing with DNAPLs?
• __________________________________________________
  ___________
• List some chemicals which could be DNAPLs. What
  are they used for?
• __________________________________________________
  ___________

11

• Draw a diagram of the different processes
  involved in the attenuation of an oil spill.
• Why is monitored natural attenuation so
  desirable?
• __________________________________________________
  ________
• In the following table with list three processes
  and what these processes will reduce.
• ProcessWhat gets reducedEg. volatilizationThe
  concentration of contaminants.
• Describe the difference between attenuation of
  organic compounds and attenuation of metals.
• __________________________________________________
  ___________
• Draw a diagram of the different electron acceptor
  zones of an oil spill.

12

• Which of the following does the Risk Paradigm not
  include?
• Looking at fundamental processes that underlie
  human health problems that are caused by
  pollutants in the environment.
• Asking questions of exposure and the adverse
  outcomes associated with exposure.
• Asking questions about the financial costs of
  remediation.
• Assessing cancer, birth defects, developmental
  disorders, and other serious health problems that
  can be caused by exposure.
• Assessing effects of pollution on organisms and
  ecosystems.
• Which of the following are the four steps in the
  process of risk assessment?
• hazard identification,
• pollution source identification,
• dose-response assessment,
• exposure assessment,
• risk characterization.
• Which of the following are questions to be asked
  during Hazard Identification?
• Does exposure to a certain substance cause injury
  or disease in humans or to the environment?
• Are certain subgroups more at risk than others?
• What is the relationship between the amount of
  exposure (or dose) and the health effects?
• Are the effects observed in experimental settings
  likely to be observed in real-world settings?
• Which of the following are questions to be asked
  during Risk Characterization
• What is the intensity, frequency, and duration of
  individuals' exposure to a substance?

13

• Pump and Treat systems of groundwater
  remediation arent used all the time because they
  are not very successful if removing all
  contaminants.
• The steps of Groundwater Remediation System
  Design are followed in this order.
• Define the Problem
• Define the Goal of Groundwater Remediation
• Screen Candidate Remedies
• Prepare Detailed Design
• Implement the Design
• Confirm the Effectiveness of the Design
• Different technologies can be used for
  remediation of groundwater but we can generally
  split them into ex-situ and in-situ methods.
• Describe any two remediation methods.