土壤與地下水污染題庫
1. Please explain the reason why the hydraulic gradient becomes steeper, forming a
characteristic lowering of the water table or potentiometric surface (also called
cone of depression) as the water approaches the borehole. (hints: using the
Darcy’s law)
2. The movement of a contaminant through a natural system, such as an aquifer, is
controlled by transport mechanisms. Please list and clarify these mechanisms.
3. Adsorption and desorption of organic molecules in soils in controlled by the
chemical properties of the molecules and the surface properties of the particular
soil. Please demonstrate the relevant properties in details.
4. A description of the chemical forms that an element takes in solution is termed its
speciation. The speciation behavior of an element in soils profoundly affects its
bioavailability. Environmental scientists argued that this concept should be
applicable to the heavy metals. Please provide your own opinions for the
statement.
5. What are the hierarchies of pollution prevention? Explain each of them.
6. What is ISO 14000? Please give benefits and pitfalls for ISO 14000.
7. What is the major agreement of Kyoto Protocol? The objective of the Kyoto
Protocol will be defeated if what event occurs?
8. To achieve project objectives in a cost-effective manner, a clear strategy for
mapping the contaminant zones must be established prior to commencement of
field or laboratory work. Please provide a detail strategy for hydrogeologic site
investigations.
9. What is NAPL? NAPLs have a tremendous impact on the remediation of
contaminated aquifers, because it is very difficult or impossible to remove all of
the residual NAPL blobs once they are trapped in individual pores. Please give a
detail explanation for the above mentioned statement.
10. Please give a sketch of the effect of falling and rising water table on the
distribution of mobile and residual phases on an LNAPL.
11. Unless the DNAPL observation well is screened directly within a DNAPL pool or
lens and is constructed correctly, the apparent DNAPL thickness can give
erroneous indications of the quantity of DNAPL in the formation. Please explain
why?
12. Give some containment methods for source control to eliminate the potential
spread of environmental contaminants.
13. Please give some examples for the abiotic transformations of heavy metals, such
as Cr, As, and Hg, in the nevironment.
14. What is dose-response curve used for? If only single values from the
dose-response curves are available, it must be kept in mind that those values will
not provide any information about the shape of the curve. Please justify this
statement.
15. Acute toxicity, which is often generated in tests because of the savings in time and
expense, may not accurately reflect chronic toxicity dose-response relationships.
Please give an example with detail explanations for above mentioned statement.
16. Given the following parameters for an aquifer, which received pollutants from
adjacent industrial area. Porosity of 0.15 and water conductivity of 5 m/day. How
long will the pollutant affect the water supply from a well 5000 m away from the
discharge point?
17. Any of the “four” major characteristics will make a waste hazardous. Please
specify each of them.
18. Site soil conditions frequently limit the selection of a treatment process. In
addition, a treatment technology may be eliminated based upon the soil
classification (e.g., particle-size distribution) or other soil characteristics (e.g., soil
moisture, pH, variability, bulk density, particle density, permeability, Eh). Please
give a throughout discussion of the influences of soil properties on the selection of
a remediation strategy.
19. Of which heavy metals commonly found in contaminated sites in Taiwan do the
plants fail to play the role of a biological alarm that would warn of toxicity? Will
the inert response of plant to the metals, which you propose, affect the selection of
treatment process? Explain why your answers are?
20. It is usual that a site that includes an unconfined aquifer separated from an
underlying confined aquifer by a confining layer. Please sketch a procedure for
installation of a monitoring well into the underlying confined aquifer without
introducing contamination from above.
21. Define the terms point source and nopoint source and give some examples of each.
Explain why nonpoint sources are often more difficult to control than point
sources.
22. (A) Define the terms: degradable pollutants, non-degradable pollutants and
persistent pollutants and give some examples of each.
23. Describe primary, secondary and tertiary wastewater treatments. What happens at
each stage in the treatments and what pollutants are removed ?
24. Define the terms: natural eutrophication and anthropogenic eutrophication and
explain the differences between them. Which inorganic nutrients are the main
causes of anthropogenic eutrophication? Describe the major pathways for their
transports from their sources to surface water? List some strategies for eliminating
these nutrients from water.
25. Define the term natural succession. Describe how inorganic nutrients can
accelerate natural succession in a lake.
26. Why chlorine gas is used to treat human sewage and drinking water? What
dangers and problems does its use pose? Suggest two alternative substances that
can be uses without causing these problems.
27. List at least three strategies for removing heavy metals from soils and describe the
physical and chemical bases behind them.
28. Describe where phosphorus is removed from sewage water in an activated sludge
wastewater treatment plant and give a balanced chemical reaction for lead
removal in the tertiary stage.
29. Why do chlorinated hydrocarbons persist in the environment? Why do they posses
threat to human health even though they are found in low concentration in water?
30. Give an example of the methods or techniques that are currently available for
eliminating chlorinated hydrocarbons from soils and describe its physical,
chemical or biological mechanisms.
31. Provide a conceptual figure to demonstrate the sequence of steps required to move
sorbate molecules between soil solution and all the sorptive sites in a typical soil
aggregate.
32. Give five reasons why it is important to know to what extent a given chemical is
present in the sorbed form in a natural system.
33. What are the most important natural sorbents and sorption mechanisms for (a)
apolar compound, (b) polar compounds, and (c) ionized compounds?
34. Why is soil organic matter (SOM) such an important sorbent for all organic
compounds? What are the most important properties of SOM with respect to the
sorption of organic compounds?
35. Provide the definition in words for (a) bioconcentration factor, (b)
biomagnification factor, (c) bioaccumulation factor.
36. For what kind of organic compounds and in which environmentally relevant cases
is adsorption of organic chemicals to inorganic surfaces in water important? Give
five examples.
37. Three polychlorinated ethanes (1,1,2,2-tetrachloroethane,
1,1,1,2-tetrachloroethane and pentachloroethane) are introduced into a lake by an
accident. Calculate the half-life for chemical transformation of each of the three
compounds in the lake (T=25 °C, pH=8.5). For each compound indicate the pH at
which the neutral and base-catalyzed reactions would be equally important. What
is (are) the transformation product(s) for these compounds?
Compound
Neutral reaction
kN at 25 °C
Base-catalyzed reaction
kB (s-1) at 25 °C
Cl2HC-CHCl2
Cl3C-CClH2
Cl3C-CHCl2
1.6x10-11
4.3x10-10
8.2x10-10
2.0x108
3.6x10-4
2.2x101
References:
Environmental Science and Technology 22:658; 23:965.
38. Tetrachloroethylene (PCE) is a common organic solvent that may contaminate
groundwater if leached through soil from a disposal site. Given its water solubility
of about 5 mmol/L, estimate the distribution coefficient for PCE in a soil
containing 20 g humus per kilogram. Is PCE immobilized well by the soil?
log K OM  2.188  0.729 log S W ater
K d  K OM f OM
Kd: the distribution coefficient of contaminants between soil and water
KOM: the distribution coefficient of contaminants between organic matter and
water.
FOM: the organic matter fraction of soil.
39. Explain why sulfur cycle in sediments is related to the transformation and
movement of some heavy metals in water.
40. Explain why in groundwater the transfer and transformation of arsenics is related
to the transformation of Fe(II)/Fe(III) species.