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CE 481 – Remediation of Contaminated Soil and Groundwater Midterm (19:45-21:45, March 27, 2013)

Name: _________________________________________ Part I: True or False Questions (1 pt each; 26 pts total) 1. ____ Under an oxidizing environment, Fe+3 will be oxidized to Fe+2.

2. ____ TSDFs are regulated under CERCLA.

3. ____ Vapor pressure of diesel is larger than that of gasoline.

4. ____ Tedlar bags are used for collection of soil samples.

5. ____ Superfund program is part of CERCLA.

6. ____ Solubility is one of four characteristics used to determine if a waste is hazardous.

7. ____ Slug test is used to determine the in-situ density of soil in a vadose zone.

8. ____ Pyrene is one of the PCBs.

9. ____ Polyethylene tubing is acceptable for sampling VOC-contaminated groundwater.

10. ____ PCE is a daughter product of biodegradation of TCE.

11. ____ Monitoring pH is often done during well purging before groundwater sampling.

12. ____ Bentonite is commonly used in installation of groundwater monitoring wells.

13. ____ In-situ biodegradation of chlorinated solvents usually occur under anaerobic conditions.

14. ____ Incineration is not an acceptable method for treating asbestos wastes.

15. ____ Hydropunch is a commonly-used technique for installation of groundwater wells.

16. ____ Hydrophobic compounds would travel slower through an aquifer than hydrophilics.

17. ____ For free product recovery from an aquifer, one should start with the product-only mode first.

18. ____ For a site remediation, it is instructive to remove the polluting source as soon as possible.

19. ____ FID is a portable instrument for detection of heavy metal contaminants.

20. ____ Constant-head permeameters are used to determine hydraulic conductivity of clay samples.

21. ____ Duplicate samples are subsamples of the same sample.

22. ____ Perchloroethylene is considered as a DNAPL.

23. ____ Cr+6 is more toxic than Cr+3.

24. ____ Benzene vapor will travel less readily through soil under more moist condition.

25. ____ Bacterial activity in a contaminated aquifer will probably reduce the ORP of the aquifer.

26. ____ ARARs are used to determine the number of groundwater monitoring wells needed.

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Part II: Fill the Blank or Write the Full Names for the Common Acronyms Used in Environmental Engineering (1 pts each; 22 pts total)

1. Water pressure head at water table = __________________________________

2. Vapor pressure of toluene at 20 oC = __________________________ mmHg.

3. Typical hydraulic conductivity of a silty formation (in cm/s) = ____________________.

4. Typical height of capillary fringe for a formation made of very coarse sand = __________ cm.

5. Typical bottle size for collection of head-space free VOC samples: _______________ mL.

6. TPH = Total __________________________ Hydrocarbon.

7. The value of Henry’s Constant (in dimensionless form) of benzene at 25 oC = ____________.

8. The pKa value of phenol = __________________________.

9. The Log(Kow) value of vinyl chloride at 25 oC = ________________________________.

10. RWQCB is the acronym for _____________________________Water Quality Control Board.

11. RI/FS = Remedial Investigation /___________________________________Study.

12. ROD = Record of ____________________________________.

13. PRPs in CERCLA is acronym for Potential ____________________ Parties.

14. Partial pressure of oxygen in the ambient air = ____________________________ atm.

15. MSDS = Material _________________ Data Sheet.

16. Henry’s constant = vapor pressure ________________________________ in water.

17. Give a common unit of dispersivity = __________________________________.

18. DNAPL = Dense Non-aqueous __________________________ Liquid.

19. Chemical formula of dichloroethylene (DCE): ___________________________________.

20. Chemical formula of dichloroethane (DCA): ____________________________________.

21. CEQA = California Environmental _______________________ Act.

22. B/T/E/X = Benzene/Toluene/__________________________________/Xylenes

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CE 481 – Remediation of Contaminated Soil and Groundwater Midterm (19:45-21:45, March 27, 2013)

Name: _________________________________________ Part IV: Calculation Question (4 problems; 52 pts total) 1. (14 pts) Four leaky 6,000-gallon underground gasoline storage tanks were removed. The

excavation resulted in a tank pit of 80'x25'x18' (LxWxH), and the excavated soils were stockpiled on site. Five grab samples were taken from the pile and analyzed for TPH using EPA method 8015. Using the average TPH value of these five samples, an engineer at CSUF Consulting Engineers, Inc. determined the amount of gasoline present in the pile to be 120 gallons. What is the value of the average TPH concentration (in mg/kg) the engineer used? (Note: Bulk density of the soil in the vadose zone = 2.0 g/cm3 or 125 lb/ft3; and density of gasoline = 0.8 g/cm3 or 50 lb/ft3)

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2. (12 pts) A kid went into a site (T = 20 oC) and played with dirt contaminated with ethylbenzene (C6H5C2H5). During his stay at the site the kid inhaled 4 cubic meters of air containing 200 ppbV of ethylbenzene and ingested a mouthful (~2 cm3) of soil containing 50 mg/kg of ethylbenzene (bulk density of soil = 1.8 g/cm3), which system (ingestion or inhalation) took in more ethylbenzene?

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3. (14 pts) The subsurface underneath a site is contaminated with 1,2-dichloropropane (C3H6Cl2) resulted from leaky USTs. Recent groundwater monitoring indicated that 1,2-dichloropropane had entered the aquifer and created a dissolved plume. Estimate the migration speed (in m/day) of this dissolved plume in the downstream direction.

The following data were obtained from RI:

Aquifer porosity = 0.40 Aquifer hydraulic conductivity = 40 m/day Groundwater gradient = 0.005 Bulk density of aquifer materials = 2.0 g/cm3 foc of aquifer materials = 0.01 Log(Kow) of 1,2-dichloropropane = 2.00 Koc = 0.63 × Kow

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4. (12 pts) Toluene (C6H5CH3) concentration of the groundwater sample taken from a contaminated aquifer was determined to be 400 ppb. It was estimated, by an engineer of the CSUF Consulting Engineers, Inc., that 20% of the total toluene mass was dissolved in the aquifer water and the other 80% was adsorbed onto the solid (no free-product phase was present). From the RI work, the following parameters were also determined: porosity of the aquifer = 0.35; and bulk density of the aquifer matrix = 1.8 g/cm3. Estimate the retardation factor by using only the given information (do not assume a value for Kow or foc).

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CE 481 Formulas for Midterm Exam Mass of contaminant in liquid = (liquid volume)(liquid conc.) = (Vl)(C) Mass of contaminant in soil = (X)(Ms) = (X)[(Vs)(b)] Mass of contaminant in air = (air volume)(conc. in mass/vol) = (Va)(G) G = HC H = Hdimensionless RT (R = 0.082 atm/(K)(M) X = KpC Koc = 0.63Kow Kp = focKoc

1 ft3 = 7.48 gallons; 1 gallon = 3.785 liters; 1 ft = 0.3048 meter; 1 g/cm3 = 62.4 lb/ft3 Atomic weight : H = 1, O = 16, C = 12, Cl = 35.5, S = 32

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