ENE 802
Physicochemical Processes in Environmental Systems
Fall Semester 2003
Dr. Susan J. Masten
Homework 1
Due: Friday, September 19, 2003. Completed assignments are to be turned in by 4
pm to either myself or to Lori Hasse in the Research Complex. Please do not turn
assignments into the CEE office in the Engineering Building.
1. A 55-gallon drum is half-filled with water and half-filled with air. A technician
disposes of 500 mL of benzene in the drum and then seals it. What is the
equilibrium concentration of benzene in the water and what is the partial pressure
of benzene in the gas phase.
2. In a factory in which metal parts are degreased with organic solvents, someone
drops a full glass bottle containing a mixture of 5 liters of tetrahydrofuran (THF) and
10 liters of methylethylketone (MEK) in a closed room at 20 oC. The room has a
total volume of 50 m3. The bottle breaks and the solvent mixture is spilled on the
floor. Soon several employees report that they can smell solvent vapors in the air.
Answer the following questions by assuming that THF and MEK form an ideal
mixture in the liquid phase.
a. What was the composition (in mole fractions) of the liquid mixture in the
bottle, and what is it at equilibrium in the remaining liquid on the floor of the
room?
b. What are the maximum (=equilibrium) concentrations of THF and MEK in
the air of the room? How much of each solvent component has evaporated?
Has the OSHA limits for THF and MEK been exceeded?
c. If the same accident happened in your sauna (volume = 15 m 3, T=80 oC), to
what maximum THF and MEK concentrations would you and your friends
been exposed?
3. Please see the handout distributed in class for this problem. Remember - be sure
to record all assumptions made in performing these calculations.
Media
Volume, m3
Air
2 x 1011
Water
9.5 x 105
Biota
4.2
Suspended
solids
45
Sediment
2.9 x 103
Organic carbon contents: Soil = 2%
5%
Sediment = 5%
Suspended solids =
Media densities (kg/m3) : Air = 1.19; Biota = 1050; Suspended solids =
1500; Water = 1000; Sediment = 1500
Compare your result with the Level 1 fugacity model available from the Canadian
Environmental Modelling Center.
4. The fugacity of 2,4,4'-trichlorobiphenyl (PCB) in a lake water at 25 oC is 10-6 Pa
(Pascals). The air water partition coefficient for this PCB is KAW = 0.006, and the
log octanol water partition coefficient is Log KOW = 5.74, both at 25 oC. The weight
fraction concentration of organic carbon in the lake sediment is 0.05 and the dry
bulk density of sediment is 1.5 kg/L. The upper 1 cm of lake sediment is assumed
to be in equilibrium with the lake water. In answering the following questions,
briefly discuss important assumptions that you make.
a. What is the meaning of the following statement: The fugacity of this PCB in lake
water equals 10-6 Pa? How might you measure the fugacity?
b. If the PCB concentration in the lake water is at equilibrium with the concentration
in air, what is the partial pressure of this PCB in the air phase?
c. Calculate the Henry’s Law constant (Pa m3/mol) for this PCB.
d. Calculate the expected sediment-water partition coefficient (KSW) for this PCB.
e. Calculate the fugacity capacities of the air, water, and sediment (upper 1 cm)
phases for this PCB.
f. Calculate the expected concentrations (mol/m3) of this PCB in the water, air, and
sediment phases.
g. If fish in this lake are exposed to the PCB by direct uptake from the lake water
(bioconcentration), calculate the expected concentration of the PCB in the fish.
5. A WI DNR employee has just returned from the field where he/she has taken a
sample of groundwater next to a leaky dichloromethane solvent storage tank. The
bottle is transparent and it is readily apparent that there are three separate phases
– air, water, and dichloromethane. A detailed GC-MS analysis of extracts from the
water and dichloromethane phases also indicates that, in addition to air, water, and
dichloromethane, the following compounds are also present: acetone, benzene,
toluene, and hexane. As environmental chemists we are interested in knowing how
the organic solutes are partitioned between air, water and dichloromethane. We
also know that it will take some time for the components in the flask to come to
equilibrium after sampling.
a. What is the minimum number of intensive variables that must be determined at
equilibrium in order to completely define the system? (Hint: the following intensive
properties are those that are needed – Temperature, Pressure, concentrations of
air (O2, N2, CO2, Ar, H2O) + all the organic compounds in the air phase,
concentrations of water, air + all organic compounds in the water phase, and the
concentrations of air, water and all the other organic compounds in the
dichloromethane phase.
b. Which ones would you specify?
6. Partial pressures of acetone and chloroform in the vapor in equilibrium with liquid
solution at 35.2oC are given in Table 1, below. (A) Plot the resulting vapor-liquid
diagram for this system! (B) Explain why there is a negative or positive deviation
from Raoult’s Law in this system (try to explain this in terms of what you have
learned about intermolecular forces).
7. What is the fugacity of pure chlorobenzene at 25 oC? What is the fugacity of 2 mg
chlorobenzene dissolved in one liter of water at 25 oC? The benzene = 1.25 x 104 in
water. The vapor pressure of pure chlorobenzene at 25 oC = 1.6 x 10-2 atm.
Table 1. Partial Pressures of Acetone and Chloroform in the Vapor in Equilibrium with Liquid
Solutions at 35.2oC.
Mole Fraction
Chloroform in
Liquid Solution
Chloroform
Acetone
Total
In mmHg
Mole Fraction
Pobs
Pcalc
Pobs
Pcalc
Pobs
Pcalc
0
0
0
344
344
344
344
0.2
34
59
270
275
304
334
0.4
82
117
183
207
265
324
0.6
148
177
102
137
250
314
0.8
225
234
42
69
267
303
1.0
293
293
0
0
293
293
Pressures expressed in mm Hg; Pobs = measured Vapor pressure; Pcalc = Calculated from
Raoult’s law.
FBI Warns of Potential Poison Attacks
Thursday , September 04, 2003
WASHINGTON — The FBI has warned law enforcement agencies that terrorists may use nicotine (search) and solani
agents."
Nicotine can be obtained from tobacco. Solanine can be obtained from potatoes.
"References to nicotine and solanine appear in numerous terrorist training manuals and documents seized in Afghanistan," t
law enforcement agencies, which was sent out late Wednesday. "The most likely technique for nicotine or solanine poisoning
contamination; however, nicotine can also be absorbed through the skin and mouth and the digestive and respiratory tracts."
The FBI said terrorist manuals "detail simple instructions" on how to produce both poisons. The FBI also said it "possesses n
terrorists plan to use nicotine or solanine in a future attack."
Acute nicotine poisoning will cause central nervous system depression, neuromuscular paralysis, lowered blood pressure, slo
common symptoms of nicotine poisoning include nausea, vomiting and abdominal pain, the FBI said.
Common symptoms of solanine poisoning occur two to 24 hours after exposure and include a harsh, scratchy sensation in the
drowsiness. Severe cases include cramps and fever -- and can result in coma and death, the FBI said.
The federal law enforcement agency also said: "There are no known instances of actual use of either poison by Islamic terror
was used in a recent domestic criminal poisoning incident, resulting in the sickening of nearly 100 people in Michigan."
The lethal dose of nicotine is about 40 to 60 milligrams. Solanine occurs naturally in "greened" potatoes, produced when the p
for long periods of time, the FBI said. A large dosage of solanine is necessary to be fatal, the bureau said.
In the second portion of the FBI bulletin, the bureau notes the upcoming second anniversary of the Sept. 11 attacks.
"Threats of undetermined reliability continue to be received and investigated by the FBI," the bureau said. "Several of these th
of September 11, 2001.
"The FBI possesses no specific information indicating that terrorists are planning attacks to coincide with the second annivers
Although Al Qaeda is not known to use anniversary dates as a factor in timing terrorist operations, increased attention in routi
the FBI said.
"While international counterterrorism efforts have eroded the capacity of Al Qaeda to plan and carry out similar large-scale att
Qaeda must continue to be viewed as a capable and determined terrorist network, committed to attacking U.S. and Western t
the United States."
Fox News' Anna Stolley contributed to this report. Source: http://www.foxnews.com/story/0,2933,96416,00.html
Information on Tetrahydrofuran
1. New Jersey's Department of Health, Right to Know Program's Hazardous Substance
Fact Sheets provide chemical information on acute and chronic health hazards,
identification, workplace exposure limits, and risk reductions.
http://www.state.nj.us/health/eoh/rtkweb/1823.pdf
2. The Environmental Defense Fund's Chemical Scorecard summarizes information
about health effects, hazard rankings, industrial and consumer product uses,
environmental releases and transfers, risk assessment values and regulatory coverage
http://www.scorecard.org/chemical-profiles/summary.tcl?edf_substance_id=109-99-9
3. National Toxicology Program Health and Safety Information Sheet
http://ntp-db.niehs.nih.gov/NTP_Reports/NTP_Chem_H&S/NTP_Chem1/Radian109-999.txt
4. Synopsis--Noncancer Inhalation Risk Values
RIVM has evaluated the noncancer oral toxicity data for tetrahydrofuran (THF) and
determined that there were no appropriate studies upon which to derive a tolerable daily
intake (TDI). Therefore, RIVM chose to do a route-to-route extrapolation from the tolerable
concentration in air (TCA) to estimate a provisional TDI of 10 ug/kg-day (0.01 mg/kg-day).
This TDI is provisional because it is derived via route-to-route extrapolation. The TDI was
estimated assuming 100% absorption for both inhalation and oral exposure. Taking the
daily breathing volume of an adult as 20 cu.m/day and the body weight as 70 kg, the TDI
can be derived by multiplying the TCA of 0.035 mg/cu.m by 20 and dividing the product by
70, resulting in a pTDI of 0.01 mg/kg-day. Click on the green circle(s) for more
information.
http://iter.ctcnet.net/publicurl/pub_view_l2_non.cfm?crn=109%2D99%2D9&type=NCO
5. Synopsis--Noncancer Inhalation Risk Values
RIVM has evaluated the noncancer inhalation toxicity data for tetrahydrofuran (THF) and
derived a tolerable concentration in air (TCA) of 35 ug/cu.m (0.035 mg/cu.m) based on a
12-week inhalation study in rats (Katahira et al., 1982). In this study, animals were
exposed 4 hours/day, 5 days/week, during 12 weeks. Therefore, the NOAEL of 295
mg/kg-day (for liver dysfunction and irritation of nose epithelium) was corrected for
continuous exposure by multiplying with 4/24 x 5/7, equaling 35 mg/cu.m (Basis ADJ).
Applying a UF of 1000 (100 for inter- and intraspecies variation and 10 for extrapolating
from the short duration study to lifespan exposure) results in a TCA of 35 ug/cu.m (0.035
mg/cu.m). Click on the green circle(s) for more information.
http://iter.ctcnet.net/publicurl/pub_view_l2_non.cfm?crn=109%2D99%2D9&type=NCI