1. (20 points total) Consider the chemical bisphenol A as a potential contaminant in soil, and surface
water, and groundwater.
a. (10 pts) What is bisphenol A (chemical formula and structure), where does it arise as a contaminant,
and what are the important properties that determine its fate and transport in the environment.
b. (10 pts) Consider this chemical in Drinking Water. What standard would you set as a primary
drinking water standard (mg/L) for bisphenol A based on the best information currently
available. Consider the risk of cancer from an oral dose at a 10
-6
allowable risk as the
determining factor. Cite all references and data used to make this assessment.
2. (20 points total) A spill occurs at a factory and consists mainly of a highly soluble contaminant
(Retardation Factor = 5), and it makes its way to the groundwater table. An off-
site groundwater well exists 1,500 meters directly downstream in the
groundwater flow path. Given that the soil is a medium/coarse sand (porosity =
0.30) and the groundwater surface elevation is 605 m (MSL) at the spill site and
422 m (MSL) at the off-site well:
a. (10 pts) Estimate how long it takes for water to flow from the spill site and the estimated
arrival time for the contaminant to show up in the off-site well.
b. (5 pts) Discuss options for preventing the contaminant from reaching the off-site well.
c. (5 pts) If the contaminant reacts quickly with hydrogen peroxide (H2O2), and hydrogen
peroxide travels at the same velocity as water, what is the maximum time that can pass
before the peroxide is added to destruct the contaminant before it reaches the off-site
well?
3. (20 points total) A stream has a low flow of 35 cfs (7Q10) and an industry proposes locating along the
stream. They project an average combined wastewater flow of 4.2 MGD having 3 primary metal
contaminants (nickel, lead, and zinc) in their water discharge (one treatment process).
a. (10 pts) Project the allowable limits on metals (μg/L) in the wastewater discharge to meet
water quality criteria. Which metal will control?
b. (5 pts) If the wastewater arises from 3 separate discharges in the plant (1.4 MGD each),
how would segregation and separate discharge of these influence the results allowable
NPDES permit limits?
c. (5 pts) What alternatives to treatment could be considered here?
4. (20 points total) An old industrial property (many industries over more than 100 years of use, including
blending of paint strippers, blending of fuels, chrome plating operations and automobile repair) is
abandoned and proposed for redevelopment. Discuss the steps you would take for assessing this site for
potential and existing contamination. What cleanup steps would you anticipate? What future monitoring
would you expect?
5. (20 points total) A manufacturing facility uses benzene in processing and maintains the air quality in the
building at 1 ppmV or less to protect worker safety.
a. (10 pts) An engineer believes that it is possible that the water fountains with bottled water
consisting of 20 Liter jugs can be contaminated with benzene from the air and fears the
drinking water may exceed the primary standard. Is there any merit to his concern?
Assume a temperature of 15oC for all calculations.
b. (10 pts) The engineer, samples the water coolers one time (3 of them) and allows the
samples to sit open to the atmosphere in his car for an hour or two before sealing them
(900 mL sample in a 1-Liter sample bottle). Discuss this sampling technique and make
recommendations to improve the engineers sampling procedure, if needed.
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