Download Second exam 2002

Name_________________________
Environmental Toxicology (ADVS 5400/6400)
Examination II
Wednesday, March 20, 2002
For questions 1-8, circle the letter corresponding to the correct statement(s). None, one or more of
the selections may be correct. Don’t guess--incorrect responses will be deducted from your score
(5 each; 40 total).
1. The following statements are true statements about chemodynamics:
a. a Henry’s Law constant (H) = 1 means solute has equal affinity for water and air
b. H > 1 means solute has greater affinity for air compared to water
c. vapor density in soil is inversely proportional to temperature
d. chemical evaporation from H2O inversely proportional to solubility
e. chemical evaporation from H2O inversely proportional to H bonding
2. The following are true for aluminum:
a. one of the least abundant metals in the earth's crust
b. is readily absorbed through the GI tract
c. is poorly absorbed via inhalation
d. liver and kidney are the major sinks
e. large oral doses can result in rickets
3. The following statements are true about chemical binding to soil (all else equal):
a. anionic chemicals more easily bound than cations
b. cationic chemicals leach from soil more better than anionic
c. acidic chemicals best at low pH
d. basic chemicals best at high pH
e. proportional to water solubility, inversely proportional to Pc of chemical
4. The following are true statements for chemical evaporation (all else equal):
a. increases from soil with increasing temperature
b. decreases from soil with increasing soil moisture
c. best for acidic chemical when water pH < pK
d. highest when chemical is neutral or uncharged
e. increases as concentration of chemical increases
5. The following are true statements regarding antidotes and/or treatments:
a. British Anti-Lewisite is the treatment of choice for chromium
b. ascorbic acid can be used to treat Cr+3 toxicity
c. L-dopa is an effective treatment for manganism
d. diethylascorbate is an effective treatment for Ni toxicity
e. metallothionein is a recognized antidote for cadmium
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6. The following are true statements regarding bioaccumulation/biomagnification:
a. to be biomagnified, compound must be persistent
b. to be biomagnified, a compound must have a high Pc
c. the Farm Pond is an outdoor model ecosystem that contains most necessary
components to study biomagnification
d. ecological magnification defines the ability of an organism to accumulate a chemical to
a concentration higher than that found in the water.
e. the ecological magnification of benzoic acid is less than that of biphenyl
7. The following are true for metal toxicology:
a. caused by cadmium, Itai-Itai disease is characterized by painful skin lesions
b. As+3 is more toxic than As+5
c. Cr+3 is more toxic but less prevalent than Cr+6
d. thallium is the causative agent of "Hatter's Disease"
e. thallium causes characteristic Friar Tuck hair loss pattern
8. The following are true for Hg toxicity:
a. methyl Hg is formed via microbial alkylation of Hg released from the earth's crust
b. the "Minamata Bay incident” was traced to Hg release from a nearby chemical plant
c. mercury is also called "mercaptan" because of its affinity for sulfhydryl molecules
d. the greatest occupational exposure is inhalation of Hg vapor
e. used as a fungicidal seed coat
9. Describe the mechanism of arsenic poisoning. Describe two biomarkers of arsenic exposure.
How would the treatments differ for acute and chronic arsenic exposures? Describe mechanisms
of treatment action (10).
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10. The uncouth billionaire Jed Jurner calls your toxicological consulting firm and asks whether
the plant Splendide mendax found in an area surrounding a mine he recently added to his land
empire would be useful in phytoremediation and reclamation of the area. Identify and describe
four essential factors for practical phytoremediation you will consider (10).
11. Free radical generation is an important mechanism postulated for a variety of chemicals, such
as nitroaromatics and divalent metals, such as iron. a) Define “free radicals;” b) describe, in
detail, how transition metals are involved in free-radical based toxic mechanisms; c) what are the
major outcomes to free-radical damage to lipids and to DNA? (10)
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12. Because he lives in an old dwelling, “Brent”is exposed to more lead than most of us. a) Name
two sources of lead and their routes of exposure common to old homes and apartments. b)
describe three toxic major effects caused by lead that Brent may suffer from; c) Describe two
biomarkers for lead exposure; d) name and describe one outwardly-visible sign indicative of
excess lead exposure (draw a picture of Brent if you want..) Any resemblance to any student, real or
imagined, is purely coincidental. (15)
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13. If Brent’s (same “hypothetical” Brent from previous question) lead exposure is 2 µg/day, and
his elimination rate constant is 0.002/day: a) what will be the maximum body burden of lead in
his body, and when will he achieve it? b) Draw a graphical representation of Brent’s blood lead
concentration over time; c) how would these numbers and the graph change if Brent took a
chelating agent that increased his elimination of lead two-fold? d) If Brent could move to a
location where he would have no lead exposure, when would he excrete “all” his lead? Draw the
graph showing this decline in lead e) would he really eliminate all lead from his body? Explain..
Clearly show all calculations! (15)
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