CHM 377 Practice Exam November 6, 2006

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CHM 377 Practice Exam November 6, 2006
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• 1. Chlorinated pesticides remain a problem today
  because
• They contribute to acid rain effects
• Of residual soil contamination
• They contribute to global warming
• They add to the ozone depletion
• (b) Of residual soil contamination

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• 2. (5 pts) When assessing the impact of an
  anthropogenic compound on the environment,
• the half-life is a constant value and not site
  specific
• the LC50 is a constant regardless of the species
• the lipophilic nature is correlated with the KOW
  value
• the ultimate fate is unimportant.
• (c) The lipophilic nature is corrected with the
  KOW value

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• 3. DDT, once considered the miracle pesticide,
  was banned from use in the US in 1973, in part
  because
• more effective pesticides became available
• production costs became prohibitive because of
  costly chemicals
• high levels of DDT in mothers milk considered
  unfit for human consumption
• found to be too easily degraded for agriculture
  use
• (c ) high levels of DDT in mothers mike
  considered unfit for human consumption

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• 4. A dioxin that can be formed from
  2,3-dichlorophenol is
• 1,6-dichlorodibenzo-p-dioxin
• 2,7-dichlorodibenzo-p-dioxin
• 1,9 dichlorodibenzo-p-dioxin
• none of the above
• (a) 1,6-dichlorodibenzo-p-dioxin

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• One of the difficulties with toxicity
  measurements is
• an individual organism may give a unique response
• response may depend upon sex, age, and general
  health
• the effects of the chemical insult may appear
  later in the life cycle of the organism than 96
  hours
• all of the above
• (d) All of the above

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Using the model below discuss the fate of DDT in
bird (answer on next slide.
Uptake
Excretion
Sites of metabolism
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• In the model given, one would expect the DDT to
  go into storage, slowly be converted to DDE which
  would then take it to the toxic site of action.
  Doubt that very much would be excreted because of
  the high Kow value of 106.

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• Draw the chemical structure for
  1,3-dichlorodibenzofuran.

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• The difference between the effect of DDT and DDE
  on the calcification of eggshells is due to
• (a) number of chlorine atoms (b) structure
• (c) chemical reactivity (d) lipophilicity
• (b) structure
• The octanol-water partition coefficient measures
• (a) ease of reduction (b) half-life
  
• (c) chlorine/hydrogen ratio (d) degree of
  lipophilicity
• (d) degree of lipophilicity

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• Herbicides are
• used to treat for insects
• more persistent then chlorinated pesticides
• linked with high cancer rates among farmers
• insoluble in aqueous systems
• (c) Linked with high cancer rates among farmers

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C4

• The general dose-response curve for essential and
  non-essential elements is shown on the left.
  Explain what would happen if a person were
  exposed to a daily dose of a non-essential
  element, e.g. Hg, that would continue to build-up
  in the body until the concentration was greater
  than c4 shown on the curve Be specific and
  discuss what would happen at c2 and c3.
• At c2 the person would begin to experience
  effects, such as shakes, that were reversible,
  at c3, the effects would be irreversible, and at
  C4 the person would have passed the acute
  concentration, thus resulting in death.

C3