20) The goal of the Stockholm Convention is to ________.
A) reduce global warming
B) reduce the ecological footprints of people around the world
C) end the use and release of the 12 POPs shown to be the most dangerous
D) prevent trade in asbestos
E) protect the ozone layer
21) The Yaqui Valley, Mexico, study showed that ________.
A) wealth is correlated with intelligence
B) infectious disease is more widespread in poor countries
C) frogs were affected by water pollution
D) developmental delays occurred in children exposed to pesticides
E) organic agriculture can be successful with government support
22) Louis Guillette is most famous for his studies ________.
A) on gonadal abnormalities in frogs
B) about the dangers of DDT
C) on neurological effects of pesticide poisoning
D) describing reproductive and developmental abnormalities in alligators in Lake Apopka
E) about the dangers of secondhand smoke
23) Order the following hazards according to the risk they pose (with the most risky first).
A) automobile accident, homicide, drowning, airplane accident
B) homicide, automobile accident, drowning, airplane accident
C) automobile accident, homicide, airplane accident, drowning
D) airplane accident, automobile accident, homicide, drowning
E) automobile accident, airplane accident, homicide, drowning
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24) The leading cause of deaths in the world are ________.
A) infectious diseases
B) cardiovascular diseases
C) cancers
D) respiratory and digestive diseases
E) injuries
25) Synergistic effects of toxicants ________.
A) have effects that tend to cancel one another out
B) typically have simple additive effects
C) are not numerous in the natural environment
D) often have effects that are multiplicative
E) always involve synthetic toxicants
26) The effect of toxicants on fetuses ________.
A) is greater than the effect on adults because of the fetuses’ rapid growth and smaller biomass
B) is less than the effect on adults because the fetuses’ metabolisms are higher
C) is less than the effect on adults because the fetuses are protected by their mothers’ immune
systems
D) has been systematically evaluated for most chemicals released into both indoor and outdoor
environments
E) can be extrapolated downward from the known effects in adults, after correction for different
weight
27) The European Union’s experience with PBDE’s has shown that ________.
A) removal of the toxin from the environment reduces its concentrations in humans
B) economic factors have superceded health concerns
C) these molecules can be rapidly metabolized by decomposers
D) human metabolism of these compounds could solve the problem without legislation
E) these molecules result in birth ratios of 9 males:1 female
28) Studies of endocrine disruptors have shown that they are closely associated with all of the
following EXCEPT ________.
A) gonadal abnormalities
B) lung cancer
C) low birth rates
D) male feminization
E) thyroid hormone abnormalities
29) People with immune systems compromised by HIV are more vulnerable to other diseases.
This effect is an example of ________.
A) negative feedback
B) synergistic effects
C) disease loop
D) additive effects
E) immunological flashback
30) Concentration of DDT (expressed as parts per million) are 0.04 ppm in zooplankton , 0.5
ppm in small fish , 2 ppm in large fish, and 25 ppm in osprey. This pattern ________.
A) is an example of synergy
B) resembles the changes in available energy in a trophic pyramid
C) suggests that the numbers of ospreys will decline, which would restore ecosystem
homeostasis
D) is not as bad as one would think at first glance, because the higher concentrations are in larger
animals, so DDT content per kilogram of biomass does not increase as much as these numbers
would suggest
E) should not be too alarming, because even the highest numbers are still too low to cause
significant damage (at most they are 25 ppm).
31) ________ are particularly good indicators of presence of pollutants in our environment.
A) Guinea pigs
B) Canaries
C) Fish
D) Mice
E) Rats
19.5 True/False Questions
1) The findings by Hunt indicated that bisphenol-A was toxic to humans.
2) Examining case studies, such as the role of serpentine asbestos in human health, is not a good
way to assess risk of toxicants for human populations.
3) Natural chemical substances include oil oozing from the ground and radioactive radon gas.
4) Radon is a highly toxic radioactive gas that is introduced into homes through the use of
electrical power generated by nuclear power plants.
5) Acute exposure to chemical agents is more difficult to detect than chronic exposure.
6) The United States still manufactures DDT, which it exports to other countries for agricultural
use. This comes back to Canada in food that has been sprayed with this pesticide.
7) Some threats to human health are unavoidable because they are wholly natural and part of the
natural environment.
8) In 2003, SARS came to Canada from Africa.
19.6 Essay Questions
1) What are endocrine disruptors? How do they work on pests? Why are they a problem for
humans? Have they been banned? Why or why not?
2) Explain and give an example of biomagnification.
3) What are epidemiological studies, and what is their value? Are there any disadvantages to
epidemiological studies?
4) How is the precautionary principle used in environmental health? What is an alternative
philosophical approach?
5) Summarize the opposing views on how much risk is posed by natural vs. synthetic toxicants.
6) Define risk assessment and risk management. Discuss how risk management combines
science and other social factors.
7) Explain how response to hazards can vary based on individual differences and types of
exposure. Give examples, where appropriate.
8) What are the most common geological hazards? How are they related? Where are they most
common and why? (Hint: Recall “the ring of fire” from Chapter 2.) Which parts of Canada are
most vulnerable to these hazards and why?
9) Imagine you are renting an older house with your friends. The landlord has installed new
furniture and carpets, but there have been recurring problems with cockroaches. One of your
roommates smokes. The house is next to a busy street and is within several kilometres away
from a petroleum refinery. Your neighbour has a surprisingly green well-manicured lawn,
without any dandelions or other weeds. What environmental health issues are you likely to
experience?
10) Explain the four main types of environmental hazards. Give examples of each. Which parts
of Canada may be most vulnerable to each of them?
19.7 Scenario-Based Questions
Read the following scenario and answer the questions below.
Mercury is a heavy metal that occurs naturally in minerals and rocks. The release of mercury
from natural sources has been relatively constant over time. However, the anthropogenic release
of mercury has increased significantly in recent years primarily because of increased fossil fuel
mining and combustion. Mercury that is released into the air eventually ends up in soils or
surface water. Once in water, microbes convert mercury into methylmercury, which is absorbed
quickly and concentrated in the tissues of predatory fish such as the shark and the swordfish.
Large fish typically concentrate more mercury than small fish. People who eat fish with high
methylmercury concentrations can show tremors, deafness, muscle incoordination, and attention
deficits. Children and pregnant women are especially sensitive to methylmercury’s toxic effects.
Learning disabilities and developmental delays are common in children who have been exposed
to significant levels of methylmercury.
1) Which of the following Canadian agencies is primarily responsible for addressing causes of
mercury pollution?
A) PHAC
B) Environment Canada
C) Heavy Metal Monitoring Group
D) Health Canada
E) Department of Fisheries and Oceans
2) After building a hydro dam, some of the mercury contained in flooded organic matter
becomes methylated. Which of the following is NOT true?
A) The local population will be advised to reduce their consumption of fish.
B) Prey fish closer to the source of contamination will have a higher mercury concentration than
the predatory fish.
C) Children and pregnant women should eat less fish than other people.
D) It is usually safer to eat younger fish.
E) It is usually safer to eat smaller fish.
3) Mercury is to methylmercury what DDT is to ________.
A) DDE
B) DEP
C) POP
D) PCB
E) PBP
4) Based on the specific health effects described above, mercury would be best classified as a
________.
A) synergist
B) neurotoxin
C) carcinogen
D) endocrine disruptor
E) allergen
5) Mercury is not readily excreted; it is stored in mammalian body tissues. This is best described
as ________.
A) distillation
B) toxification
C) biomagnification
D) bioaccumulation
E) synergism
6) Concentrations of methylmercury are higher in large fish relative to that in small fish. This is
best described as ________.
A) distillation
B) toxification
C) biomagnification
D) bioaccumulation
E) synergism
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