Environmental Health and Toxicology
1. Susceptibility to infectious diseases is increased, especially in the Third World, by (p. 184)
A. high morbidity rates.
B. low fecundity rates.
C. malnutrition.
D. low fertility rates.
E. all of the above.
2. A toxin (p. 188)
A. reacts with cellular component to cause cell death.
B. usually forms an acid when in contact with water present in mucous membranes.
C. acts exclusively on the immune system by stimulating production of antibodies.
D. usually combines with the blood to inhibit oxygen uptake.
E. none of the above.
3. A mutagen creates its effect by (p. 188)
A. altering the balance of carbon dioxide and oxygen in the atmosphere.
B. damaging genetic material (DNA).
C. causing scar tissue to form in the lungs.
D. activating the immune system.
E. all of the above.
4. In medical terms, stress refers to (p. 190)
A. injury caused by accidents.
B. damage caused by naturally occurring chemicals in plants.
C. substances that cause cancer.
D. a variety of factors that put a strain on an organism.
E. none of the above.
5. Once inside the body of an organism, fat soluble toxins are likely to (p. 193)
A. bioaccumulate.
B. biomagnify.
C. be flushed out with a lot of water.
D. be readily broken down by metabolic processes.
E. none of the above.
6. Biomagnification occurs when (pp. 193-194)
A. chemicals become very unstable and are quickly broken down.
B. chemicals synergistic reactions.
C. organisms at higher trophic levels concentrate toxins accumulated at lower trophic levels.
D. toxins are brought into the body and stimulate the uptake of other toxins.
E. none of the above.
7. A worker who smokes and has also been exposed to asbestos has a greater risk of lung cancer than does a smoker who is not exposed to asbestos. This is an example of (p. 194)
A. a synergistic effect.
B. an antagonistic effect.
C. an additive effect.
D. a multiplicative effect.
E. none of the above.
8. The chief detoxifying organ in mammals is the (p. 194)
A. kidney.
B. liver.
C. epithelial linings of the small intestines.
D. large intestines.
E. none of the above.
9. LD50 in toxicology refers to (p. 195)
A. the dose of a chemical that produces death in 50 percent of the test population.
B. the dose of a chemical that produces morbidity in 50 percent of the test population.
C. the dose of a chemical that produces the desired effect in 50 percent of the test population.
D. the dose of a chemical that produces a carcinogenic effect in 50 percent of the test population.
E. none of the above.
10. Carcinogens and mutagens are dangerous at levels far below their acute lethal dose level because (p. 196)
A. humans rarely receive a lethal dose.
B. humans can often detoxify these chemicals before they have an effect.
C. they tend to be water soluble and, therefore, ubiquitous.
D. they can effect a single cell out of millions, causing a cancer that can grow and effect a whole organism.
E. all of the above.
11. A chronic exposure to a chemical (p. 196)
A. occurs over a very short period of time.
B. is usually short lived, but intense.
C. occurs over a very long period of time.
D. is usually fatal.
E. none of the above.
12. Determining the exact effect of low dose chronic chemical exposure is difficult because (pp. 196-197)
A. these studies are often expensive and require a large test population.
B. they are often inferred from studies of massive doses and responses to doses may not be the same across a range of doses.
C. other factors, like aging and disease, might mask the effect of the exposure.
D. none of the above.
E. all of the above.
13. Assessing risks is difficult for many people because (p. 198)
A. political considerations cause some people to down play some risks while emphasizing others.
B. judging risk by probability is more difficult than judging risk by personal experience.
C. news media overreport some risks and underreport other risks.
D. people are often more comfortable with older technologies than with newer ones, despite the risks of either one.
E. all of the above.
14. When setting standards for environmental toxins, risk assessors need to consider all of the following EXCEPT (p. 199)
A. combined effects of exposure to multiple sources of damage.
B. that some members of the population are more sensitive to exposure than others.
C. whether members of the population are willing to accept the risk of exposure.
D. identification of the hazard.
E. the effects of chronic exposure as well as acute exposure.
15. According to the Environmental Protection Agency, which of the following poses a relatively high risk to human welfare? (p. 200)
A. thermal pollution
B. species extinction and loss of biodiversity
C. exposure to pesticides
D. exposure to groundwater pollution
E. acid rain