chapter 10 environmental science – Flashcards
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Figures such as these ________.
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are used by scientists in risk assessment
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The LD50 indicates the ________.
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amount of toxicant it takes to kill half the population
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Assume that the scales for graphs (a) and (b) are identical. Compare the graphs. Which of the following statements is true?
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The toxicant shown in (b) has a lower toxicity than the toxicant shown in (a).
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Most widely used herbicide in the U.S.; an endocrine disruptor
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atrazine
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Insecticide used to kill mosquitos; banned in the U.S. in 1973 due to its toxicity
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DDT
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Toxicant present in paint; damages the brain, liver, kidney, and stomach when ingested
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lead
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Toxicant used as a flame retardant and insulator; scars the lungs when inhaled
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asbestos
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Used as a sleeping pill for pregnant women; teratogen that now is banned
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thalidomide
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Neurotoxin that magnifies within food webs; typically found in polluted bodies of water; it poisoned thousands of people when it was dumped into the waters off Japan; people who ate contaminated fish from the waters exhibited convulsions, slurred speech, loss of muscle control, and sudden fits of laughter; some people died
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mercury
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Rachel Carson's book Silent Spring primarily focuses on the environmental problems associated with ________.
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pesticide toxicity
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________ are best defined as substances that cause cancer.
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Carcinogens
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________ are best defined as substances that cause birth defects.
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Teratogens
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Carcinogens may be difficult to identify because ________.
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there is a long lag time between exposure to the agent and disease
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PCB contamination ________.
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is a continuing problem because PCB's are non-biodegradable and persist in the environment
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Toxicants that cause harm by affecting the immune system include ________.
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allergens
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The book Our Stolen Future was important because it ________.
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focused on the impacts of endocrine-disrupting chemicals on humans
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The worldwide drop in sperm counts among men has been attributed to ________.
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endocrine disruptors
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Bisphenol-A is ________.
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an estrogen mimic that is used in plastic manufacturing
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Transport of airborne toxicants, a specific problem in agricultural environments, is called pesticide ________.
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drift
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Pesticides in the United States are registered through the ________.
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EPA
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The Toxic Substances Control Act regulates ________.
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industrial chemicals
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FIFRA ________.
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and its later amendments charge the EPA with registering new pesticides and regulating their sale, use, and labeling
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Aquatic animals such as fish and frogs are especially good indicators of pollution because ________.
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most chemicals are water soluble so they enter these organisms through drinking or skin absorption
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________ is/are known to have (a) short persistence time(s).
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Bt
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The bald eagle, brown pelican, and peregrine falcon all are ________.
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susceptible to eggshell damage caused by DDT
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What very likely killed sea otters off the CA coast in 1998-2000?
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infection from sewage run-off from cat litter boxes from urban areas
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Chemicals used in cosmetics in the U.S. are ________.
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not reviewed before being sold
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Of the chemicals that fall under the TSCA ________% have been tested for toxicity and ________ % have been tested for endocrine, nervous, or immune system damage.
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10; 2
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The goal of the Stockholm Convention is to ________.
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end the use and release of 12 POPs shown to be the most dangerous
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The Yaqui Valley, Mexico, study showed that ________.
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developmental delays occurred in children exposed to pesticides
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Louis Guillette is most famous for his studies ________.
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describing reproductive and developmental abnormalities in alligators in Lake Apopka
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Tyrone Hayes is most famous for his studies ________.
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on gonadal abnormalities in frogs
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Infectious disease accounts for ________% of deaths globally.
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25
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Synergistic effects of toxicants ________.
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often have effects that are multiplicative
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The effect of toxicants on fetuses and young children ________.
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is greater because of their rapid growth and smaller biomass
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The European Union's experience with PBDE's has shown that ________.
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if the toxin is removed from the environment, concentrations in human tissues fall
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Studies of endocrine disruptors have shown that they are closely associated with all of the following except ________.
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lung cancer
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Which of the following U.S. agencies is primarily responsible for addressing issues regarding mercury pollution?
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EPA
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Prior to 2005, no rules regulating mercury emissions from coal-fired power plants existed in the U.S. This represents the ________.
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innocent-until-proven-guilty approach
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Mercury is to methyl mercury as DDT is to ________.
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DDE
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Based upon the specific health effects described above, mercury would be best classified as a ________.
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neurotoxin
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Mercury is not readily excreted; it is stored in mammalian body tissues. This is best described as _________.
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bioaccumulation
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Concentrations of methyl mercury are higher in large fish relative to concentration in the air. This is best described as ________.
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biomagnification
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Which of the following statements about the United States and Europe are true regarding toxins?
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European nations tend to use the precautionary principle, whereas the United States follows the innocent-until-proven-guilty approach
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Some indoor chemicals hazards are ________.
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Radon and asbestos
