EVR Chapter 10
For each of the categories, select the option that is most likely to keep the public safe.
every year to every 9 years 0.0005% to 0.001% high- and low-risk areas, but selectively target areas with the greatest risk 15 ppb 10% publish water test results when lead levels are high
Why is epidemiology important for understanding human toxicology?
following individuals with exposure to toxicants or mutagens allows for the calculation of the rates at which health problems are likely to develop
Based on the health problems of Puget Sound killer whales, we would expect to find __________.
high levels of polychlorinated biphenyls in salmon in the puget sound
Which one of the following United States federal agencies does NOT handle risk management decisions concerning environmental health and toxicology?
housing and urban development (HUD)
What does the red graph line represent?
incidence of cholera
Which of the following appears to be true?
increasing aerosol viscosity leads to an increase in the distance polycyclic aromatic hydrocarbons travel
Which of the following can spread quickly as a result of human mobility?
infectious diseases
Which of these is a major concern driving the push to ban BPA?
it mimics the female sex hormone estrogen
________ is a naturally occurring substance that seeps up from the ground and is potentially toxic to people.
radon gas
Alligators in polluted lakes in Florida have been shown to have a higher prevalence of ________ than alligators in uncontaminated lakes.
reproductive abnormalities
Which of the following statements about chronic versus acute exposure is true?
safe levels for chronic exposure to a toxicant are lower than safe levels for acute exposure
What does the left y-axis show?
sea surface temperature anomaly, in degrees celsius
In which of the following years was the sea surface temperature more than 1ºC above the average temperature? Select all that apply.
1983 1987 1997
In which of the following years did the incidence of cholera reach its lowest level?
1989
In what percentage of Americans is BPA traceable within their bodies?
90%
Mercury is to methylmercury as DDT is to ________.
DDE
Which 3 of the following 6 graphs would best support the hypothesis that lead in the water was causing elevated lead levels in children? Drag a check mark to the three graphs that best support the hypothesis. Drag an X to the three that do not support the hypothesis. (WLL stands for water lead level, and BLL stands for blood lead level.)
NOT check, x, x, check, check, x (2/6 wrong) NOT check, check, x, x, check, x NOT check, x, x, x, check, x (1/6 wrong)
You conduct an experiment exposing polycyclic aromatic hydrocarbons to ozone. Which of the following is most likely?
NOT the polycyclic aromatic hydrocarbons will be enhanced
The "dirty dozen" POPs targeted by the Stockholm Convention include ________.
PCBs
A low LD50 indicates __________.
a high toxicity
__________ is an organism that transmits a pathogen to a host.
a vector
although it is not harmful, when compound D is inhaled, it activates the body's defenses in a small percentage of people, causing respiratory problems
allergen
Bisphenol A is ________.
an estrogen mimic used in plastic manufacturing
Which age group has a higher relative exposure risk to BPA?
babies and small children
The problems with the Puget Sound killer whale population have taught us to __________.
be very careful when adding new chemical compounds to natural environments
The concentration of DDT in a certain lake is 0.0000003 ppm (parts per million), while the concentration of DDT in the tissues of a nearby osprey (a fish-eating bird) is 25 ppm. This is an example of ________.
biomagnification
You are a toxicologist studying polycyclic aromatic hydrocarbons. Which of the following diseases should concern you the most?
cancer
Is this statement supported or not supported by the data on the graph? As global warming causes sea surface temperatures to increase in the future, the incidence of cholera in Bangladesh will also increase
cannot be determined from the graph
people in a city are exposed, over a long period of time, to high levels of compound F that has entered their water supply from a nearby landfill. residents in the city experience elevated rates of stomach and intestinal cancers over the next 30 years
carcinogen
persistent exposure to compound C in workers in steel foundries causes higher incidence of throat and lung cancer later in life
carcinogen
________ are substances that cause cancer.
carcinogens
__________ exposure to a chemical occurs at low levels over a long period of time.
chronic
Hunt and her team designed an experiment to test her hypothesis about the effect of BPA on mice. They administered daily doses of BPA to groups of female mice over three, five, or seven days and then tested these mice for genetic abnormalities that occur during meiosis, the division of chromosomes during egg formation. Drag the labels to identify the components of Hunt's experiment. Labels may be used once, more than once, or not at all.
control, treatment, treatment, treatment independent, independent, dependent
How is the population of killer whales in the Puget Sound changing? The killer whale population is __________.
declining in animals of all ages
Which of the following would likely be the best way to decrease polycyclic aromatic hydrocarbons?
decrease fossil fuel burning
The leading cause of death in the world today is __________.
disease
All of the following statements are true of allergens EXCEPT:
everyone is affected by an allergen at a high enough dose
Just because one hypothesis may help to explain a phenomenon does not mean it is the only hypothesis that could explain it. Imagine you are a scientist investigating why frog populations are declining in a state county with several hundred ponds. There could be multiple reasons why frog populations are declining in the county, and therefore, it would be wise to test multiple hypotheses. Some experiments may be observational, in which the researcher observes and measures naturally occurring variations in the dependent variable. Other experiments may be manipulative, in which the researcher directly manipulates the independent variable to test the effect on the dependent variable being measured. Match the experiments to the hypotheses they test. Make sure to distinguish between the observational experiments and the manipulative experiments.
genetically analyze; set up a pond system locate similar ponds; find 20 shaded ponds identify ponds; expose one group of frogs measure levels; expose tadpoles
Managing environmental risks requires assessing the relative danger or risks and planning appropriately. As mortal creatures, we assess risks to our health and well-being on a regular basis. For example, of the following potential causes of human death (data from 2012), which posed the greatest danger to human life?
motor vehicle accident
Based upon the specific health effects described above, mercury would be best classified as a(n) ________.
neurotoxin
chronic exposure to high levels of compound E in rabbits slows their reaction speeds, increasing their risk of being eaten by a predator
neurotoxin
Can you identify the steps in the scientific method that correspond to Hunt's experiments? Drag each statement under the step in the scientific method that it demonstrates.
observation: the eggs of mice question: could bisphenol A from hypothesis: the frequency of genetic prediction: if mice are exposed to
________ are examples of indoor chemical hazards.
radon and asbestos
The health problems of Puget Sound killer whales include __________.
symptoms similar to AIDS
a human embryo exposed to compound G in the womb experiences an increased probability of being born with more than 10 fingers or toes
teratogen or endocrine disruptor
exposure to compound A at critical points in development causes female fish to develop male-like characteristics, rendering them infertile
teratogen or endocrine disruptor
What is a threshold dose with regard to a dose-response curve?
the dosage in which a response is first elicited
Frauke Hoffmann and Werner Kloas wanted to test if birth control could in some way be responsible for declining frog populations. It was already established that women who take birth control pills excrete large amounts of estrogen and that estrogen could pass through a wastewater treatment plant. Therefore, they decided to test if estrogen did, in fact, reduce male fertility. Hoffman and Kloas evaluated the influence of estrogen on frog mating behavior. They assumed that if frogs had fewer or shorter mating calls, they would mate less and have reduced fertility. This in turn would result in fewer mating events and a possible reduction in the frog population. There are multiple ways Hoffman & Kloas could have designed their experiment. Match each description of an experimental design (one is the actual design they used) to the graph setup that matches the data that would be collected by that experiment. In the next part, you will look at data on these graphs.
try switching b & e a. in 20 ponds, measure the estrogen concentration in the water and the length of mating calls made by the males b. find frog populations in typical ponds and populations in ponds containing wastewater; measure the number of mating call clicks made by the males c. soak one group of frogs in control water and three groups in water with three difference concentrations of mating call clicks made by the males d. in 20 ponds, measure the estrogen concentration in the water and the number of mating call clicks made by the males e. find frog populations in typical ponds and populations in ponds containing wastewater; measure if the frogs have a high or a low number of mating call clicks f. soak one group of frogs in water containing estrogen and another in control water; measure the number of mating call clicks made by the males
Which of the following is an example of synergistic effects?
two gases chemically combine to become a different pollutant with new, unique properties
________ are examples of naturally occurring biological hazards.
viruses and salmonella
After an experiment has been conducted, the researchers must evaluate if their experiment did or did not support their hypothesis. Below are hypothetical data from the experiments in the previous part. Do they or do they not support the hypothesis that birth control pills could be causing some frog population declines? Mark the results that support the hypothesis with a check mark. Mark the results that do not support the hypothesis with an X.
x, x, check check, x, check
Researchers have observed that declines in amphibian populations are more pronounced near cities and towns, and especially in habitats associated with waste water treatment facilities. Could high numbers of women taking birth control pills in these densely populated areas really be responsible for frog population declines? In this activity, you will reconstruct the connections underlying the hypothesis that human birth control is causing frog population declines near cities and towns. Place the steps leading from birth control pills to frog population declines in order.
2. women who take birth control pills 3. wastewater treatment plants 4. male frogs in ponds 5. male frogs that absorb estrogen 6. .reduced male fertility
The Lead and Copper Rule of the Safe Drinking Water Act states that if more than 10% of homes test above 15 ppb (parts per billion) for lead, a city is legally required to take corrective action and warn residents about lead in their water. The DEQ reported that less than 10% of homes in Flint had high lead levels, and therefore no action was taken. Many people in Flint didn't trust the DEQ results given other problems with the water and the symptoms they were experiencing. One resident contacted an expert on lead in municipal water, and the expert questioned if the sample size in the DEQ study was large enough. Sample size refers to the number of samples collected and tested in a particular study. With the expert's help, the community initiated a lead testing project they called the Flint Water Study (FWS). They sampled many more locations than the DEQ did, and they arrived at a far different conclusion. This table shows the FWS results compared to the DEQ results. (Flint is divided into 9 areas called wards, and water samples were taken from each ward.) Drag the numbers and terms on the left to answer the questions on the right. Not all terms will be used.
69, 270 4 2 9, 19 more
A child enters the pediatrician's office with symptoms that include anemia, hearing loss, and kidney and stomach problems. The family has recently moved into a 50-year-old home and is doing renovations. What might be the problem with this child?
lead poisoning
In many waterways around the United States, polychlorinated biphenyls (PCBs) have contaminated the sediments and wildlife. Given that most of the PCBs in the environment were released before 1980 and are still present in these ecosystems, which of the following choices best describes this phenomenon?
long persistence
Experiments in environmental toxicology can sometimes be manipulative experiments in which the researcher actively chooses and manipulates the independent variable. In Hunt's study, for example, dosages of BPA were manipulated and the effects were measured. In manipulative studies, the researcher controls all the other variables in the experiment, so any health effects observed in the test subjects can be attributed to differences in the independent variable. In other cases, researchers use natural experiments in which the dependent variable (typically a measure of organism health) is measured under differing contexts that are not manipulated. Say, for example, that an accidental chemical spill contaminates five ponds. To determine the possible effects of the toxic chemical on frogs, a researcher could compare the hatching rate of frog eggs laid in those five ponds to the hatching rate of eggs laid in five uncontaminated ponds nearby. This would be an example of a natural experiment because concentrations of the toxic chemical in the ponds were not controlled by the experimenter, but rather resulted from the chemical spill. Drag type of experiment on the left to the example of experiment on the right.
natural natural natural manipulative manipulative manipulative natural
factory workers exposed to elevated levels of compound B experience uncontrollable twitching and problems coordinating their movements
neurotoxin
The flat line at the left in (b) probably represents ________.
no visible effect because the body's physiological processes can cope with low doses of a toxicant
In which of the following conditions are polycyclic aromatic hydrocarbons most likely to be oxidized?
over a warm, humid area
Which of the following describes a scenario involving pesticide drift?
pesticides being used in a mountain valley are carried by air currents into the surrounding hills, killing amphibians living in the hills' streams
Within a political context, what does risk management influence with regards to environmental health and toxicology?
policy
The precautionary principle approach to chemical testing __________.
prevents products from entering the marketplace until well tested
Which important environmental book exposed the hazards of using the insecticide DDT?
silent spring
Assume that the scales for graphs (a) and (b) are identical. Compare the graphs. Which of the following statements is true?
the toxicant shown in (b) has a lower toxicity than the toxicant shown in (a)
Which of the following statements is supported by the data in the graph?
there is a positive correlation between sea surface temperature and the incidence of cholera
How do endocrine disruptors affect human health at very low doses?
they mimic or block hormones that direct reproductive and developmental processes
How do toxicants get transported over vast distances?
toxicants are carried by the wind as well as the waters of streams and the oceans
