Toxicology Practice Questions

Which of the following is true? In the past 30 years, average lead levels in U.S children have decreased. In the past 30 years, average lead levels in U.S children have increased. n the past 30 years, average lead levels in U.S children have not changed. In the past 30 years, average lead levels in U.S children have varied with the age of the mother.

In the past 30 years, average lead levels in U.S children have decreased.

Some indoor chemical hazard(s) are ________.

Radon and asbestos

A low LD50 indicates _______.

a high toxicity

Which dose-response curve indicates a complex response to toxicants, such as those associated with endocrine disrupters?

unconventional dose-response curve

The LD50 indicates the ________.

amount of toxicant it takes to kill half the population

Bisphenol-A is ________.

an estrogen mimic that is used in plastic manufacturing

Figures With cureves.

are used by scientists in risk assessment

Synthetic pesticides can become airborne, travel in the atmosphere and deposit in oceans or at the poles in a process called _______, which results in pesticide concentrates near the poles.

global distillation

A _______ LD50 indicates low toxicity while a _______ LD50 indicates high toxicity.

high; low

PCB contamination ________.

is a continuing problem because PCBs are non-biodegradable and persist in the environment

Biomagnification _______.

is the increase in toxicant concentration in an animal's body tissue, as it moves up to the top trophic levels in the food chain

Which of the following is NOT assessed by a toxicologist to determine the potential for environmental damage of a new chemical? A.The origin of the toxic substance. B.Toxicity of the compound. C.Determine antibiotic resistance that may have evolved over long periods of exposure. D.determining the probability that an organism will encounter the toxicant.

C.determine antibiotic resistance that may have evolved over long periods of exposure.

Many developing countries continue to use DDT, even though it has been banned in many other places. Why?

DDT is used to control disease vectors.

You wish to contact the federal agency responsible for testing the safety of all new chemicals produced in the U.S. Who do you contact?

Environmental Protection Agency

_______ studies are comparisons that track the fate of large groups of people for long periods of time in order to help answer an environmental question.

Epidemiological

Which of the following statements about the United States and Europe are true regarding toxins?

European nations tend to use the precautionary principle, whereas the United States follows the innocent-until-proven-guilty approach.

How is global climate change associated with infectious disease?

Global climate change is facilitating the spread of tropical diseases to temperate regions.

The important environmental book called __________ exposed the hazards of using the insecticide DDT.

Silent Spring

Exposure to low amounts of a chemical over long periods of time is _______.

chronic exposure

In the U.S., which of the following trends is correct? A.There has been a decrease in both the number of chemicals in the environment and the number of children with chronic childhood diseases. B. There has been a decrease in the number of chemicals in the environment and an increase in the number of children with chronic childhood diseases. C.There has been an increase in the number of chemicals in the environment and a decrease in the number of children with chronic childhood diseases. D.There has been an increase in both the number of chemicals in the environment and the number of children with chronic childhood diseases.

There has been an increase in both the number of chemicals in the environment and the number of children with chronic childhood diseases.

How do endocrine disruptors affect human health at very low doses?

They mimic or block hormones that direct reproductive and developmental processes.

You wish to avoid excess contact with PFCs. You should get rid of which of the following?

non-stick pans

What law is supposed to ensure the safety of all new chemicals?

Toxic Substances Control Act

Read the following scenario and answer the question(s) below. Mercury is a heavy metal that occurs naturally in minerals and rocks. Release of mercury from natural sources has been relatively constant over time. However, anthropogenic release of mercury has increased significantly in recent years primarily due to 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 methyl mercury, which is absorbed quickly and concentrated in the tissues of predatory fish such as shark and swordfish. Large fish typically concentrate more mercury than small fish. People who eat fish with high methyl mercury concentrations can show tremors, deafness, muscle dysfunction, and attention deficits. Pregnant women and children are especially sensitive to methyl mercury's toxic effects. Learning disabilities and developmental delays are common in children who have been exposed to significant levels of methyl mercury. Mercury is not readily excreted; it is stored in mammalian body tissues. This is best described as ________.

bioaccumulation

Read the following scenario and answer the question(s) below. Mercury is a heavy metal that occurs naturally in minerals and rocks. Release of mercury from natural sources has been relatively constant over time. However, anthropogenic release of mercury has increased significantly in recent years primarily due to 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 methyl mercury, which is absorbed quickly and concentrated in the tissues of predatory fish such as shark and swordfish. Large fish typically concentrate more mercury than small fish. People who eat fish with high methyl mercury concentrations can show tremors, deafness, muscle dysfunction, and attention deficits. Pregnant women and children are especially sensitive to methyl mercury's toxic effects. Learning disabilities and developmental delays are common in children who have been exposed to significant levels of methyl mercury. Concentrations of methyl mercury are higher in large fish relative to concentration in the air. This is best described as ________.

biomagnification

Your blood is found to have detectable levels of mercury, lead, several pesticides, PCBs, and numerous other chemicals. This is called your _____________.

body burden

Environmental health advocates criticize the process of risk management, saying that it gives too much weight to _______.

economic interests

BPA and phthalates are known _________.

endocrine disruptors

The worldwide drop in sperm counts among men has been attributed to ________.

endocrine disruptors

Properties of toxicants likely to build up in animals through bioaccumulation are ________.

non-biodegradable, lipid-soluble

A child enters the pediatrician's office with symptoms that include anemia, hearing loss, kidney, and stomach problems. The family has just recently moved into a 50-year-old home and is doing renovations. What might be the problem with this child?

lead poisoning

Read the following scenario and answer the question(s) below. Mercury is a heavy metal that occurs naturally in minerals and rocks. Release of mercury from natural sources has been relatively constant over time. However, anthropogenic release of mercury has increased significantly in recent years primarily due to 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 methyl mercury, which is absorbed quickly and concentrated in the tissues of predatory fish such as shark and swordfish. Large fish typically concentrate more mercury than small fish. People who eat fish with high methyl mercury concentrations can show tremors, deafness, muscle dysfunction, and attention deficits. Pregnant women and children are especially sensitive to methyl mercury's toxic effects. Learning disabilities and developmental delays are common in children who have been exposed to significant levels of methyl mercury. Based upon the specific health effects described above, mercury would be best classified as a ________.

neurotoxin

If an evaluating committee places the burden of proof of the safety of a new chemical on the manufacturer of the chemical, then the committee is using the _______.

precautionary principle

The precautionary principle approach to chemical testing _______.

prevents products from entering the marketplace until they have been well tested and proven safe

The flat line at the left in curve graphs probably represents ________.

the body's immune system and other defenses which are deployed against the toxicant

The bald eagle, osprey, and peregrine falcon all are ________.

top consumers susceptible to eggshell damage caused by DDT

What does it mean to say that infants can be born 'pre-polluted?"

toxins from its mother while in the womb