EHS Chap 3

A chemical (or substance) that causes or is suspected of causing cancer, a disease associated with unregulated proliferation of cells in the body.

carcinogen

An immunologically mediated adverse reaction to a chemical resulting form previous sensitization to that chemical or to a structurally similar one.

chemical allergy

Several agents that individually have no known toxic effects interact to produce a toxic effect.

coalitive interaction

The time period between initial exposure to a factor and a measurable response.

latency

The dosage (mg/kg body weight) that causes death in 50% of exposed animals.

lethal dose 50 (LD50)

Any agent capable of producing a deleterious response in a biological system.

poison

One chemical that is not toxic causes another chemical to become more toxic.

potentiation

The process of determining risks to health attributable to environmental or other hazards; involves (1) hazard assessment, (2) dose-response assessment, (3) exposure assessment, and (4) risk characterization.

risk assessment

The adoption of steps to eliminate identified risks or lower them to acceptable levels (often as determined by a government agency that has taken into account input from the public).

risk management

A reciprocal exchange of DNA between a pair of DNA molecules.

sister chromatid exchange (SCE)

The toxicity or hazards that are related to exposure to a particular chemical

spectrum of toxic dose

Chemical substances that are foreign to the biological system; they include naturally occurring compounds, drugs, environment agents, carcinogens, and insecticides.

xenobiotics

1. An example of in vitro testing for toxicology is: A. Experiments with normal volunteers B. Experiments with volunteers who have had unintentional exposures C. Studies of animals exposed to toxins D. Dose-response assessments in human populations E. Experiments with cells derived from human sources

A. Experiments with cells derived from human sources (correct)

9. Of the following routes of exposure, which one has the most rapid effect? A. Intravenous B. Ingestion C. Dermal D. Intramuscular E. Inhalation

A. Intravenous

7. Hazard identification refers to the question of A. What are the health effects that this agent can cause? B. What is the relationship between dose and occurrence of health effects in humans? C. What exposures are currently experienced or anticipated under different conditions? D. What is the estimated occurrence of the adverse effect in a given population? E. None of the above.

A. What are the health effects that this agent can cause? (correct)

18. What type of combination of two chemicals produces an effect that is equal to their individual effects taken together A. Additive B. Synergistic C. Potentiative D. Coalitive E. Antagonistic

Additive

8. In comparison with the general population, workers may receive exposures to toxic chemicals that are A. At lower levels for shorter time periods B. At higher concentrations for much longer time periods C. Confined to a single time episode D. More likely to be associated with acute effects than long-term effects E. None of the above

B. At higher concentrations for much longer time periods (correct)

4. Direct adverse effects of xenobiotics do not include A. Cell replacement B. Interference with nutrition C. Damage to an enzyme system D. Disruption of protein synthesis E. DNA damage

B. Interference with nutrition (correct)

22. Which of the following is not likely to characterize the approach of toxicology A. Laboratory studies of the role of xenobiotics in carcinogenesis in mice B. Studies of disease occurrence in populations according to person variables C. In vitro studies D. In vivo studies E. They all characterize the toxicologic approach.

B. Studies of disease occurrence in populations according to person variables

17. The poisonous substance in Amanita phalloides ("death cap" mushroom) is an example of a: A. Toxicant B. Toxin C. Anthropogenic form of poison D. A poison caused by bacterial activity E. None of the above

B. Toxin

5. Dose-response assessment refers to the question of A. What are the health effects that this agent can cause? B. What is the relationship between dose and occurrence of health effects in humans (or animals)? C. What exposures are currently experienced or anticipated under different conditions? D. What is the estimated occurrence of the adverse effect in a given population? E. None of the above.

B. What is the relationship between dose and occurrence of health effects in humans (or animals)? (correct)

14. Subacute exposures are those that last A. Less than 24 hours and occur once B. Less than 24 hours and occur more than once C. One month or less D. One to three months E. More than three months

C. One month or less(*)

20. What type of interaction between two chemicals causes one chemical that is not toxic to become more toxic A. Additive B. Synergistic C. Potentiative D. Coalitive E. Antagonistic

C. Potentiative

2. An internal dose refers to A. The dose acquired by contact with contaminated environmental sources B. The amount of a substance that is available to the internal organs of the body C. The portion of a substance that becomes internalized in the body D. The quantity of a substance that is administered E. None of the above

C. The portion of a substance that becomes internalized in the body (correct)

6. Exposure assessment refers to the question A. What are the health effects that this agent can cause? B. What is the relationship between dose and occurrence of health effects in humans? C. What exposures are currently experienced or anticipated under different conditions? D. What is the estimated occurrence of the adverse effect in a given population? E. None of the above.

C. What exposures are currently experienced or anticipated under different conditions? (correct)

16. The existence of a dose-response relationship may be used to establish the following kinds of information A. Causal association between a toxin and biological effects B. Minimum dosages needed to produce a biological effect C. Rate of accumulation of harmful effects D. All of the above E. A & B only

D. All of the above(*)

19. What type of interaction among several agents that have no known toxic effects produces a toxic effect? A. Additive B. Synergistic C. Potentiative D. Coalitive E. Antagonistic

D. Coalitive

3. Chose the incorrect statement below. Thalidomide is an example of a drug that A. Was a potent teratogen B. Was developed before the advent of rigorous clinical trials C. Was used to treat morning sickness during pregnancy D. Was associated with heart problems among adults E. None of the above

D. Was associated with heart problems among adults(correct)

11. Risk characterization refers to the question of A. What are the health effects that this agent can cause? B. What is the relationship between dose and occurrence of health effects in humans? C. What exposures are currently experienced or anticipated under different conditions? D. What is the estimated occurrence of the adverse effect in a given population? E. None of the above.

D. What is the estimated occurrence of the adverse effect in a given population? (*)

13. Specific examples of xenobiotics are A. Antibiotics B. Therapeutic drugs C. Dioxins D. PCBs E. All of the above

E. All of the above(*)

15. The concentration and toxicity of a chemical in the body are affected by A. Route of entry into the body B. Received dose of the chemical C. Duration of exposure D. Individual sensitivity E. All of the above

E. All of the above(*)

21. Which of the following abbreviations is used to describe toxic effects of chemicals? A. VOCs B. TLV C. TFR D. AQI E. LD50

E. LD50

12. Risk management refers to the question of A. What are the health effects that this agent can cause? B. What is the relationship between dose and occurrence of health effects in humans? C. What exposures are currently experienced or anticipated under different conditions? D. What is the estimated occurrence of the adverse effect in a given population? E. None of the above.

E. None of the above.(*)

10. One of the founders of toxicology was A. Socrates B. Theophrastus C. Claudius D. Da Vinci E. Paracelsus

E. Paracelsus(*)

The combination of two chemicals produces an effect that is equal to their individual effects added together

additive

Setting priorities, deciding at what time to deal with an environmental problem, and determining who will deal with the problem.

agenda setting

Occurs when two chemicals administered together interfere with each other's actions or one interferes with the action of the other.

antagonism

The amount of a substance administered at one time.

dose

The study of how ecological systems-their structure, dynamics, and function-are affected by pollutants.

environmental toxicology

Proximity and/or contact with a source of a disease agent in such a manner that effective transmission of the agent or harmful effects of the agent may occur.

exposure

The inherent capability of an agent or a situation to have an adverse effect; a factor or exposure that may adversely affect health.

hazard

As applied to toxicology, indicates that the combined effect of exposures to two or more chemicals is greater than the sum of their individual effects

synergism

As applied to toxicology, the lowest dose of a chemical at which a particular response may occur

threshold

A material or factor that can be harmful to biological systems

toxic agent

A material that has toxic properties

toxic substance

Toxic substances that are man-made or result from human (anthropogenic) activity.

toxicants

The degree to which something is poisonous; denotes that amount of a substance that can produce a deleterious effect

toxicity

Scientist who investigates in living organisms the adverse effects of chemical (including their cellular, biochemical, and molecular mechanisms of action) and assesses the probability of the occurrence of such effects.

toxicologist

The study of the adverse effects of chemicals on living organisms

toxicology

Usually refers to a toxic substance made by living organisms including reptiles, insects, plants, and microorganisms.

toxin