US EPA Human Health and Eco Risk

Question 1

Which of the following is false?
1. Different tumor sites are usually observed following either perinatal or adult exposure.
2. Perinatal exposure in conjunction with adult exposure usually increases the incidence of tumors or reduces the latent period before tumors are observed.

Answer 1

1. The SAME tumor sites are usually observed following either perinatal or adult exposure.

Question 2

What term is the study of the distribution of disease in human populations and the factors that may influence that distribution.

Answer 2

Epidemiology

Question 3

What are the two major types of cancer studies?

Answer 3

Analytical and Descriptive

Question 4

Which cancer study type includes case-control and cohort designs, generally relied on for identifying a casual association between human exposure and adverse health effects?

Answer 4

Analytical epidemiological studies

Question 5

During what type of studies are groups of individuals with (cases) and without (controls) a particular disease are identified and compared to determine differences in exposure?

Answer 5

Case-Control

Question 6

During what types of studies are a group of “exposed’ and “non-exposed” individuals identified and studied over time to determine differences in disease occurrence.

Answer 6

Cohort
(i.e. rare cancers)

Question 7

Which studies can be performed wither prospectively or retrospectively from historical records?

Answer 7

Cohort
(i.e. commonly occurring cancers)

Question 8

Which epidemiologic studies examine symptoms or disease rates among populations in relation to personal characteristics such as age, gender, race, and temporal or environmental conditions.

Answer 8

Descriptive epidemiologic studies

Question 9

Which epidemiologic studies are most frequently used to generate hypotheses about exposure factors, but subsequent analytical designs are necessary to infer causality? These studies are used to identify patterns or trends in disease occurrence over time or in different geographical locations, but typical limitations in the characterization of populations in these studies make it difficult to infer the causal agent or degree of exposure.

Answer 9

Descriptive studies

Question 10

These studies describe a particular effect in an individual or group of individuals who were exposed to a substance. These reports are often anecdotal or highly selective in nature and generally are of limited use for hazard assessment.

Answer 10

Case Reports

Question 11

What is a confounder?

Answer 11

A variable that is related to both the health outcome of concern (cancer) and exposure.

Question 12

If the effect of exposure is diminished or eliminated by another variable, it said to be what type of interaction?

Answer 12

Antagonist

Question 13

Which of the following is not considered a guideline to aid in judging causality?
1. Consistency of the observed association
2. Strength of the observed association
3. Specificity of the observed association
4. Temporal relationship of the observed association
5. Biological gradient
6. Biological plausibility
7. Coherence
8. Experimental evidence
9. Analogy

Answer 13

They are all guidelines to judge casuality

Question 14

How many rodents/sex/group per treatment are used in carcinogenicity studies, and what is the duration?

Answer 14

Current standardized carcinogenicity studies in rodents test at least 50 animals per sex per dose group in each of three treatment groups and in a concurrent control group, usually for 18 to 24 months, depending on the rodent species tested (OECD, 1981; U.S. EPA, 1998c).

Question 15

Name signs of treatment-related toxicity:

Answer 15

(a) significant reduction of body weight gain (e.g., greater than 10%),
(b) significant increases in abnormal behavioral and clinical signs,
(c) significant changes in hematology or clinical chemistry,
(d) saturation of absorption and detoxification mechanisms, or
(e) marked changes in organ weight, morphology, and histopathology.

Question 16

Ture or False:
When cancer effects in exposed humans are attributed to exposure to an agent, the default option is that the resulting data are predictive of cancer in any other exposed human population.

Answer 16

True

Question 17

True or False:
When cancer effects are not found in an exposed human population, this information by itself is generally sufficient to conclude that the agent poses no carcinogenic hazard to this or other populations of potentially exposed humans, including susceptible subpopulations or lifestages.

Answer 17

False

When cancer effects are not found in an exposed human population, this information by itself is NOT generally sufficient to conclude that the agent poses no carcinogenic hazard to this or other populations of potentially exposed humans, including susceptible subpopulations or lifestages.

Question 18

What is the differences between variability and uncertainty?

Answer 18

Variability refers to true heterogeneity or diversity. This may be due to differences in exposure or differences in response.

Uncertainty occurs because of lack of knowledge. Uncertainty can be reduced by collecting more and better data while variability is an inherent property of the population being evaluated. Variability cannot be eliminated.

Question 19

What is dose metric?

Answer 19

Dose metric is a measure of the internal dose of a chemical agent. It is a measure of the tissue concentration of the toxicologically active chemical species that reflects a time-normalized (AUC) or instantaneous (Cmax) measure of concentration.

Question 20

For acute, reversible effects, , what is the most appropriate dose metric?

Answer 20

Cmax

Question 20

True or False:
Clearance is mathematically inversely related to AUC

Answer 20

True
AUC = dose/clearance

Question 20

For chronic effects, what is the most appropriate dose metric?

Answer 20

AUC

Question 21

What is intrinsic clearance

Answer 21

A ratio of theoretical maximal initial velocity of the reaction to the Michaelis constant (Vmax/Km). Not bound by hepatic blood flow

Question 21

What is hepatic clearance?

Answer 21

Based on Vmax/Km but is governed by hepatic blood flow. Cannot exceed hepatic blood flow.

Question 22

What is the selection of the dose metric based on?

Answer 22

Weight-of-evidence approach emphasizing both qualitative and quantitative evidence.

Question 23

What formula is calculated to create the composite factor?

Answer 23

CF = EFAK × EFAD × EFHK × EFHD
CF = composite factor
EFAK = interspecies TK extrapolation factor
EFAD = interspecies TD extrapolation factor
EFHK = intraspecies TK extrapolation factor
EFHD = intraspecies TD extrapolation factor

Question 24

The ecological risk assessment process is based on what to major elements?

Answer 24

Characterization of Effects
Characterization of Exposure

Question 25

What are the three phases of risk assessment:

Answer 25

Problem formulation, analysis, and risk characterization

Question 26

What are risk hypotheses and why are they important?

Answer 26

Risk hypotheses are proposed answers to questions risk assessors have about what responses assessment endpoints will show when they are exposed to stressors and how exposure will occur. Risk hypotheses clarify and articulate relationships that are posited through the consideration of available data, information from scientific literature, and the best professional judgment of risk assessors developing the conceptual models. This explicit process opens the risk assessment to peer review and evaluation to ensure the scientific validity of the work. Risk hypotheses are not equivalent to statistical testing of null and alternative hypotheses. However, predictions generated from risk hypotheses can be tested in a variety of ways, including standard statistical approaches.

Question 27

What term describes an assumption made in order to evaluate logical or empirical consequences, or suppositions tentatively accepted to provide a basis for evaluation?

Answer 27

Hypothesis

Question 28

Which of the following is not one of Koch’s postulates?
1. A pathogen must be consistently found in association with a given disease.
2. The pathogen must be isolated from the host and grown in pure culture.
3. When inoculated into test animals, any disease symptoms must be expressed.
4. The pathogen must again be isolated from the test organism.

Answer 28

4. When inoculated into test animals, the same disease symptoms must be expressed.