Lecture 10

Question 1

What is risk assessment?

Answer 1

A policy tool designed to facilitate management of environmental health hazards. Integrates information from various scientific domains, such as:

environmental science
chemistry
exposurre science
toxicology
epidemiology
statistics
behavioral science

Question 2

Who used risk assessment?

Answer 2

Federal and international agencies
state environmental/health agencies
industry
non-governmental groups

Question 3

What are the four main steps of risk assessment?

Answer 3

1. hazard identification
2. dose-response
3. exposure assessment
4. risk characterization

Question 4

Define hazard identification.

Answer 4

1st step

identify chemicals of concern

evaluate evidence that exposure elicits an adverse response

assess potential health effects

identify vulnerable groups/sensitive subpopulations

Question 5

Define dose-response assessment.

Answer 5

2nd step

quantitatively characterize relationship between dose & adverse health effects

uses data from: epidemiologic studies (gold standard), toxicological studies (most common), and in vitro studies

Question 6

What are terms in dose-response assessment.

Answer 6

reference value

critical endpoint

principal study

point of departure

noael

loael

Question 7

What is a reference value?

Answer 7

quantitative metric of exposure that is likely to be without an appreciable risk of deleterious effects over a lifetime

can be thought of as the maximum acceptable dose of a toxic substance. calculated by dividing a point of departure by the product of uncertainty factors

Question 8

What is a critical endpoint?

Answer 8

health effect upon which a reference value is based

Question 9

What is a principle study?

Answer 9

study from which quantitative dose-response information i acquired for development of reference values

Question 10

What is a point of departure (POD)

Answer 10

dose-response point that marks the beginning of a low-dose extrapolation

bmdl, noael, loael

Question 11

What is a NOAEL?

Answer 11

no observed adverse effect level (homo)

Question 12

What is a LOAEL?

Answer 12

lowest observed adverse effect level (lumo)

Question 13

Describe the dose response curve for a non-carcinogen.

Answer 13

An assumption in risk assessment for a carcinogen dose-response curve is that any dose of said carcinogen will cause a response in humans

Question 14

What are uncertainty factors?

Answer 14

Allows us to err on the side of caution

so like 101010*etc

Question 15

Define exposure assessment.

Answer 15

3rd step

Quantitatively characterize human contact with the chemical.

Predict magnitude of humane exposure in the form of external dose.

Generally, exposure = concentration * frequency * duration

Question 16

What is an exposure model?

Answer 16

It helps to estimate the intake of a chemical.

Question 17

Describe the three types of exposure models.

Answer 17

Question 18

Define risk-characterization.

Answer 18

4th step

integrates information from other steps

typically includes:

• prediction of carcinogenic risks OR the potential for non-carcinogenic hazard
• estimation of population burden (cancer)
• discussion of unertainty

Question 19

How do you describe population burden.

Answer 19

For cancer: “The number of cancers expected in the population exposed to _____ over the duration of a lifetime…”